支持Head获取对象元信息操作，支持从redis获取元信息；调整内部超时检查逻辑；

14 files changed, 1244 insertions, 62 deletions

diff --git a/cache/include/cache_evbase_client.h b/cache/include/cache_evbase_client.h
index 15bf3c3..529a805 100644
--- a/cache/include/cache_evbase_client.h
+++ b/cache/include/cache_evbase_client.h
@@ -34,6 +34,7 @@ struct cache_evbase_instance *cache_evbase_instance_new(const char* profile_path
 
 //GET�ӿڣ��ɹ�����0��ʧ�ܷ���-1��future�ص���������������߳���ִ�У���ͬ
 int cache_evbase_fetch_object(struct cache_evbase_instance *instance, struct future* f, struct tango_cache_meta_get *meta);
+int cache_evbase_head_object(struct cache_evbase_instance *instance, struct future* f, struct tango_cache_meta_get *meta);
 struct tango_cache_result *cache_evbase_read_result(void *promise_result);
 
 //DELETE�ӿ�
diff --git a/cache/include/tango_cache_client.h b/cache/include/tango_cache_client.h
index 109c258..1e45187 100644
--- a/cache/include/tango_cache_client.h
+++ b/cache/include/tango_cache_client.h
@@ -19,6 +19,8 @@ enum CACHE_ERR_CODE
 	CACHE_ERR_WIREDLB,
 	CACHE_ERR_SOCKPAIR,
 	CACHE_ERR_INTERNAL,
+	CACHE_ERR_REDIS_JSON,
+	CACHE_ERR_REDIS_CONNECT,
 };
 
 enum PUT_MEMORY_COPY_WAY
@@ -79,7 +81,7 @@ enum CACHE_HTTP_HDR_TYPE
 
 struct tango_cache_meta_get
 {
-	const char* url; //����:URL���ǽṹ����־:�ļ�����CACHE_OBJECT_KEY_HASH_SWITCH=0ʱ��󳤶�256�ֽڣ�=1ʱ������
+	const char* url; //����:URI���ǽṹ����־:�ļ�·��������Ҫ��'/'��ͷ��CACHE_OBJECT_KEY_HASH_SWITCH=0ʱ��󳤶�256�ֽڣ�=1ʱ������
 	struct request_freshness get;
 };
 
@@ -112,6 +114,7 @@ struct tango_cache_instance *tango_cache_instance_new(struct event_base* evbase,
 //ʧ��ʱ�ص�promise_failed(��һ��)��ʹ��get_last_error��ȡ�����룻
 //future������ΪNULL
 int tango_cache_fetch_object(struct tango_cache_instance *instance, struct future* f, struct tango_cache_meta_get *meta);
+int tango_cache_head_object(struct tango_cache_instance *instance, struct future* f, struct tango_cache_meta_get *meta);
 //��promise_success��result������ȡ���
 struct tango_cache_result *tango_cache_read_result(future_result_t *promise_result);
 
diff --git a/cache/src/README.txt b/cache/src/README.txt
new file mode 100644
index 0000000..cdd34c9
--- /dev/null
+++ b/cache/src/README.txt
@@ -0,0 +1,2 @@
+HEAD����֧�ִ�minio��redis����������ȡ��Ĭ������´�minio��ȡ��
+�����redis��ȡ������ʱ�Ӻ궨��-DHEAD_OBJECT_FROM_REDIS
\ No newline at end of file
diff --git a/cache/src/cJSON/cJSON.c b/cache/src/cJSON/cJSON.c
new file mode 100644
index 0000000..35452cb
--- /dev/null
+++ b/cache/src/cJSON/cJSON.c
@@ -0,0 +1,596 @@
+/*
+  Copyright (c) 2009 Dave Gamble
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*/
+
+/* cJSON */
+/* JSON parser in C. */
+
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+#include <float.h>
+#include <limits.h>
+#include <ctype.h>
+#include "cJSON.h"
+
+static const char *ep;
+
+const char *cJSON_GetErrorPtr(void) {return ep;}
+
+static int cJSON_strcasecmp(const char *s1,const char *s2)
+{
+	if (!s1) return (s1==s2)?0:1;if (!s2) return 1;
+	for(; tolower(*s1) == tolower(*s2); ++s1, ++s2)	if(*s1 == 0)	return 0;
+	return tolower(*(const unsigned char *)s1) - tolower(*(const unsigned char *)s2);
+}
+
+static void *(*cJSON_malloc)(size_t sz) = malloc;
+static void (*cJSON_free)(void *ptr) = free;
+
+static char* cJSON_strdup(const char* str)
+{
+      size_t len;
+      char* copy;
+
+      len = strlen(str) + 1;
+      if (!(copy = (char*)cJSON_malloc(len))) return 0;
+      memcpy(copy,str,len);
+      return copy;
+}
+
+void cJSON_InitHooks(cJSON_Hooks* hooks)
+{
+    if (!hooks) { /* Reset hooks */
+        cJSON_malloc = malloc;
+        cJSON_free = free;
+        return;
+    }
+
+	cJSON_malloc = (hooks->malloc_fn)?hooks->malloc_fn:malloc;
+	cJSON_free	 = (hooks->free_fn)?hooks->free_fn:free;
+}
+
+/* Internal constructor. */
+static cJSON *cJSON_New_Item(void)
+{
+	cJSON* node = (cJSON*)cJSON_malloc(sizeof(cJSON));
+	if (node) memset(node,0,sizeof(cJSON));
+	return node;
+}
+
+/* Delete a cJSON structure. */
+void cJSON_Delete(cJSON *c)
+{
+	cJSON *next;
+	while (c)
+	{
+		next=c->next;
+		if (!(c->type&cJSON_IsReference) && c->child) cJSON_Delete(c->child);
+		if (!(c->type&cJSON_IsReference) && c->valuestring) cJSON_free(c->valuestring);
+		if (c->string) cJSON_free(c->string);
+		cJSON_free(c);
+		c=next;
+	}
+}
+
+/* Parse the input text to generate a number, and populate the result into item. */
+static const char *parse_number(cJSON *item,const char *num)
+{
+	double n=0,sign=1,scale=0;int subscale=0,signsubscale=1;
+
+	if (*num=='-') sign=-1,num++;	/* Has sign? */
+	if (*num=='0') num++;			/* is zero */
+	if (*num>='1' && *num<='9')	do	n=(n*10.0)+(*num++ -'0');	while (*num>='0' && *num<='9');	/* Number? */
+	if (*num=='.' && num[1]>='0' && num[1]<='9') {num++;		do	n=(n*10.0)+(*num++ -'0'),scale--; while (*num>='0' && *num<='9');}	/* Fractional part? */
+	if (*num=='e' || *num=='E')		/* Exponent? */
+	{	num++;if (*num=='+') num++;	else if (*num=='-') signsubscale=-1,num++;		/* With sign? */
+		while (*num>='0' && *num<='9') subscale=(subscale*10)+(*num++ - '0');	/* Number? */
+	}
+
+	n=sign*n*pow(10.0,(scale+subscale*signsubscale));	/* number = +/- number.fraction * 10^+/- exponent */
+	
+	item->valuedouble=n;
+	item->valueint=(int)n;
+	item->type=cJSON_Number;
+	return num;
+}
+
+/* Render the number nicely from the given item into a string. */
+static char *print_number(cJSON *item)
+{
+	char *str;
+	double d=item->valuedouble;
+	if (fabs(((double)item->valueint)-d)<=DBL_EPSILON && d<=INT_MAX && d>=INT_MIN)
+	{
+		str=(char*)cJSON_malloc(21);	/* 2^64+1 can be represented in 21 chars. */
+		if (str) sprintf(str,"%d",item->valueint);
+	}
+	else
+	{
+		str=(char*)cJSON_malloc(64);	/* This is a nice tradeoff. */
+		if (str)
+		{
+			if (fabs(floor(d)-d)<=DBL_EPSILON && fabs(d)<1.0e60)sprintf(str,"%.0f",d);
+			else if (fabs(d)<1.0e-6 || fabs(d)>1.0e9)			sprintf(str,"%e",d);
+			else												sprintf(str,"%f",d);
+		}
+	}
+	return str;
+}
+
+static unsigned parse_hex4(const char *str)
+{
+	unsigned h=0;
+	if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0;
+	h=h<<4;str++;
+	if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0;
+	h=h<<4;str++;
+	if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0;
+	h=h<<4;str++;
+	if (*str>='0' && *str<='9') h+=(*str)-'0'; else if (*str>='A' && *str<='F') h+=10+(*str)-'A'; else if (*str>='a' && *str<='f') h+=10+(*str)-'a'; else return 0;
+	return h;
+}
+
+/* Parse the input text into an unescaped cstring, and populate item. */
+static const unsigned char firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
+static const char *parse_string(cJSON *item,const char *str)
+{
+	const char *ptr=str+1;char *ptr2;char *out;int len=0;unsigned uc,uc2;
+	if (*str!='\"') {ep=str;return 0;}	/* not a string! */
+	
+	while (*ptr!='\"' && *ptr && ++len) if (*ptr++ == '\\') ptr++;	/* Skip escaped quotes. */
+	
+	out=(char*)cJSON_malloc(len+1);	/* This is how long we need for the string, roughly. */
+	if (!out) return 0;
+	
+	ptr=str+1;ptr2=out;
+	while (*ptr!='\"' && *ptr)
+	{
+		if (*ptr!='\\') *ptr2++=*ptr++;
+		else
+		{
+			ptr++;
+			switch (*ptr)
+			{
+				case 'b': *ptr2++='\b';	break;
+				case 'f': *ptr2++='\f';	break;
+				case 'n': *ptr2++='\n';	break;
+				case 'r': *ptr2++='\r';	break;
+				case 't': *ptr2++='\t';	break;
+				case 'u':	 /* transcode utf16 to utf8. */
+					uc=parse_hex4(ptr+1);ptr+=4;	/* get the unicode char. */
+
+					if ((uc>=0xDC00 && uc<=0xDFFF) || uc==0)	break;	/* check for invalid.	*/
+
+					if (uc>=0xD800 && uc<=0xDBFF)	/* UTF16 surrogate pairs.	*/
+					{
+						if (ptr[1]!='\\' || ptr[2]!='u')	break;	/* missing second-half of surrogate.	*/
+						uc2=parse_hex4(ptr+3);ptr+=6;
+						if (uc2<0xDC00 || uc2>0xDFFF)		break;	/* invalid second-half of surrogate.	*/
+						uc=0x10000 + (((uc&0x3FF)<<10) | (uc2&0x3FF));
+					}
+
+					len=4;if (uc<0x80) len=1;else if (uc<0x800) len=2;else if (uc<0x10000) len=3; ptr2+=len;
+					
+					switch (len) {
+						case 4: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6;
+						case 3: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6;
+						case 2: *--ptr2 =((uc | 0x80) & 0xBF); uc >>= 6;
+						case 1: *--ptr2 =(uc | firstByteMark[len]);
+					}
+					ptr2+=len;
+					break;
+				default:  *ptr2++=*ptr; break;
+			}
+			ptr++;
+		}
+	}
+	*ptr2=0;
+	if (*ptr=='\"') ptr++;
+	item->valuestring=out;
+	item->type=cJSON_String;
+	return ptr;
+}
+
+/* Render the cstring provided to an escaped version that can be printed. */
+static char *print_string_ptr(const char *str)
+{
+	const char *ptr;char *ptr2,*out;int len=0;unsigned char token;
+	
+	if (!str) return cJSON_strdup("");
+	ptr=str;while ((token=*ptr) && ++len) {if (strchr("\"\\\b\f\n\r\t",token)) len++; else if (token<32) len+=5;ptr++;}
+	
+	out=(char*)cJSON_malloc(len+3);
+	if (!out) return 0;
+
+	ptr2=out;ptr=str;
+	*ptr2++='\"';
+	while (*ptr)
+	{
+		if ((unsigned char)*ptr>31 && *ptr!='\"' && *ptr!='\\') *ptr2++=*ptr++;
+		else
+		{
+			*ptr2++='\\';
+			switch (token=*ptr++)
+			{
+				case '\\':	*ptr2++='\\';	break;
+				case '\"':	*ptr2++='\"';	break;
+				case '\b':	*ptr2++='b';	break;
+				case '\f':	*ptr2++='f';	break;
+				case '\n':	*ptr2++='n';	break;
+				case '\r':	*ptr2++='r';	break;
+				case '\t':	*ptr2++='t';	break;
+				default: sprintf(ptr2,"u%04x",token);ptr2+=5;	break;	/* escape and print */
+			}
+		}
+	}
+	*ptr2++='\"';*ptr2++=0;
+	return out;
+}
+/* Invote print_string_ptr (which is useful) on an item. */
+static char *print_string(cJSON *item)	{return print_string_ptr(item->valuestring);}
+
+/* Predeclare these prototypes. */
+static const char *parse_value(cJSON *item,const char *value);
+static char *print_value(cJSON *item,int depth,int fmt);
+static const char *parse_array(cJSON *item,const char *value);
+static char *print_array(cJSON *item,int depth,int fmt);
+static const char *parse_object(cJSON *item,const char *value);
+static char *print_object(cJSON *item,int depth,int fmt);
+
+/* Utility to jump whitespace and cr/lf */
+static const char *skip(const char *in) {while (in && *in && (unsigned char)*in<=32) in++; return in;}
+
+/* Parse an object - create a new root, and populate. */
+cJSON *cJSON_ParseWithOpts(const char *value,const char **return_parse_end,int require_null_terminated)
+{
+	const char *end=0;
+	cJSON *c=cJSON_New_Item();
+	ep=0;
+	if (!c) return 0;       /* memory fail */
+
+	end=parse_value(c,skip(value));
+	if (!end)	{cJSON_Delete(c);return 0;}	/* parse failure. ep is set. */
+
+	/* if we require null-terminated JSON without appended garbage, skip and then check for a null terminator */
+	if (require_null_terminated) {end=skip(end);if (*end) {cJSON_Delete(c);ep=end;return 0;}}
+	if (return_parse_end) *return_parse_end=end;
+	return c;
+}
+/* Default options for cJSON_Parse */
+cJSON *cJSON_Parse(const char *value) {return cJSON_ParseWithOpts(value,0,0);}
+
+/* Render a cJSON item/entity/structure to text. */
+char *cJSON_Print(cJSON *item)				{return print_value(item,0,1);}
+char *cJSON_PrintUnformatted(cJSON *item)	{return print_value(item,0,0);}
+
+/* Parser core - when encountering text, process appropriately. */
+static const char *parse_value(cJSON *item,const char *value)
+{
+	if (!value)						return 0;	/* Fail on null. */
+	if (!strncmp(value,"null",4))	{ item->type=cJSON_NULL;  return value+4; }
+	if (!strncmp(value,"false",5))	{ item->type=cJSON_False; return value+5; }
+	if (!strncmp(value,"true",4))	{ item->type=cJSON_True; item->valueint=1;	return value+4; }
+	if (*value=='\"')				{ return parse_string(item,value); }
+	if (*value=='-' || (*value>='0' && *value<='9'))	{ return parse_number(item,value); }
+	if (*value=='[')				{ return parse_array(item,value); }
+	if (*value=='{')				{ return parse_object(item,value); }
+
+	ep=value;return 0;	/* failure. */
+}
+
+/* Render a value to text. */
+static char *print_value(cJSON *item,int depth,int fmt)
+{
+	char *out=0;
+	if (!item) return 0;
+	switch ((item->type)&255)
+	{
+		case cJSON_NULL:	out=cJSON_strdup("null");	break;
+		case cJSON_False:	out=cJSON_strdup("false");break;
+		case cJSON_True:	out=cJSON_strdup("true"); break;
+		case cJSON_Number:	out=print_number(item);break;
+		case cJSON_String:	out=print_string(item);break;
+		case cJSON_Array:	out=print_array(item,depth,fmt);break;
+		case cJSON_Object:	out=print_object(item,depth,fmt);break;
+	}
+	return out;
+}
+
+/* Build an array from input text. */
+static const char *parse_array(cJSON *item,const char *value)
+{
+	cJSON *child;
+	if (*value!='[')	{ep=value;return 0;}	/* not an array! */
+
+	item->type=cJSON_Array;
+	value=skip(value+1);
+	if (*value==']') return value+1;	/* empty array. */
+
+	item->child=child=cJSON_New_Item();
+	if (!item->child) return 0;		 /* memory fail */
+	value=skip(parse_value(child,skip(value)));	/* skip any spacing, get the value. */
+	if (!value) return 0;
+
+	while (*value==',')
+	{
+		cJSON *new_item;
+		if (!(new_item=cJSON_New_Item())) return 0; 	/* memory fail */
+		child->next=new_item;new_item->prev=child;child=new_item;
+		value=skip(parse_value(child,skip(value+1)));
+		if (!value) return 0;	/* memory fail */
+	}
+
+	if (*value==']') return value+1;	/* end of array */
+	ep=value;return 0;	/* malformed. */
+}
+
+/* Render an array to text */
+static char *print_array(cJSON *item,int depth,int fmt)
+{
+	char **entries;
+	char *out=0,*ptr,*ret;int len=5;
+	cJSON *child=item->child;
+	int numentries=0,i=0,fail=0;
+	
+	/* How many entries in the array? */
+	while (child) numentries++,child=child->next;
+	/* Explicitly handle numentries==0 */
+	if (!numentries)
+	{
+		out=(char*)cJSON_malloc(3);
+		if (out) strcpy(out,"[]");
+		return out;
+	}
+	/* Allocate an array to hold the values for each */
+	entries=(char**)cJSON_malloc(numentries*sizeof(char*));
+	if (!entries) return 0;
+	memset(entries,0,numentries*sizeof(char*));
+	/* Retrieve all the results: */
+	child=item->child;
+	while (child && !fail)
+	{
+		ret=print_value(child,depth+1,fmt);
+		entries[i++]=ret;
+		if (ret) len+=strlen(ret)+2+(fmt?1:0); else fail=1;
+		child=child->next;
+	}
+	
+	/* If we didn't fail, try to malloc the output string */
+	if (!fail) out=(char*)cJSON_malloc(len);
+	/* If that fails, we fail. */
+	if (!out) fail=1;
+
+	/* Handle failure. */
+	if (fail)
+	{
+		for (i=0;i<numentries;i++) if (entries[i]) cJSON_free(entries[i]);
+		cJSON_free(entries);
+		return 0;
+	}
+	
+	/* Compose the output array. */
+	*out='[';
+	ptr=out+1;*ptr=0;
+	for (i=0;i<numentries;i++)
+	{
+		strcpy(ptr,entries[i]);ptr+=strlen(entries[i]);
+		if (i!=numentries-1) {*ptr++=',';if(fmt)*ptr++=' ';*ptr=0;}
+		cJSON_free(entries[i]);
+	}
+	cJSON_free(entries);
+	*ptr++=']';*ptr++=0;
+	return out;	
+}
+
+/* Build an object from the text. */
+static const char *parse_object(cJSON *item,const char *value)
+{
+	cJSON *child;
+	if (*value!='{')	{ep=value;return 0;}	/* not an object! */
+	
+	item->type=cJSON_Object;
+	value=skip(value+1);
+	if (*value=='}') return value+1;	/* empty array. */
+	
+	item->child=child=cJSON_New_Item();
+	if (!item->child) return 0;
+	value=skip(parse_string(child,skip(value)));
+	if (!value) return 0;
+	child->string=child->valuestring;child->valuestring=0;
+	if (*value!=':') {ep=value;return 0;}	/* fail! */
+	value=skip(parse_value(child,skip(value+1)));	/* skip any spacing, get the value. */
+	if (!value) return 0;
+	
+	while (*value==',')
+	{
+		cJSON *new_item;
+		if (!(new_item=cJSON_New_Item()))	return 0; /* memory fail */
+		child->next=new_item;new_item->prev=child;child=new_item;
+		value=skip(parse_string(child,skip(value+1)));
+		if (!value) return 0;
+		child->string=child->valuestring;child->valuestring=0;
+		if (*value!=':') {ep=value;return 0;}	/* fail! */
+		value=skip(parse_value(child,skip(value+1)));	/* skip any spacing, get the value. */
+		if (!value) return 0;
+	}
+	
+	if (*value=='}') return value+1;	/* end of array */
+	ep=value;return 0;	/* malformed. */
+}
+
+/* Render an object to text. */
+static char *print_object(cJSON *item,int depth,int fmt)
+{
+	char **entries=0,**names=0;
+	char *out=0,*ptr,*ret,*str;int len=7,i=0,j;
+	cJSON *child=item->child;
+	int numentries=0,fail=0;
+	/* Count the number of entries. */
+	while (child) numentries++,child=child->next;
+	/* Explicitly handle empty object case */
+	if (!numentries)
+	{
+		out=(char*)cJSON_malloc(fmt?depth+4:3);
+		if (!out)	return 0;
+		ptr=out;*ptr++='{';
+		if (fmt) {*ptr++='\n';for (i=0;i<depth-1;i++) *ptr++='\t';}
+		*ptr++='}';*ptr++=0;
+		return out;
+	}
+	/* Allocate space for the names and the objects */
+	entries=(char**)cJSON_malloc(numentries*sizeof(char*));
+	if (!entries) return 0;
+	names=(char**)cJSON_malloc(numentries*sizeof(char*));
+	if (!names) {cJSON_free(entries);return 0;}
+	memset(entries,0,sizeof(char*)*numentries);
+	memset(names,0,sizeof(char*)*numentries);
+
+	/* Collect all the results into our arrays: */
+	child=item->child;depth++;if (fmt) len+=depth;
+	while (child)
+	{
+		names[i]=str=print_string_ptr(child->string);
+		entries[i++]=ret=print_value(child,depth,fmt);
+		if (str && ret) len+=strlen(ret)+strlen(str)+2+(fmt?2+depth:0); else fail=1;
+		child=child->next;
+	}
+	
+	/* Try to allocate the output string */
+	if (!fail) out=(char*)cJSON_malloc(len);
+	if (!out) fail=1;
+
+	/* Handle failure */
+	if (fail)
+	{
+		for (i=0;i<numentries;i++) {if (names[i]) cJSON_free(names[i]);if (entries[i]) cJSON_free(entries[i]);}
+		cJSON_free(names);cJSON_free(entries);
+		return 0;
+	}
+	
+	/* Compose the output: */
+	*out='{';ptr=out+1;if (fmt)*ptr++='\n';*ptr=0;
+	for (i=0;i<numentries;i++)
+	{
+		if (fmt) for (j=0;j<depth;j++) *ptr++='\t';
+		strcpy(ptr,names[i]);ptr+=strlen(names[i]);
+		*ptr++=':';if (fmt) *ptr++='\t';
+		strcpy(ptr,entries[i]);ptr+=strlen(entries[i]);
+		if (i!=numentries-1) *ptr++=',';
+		if (fmt) *ptr++='\n';*ptr=0;
+		cJSON_free(names[i]);cJSON_free(entries[i]);
+	}
+	
+	cJSON_free(names);cJSON_free(entries);
+	if (fmt) for (i=0;i<depth-1;i++) *ptr++='\t';
+	*ptr++='}';*ptr++=0;
+	return out;	
+}
+
+/* Get Array size/item / object item. */
+int    cJSON_GetArraySize(cJSON *array)							{cJSON *c=array->child;int i=0;while(c)i++,c=c->next;return i;}
+cJSON *cJSON_GetArrayItem(cJSON *array,int item)				{cJSON *c=array->child;  while (c && item>0) item--,c=c->next; return c;}
+cJSON *cJSON_GetObjectItem(cJSON *object,const char *string)	{cJSON *c=object->child; while (c && cJSON_strcasecmp(c->string,string)) c=c->next; return c;}
+
+/* Utility for array list handling. */
+static void suffix_object(cJSON *prev,cJSON *item) {prev->next=item;item->prev=prev;}
+/* Utility for handling references. */
+static cJSON *create_reference(cJSON *item) {cJSON *ref=cJSON_New_Item();if (!ref) return 0;memcpy(ref,item,sizeof(cJSON));ref->string=0;ref->type|=cJSON_IsReference;ref->next=ref->prev=0;return ref;}
+
+/* Add item to array/object. */
+void   cJSON_AddItemToArray(cJSON *array, cJSON *item)						{cJSON *c=array->child;if (!item) return; if (!c) {array->child=item;} else {while (c && c->next) c=c->next; suffix_object(c,item);}}
+void   cJSON_AddItemToObject(cJSON *object,const char *string,cJSON *item)	{if (!item) return; if (item->string) cJSON_free(item->string);item->string=cJSON_strdup(string);cJSON_AddItemToArray(object,item);}
+void	cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item)						{cJSON_AddItemToArray(array,create_reference(item));}
+void	cJSON_AddItemReferenceToObject(cJSON *object,const char *string,cJSON *item)	{cJSON_AddItemToObject(object,string,create_reference(item));}
+
+cJSON *cJSON_DetachItemFromArray(cJSON *array,int which)			{cJSON *c=array->child;while (c && which>0) c=c->next,which--;if (!c) return 0;
+	if (c->prev) c->prev->next=c->next;if (c->next) c->next->prev=c->prev;if (c==array->child) array->child=c->next;c->prev=c->next=0;return c;}
+void   cJSON_DeleteItemFromArray(cJSON *array,int which)			{cJSON_Delete(cJSON_DetachItemFromArray(array,which));}
+cJSON *cJSON_DetachItemFromObject(cJSON *object,const char *string) {int i=0;cJSON *c=object->child;while (c && cJSON_strcasecmp(c->string,string)) i++,c=c->next;if (c) return cJSON_DetachItemFromArray(object,i);return 0;}
+void   cJSON_DeleteItemFromObject(cJSON *object,const char *string) {cJSON_Delete(cJSON_DetachItemFromObject(object,string));}
+
+/* Replace array/object items with new ones. */
+void   cJSON_ReplaceItemInArray(cJSON *array,int which,cJSON *newitem)		{cJSON *c=array->child;while (c && which>0) c=c->next,which--;if (!c) return;
+	newitem->next=c->next;newitem->prev=c->prev;if (newitem->next) newitem->next->prev=newitem;
+	if (c==array->child) array->child=newitem; else newitem->prev->next=newitem;c->next=c->prev=0;cJSON_Delete(c);}
+void   cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem){int i=0;cJSON *c=object->child;while(c && cJSON_strcasecmp(c->string,string))i++,c=c->next;if(c){newitem->string=cJSON_strdup(string);cJSON_ReplaceItemInArray(object,i,newitem);}}
+
+/* Create basic types: */
+cJSON *cJSON_CreateNull(void)					{cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_NULL;return item;}
+cJSON *cJSON_CreateTrue(void)					{cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_True;return item;}
+cJSON *cJSON_CreateFalse(void)					{cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_False;return item;}
+cJSON *cJSON_CreateBool(int b)					{cJSON *item=cJSON_New_Item();if(item)item->type=b?cJSON_True:cJSON_False;return item;}
+cJSON *cJSON_CreateNumber(double num)			{cJSON *item=cJSON_New_Item();if(item){item->type=cJSON_Number;item->valuedouble=num;item->valueint=(int)num;}return item;}
+cJSON *cJSON_CreateString(const char *string)	{cJSON *item=cJSON_New_Item();if(item){item->type=cJSON_String;item->valuestring=cJSON_strdup(string);}return item;}
+cJSON *cJSON_CreateArray(void)					{cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_Array;return item;}
+cJSON *cJSON_CreateObject(void)					{cJSON *item=cJSON_New_Item();if(item)item->type=cJSON_Object;return item;}
+
+/* Create Arrays: */
+cJSON *cJSON_CreateIntArray(const int *numbers,int count)		{int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateNumber(numbers[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;}
+cJSON *cJSON_CreateFloatArray(const float *numbers,int count)	{int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateNumber(numbers[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;}
+cJSON *cJSON_CreateDoubleArray(const double *numbers,int count)	{int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateNumber(numbers[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;}
+cJSON *cJSON_CreateStringArray(const char **strings,int count)	{int i;cJSON *n=0,*p=0,*a=cJSON_CreateArray();for(i=0;a && i<count;i++){n=cJSON_CreateString(strings[i]);if(!i)a->child=n;else suffix_object(p,n);p=n;}return a;}
+
+/* Duplication */
+cJSON *cJSON_Duplicate(cJSON *item,int recurse)
+{
+	cJSON *newitem,*cptr,*nptr=0,*newchild;
+	/* Bail on bad ptr */
+	if (!item) return 0;
+	/* Create new item */
+	newitem=cJSON_New_Item();
+	if (!newitem) return 0;
+	/* Copy over all vars */
+	newitem->type=item->type&(~cJSON_IsReference),newitem->valueint=item->valueint,newitem->valuedouble=item->valuedouble;
+	if (item->valuestring)	{newitem->valuestring=cJSON_strdup(item->valuestring);	if (!newitem->valuestring)	{cJSON_Delete(newitem);return 0;}}
+	if (item->string)		{newitem->string=cJSON_strdup(item->string);			if (!newitem->string)		{cJSON_Delete(newitem);return 0;}}
+	/* If non-recursive, then we're done! */
+	if (!recurse) return newitem;
+	/* Walk the ->next chain for the child. */
+	cptr=item->child;
+	while (cptr)
+	{
+		newchild=cJSON_Duplicate(cptr,1);		/* Duplicate (with recurse) each item in the ->next chain */
+		if (!newchild) {cJSON_Delete(newitem);return 0;}
+		if (nptr)	{nptr->next=newchild,newchild->prev=nptr;nptr=newchild;}	/* If newitem->child already set, then crosswire ->prev and ->next and move on */
+		else		{newitem->child=newchild;nptr=newchild;}					/* Set newitem->child and move to it */
+		cptr=cptr->next;
+	}
+	return newitem;
+}
+
+void cJSON_Minify(char *json)
+{
+	char *into=json;
+	while (*json)
+	{
+		if (*json==' ') json++;
+		else if (*json=='\t') json++;	// Whitespace characters.
+		else if (*json=='\r') json++;
+		else if (*json=='\n') json++;
+		else if (*json=='/' && json[1]=='/')  while (*json && *json!='\n') json++;	// double-slash comments, to end of line.
+		else if (*json=='/' && json[1]=='*') {while (*json && !(*json=='*' && json[1]=='/')) json++;json+=2;}	// multiline comments.
+		else if (*json=='\"'){*into++=*json++;while (*json && *json!='\"'){if (*json=='\\') *into++=*json++;*into++=*json++;}*into++=*json++;} // string literals, which are \" sensitive.
+		else *into++=*json++;			// All other characters.
+	}
+	*into=0;	// and null-terminate.
+}
diff --git a/cache/src/cJSON/cJSON.h b/cache/src/cJSON/cJSON.h
new file mode 100644
index 0000000..867b7c3
--- /dev/null
+++ b/cache/src/cJSON/cJSON.h
@@ -0,0 +1,143 @@
+/*
+  Copyright (c) 2009 Dave Gamble
+ 
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+ 
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+ 
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*/
+
+#ifndef cJSON__h
+#define cJSON__h
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+/* cJSON Types: */
+#define cJSON_False 0
+#define cJSON_True 1
+#define cJSON_NULL 2
+#define cJSON_Number 3
+#define cJSON_String 4
+#define cJSON_Array 5
+#define cJSON_Object 6
+	
+#define cJSON_IsReference 256
+
+/* The cJSON structure: */
+typedef struct cJSON {
+	struct cJSON *next,*prev;	/* next/prev allow you to walk array/object chains. Alternatively, use GetArraySize/GetArrayItem/GetObjectItem */
+	struct cJSON *child;		/* An array or object item will have a child pointer pointing to a chain of the items in the array/object. */
+
+	int type;					/* The type of the item, as above. */
+
+	char *valuestring;			/* The item's string, if type==cJSON_String */
+	int valueint;				/* The item's number, if type==cJSON_Number */
+	double valuedouble;			/* The item's number, if type==cJSON_Number */
+
+	char *string;				/* The item's name string, if this item is the child of, or is in the list of subitems of an object. */
+} cJSON;
+
+typedef struct cJSON_Hooks {
+      void *(*malloc_fn)(size_t sz);
+      void (*free_fn)(void *ptr);
+} cJSON_Hooks;
+
+/* Supply malloc, realloc and free functions to cJSON */
+extern void cJSON_InitHooks(cJSON_Hooks* hooks);
+
+
+/* Supply a block of JSON, and this returns a cJSON object you can interrogate. Call cJSON_Delete when finished. */
+extern cJSON *cJSON_Parse(const char *value);
+/* Render a cJSON entity to text for transfer/storage. Free the char* when finished. */
+extern char  *cJSON_Print(cJSON *item);
+/* Render a cJSON entity to text for transfer/storage without any formatting. Free the char* when finished. */
+extern char  *cJSON_PrintUnformatted(cJSON *item);
+/* Delete a cJSON entity and all subentities. */
+extern void   cJSON_Delete(cJSON *c);
+
+/* Returns the number of items in an array (or object). */
+extern int	  cJSON_GetArraySize(cJSON *array);
+/* Retrieve item number "item" from array "array". Returns NULL if unsuccessful. */
+extern cJSON *cJSON_GetArrayItem(cJSON *array,int item);
+/* Get item "string" from object. Case insensitive. */
+extern cJSON *cJSON_GetObjectItem(cJSON *object,const char *string);
+
+/* For analysing failed parses. This returns a pointer to the parse error. You'll probably need to look a few chars back to make sense of it. Defined when cJSON_Parse() returns 0. 0 when cJSON_Parse() succeeds. */
+extern const char *cJSON_GetErrorPtr(void);
+	
+/* These calls create a cJSON item of the appropriate type. */
+extern cJSON *cJSON_CreateNull(void);
+extern cJSON *cJSON_CreateTrue(void);
+extern cJSON *cJSON_CreateFalse(void);
+extern cJSON *cJSON_CreateBool(int b);
+extern cJSON *cJSON_CreateNumber(double num);
+extern cJSON *cJSON_CreateString(const char *string);
+extern cJSON *cJSON_CreateArray(void);
+extern cJSON *cJSON_CreateObject(void);
+
+/* These utilities create an Array of count items. */
+extern cJSON *cJSON_CreateIntArray(const int *numbers,int count);
+extern cJSON *cJSON_CreateFloatArray(const float *numbers,int count);
+extern cJSON *cJSON_CreateDoubleArray(const double *numbers,int count);
+extern cJSON *cJSON_CreateStringArray(const char **strings,int count);
+
+/* Append item to the specified array/object. */
+extern void cJSON_AddItemToArray(cJSON *array, cJSON *item);
+extern void	cJSON_AddItemToObject(cJSON *object,const char *string,cJSON *item);
+/* Append reference to item to the specified array/object. Use this when you want to add an existing cJSON to a new cJSON, but don't want to corrupt your existing cJSON. */
+extern void cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item);
+extern void	cJSON_AddItemReferenceToObject(cJSON *object,const char *string,cJSON *item);
+
+/* Remove/Detatch items from Arrays/Objects. */
+extern cJSON *cJSON_DetachItemFromArray(cJSON *array,int which);
+extern void   cJSON_DeleteItemFromArray(cJSON *array,int which);
+extern cJSON *cJSON_DetachItemFromObject(cJSON *object,const char *string);
+extern void   cJSON_DeleteItemFromObject(cJSON *object,const char *string);
+	
+/* Update array items. */
+extern void cJSON_ReplaceItemInArray(cJSON *array,int which,cJSON *newitem);
+extern void cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem);
+
+/* Duplicate a cJSON item */
+extern cJSON *cJSON_Duplicate(cJSON *item,int recurse);
+/* Duplicate will create a new, identical cJSON item to the one you pass, in new memory that will
+need to be released. With recurse!=0, it will duplicate any children connected to the item.
+The item->next and ->prev pointers are always zero on return from Duplicate. */
+
+/* ParseWithOpts allows you to require (and check) that the JSON is null terminated, and to retrieve the pointer to the final byte parsed. */
+extern cJSON *cJSON_ParseWithOpts(const char *value,const char **return_parse_end,int require_null_terminated);
+
+extern void cJSON_Minify(char *json);
+
+/* Macros for creating things quickly. */
+#define cJSON_AddNullToObject(object,name)		cJSON_AddItemToObject(object, name, cJSON_CreateNull())
+#define cJSON_AddTrueToObject(object,name)		cJSON_AddItemToObject(object, name, cJSON_CreateTrue())
+#define cJSON_AddFalseToObject(object,name)		cJSON_AddItemToObject(object, name, cJSON_CreateFalse())
+#define cJSON_AddBoolToObject(object,name,b)	cJSON_AddItemToObject(object, name, cJSON_CreateBool(b))
+#define cJSON_AddNumberToObject(object,name,n)	cJSON_AddItemToObject(object, name, cJSON_CreateNumber(n))
+#define cJSON_AddStringToObject(object,name,s)	cJSON_AddItemToObject(object, name, cJSON_CreateString(s))
+
+/* When assigning an integer value, it needs to be propagated to valuedouble too. */
+#define cJSON_SetIntValue(object,val)			((object)?(object)->valueint=(object)->valuedouble=(val):(val))
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/cache/src/cache_evbase_client.cpp b/cache/src/cache_evbase_client.cpp
index 0f9059b..6cd4ea6 100644
--- a/cache/src/cache_evbase_client.cpp
+++ b/cache/src/cache_evbase_client.cpp
@@ -17,6 +17,9 @@
 #include "cache_evbase_client.h"
 #include "tango_cache_transfer.h"
 #include "tango_cache_tools.h"
+#ifdef HEAD_OBJECT_FROM_REDIS
+#include "tango_cache_redis.h"
+#endif
 
 enum CACHE_ASYN_CMD
 {
@@ -28,6 +31,7 @@ enum CACHE_ASYN_CMD
 	CACHE_ASYN_UPLOAD_FRAG_EVBUF,
 	CACHE_ASYN_UPLOAD_END,
 	CACHE_ASYN_DELETE,
+	CACHE_ASYN_HEAD,
 };
 
 struct databuffer
@@ -158,7 +162,15 @@ static void cache_asyn_ioevent_dispatch(struct databuffer *buffer)
 			tango_cache_fetch_start(ctx_asyn->ctx);
 			cache_asyn_ctx_destroy(ctx_asyn);
 			break;
-
+		case CACHE_ASYN_HEAD:
+#ifdef HEAD_OBJECT_FROM_REDIS
+			tango_cache_head_redis(ctx_asyn->ctx);
+#else
+			tango_cache_fetch_start(ctx_asyn->ctx);
+#endif
+			cache_asyn_ctx_destroy(ctx_asyn);
+			break;
+			
 		case CACHE_ASYN_DELETE:
 			cache_delete_minio_object(ctx_asyn->ctx);
 			cache_asyn_ctx_destroy(ctx_asyn);
@@ -450,7 +462,7 @@ int cache_evbase_fetch_object(struct cache_evbase_instance *instance, struct fut
 
 	ctx_asyn = (struct cache_evbase_ctx *)calloc(1, sizeof(struct cache_evbase_ctx));
 	ctx_asyn->instance_asyn = instance;
-	ctx_asyn->ctx = tango_cache_fetch_prepare(instance->instance, f, meta);
+	ctx_asyn->ctx = tango_cache_fetch_prepare(instance->instance, CACHE_REQUEST_GET, f, meta);
 	if(ctx_asyn->ctx == NULL)
 	{
 		free(ctx_asyn);
@@ -473,6 +485,36 @@ int cache_evbase_fetch_object(struct cache_evbase_instance *instance, struct fut
 	return 0;
 }
 
+int cache_evbase_head_object(struct cache_evbase_instance *instance, struct future* f, struct tango_cache_meta_get *meta)
+{
+	struct cache_evbase_ctx *ctx_asyn;
+	struct databuffer *buffer;
+
+	ctx_asyn = (struct cache_evbase_ctx *)calloc(1, sizeof(struct cache_evbase_ctx));
+	ctx_asyn->instance_asyn = instance;
+	ctx_asyn->ctx = tango_cache_fetch_prepare(instance->instance, CACHE_REQUEST_HEAD, f, meta);
+	if(ctx_asyn->ctx == NULL)
+	{
+		free(ctx_asyn);
+		return -1;
+	}
+
+	buffer = (struct databuffer *)malloc(sizeof(struct databuffer));
+	buffer->ctx_asyn = ctx_asyn;
+	buffer->cmd_type = CACHE_ASYN_HEAD;
+
+	if(iothread_notify_event(instance->notify_sendfd, &buffer, sizeof(void *), 2) != sizeof(void *))
+	{
+		tango_cache_set_fail_state(ctx_asyn->ctx, CACHE_ERR_SOCKPAIR);
+		promise_failed(future_to_promise(f), FUTURE_ERROR_CANCEL, tango_cache_get_errstring(ctx_asyn->ctx));
+		tango_cache_ctx_destroy(ctx_asyn->ctx);
+		cache_asyn_ctx_destroy(ctx_asyn);
+		free(buffer);
+		return -2;
+	}
+	return 0;
+}
+
 int cache_evbase_delete_object(struct cache_evbase_instance *instance, struct future* f, const char *objkey)
 {
 	struct cache_evbase_ctx *ctx_asyn;
diff --git a/cache/src/tango_cache_client.cpp b/cache/src/tango_cache_client.cpp
index baf58dc..1575437 100644
--- a/cache/src/tango_cache_client.cpp
+++ b/cache/src/tango_cache_client.cpp
@@ -17,6 +17,9 @@
 #include "tango_cache_transfer.h"
 #include "tango_cache_tools.h"
 #include "tango_cache_xml.h"
+#ifdef HEAD_OBJECT_FROM_REDIS
+#include "tango_cache_redis.h"
+#endif
 
 int TANGO_CACHE_VERSION_20181009=0;
 
@@ -91,6 +94,8 @@ const char *tango_cache_get_errstring(const struct tango_cache_ctx *ctx)
 		case CACHE_ERR_WIREDLB:	return "wiredlb error";
 		case CACHE_ERR_SOCKPAIR:return "socketpair error";
 		case CACHE_ERR_INTERNAL:return "internal error";
+		case CACHE_ERR_REDIS_JSON:return "parse redis json error";
+		case CACHE_ERR_REDIS_CONNECT:return "redis is not connected";
 		default: return ctx->error;
 	}
 }
@@ -137,6 +142,7 @@ static void update_statistics(struct tango_cache_ctx *ctx, struct cache_statisti
 			}
 			break;
 		case CACHE_REQUEST_GET:
+		case CACHE_REQUEST_HEAD:
 			if(ctx->fail_state)
 			{
 				if(ctx->error_code == CACHE_CACHE_MISS || ctx->error_code == CACHE_TIMEOUT)
@@ -204,6 +210,7 @@ void tango_cache_ctx_destroy(struct tango_cache_ctx *ctx)
 	switch(ctx->method)
 	{
 		case CACHE_REQUEST_GET:
+		case CACHE_REQUEST_HEAD:
 			easy_string_destroy(&ctx->get.response_tag);
 			break;
 
@@ -431,7 +438,7 @@ int tango_cache_upload_once_evbuf(struct tango_cache_instance *instance, struct
 	return tango_cache_upload_once_start_evbuf(ctx, way, evbuf);
 }
 
-struct tango_cache_ctx *tango_cache_fetch_prepare(struct tango_cache_instance *instance, struct future* f, struct tango_cache_meta_get *meta)
+struct tango_cache_ctx *tango_cache_fetch_prepare(struct tango_cache_instance *instance, enum CACHE_REQUEST_METHOD method, struct future* f, struct tango_cache_meta_get *meta)
 {
 	struct tango_cache_ctx *ctx;	
 	char sha256[72];
@@ -439,7 +446,7 @@ struct tango_cache_ctx *tango_cache_fetch_prepare(struct tango_cache_instance *i
 	ctx = (struct tango_cache_ctx *)calloc(1, sizeof(struct tango_cache_ctx));
 	ctx->instance = instance;
 	ctx->future = f;
-	ctx->method = CACHE_REQUEST_GET;
+	ctx->method = method;
 	ctx->get.state = GET_STATE_START;
 	ctx->get.max_age = meta->get.max_age;
 	ctx->get.min_fresh = meta->get.min_fresh;
@@ -467,7 +474,7 @@ int tango_cache_fetch_object(struct tango_cache_instance *instance, struct futur
 {
 	struct tango_cache_ctx *ctx;
 
-	ctx = tango_cache_fetch_prepare(instance, f, meta);
+	ctx = tango_cache_fetch_prepare(instance, CACHE_REQUEST_GET, f, meta);
 	if(ctx == NULL)
 	{
 		return -1;
@@ -475,6 +482,22 @@ int tango_cache_fetch_object(struct tango_cache_instance *instance, struct futur
 	return tango_cache_fetch_start(ctx);
 }
 
+int tango_cache_head_object(struct tango_cache_instance *instance, struct future* f, struct tango_cache_meta_get *meta)
+{
+	struct tango_cache_ctx *ctx;
+
+	ctx = tango_cache_fetch_prepare(instance, CACHE_REQUEST_HEAD, f, meta);
+	if(ctx == NULL)
+	{
+		return -1;
+	}
+#ifdef HEAD_OBJECT_FROM_REDIS
+	return tango_cache_head_redis(ctx);
+#else
+	return tango_cache_fetch_start(ctx);
+#endif
+}
+
 struct tango_cache_ctx *tango_cache_delete_prepare(struct tango_cache_instance *instance, struct future* f, const char *objkey)
 {
 	struct tango_cache_ctx *ctx;	
@@ -585,6 +608,7 @@ static void check_multi_info(CURLM *multi)
 		switch(ctx->method)
 		{
 			case CACHE_REQUEST_GET:
+			case CACHE_REQUEST_HEAD:
 				tango_cache_curl_get_done(ctx, res, res_code);
 				break;
 			case CACHE_REQUEST_PUT:
@@ -732,7 +756,20 @@ static int load_local_configure(struct tango_cache_instance *instance, const cha
 	MESA_load_profile_uint_def(profile_path, section, "MAX_USED_MEMORY_SIZE_MB", &intval, 5120);
 	longval = intval;
 	instance->cache_limit_size = longval * 1024 * 1024;
-	MESA_load_profile_string_def(profile_path, section, "CACHE_BUCKET_NAME", instance->bucketname, 256, "openbucket");
+	if(MESA_load_profile_string_nodef(profile_path, section, "CACHE_BUCKET_NAME", instance->bucketname, 256) < 0)
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_FATAL, "Load config %s [%s] CACHE_BUCKET_NAME not found.\n", profile_path, section);
+		return -1;
+	}
+#ifdef HEAD_OBJECT_FROM_REDIS
+	MESA_load_profile_string_def(profile_path, section, "CACHE_REDIS_KEY", instance->redis_key, 256, instance->bucketname);
+	if(MESA_load_profile_string_nodef(profile_path, section, "CACHE_REDIS_IP", instance->redis_ip, 256) < 0)
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_FATAL, "Load config %s [%s] CACHE_REDIS_IP not found.\n", profile_path, section);
+		return -1;
+	}
+	MESA_load_profile_int_def(profile_path, section, "CACHE_REDIS_PORT", &instance->redis_port, 6379);
+#endif
 	MESA_load_profile_uint_def(profile_path, section, "CACHE_OBJECT_KEY_HASH_SWITCH", &instance->hash_object_key, 1);
 	MESA_load_profile_uint_def(profile_path, section, "MINIO_LISTEN_PORT", &instance->minio_port, 9000);
 	if(MESA_load_profile_string_nodef(profile_path, section, "MINIO_IP_LIST", instance->minio_iplist, 4096) < 0)
@@ -792,8 +829,19 @@ struct tango_cache_instance *tango_cache_instance_new(struct event_base* evbase,
 	curl_multi_setopt(instance->multi_hd, CURLMOPT_TIMERFUNCTION, curl_timer_function_cb);
 	curl_multi_setopt(instance->multi_hd, CURLMOPT_TIMERDATA, instance);
 
+#ifdef HEAD_OBJECT_FROM_REDIS
+	if(redis_asyn_connect_init(instance, instance->redis_ip, instance->redis_port))
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_FATAL, "redis_asyn_connect_init %s:%u failed.", instance->redis_ip, instance->redis_port);
+		free(instance);
+		return NULL;
+	}
+	else
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_FATAL, "redis_asyn_connect_init %s:%u success.", instance->redis_ip, instance->redis_port);
+	}
+#endif
 	evtimer_assign(&instance->timer_event, evbase, libevent_timer_event_cb, instance);
-
 	return instance;
 }
 
diff --git a/cache/src/tango_cache_client_in.h b/cache/src/tango_cache_client_in.h
index 9dfb97e..aa67ec8 100644
--- a/cache/src/tango_cache_client_in.h
+++ b/cache/src/tango_cache_client_in.h
@@ -6,6 +6,9 @@
 
 #include <event2/event.h>  
 #include <event.h>
+#ifdef HEAD_OBJECT_FROM_REDIS
+#include <hiredis/async.h>
+#endif
 
 #include <MESA/wiredLB.h>
 #include "tango_cache_client.h"
@@ -20,6 +23,7 @@ enum CACHE_REQUEST_METHOD
 	CACHE_REQUEST_PUT,
 	CACHE_REQUEST_DELETE,
 	CACHE_REQUEST_DELETE_MUL,
+	CACHE_REQUEST_HEAD,
 };
 
 enum GET_OBJECT_STATE
@@ -67,6 +71,13 @@ struct tango_cache_instance
 	long max_cnn_host;
 	u_int32_t upload_block_size; //minio�ֶ��ϴ������С����
 	enum CACHE_ERR_CODE error_code;
+#ifdef HEAD_OBJECT_FROM_REDIS
+	redisAsyncContext *redis_ac;
+	char redis_key[256];
+	char redis_ip[128];
+	int redis_port;
+	int redis_connecting;
+#endif
 };
 
 struct multipart_etag_list
@@ -146,7 +157,7 @@ void tango_cache_set_fail_state(struct tango_cache_ctx *ctx, enum CACHE_ERR_CODE
 const char *tango_cache_get_errstring(const struct tango_cache_ctx *ctx);
 
 struct tango_cache_ctx *tango_cache_update_prepare(struct tango_cache_instance *instance, struct future* f, struct tango_cache_meta_put *meta);
-struct tango_cache_ctx *tango_cache_fetch_prepare(struct tango_cache_instance *instance, struct future* f, struct tango_cache_meta_get *meta);
+struct tango_cache_ctx *tango_cache_fetch_prepare(struct tango_cache_instance *instance, enum CACHE_REQUEST_METHOD method, struct future* f, struct tango_cache_meta_get *meta);
 struct tango_cache_ctx *tango_cache_delete_prepare(struct tango_cache_instance *instance, struct future* f, const char *objkey);
 
 #endif
diff --git a/cache/src/tango_cache_redis.cpp b/cache/src/tango_cache_redis.cpp
new file mode 100644
index 0000000..dfc5e3b
--- /dev/null
+++ b/cache/src/tango_cache_redis.cpp
@@ -0,0 +1,243 @@
+#include <sys/types.h>
+#include <unistd.h> 
+#include <stdio.h> 
+#include <stdlib.h>
+#include <assert.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <time.h>
+#include <string.h>
+
+#include <hiredis/hiredis.h>
+#include <hiredis/async.h>
+#include <hiredis/adapters/libevent.h>
+
+#include "tango_cache_transfer.h"
+#include "tango_cache_tools.h"
+#include "tango_cache_redis.h"
+#include "cJSON.h"
+
+#define PARSE_JSON_RET_ERROR -1
+#define PARSE_JSON_RET_TIMEOUT  0
+#define PARSE_JSON_RET_SUCC  1
+
+#define CACHE_REDIS_CONNECT_IDLE 0
+#define CACHE_REDIS_CONNECTING   1
+#define CACHE_REDIS_CONNECTED    2
+#define CACHE_REDIS_DISCONNECTED 3
+
+struct http_hdr_name
+{
+	const char *json_name;
+	const char *http_name;
+};
+struct http_hdr_name g_http_hdr_name[HDR_CONTENT_NUM]=
+{
+	{"content-type", "Content-Type: "},
+	{"content-encoding", "Content-Encoding: "},
+	{"content-disposition", "Content-Disposition: "},
+	{"content-md5", "Content-MD5: "}
+};
+
+void redis_asyn_disconnect_cb(const struct redisAsyncContext *ac, int status)
+{
+	struct tango_cache_instance *instance = (struct tango_cache_instance *)redisAsyncGetConnectionData(ac);
+	
+	if(status == REDIS_OK)
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_INFO, "Redis disconnect %s:%u success.", instance->redis_ip, instance->redis_port);
+	}
+	else
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_INFO, "Redis disconnect %s:%u failed: %s.", instance->redis_ip, instance->redis_port, ac->errstr);
+	}
+	instance->redis_connecting = CACHE_REDIS_DISCONNECTED;
+}
+
+void redis_asyn_connect_cb(const struct redisAsyncContext *ac, int status)
+{
+	struct tango_cache_instance *instance = (struct tango_cache_instance *)redisAsyncGetConnectionData(ac);
+
+	if(status == REDIS_OK)
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_INFO, "Redis connect %s:%u success.", instance->redis_ip, instance->redis_port);
+		instance->redis_connecting = CACHE_REDIS_CONNECTED;
+	}
+	else
+	{
+		MESA_HANDLE_RUNTIME_LOGV2(instance->runtime_log, RLOG_LV_INFO, "Redis connect %s:%u failed.", instance->redis_ip, instance->redis_port, ac->errstr);
+		instance->redis_connecting = CACHE_REDIS_CONNECT_IDLE;
+	}
+}
+
+int redis_asyn_connect_init(struct tango_cache_instance *instance, const char *redisip, int redis_port)
+{
+	instance->redis_ac = redisAsyncConnect(redisip, redis_port);
+	if(instance->redis_ac == NULL)
+	{
+		return -1;
+	}
+	instance->redis_connecting = CACHE_REDIS_CONNECTING;
+	redisLibeventAttach(instance->redis_ac, instance->evbase);
+	redisAsyncSetConnectionData(instance->redis_ac, instance);
+	redisAsyncSetConnectCallback(instance->redis_ac, redis_asyn_connect_cb);
+	redisAsyncSetDisconnectCallback(instance->redis_ac, redis_asyn_disconnect_cb);
+	return 0;
+}
+
+int parse_minio_events_json(struct tango_cache_ctx *ctx, const char *jcontent)
+{
+	cJSON *root, *pobject = NULL, *ptarget, *plastMod, *pexpires;
+	int ret = PARSE_JSON_RET_ERROR;
+	char usertag[2048];
+	size_t datalen;
+
+	//Records[0]->s3->object->key...userMetaData->metas...
+	if(NULL == (root=cJSON_Parse(jcontent)))
+	{
+		goto out_json;
+	}
+	if(NULL==(pobject=cJSON_GetObjectItem(root, "Records")) || pobject->type!=cJSON_Array)
+	{
+		goto out_json;
+	}
+	if(NULL == (pobject=cJSON_GetArrayItem(pobject, 0))) //��һ������Ԫ�أ�һ��ֻ��һ��
+	{
+		goto out_json;
+	}
+	if(NULL == (pobject=cJSON_GetObjectItem(pobject, "s3")) || pobject->type!=cJSON_Object)
+	{
+		goto out_json;
+	}
+	if(NULL == (pobject=cJSON_GetObjectItem(pobject, "object")) || pobject->type!=cJSON_Object)
+	{
+		goto out_json;
+	}
+	//��ȡ���
+	if(NULL == (ptarget=cJSON_GetObjectItem(pobject, "size")) || ptarget->type!=cJSON_Number)
+	{
+		goto out_json;
+	}
+	ctx->get.result.tlength = ptarget->valueint; //TODO: ������4GB��ô�죿
+	if(NULL == (ptarget=cJSON_GetObjectItem(pobject, "userMetadata")) || ptarget->type!=cJSON_Object)
+	{
+		goto out_json;
+	}
+	if(NULL==(plastMod=cJSON_GetObjectItem(ptarget, "X-Amz-Meta-Lm")) || NULL==(pexpires=cJSON_GetObjectItem(ptarget, "expires")))
+	{
+		goto out_json;
+	}
+	ctx->get.need_hdrs = RESPONSE_HDR_ALL;
+	ctx->get.last_modify = atol(plastMod->valuestring);
+	ctx->get.expires = expires_hdr2timestamp(pexpires->valuestring, strlen(pexpires->valuestring));
+	if(!check_expires_fresh_header(ctx))
+	{
+		ret = PARSE_JSON_RET_TIMEOUT;
+		goto out_json;
+	}
+	
+	if(NULL!=(plastMod=cJSON_GetObjectItem(ptarget, "X-Amz-Meta-User")))
+	{
+		if((datalen = Base64_DecodeBlock((unsigned char*)plastMod->valuestring, strlen(plastMod->valuestring), (unsigned char*)usertag, 2048))>0)
+		{
+			easy_string_savedata(&ctx->get.response_tag, usertag, datalen);
+		}
+	}
+	for(int i=0; i<HDR_CONTENT_NUM; i++)
+	{
+		if(NULL != (plastMod=cJSON_GetObjectItem(ptarget, g_http_hdr_name[i].json_name)))
+		{
+			easy_string_savedata(&ctx->response, g_http_hdr_name[i].http_name, strlen(g_http_hdr_name[i].http_name));
+			easy_string_savedata(&ctx->response, plastMod->valuestring, strlen(plastMod->valuestring));
+			easy_string_savedata(&ctx->response, "\r\n", strlen("\r\n"));
+		}
+	}	
+	return PARSE_JSON_RET_SUCC;
+	
+out_json:
+	cJSON_Delete(root); 
+	return ret;
+}
+
+void redis_hget_command_cb(struct redisAsyncContext *ac, void *vreply, void *privdata)
+{
+	redisReply *reply = (redisReply *)vreply;
+	struct tango_cache_ctx *ctx  = (struct tango_cache_ctx *)privdata;
+	int ret;
+
+	if(reply == NULL || reply->type!=REDIS_REPLY_STRING)
+	{
+		if(reply->type == REDIS_REPLY_NIL)
+		{
+			tango_cache_set_fail_state(ctx, CACHE_CACHE_MISS);
+			ctx->get.result.type = RESULT_TYPE_MISS;
+			promise_success(future_to_promise(ctx->future), &ctx->get.result);
+			
+		}
+		else
+		{
+			if(ac->err)	MESA_HANDLE_RUNTIME_LOGV2(ctx->instance->runtime_log, RLOG_LV_FATAL, "redis_hget_command_cb error: %s.", ac->errstr);			
+			tango_cache_set_fail_state(ctx, CACHE_ERR_REDIS_JSON);
+			promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, tango_cache_get_errstring(ctx));
+		}
+		tango_cache_ctx_destroy(ctx);
+		return;
+	}
+
+	ret = parse_minio_events_json(ctx, reply->str);
+	switch(ret)
+	{
+		case PARSE_JSON_RET_ERROR:
+			tango_cache_set_fail_state(ctx, CACHE_ERR_REDIS_JSON);
+			promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, tango_cache_get_errstring(ctx));
+			tango_cache_ctx_destroy(ctx);
+			break;
+		case PARSE_JSON_RET_TIMEOUT:
+			if(ctx->get.state == GET_STATE_DELETE)
+			{
+				ctx->get.state = GET_STATE_END;
+				cache_delete_minio_object(ctx);
+			}
+			break;
+		case PARSE_JSON_RET_SUCC:
+			fetch_header_over_biz(ctx);
+			ctx->get.result.type = RESULT_TYPE_END;
+			promise_success(future_to_promise(ctx->future), &ctx->get.result);
+			tango_cache_ctx_destroy(ctx);
+			break;
+		default: assert(0);break;
+	}
+}
+
+int tango_cache_head_redis(struct tango_cache_ctx *ctx)
+{
+	int ret = -1;
+
+	ctx->instance->statistic.get_recv_num += 1;
+	switch(ctx->instance->redis_connecting)
+	{
+		case CACHE_REDIS_CONNECTED:
+			ret = redisAsyncCommand(ctx->instance->redis_ac, redis_hget_command_cb, ctx, "HGET %s %s/%s", 
+				ctx->instance->redis_key, ctx->instance->bucketname, ctx->object_key);
+			if(ret < 0)
+			{
+				redisAsyncDisconnect(ctx->instance->redis_ac);
+				redis_asyn_connect_init(ctx->instance, ctx->instance->redis_ip, ctx->instance->redis_port);
+				tango_cache_set_fail_state(ctx, CACHE_ERR_REDIS_CONNECT);
+				promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, tango_cache_get_errstring(ctx));
+				tango_cache_ctx_destroy(ctx);
+			}
+			break;
+		case CACHE_REDIS_DISCONNECTED:
+		case CACHE_REDIS_CONNECT_IDLE:
+			redis_asyn_connect_init(ctx->instance, ctx->instance->redis_ip, ctx->instance->redis_port);
+		case CACHE_REDIS_CONNECTING:
+			tango_cache_set_fail_state(ctx, CACHE_ERR_REDIS_CONNECT);
+			promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, tango_cache_get_errstring(ctx));
+			tango_cache_ctx_destroy(ctx);
+			break;
+		default: assert(0);break;
+	}
+	return ret;
+}
+
diff --git a/cache/src/tango_cache_redis.h b/cache/src/tango_cache_redis.h
new file mode 100644
index 0000000..de0acae
--- /dev/null
+++ b/cache/src/tango_cache_redis.h
@@ -0,0 +1,13 @@
+#ifndef __TANGO_CACHE_REDIS_H__
+#define __TANGO_CACHE_REDIS_H__
+
+#include <event2/event.h>  
+#include <event.h>
+
+#include "tango_cache_client_in.h"
+
+int tango_cache_head_redis(struct tango_cache_ctx *ctx);
+int redis_asyn_connect_init(struct tango_cache_instance *instance, const char *redisip, int redis_port);
+
+#endif
+
diff --git a/cache/src/tango_cache_transfer.cpp b/cache/src/tango_cache_transfer.cpp
index 1889341..87d870e 100644
--- a/cache/src/tango_cache_transfer.cpp
+++ b/cache/src/tango_cache_transfer.cpp
@@ -174,7 +174,6 @@ int curl_get_minio_uploadID(struct tango_cache_ctx *ctx)
 	
 	if(NULL == (ctx->curl=curl_easy_init())) 
 	{
-		free(ctx);
 		return -1;
 	}
 	
@@ -209,6 +208,7 @@ int cache_delete_minio_object(struct tango_cache_ctx *ctx)
 	ctx->instance->statistic.del_recv_num += 1;
 	if(NULL == (ctx->curl=curl_easy_init())) 
 	{
+		tango_cache_ctx_destroy(ctx); //�ս���
 		return 0;
 	}
 
@@ -368,7 +368,7 @@ int cache_kick_upload_minio_end(struct tango_cache_ctx *ctx)
 	switch(ctx->put.state)
 	{
 		case PUT_STATE_START:
-			http_put_complete_part_evbuf(ctx);
+			ret = http_put_complete_part_evbuf(ctx);
 			break;
 
 		case PUT_STATE_PART:
@@ -652,24 +652,16 @@ int tango_cache_multi_delete_start(struct tango_cache_ctx *ctx)
 	return 0;
 }
 
-
-static size_t curl_get_response_body_cb(void *ptr, size_t size, size_t count, void *userp)
+bool fetch_header_over_biz(struct tango_cache_ctx *ctx)
 {
-	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;
-
-	if(ctx->fail_state || ctx->get.state==GET_STATE_DELETE)
-	{
-		return size*count;
-	}
-	
 	if(ctx->get.need_hdrs!=RESPONSE_HDR_ALL) //��Expiresʱ
 	{
 		tango_cache_set_fail_state(ctx, CACHE_ERR_INTERNAL);
 		ctx->get.state	= GET_STATE_DELETE;
 		promise_failed(future_to_promise(ctx->future), FUTURE_ERROR_CANCEL, tango_cache_get_errstring(ctx));
-		return size*count;
+		return false;
 	}
-
+	
 	if(ctx->get.response_tag.len > 0)
 	{
 		ctx->get.result.data_frag = ctx->get.response_tag.buff;
@@ -686,6 +678,23 @@ static size_t curl_get_response_body_cb(void *ptr, size_t size, size_t count, vo
 		promise_success(future_to_promise(ctx->future), &ctx->get.result);
 		easy_string_destroy(&ctx->response);
 	}
+	return true;
+}
+
+static size_t curl_get_response_body_cb(void *ptr, size_t size, size_t count, void *userp)
+{
+	struct tango_cache_ctx *ctx = (struct tango_cache_ctx *)userp;
+
+	if(ctx->fail_state || ctx->get.state==GET_STATE_DELETE)
+	{
+		return size*count;
+	}
+	
+	if(!fetch_header_over_biz(ctx))
+	{
+		return size*count;
+	}
+	
 	ctx->get.result.data_frag = (const char *)ptr;
 	ctx->get.result.size = size * count;
 	ctx->get.result.type = RESULT_TYPE_BODY;
@@ -693,14 +702,16 @@ static size_t curl_get_response_body_cb(void *ptr, size_t size, size_t count, vo
 	return size*count;
 }
 
-static bool check_expires_header(struct tango_cache_ctx *ctx, const char *expires_val, size_t len)
+bool check_expires_fresh_header(struct tango_cache_ctx *ctx)
 {
-	time_t time_gmt;
+	time_t now_gmt;
 
-	ctx->get.expires = expires_hdr2timestamp(expires_val, len);
-	time_gmt = get_gmtime_timestamp(time(NULL));
+	if(ctx->get.need_hdrs != RESPONSE_HDR_ALL)
+		return true;
+
+	now_gmt = get_gmtime_timestamp(time(NULL));
 	
-	if(time_gmt > ctx->get.expires)
+	if(now_gmt > ctx->get.expires)
 	{
 		tango_cache_set_fail_state(ctx, CACHE_TIMEOUT);
 		ctx->get.state  = GET_STATE_DELETE; //����ʧЧʱ���������ʱ����ɾ������
@@ -709,17 +720,7 @@ static bool check_expires_header(struct tango_cache_ctx *ctx, const char *expire
 		easy_string_destroy(&ctx->response);
 		return false;
 	}
-	return true;
-}
-
-static bool check_fresh_header(struct tango_cache_ctx *ctx)
-{
-	time_t now_gmt;
-
-	if(ctx->get.need_hdrs != RESPONSE_HDR_ALL)
-		return true;
-
-	now_gmt = get_gmtime_timestamp(time(NULL));
+	
 	if(ctx->get.last_modify+ctx->get.max_age > now_gmt || now_gmt+ctx->get.min_fresh>ctx->get.expires)
 	{
 		tango_cache_set_fail_state(ctx, CACHE_TIMEOUT);
@@ -791,7 +792,8 @@ static size_t curl_get_response_header_cb(void *ptr, size_t size, size_t count,
 			if(strcmp_one_word_mesa_equal_len("expires", "EXPIRES", start, 7))
 			{
 				ctx->get.need_hdrs |= RESPONSE_HDR_EXPIRES;
-				if(!check_expires_header(ctx, pos_colon + 1, raw_len - datalen - 1) || !check_fresh_header(ctx))
+				ctx->get.expires = expires_hdr2timestamp(pos_colon + 1, raw_len - datalen - 1);
+				if(!check_expires_fresh_header(ctx))
 				{
 					return raw_len;
 				}
@@ -802,7 +804,7 @@ static size_t curl_get_response_header_cb(void *ptr, size_t size, size_t count,
 			{
 				ctx->get.need_hdrs |= RESPONSE_HDR_LAST_MOD;
 				sscanf(pos_colon+1, "%lu", &ctx->get.last_modify);
-				if(!check_fresh_header(ctx))
+				if(!check_expires_fresh_header(ctx))
 				{
 					return raw_len;
 				}
@@ -839,21 +841,18 @@ void tango_cache_curl_get_done(struct tango_cache_ctx *ctx, CURLcode res, long r
 		case GET_STATE_START:
 			if(!ctx->fail_state && check_get_result_code(ctx, res, res_code))
 			{
-				ctx->get.result.type = RESULT_TYPE_END;
-				promise_success(future_to_promise(ctx->future), &ctx->get.result);
+				if(ctx->method!=CACHE_REQUEST_HEAD || fetch_header_over_biz(ctx)) //HEAD���ֵ��ֶβ�ȫ�Ȳ�ɾ������������ޣ�
+				{
+					ctx->get.result.type = RESULT_TYPE_END;
+					promise_success(future_to_promise(ctx->future), &ctx->get.result);
+				}
 			}
 			tango_cache_ctx_destroy(ctx);
 			break;
 			
 		case GET_STATE_DELETE:
-			if(cache_delete_minio_object(ctx))
-			{
-				ctx->get.state = GET_STATE_END;
-			}
-			else
-			{
-				tango_cache_ctx_destroy(ctx);
-			}
+			ctx->get.state = GET_STATE_END;
+			cache_delete_minio_object(ctx);
 			break;
 			
 		case GET_STATE_END:
@@ -877,6 +876,10 @@ int tango_cache_fetch_start(struct tango_cache_ctx *ctx)
 
 	snprintf(minio_url, 256, "http://%s/%s/%s", ctx->hostaddr, ctx->instance->bucketname, ctx->object_key);
 	curl_easy_setopt(ctx->curl, CURLOPT_URL, minio_url);
+	if(ctx->method == CACHE_REQUEST_HEAD)
+	{
+		curl_easy_setopt(ctx->curl, CURLOPT_NOBODY, 1L);
+	}
 	curl_easy_setopt(ctx->curl, CURLOPT_USERAGENT, "aws-sdk-cpp/1.5.24 Linux/3.10.0-327.el7.x86_64 x86_64 pangu_cache");
 	curl_easy_setopt(ctx->curl, CURLOPT_NOSIGNAL,1L);
 	curl_easy_setopt(ctx->curl, CURLOPT_WRITEFUNCTION, curl_get_response_body_cb);
diff --git a/cache/src/tango_cache_transfer.h b/cache/src/tango_cache_transfer.h
index f976fd1..9c85eb5 100644
--- a/cache/src/tango_cache_transfer.h
+++ b/cache/src/tango_cache_transfer.h
@@ -6,6 +6,9 @@
 
 #include "tango_cache_client_in.h"
 
+bool check_expires_fresh_header(struct tango_cache_ctx *ctx);
+bool fetch_header_over_biz(struct tango_cache_ctx *ctx);
+
 void tango_cache_curl_put_done(struct tango_cache_ctx *ctx, CURLcode res, long res_code);
 void tango_cache_curl_get_done(struct tango_cache_ctx *ctx, CURLcode res, long res_code);
 void tango_cache_curl_del_done(struct tango_cache_ctx *ctx, CURLcode res, long res_code);
diff --git a/cache/test/cache_evbase_test.cpp b/cache/test/cache_evbase_test.cpp
index 9670cbc..9077f19 100644
--- a/cache/test/cache_evbase_test.cpp
+++ b/cache/test/cache_evbase_test.cpp
@@ -68,6 +68,43 @@ void get_future_failed(enum e_future_error err, const char * what, void * user)
 	runing_over = 2;
 }
 
+void head_future_success(future_result_t* result, void * user)
+{
+	struct tango_cache_result *res = cache_evbase_read_result(result);
+	struct future_pdata *pdata = (struct future_pdata *)user;
+	char buffer[1024];
+
+	switch(res->type)
+	{
+		case RESULT_TYPE_USERTAG:
+		case RESULT_TYPE_HEADER:
+			memcpy(buffer, res->data_frag, res->size>=1024?1023:res->size);
+			buffer[res->size] = '\0';
+			printf("%s", buffer);
+			break;
+		case RESULT_TYPE_BODY:
+			assert(0);
+			break;
+		case RESULT_TYPE_MISS:
+			printf("cache not hit/fresh\n");
+		case RESULT_TYPE_END:
+			if(res->type != RESULT_TYPE_MISS)
+				printf("HEAD cache over, total length: %ld\n", res->tlength);
+			future_destroy(pdata->future);
+			free(pdata);
+			runing_over = 1;
+			break;
+		default:break;
+	}
+}
+
+void head_future_failed(enum e_future_error err, const char * what, void * user)
+{
+	printf("HEAD fail: %s\n", what);
+	runing_over = 2;
+}
+
+
 void put_future_success(future_result_t* result, void * user)
 {
 	struct future_pdata *pdata = (struct future_pdata *)user;
@@ -201,15 +238,18 @@ int main(int argc, char **argv)
 		{
 			sprintf(filename_out, "file_index_%u.bin", index);
 			pdata->future = future_create(get_future_success, get_future_failed, pdata);
-			promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 			pdata->fp = fopen(filename_out, "w");
 			
 			cache_evbase_fetch_object(instance_asyn, pdata->future, &getmeta);
 		}
+		else if(!strcasecmp(p, "HEAD"))
+		{
+			pdata->future = future_create(head_future_success, head_future_failed, pdata);			
+			cache_evbase_head_object(instance_asyn, pdata->future, &getmeta);
+		}
 		else if(!strcasecmp(p, "DEL"))
 		{
 			pdata->future = future_create(del_future_success, del_future_failed, pdata);
-			promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 			sprintf(pdata->filename, "%s", filename_in);
 			cache_evbase_delete_object(instance_asyn, pdata->future, filename_in);
 		}
@@ -218,7 +258,6 @@ int main(int argc, char **argv)
 			size_t filelen;
 			p = get_file_content(filename_in, &filelen);
 			pdata->future = future_create(put_future_success, put_future_failed, pdata);
-			promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 			
 			cache_evbase_upload_once_data(instance_asyn, pdata->future, PUT_MEM_FREE, p, filelen, &putmeta, pdata->filename, 256);
 		}
@@ -226,7 +265,6 @@ int main(int argc, char **argv)
 		{
 			size_t readlen;
 			pdata->future = future_create(put_future_success, put_future_failed, pdata);
-			promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 			struct evbuffer *evbuf = evbuffer_new();
 			char buffer[1024];
 			
@@ -246,7 +284,6 @@ int main(int argc, char **argv)
 		else
 		{
 			pdata->future = future_create(put_future_success, put_future_failed, pdata);
-			promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 
 			ctx = cache_evbase_update_start(instance_asyn, pdata->future, &putmeta);
 			cache_evbase_get_object_path(ctx, pdata->filename, 256);
@@ -265,7 +302,7 @@ int main(int argc, char **argv)
 	}
 
 	printf("Waiting to finish.......\n");
-	static int num=0;
+	//static int num=0;
 	while(!runing_over)
 	{
 		/*if(++num==10)
diff --git a/cache/test/tango_cache_test.c b/cache/test/tango_cache_test.c
index 36a2bc3..c24ac41 100644
--- a/cache/test/tango_cache_test.c
+++ b/cache/test/tango_cache_test.c
@@ -79,6 +79,40 @@ void get_future_failed(enum e_future_error err, const char * what, void * user)
 	printf("GET fail: %s\n", what);
 }
 
+void head_future_success(future_result_t* result, void * user)
+{
+	struct tango_cache_result *res = tango_cache_read_result(result);
+	struct future_pdata *pdata = (struct future_pdata *)user;
+	char buffer[1024];
+
+	switch(res->type)
+	{
+		case RESULT_TYPE_USERTAG:
+		case RESULT_TYPE_HEADER:
+			memcpy(buffer, res->data_frag, res->size>=1024?1023:res->size);
+			buffer[res->size] = '\0';
+			printf("%s", buffer);
+			break;
+		case RESULT_TYPE_BODY:
+			assert(0);
+			break;
+		case RESULT_TYPE_MISS:
+			printf("cache not hit/fresh\n");
+		case RESULT_TYPE_END:
+			if(res->type != RESULT_TYPE_MISS)
+				printf("HEAD cache over, total length: %ld\n", res->tlength);
+			future_destroy(pdata->future);
+			free(pdata);
+			break;
+		default:break;
+	}
+}
+
+void head_future_failed(enum e_future_error err, const char * what, void * user)
+{
+	printf("HEAD fail: %s\n", what);
+}
+
 void put_future_success(future_result_t* result, void * user)
 {
 	struct future_pdata *pdata = (struct future_pdata *)user;
@@ -182,6 +216,7 @@ static void dummy_accept_callback(evutil_socket_t fd, short events, void *arg)
 			p = method;
 
 			memset(&putmeta, 0, sizeof(struct tango_cache_meta_put));
+			memset(&getmeta, 0, sizeof(struct tango_cache_meta_get));
 			putmeta.url = s;
 			putmeta.std_hdr[HDR_CONTENT_TYPE] = "Content-Type: maintype/subtype";
 			putmeta.std_hdr[HDR_CONTENT_ENCODING] = "Content-Encoding: gzip";
@@ -197,16 +232,22 @@ static void dummy_accept_callback(evutil_socket_t fd, short events, void *arg)
 				sprintf(filename, "file_index_%u.bin", index++);
 				pdata->fp = fopen(filename, "w");
 				pdata->future = future_create(get_future_success, get_future_failed, pdata);
-				promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 
 				tango_cache_fetch_object(tango_instance, pdata->future, &getmeta);
 			}
+			else if(!strcasecmp(p, "HEAD"))
+			{				
+				sprintf(filename, "file_index_%u.bin", index++);
+				pdata->fp = fopen(filename, "w");
+				pdata->future = future_create(head_future_success, head_future_failed, pdata);
+
+				tango_cache_head_object(tango_instance, pdata->future, &getmeta);
+			}
 			else if(!strcasecmp(p, "PUTONCE"))
 			{
 				size_t filelen;
 				p = get_file_content(s, &filelen);
 				pdata->future = future_create(put_future_success, put_future_failed, pdata);
-				promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 				
 				tango_cache_upload_once_data(tango_instance, pdata->future, PUT_MEM_FREE, p, filelen, &putmeta, pdata->filename, 256);
 			}
@@ -214,7 +255,6 @@ static void dummy_accept_callback(evutil_socket_t fd, short events, void *arg)
 			{
 				size_t readlen;
 				pdata->future = future_create(put_future_success, put_future_failed, pdata);
-				promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 				struct evbuffer *evbuf = evbuffer_new();
 				char buffer[1024];
 				
@@ -234,14 +274,12 @@ static void dummy_accept_callback(evutil_socket_t fd, short events, void *arg)
 			else if(!strcasecmp(p, "DEL"))
 			{
 				pdata->future = future_create(del_future_success, del_future_failed, pdata);
-				promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 				sprintf(pdata->filename, "%s", s);
 				tango_cache_delete_object(tango_instance, pdata->future, s);
 			}
 			else if(!strcasecmp(p, "DELMUL")) //TODO
 			{
 				pdata->future = future_create(del_future_success, del_future_failed, pdata);
-				promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 				sprintf(pdata->filename, "%s", s);
 
 				for(pstart = strtok_r(s, ";", &save_ptr); pstart != NULL; pstart = strtok_r(NULL, ";", &save_ptr))
@@ -253,7 +291,6 @@ static void dummy_accept_callback(evutil_socket_t fd, short events, void *arg)
 			else
 			{
 				pdata->future = future_create(put_future_success, put_future_failed, pdata);
-				promise_set_ctx(future_to_promise(pdata->future), NULL, NULL);
 			
 				ctx = tango_cache_update_start(tango_instance, pdata->future, &putmeta);
 				tango_cache_get_object_path(ctx, pdata->filename, 256);