tango-tfe/plugin/business/pangu-http/src/pangu_web_cache.cpp

#include "pangu_web_cache.h"
#include <tango_cache_pending.h>
#include <tango_cache_client.h>

#include <tfe_proxy.h>
#include <tfe_http.h>
#include <tfe_utils.h>

#include <MESA/MESA_prof_load.h>
#include <MESA/field_stat2.h>

#include <event2/event.h>
#include <event2/buffer.h>

extern "C" 
{
#include <dablooms.h>
}

#include <cjson/cJSON.h>

#include <pthread.h>

enum cache_stat_field
{
	STAT_CACHE_QUERY,
	STAT_CACHE_QUERY_FORBIDDEN,
	STAT_CACHE_QUERY_VERIFY,
	STAT_CACHE_QUERY_HIT,
	STAT_CACHE_QUERY_BYTES,
	STAT_CACHE_OVERRIDE_QUERY,
	STAT_CACHE_OVERRIDE_HIT,	
	STAT_CACHE_OVERRIDE_BYTES,
	STAT_CACHE_QUERY_ERR,
	STAT_CACHE_QUERY_ABANDON,
	STAT_CACHE_QUERYING,
	STAT_CACHE_PENDING,
	STAT_CACHE_UPLOAD_CNT,
	STAT_CACHE_UPLOAD_BYPASS,
	STAT_CACHE_UPLOAD_OVERRIDE,
	STAT_CACHE_UPLOAD_FORBIDEN,
	STAT_CACHE_UPLOAD_ABANDON,
	STAT_CACHE_UPLOAD_ERR,
	STAT_CACHE_UPLOAD_BYTES,
	STAT_CACHE_UPLOADING,
	STAT_CACHE_MEMORY,
	STAT_CACHE_ACTIVE_SESSION,

	STAT_CACHE_QUERY_HIT_OJB_SIZE,
	STAT_CACHE_UPLOAD_OBJ_SIZE,
	STAT_CACHE_OVERRIDE_HIT_OBJ_SIZE,
	STAT_CACHE_OVERRIDE_UPLOAD_OBJ_SIZE,
	__CACHE_STAT_MAX
};
	
struct cache_key_descr
{
	int is_not_empty;
	size_t qs_num;
	char** ignore_qs;
	char* include_cookie;
};
struct cache_param
{
	int ref_cnt;
	struct cache_key_descr key_descr;
	
	char no_revalidate;
	char cache_dyn_url;
	char cache_cookied_cont;
	char ignore_req_nocache;
	char ignore_res_nocache;
	char force_caching;
	
	int min_use;
	time_t pinning_time_sec;
	time_t inactive_time_sec;
	long max_cache_size;
	long max_cache_obj_size;
	pthread_mutex_t lock;
};
struct cache_bloom
{
	int thread_id;
	size_t size;
	double error_rate;
	char filename[TFE_PATH_MAX];
	counting_bloom_t *bloom;
};
struct cache_handle
{
	unsigned int thread_count;
	int cache_undefined_obj_enabled;
	int query_undefined_obj_enabled;
	size_t cache_undefined_obj_min_size;
	int minimum_cache_seconds;
	struct tango_cache_instance **clients;

	long long get_concurrency_max;
	long long put_concurrency_max;

	screen_stat_handle_t fs_handle;
	long long stat_val[__CACHE_STAT_MAX];
	int fs_id[__CACHE_STAT_MAX];
	struct event_base* gc_evbase;
	struct event* gcev;	

	
	int cache_policy_enabled;	//otherwise use default cache policy
	struct cache_param default_cache_policy;
	Maat_feather_t ref_feather;
	int cache_param_idx;
	int table_url_constraint;
	int table_cookie_constraint;

	int cache_key_bloom_life;
	size_t cache_key_bloom_size;
	struct cache_bloom *cache_key_bloom;
	void* logger;
};
struct cache_update_context
{
	struct cache_handle* ref_cache_handle;
	struct tango_cache_ctx * write_ctx;
};
static void web_cache_stat_cb(evutil_socket_t fd, short what, void * arg)
{
	struct cache_handle* cache=(struct cache_handle *)arg;
	struct cache_statistics client_stat_sum, client_stat;
	memset(&client_stat_sum, 0, sizeof(client_stat_sum));
	long long *val_sum = (long long *)&client_stat_sum;
	long long *val = NULL;
	int i=0, j=0;
	for(i=0; i<cache->thread_count;i++)
	{
		tango_cache_get_statistics(cache->clients[i], &client_stat);
		val=(long long*)&client_stat;
		for(j=0; j<sizeof(client_stat)/sizeof(long long); j++)
		{
			val_sum[j]+=val[j];
		}
	}
	for(i=0;i<__CACHE_STAT_MAX;i++)
	{
		if(ATOMIC_READ(&(cache->stat_val[i]))!=0)
		{
			switch(i)
			{
				case STAT_CACHE_UPLOAD_BYTES:
				case STAT_CACHE_QUERY_BYTES:
				case STAT_CACHE_OVERRIDE_BYTES:
					//translate bytes to mega bytes.
					FS_operate(cache->fs_handle, cache->fs_id[i], 0, FS_OP_SET, ATOMIC_READ(&(cache->stat_val[i]))/(1024*1024));
					break;
				default:					
					FS_operate(cache->fs_handle, cache->fs_id[i], 0, FS_OP_SET, ATOMIC_READ(&(cache->stat_val[i])));
					break;
			}
		}
	}

	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_QUERY], 0, FS_OP_SET, client_stat_sum.get_recv_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_QUERY_HIT], 0, FS_OP_SET, client_stat_sum.get_succ_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_QUERY_ERR], 0, FS_OP_SET, client_stat_sum.get_error_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_UPLOAD_CNT], 0, FS_OP_SET, client_stat_sum.put_recv_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_UPLOAD_ERR], 0, FS_OP_SET, client_stat_sum.put_error_num);	
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_MEMORY], 0, FS_OP_SET, client_stat_sum.memory_used/(1024*1024));
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_ACTIVE_SESSION], 0, FS_OP_SET, client_stat_sum.session_num);
	FS_operate(cache->fs_handle, cache->fs_id[STAT_CACHE_UPLOAD_ABANDON], 0, FS_OP_SET, client_stat_sum.totaldrop_num);
	FS_passive_output(cache->fs_handle);
	return;
}
struct cache_stat_sepc
{
	const char* name;
	enum field_dsp_style_t style;
	enum field_calc_algo calc_type;
};

static void set_stat_spec(struct cache_stat_sepc* spec, const char* name, enum field_dsp_style_t style, enum field_calc_algo calc_type)
{
	spec->name=name;
	spec->style=style;
	spec->calc_type=calc_type;
	return;
}
void cache_stat_init(struct cache_handle* cache)
{
	const char* fieldstat_output="./cache.fieldstat";
	const char* app_name="tango_cache";
	const char* obj_size_bins_KB="10,100,1000,10000";
	
	int value=0, i=0;
	screen_stat_handle_t fs_handle=NULL;
	fs_handle=FS_create_handle();
	FS_set_para(fs_handle, OUTPUT_DEVICE, fieldstat_output, strlen(fieldstat_output)+1);
	value=1;
	FS_set_para(fs_handle, PRINT_MODE, &value, sizeof(value));
	value=0;
	FS_set_para(fs_handle, CREATE_THREAD, &value, sizeof(value));
	FS_set_para(fs_handle, APP_NAME, app_name, strlen(app_name)+1);
	FS_set_para(fs_handle, HISTOGRAM_GLOBAL_BINS, obj_size_bins_KB, strlen(obj_size_bins_KB)+1);

	cache->fs_handle=fs_handle;

	struct cache_stat_sepc spec[__CACHE_STAT_MAX];
	
	set_stat_spec(&spec[STAT_CACHE_QUERY], "cache_get",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_FORBIDDEN], "get_forbid",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_VERIFY], "get_verify",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_HIT], "hit_num",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_BYTES], "downloaded(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_QUERY], "or_qry",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_HIT], "or_hit",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_BYTES], "or_download(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_ERR], "get_err",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_ABANDON], "get_abandon",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERYING], "getting",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_PENDING], "pending",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_CNT], "cache_put",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_BYPASS], "cache_bypass",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_OVERRIDE], "or_put",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_FORBIDEN], "put_forbid",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_ABANDON], "put_abandon",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_ERR], "put_err",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_BYTES], "put(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOADING], "putting",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_MEMORY], "used_mem(MB)",FS_STYLE_STATUS, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_ACTIVE_SESSION], "active_sess",FS_STYLE_STATUS, FS_CALC_CURRENT);

	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_HIT_OBJ_SIZE], "or_hit_obj(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_QUERY_HIT_OJB_SIZE], "hitted_obj(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_UPLOAD_OBJ_SIZE], "cached_obj(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);
	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_UPLOAD_OBJ_SIZE], "or_cached(KB)",FS_STYLE_HISTOGRAM, FS_CALC_CURRENT);

	
	for(i=0;i<__CACHE_STAT_MAX;i++)
	{
		cache->fs_id[i]=FS_register(cache->fs_handle, spec[i].style, spec[i].calc_type, spec[i].name);
	}
//	value=cache->fs_id[STAT_CACHE_QUERY_HIT];
//	FS_set_para(cache->fs_handle, ID_INVISBLE, &value, sizeof(value));

	FS_register_ratio(cache->fs_handle,
					cache->fs_id[STAT_CACHE_QUERY_HIT], 
					cache->fs_id[STAT_CACHE_QUERY], 	
					1,
					FS_STYLE_STATUS,
					FS_CALC_CURRENT,
					"cache_hit");

	value=cache->fs_id[STAT_CACHE_OVERRIDE_HIT];
	FS_set_para(cache->fs_handle, ID_INVISBLE, &value, sizeof(value));

	FS_register_ratio(cache->fs_handle,
					cache->fs_id[STAT_CACHE_OVERRIDE_HIT], 
					cache->fs_id[STAT_CACHE_OVERRIDE_QUERY], 
					1,
					FS_STYLE_STATUS,
					FS_CALC_CURRENT,
					"override_hit");

	
	FS_start(cache->fs_handle);
	
	struct timeval gc_delay = {0, 500*1000};	//Microseconds, we set 500 miliseconds here.
	cache->gcev = event_new(cache->gc_evbase, -1, EV_PERSIST, web_cache_stat_cb, cache);	
    evtimer_add(cache->gcev, &gc_delay);	
	return;
}


time_t time_unit_sec(const char* str)
{
	time_t value=0;
	sscanf(str, "%ld", &value);
	switch(str[strlen(str)-1])
	{
		case 's':
			break;
		case 'm':
			value*=60;
			break;
		case 'h':
			value*=3600;
			break;
		case 'd':
			value*=((size_t)24*3600);
			break;
		default:
			break;
	}
	return value;
}
size_t storage_unit_byte(const char* str)
{
	size_t value=0;
	sscanf(str, "%ld", &value);
	switch(str[strlen(str)-1])
	{
		case 'b':
			break;
		case 'k':
			value*=1024;
			break;
		case 'm':
			value*=((size_t)1024*1024);
			break;
		case 'g':
			value*=((size_t)1024*1024*1024);
			break;
		case 't':
			if(value<1024)
			{
#pragma GCC diagnostic ignored "-Woverflow"
				value*=((size_t)1024*1024*1024*1024);

			}
			else	//maximum 1PB
			{
				value=(size_t)1024*(1024*1024*1024*1024);
			}
			break;
		default:
			break;
	}
	return value;
}


//A URL is considered dynamic if it ends in “.asp(x)” or contains a question mark (?), a semicolon (;), or “cgi”.
char is_dynamic_url(const char* url)
{
	if(strchr(url, '?')
		|| strchr(url, ';')
		|| strstr(url, "cgi")
		|| 0==strcmp(url+strlen(url)-3,"asp")
		|| 0==strcmp(url+strlen(url)-4, "aspx"))
	{
		return 1;
	}
	return 0;
}
char * cookie_scanvalue(const char * key, const char * qs, char * val, size_t val_len)
{
    int i=0, key_len=0;

	key_len = strlen(key);
    while(qs[0] != '\0')
    {
        if ( strncmp(key, qs, key_len) == 0 )
            break;
        qs += strcspn(qs, ";") + 1;
    }

    if ( qs[0] == '\0' ) return NULL;

    qs += strcspn(qs, "=;");
    if ( qs[0] == '=' )
    {
        qs++;
        i = strcspn(qs, "=;");
        strncpy(val, qs, (val_len-1)<(i+1) ? (val_len-1) : (i+1));
    }
    else
    {
        if ( val_len > 0 )
            val[0] = '\0';
    }

    return val;
}


char* get_cache_key(const struct tfe_http_half * request, const struct cache_key_descr* desc)
{
	if(desc==NULL|| !desc->is_not_empty)
	{
		return NULL;
	}
	int i=0, shall_ignore=0;
	
	char *token=NULL,*sub_token=NULL,*saveptr;
	char* url=tfe_strdup(request->req_spec.url);
	const char* cookie=NULL;
	char cookie_val[256]={0};	 //most 256 bytes for cookie key
	size_t key_size=strlen(url)+sizeof(cookie_val);
	char* cache_key=ALLOC(char, key_size);
	char* query_string=NULL;
	
	if(desc->qs_num>0)
	{
		query_string=strchr(url, '?');
		if(query_string!=NULL)
		{
			strncat(cache_key, url, MIN(query_string-url,key_size));
			query_string++;
			for (token = query_string; ; token= NULL)
			{
				sub_token= strtok_r(token,"&", &saveptr);
				if (sub_token == NULL)
					break;
				shall_ignore=0;
				for(i=0; i<desc->qs_num; i++)
				{
					if(0==strncasecmp(sub_token, desc->ignore_qs[i], strlen(desc->ignore_qs[i])))
					{
						shall_ignore=1;
						break;
					}
				}
				if(!shall_ignore)
				{
					strncat(cache_key, sub_token, key_size);
				}
			}
		}
		else
		{
			strncat(cache_key, url, key_size);
		}
	}
	else
	{
		strncat(cache_key, url, key_size);
	}
	if(desc->include_cookie && (cookie=tfe_http_std_field_read(request, TFE_HTTP_COOKIE))!=NULL)
	{
		cookie_scanvalue(desc->include_cookie, cookie, cookie_val, sizeof(cookie_val));
		if(strlen(cookie_val)>0)
		{
			strncat(cache_key, cookie_val, key_size);
		}
	}
	FREE(&(url));
	return cache_key;
}

void cache_param_new(int idx, const struct Maat_rule_t* rule, const char* srv_def_large, 
												MAAT_RULE_EX_DATA* ad, long argl, void *argp)
{
	struct cache_handle* cache=(struct cache_handle*) argp;
	int i=0;
	size_t len=0;
	*ad=NULL;
	if(rule->serv_def_len<strlen("{}")+1)
	{
		return;
	}
	cJSON *json=NULL, *key_desc=NULL, *qs=NULL,*item=NULL;
	json=cJSON_Parse(srv_def_large);
	if(json==NULL)
	{
		TFE_LOG_ERROR(cache->logger, "invalid cache parameter: id = %d", rule->config_id);
		return;
	}
	struct cache_param* param=ALLOC(struct cache_param, 1);
	
	*param=cache->default_cache_policy;
	param->ref_cnt=1;
	pthread_mutex_init(&(param->lock), NULL);
	key_desc=cJSON_GetObjectItem(json,"cache_key");
	if(key_desc && key_desc->type==cJSON_Object)
	{
		param->key_descr.is_not_empty=1;
		qs=cJSON_GetObjectItem(key_desc,"ignore_qs");
		if(qs && qs->type==cJSON_Array)
		{		
			param->key_descr.qs_num=cJSON_GetArraySize(qs);
			param->key_descr.ignore_qs=ALLOC(char*, param->key_descr.qs_num);
			for(i=0; i<param->key_descr.qs_num; i++)
			{
				item=cJSON_GetArrayItem(qs, i);
				len=strlen(item->valuestring)+2;
				param->key_descr.ignore_qs[i]=ALLOC(char, len);
				strncat(param->key_descr.ignore_qs[i], item->valuestring, len);
				strncat(param->key_descr.ignore_qs[i], "=", len);
			}
		}		
		item=cJSON_GetObjectItem(key_desc,"cookie");
		if(item && item->type==cJSON_String) param->key_descr.include_cookie=tfe_strdup(param->key_descr.include_cookie);

	}


	
	item=cJSON_GetObjectItem(json,"no_revalidate");
	if(item && item->type==cJSON_Number) param->no_revalidate=item->valueint;
	
	item=cJSON_GetObjectItem(json,"cache_dyn_url");
	if(item && item->type==cJSON_Number) param->cache_dyn_url=item->valueint;
	
	item=cJSON_GetObjectItem(json,"cache_cookied_cont");
	if(item && item->type==cJSON_Number) param->cache_cookied_cont=item->valueint;
	
	item=cJSON_GetObjectItem(json,"ignore_req_nocache");
	if(item && item->type==cJSON_Number) param->ignore_req_nocache=item->valueint;
	
	item=cJSON_GetObjectItem(json,"ignore_res_nocache");	
	if(item && item->type==cJSON_Number) param->ignore_res_nocache=item->valueint;
	
	item=cJSON_GetObjectItem(json,"force_caching");	
	if(item && item->type==cJSON_Number) param->force_caching=item->valueint;

	item=cJSON_GetObjectItem(json,"min_use");	
	if(item && item->type==cJSON_Number) param->min_use=item->valueint;
	
	item=cJSON_GetObjectItem(json,"pinning_time");
	if(item && item->type==cJSON_String) param->pinning_time_sec=time_unit_sec(item->valuestring);
	
	item=cJSON_GetObjectItem(json,"inactive_time");
	if(item && item->type==cJSON_String) param->inactive_time_sec=time_unit_sec(item->valuestring);

	item=cJSON_GetObjectItem(json,"max_cache_size");
	if(item && item->type==cJSON_String) param->max_cache_size=storage_unit_byte(item->valuestring);

	item=cJSON_GetObjectItem(json,"max_cache_obj_size");
	if(item && item->type==cJSON_String) param->max_cache_obj_size=storage_unit_byte(item->valuestring);
		
	cJSON_Delete(json);
	*ad=param;
	return;
}
void cache_param_free(int idx, const struct Maat_rule_t* rule, const char* srv_def_large, MAAT_RULE_EX_DATA* ad, long argl, void *argp)
{
	int i=0;
	if(*ad==NULL)
	{
		return;
	}
	struct cache_param* param=(struct cache_param*)*ad;
	pthread_mutex_lock(&(param->lock));
	param->ref_cnt--;
	if(param->ref_cnt>0)
	{	
		pthread_mutex_unlock(&(param->lock));
		return;
	}
	pthread_mutex_unlock(&(param->lock));
	pthread_mutex_destroy(&(param->lock));
	for(i=0; i<param->key_descr.qs_num; i++)
	{
		FREE(&(param->key_descr.ignore_qs[i]));
	}
	FREE(&(param->key_descr.ignore_qs));
	FREE(&(param->key_descr.include_cookie));
	FREE(&(param));
	return;
}
void cache_param_dup(int idx,	MAAT_RULE_EX_DATA *to, MAAT_RULE_EX_DATA *from, long argl, void *argp)
{
	struct cache_param* from_param=*((struct cache_param**)from);
	pthread_mutex_lock(&(from_param->lock));
	from_param->ref_cnt++;
	pthread_mutex_unlock(&(from_param->lock));
	*((struct cache_param**)to)=from_param;
	return;
}

static void cache_key_bloom_gc_cb(evutil_socket_t fd, short what, void * arg)
{
	struct cache_bloom* p_bloom= (struct cache_bloom*) arg;
	counting_bloom_t* new_bloom=NULL;

	new_bloom=new_counting_bloom(p_bloom->size, p_bloom->error_rate, p_bloom->filename);
	free_counting_bloom(p_bloom->bloom);
	p_bloom->bloom=new_bloom;
	return;
}

struct cache_handle* create_web_cache_handle(const char* profile_path, const char* section, 
													struct event_base* gc_evbase, Maat_feather_t feather, void *logger)
{
	struct cache_handle* cache=ALLOC(struct cache_handle, 1);
	int temp=0;	
	struct event* ev=NULL;
	cache->logger=logger;
	cache->thread_count=tfe_proxy_get_work_thread_count();
	cache->clients=ALLOC(struct tango_cache_instance *, cache->thread_count);
	cache->cache_key_bloom=ALLOC(struct cache_bloom, cache->thread_count);
	struct cache_bloom* p_bloom=NULL; 
	MESA_load_profile_int_def(profile_path, section, "cache_policy_enabled", 
								&(cache->cache_policy_enabled), 1);

	
	MESA_load_profile_int_def(profile_path, section, "cache_key_bloom_size", 
								(int*)&(cache->cache_key_bloom_size), 16*1000*1000);
	MESA_load_profile_int_def(profile_path, section, "cache_key_bloom_life", 
								&(cache->cache_key_bloom_life), 30*60);
	char bloom_filename[TFE_PATH_MAX]{0};
	struct timeval gc_refresh_delay = {cache->cache_key_bloom_life, 0};
	int i=0;
	
	struct tango_cache_parameter *cache_client_param=tango_cache_parameter_new(profile_path, section, logger);
	for(i=0; i<cache->thread_count; i++)
	{
		if(cache->cache_policy_enabled)
		{
			p_bloom=cache->cache_key_bloom+i;
			p_bloom->thread_id=i;
			p_bloom->size=cache->cache_key_bloom_size;
			p_bloom->error_rate=0.01;
			snprintf(p_bloom->filename, sizeof(p_bloom->filename), "/tmp/pangu_cache_blooms.%d", i);
			p_bloom->bloom=new_counting_bloom(p_bloom->size, p_bloom->error_rate, p_bloom->filename);
			if(p_bloom->bloom==NULL)
			{
				goto error_out;
			}
			ev = event_new(tfe_proxy_get_work_thread_evbase(i), -1, EV_PERSIST, cache_key_bloom_gc_cb, p_bloom);	
			evtimer_add(ev, &gc_refresh_delay);
		}
	
		cache->clients[i]=tango_cache_instance_new(cache_client_param,tfe_proxy_get_work_thread_evbase(i), logger);
		if(cache->clients[i]==NULL)
		{
			goto error_out;
		}
	}
	
	MESA_load_profile_int_def(profile_path, section, "get_concurrency_max", &temp, 1000*1000);
	cache->get_concurrency_max=temp;
	MESA_load_profile_int_def(profile_path, section, "put_concurrency_max", &(temp), 1000*1000);
	cache->put_concurrency_max=temp;
	MESA_load_profile_int_def(profile_path, section, "query_undefined_obj", &(cache->query_undefined_obj_enabled), 1);
	MESA_load_profile_int_def(profile_path, section, "cache_undefined_obj", &(cache->cache_undefined_obj_enabled), 1);
	MESA_load_profile_int_def(profile_path, section, "cached_undefined_obj_minimum_size", &(temp), 100*1024);
	cache->cache_undefined_obj_min_size=temp;

	cache->gc_evbase=gc_evbase;	

	cache->default_cache_policy.key_descr.qs_num=0;
	cache->default_cache_policy.no_revalidate=0;
	cache->default_cache_policy.cache_dyn_url=0;
	cache->default_cache_policy.cache_cookied_cont=0;
	cache->default_cache_policy.ignore_req_nocache=0;
	cache->default_cache_policy.ignore_res_nocache=0;
	cache->default_cache_policy.force_caching=0;
	cache->default_cache_policy.min_use=0;
	cache->default_cache_policy.pinning_time_sec=0;
	cache->default_cache_policy.inactive_time_sec=0;
	cache->default_cache_policy.max_cache_size=0;
	cache->default_cache_policy.max_cache_obj_size=1024*1024*1024;//<1GB by default

	if(cache->cache_policy_enabled)
	{
		cache->table_url_constraint=Maat_table_register(feather, "PXY_CACHE_HTTP_URL");
		cache->table_cookie_constraint=Maat_table_register(feather, "PXY_CACHE_HTTP_COOKIE");
		
		cache->cache_param_idx=Maat_rule_get_ex_new_index(feather, "PXY_CACHE_COMPILE", 
														cache_param_new, cache_param_free, cache_param_dup,
														0, cache);
		cache->ref_feather=feather;
	}
	cache_stat_init(cache);
	return cache;
error_out:
	free(cache);
	return NULL;
}

static char* read_http1_hdr(const char* hdr, const char* field_name)
{	
	const char *p=NULL, *q=NULL;
	char* value=NULL;
	p=strcasestr(hdr, field_name);
	if(p==NULL)
	{
		return NULL;
	}
	p=strstr(p, ":");
	if(p==NULL)
	{
		return NULL;
	}
	p++;
	q=strcasestr(p, "\r\n");
	if(q==NULL)
	{
		return NULL;
	}
	value=(char*) calloc(sizeof(char), (q-p+1));
	memcpy(value, p, q-p);
	return value;
}
struct cache_query_context
{
	struct cache_handle* ref_handle;
	char* url;

	struct cached_meta meta;
	
	struct tango_cache_result* ref_tango_cache_result;
	struct future* f_tango_cache_fetch;
};

enum cache_query_result_type cache_query_result_get_type(future_result_t * result)
{
	struct cache_query_context* ctx=(struct cache_query_context*)result;
	struct tango_cache_result* cache_result=ctx->ref_tango_cache_result;
	enum cache_query_result_type map[__CACHE_QUERY_RESULT_MAX];
	map[RESULT_TYPE_BODY]=CACHE_QUERY_RESULT_DATA;
	map[RESULT_TYPE_HEADER]=CACHE_QUERY_RESULT_META;
	map[RESULT_TYPE_USERTAG]=CACHE_QUERY_RESULT_IRRELEVANT;
	map[RESULT_TYPE_END]=CACHE_QUERY_RESULT_END;
	map[RESULT_TYPE_MISS]=CACHE_QUERY_RESULT_MISS;
	return map[cache_result->type];
}

size_t cache_query_result_get_data(future_result_t * result, const unsigned char** pp_data)
{
	struct cache_query_context* ctx=(struct cache_query_context*)result;
	struct tango_cache_result* cache_result=ctx->ref_tango_cache_result;
	assert(cache_result->type==RESULT_TYPE_BODY);
	*pp_data=(const unsigned char*)cache_result->data_frag;
	return cache_result->size;
}

void cache_query_ctx_free_cb(void* p)
{
	struct cache_query_context* ctx=(struct cache_query_context*)p;
	future_destroy(ctx->f_tango_cache_fetch);
	ctx->f_tango_cache_fetch=NULL;
	FREE(&(ctx->url));
	FREE(&(ctx->meta.etag));
	FREE(&(ctx->meta.last_modified));
	FREE(&(ctx->meta.content_type));
	free(ctx);
}
const struct cached_meta* cache_query_result_read_meta(future_result_t * result)
{
	struct cache_query_context* ctx=(struct cache_query_context*)result;
	return &(ctx->meta);
}
void cached_meta_set(struct cached_meta* meta, enum CACHE_RESULT_TYPE type, const char* data_frag, size_t size)
{
	switch(type)
	{
		case RESULT_TYPE_HEADER:
			meta->content_type=read_http1_hdr((const char*)data_frag, "content-type");
			break;
		case RESULT_TYPE_USERTAG:
			meta->last_modified=read_http1_hdr(data_frag, "Last-Modified");
			if(meta->last_modified!=NULL && 0==strcasecmp(meta->last_modified, "Thu, 01 Jan 1970 00:00:00 GMT"))
			{
				FREE(&(meta->last_modified));
			}
			meta->etag=read_http1_hdr(data_frag, "etag");
			break;
		default:
			assert(0);
			break;
	}
	return;
}

static void cache_query_obj_on_succ(future_result_t * result, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_query_context* ctx=(struct cache_query_context*)promise_get_ctx(p);
	ctx->ref_tango_cache_result=tango_cache_read_result(result);
	switch(ctx->ref_tango_cache_result->type)
	{
		case RESULT_TYPE_HEADER:
			ATOMIC_INC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERY_HIT]));
			FS_operate(ctx->ref_handle->fs_handle, ctx->ref_handle->fs_id[STAT_CACHE_QUERY_HIT_OJB_SIZE], 0, FS_OP_SET, ctx->ref_tango_cache_result->tlength/1024);
			cached_meta_set(&ctx->meta, RESULT_TYPE_HEADER, ctx->ref_tango_cache_result->data_frag, ctx->ref_tango_cache_result->size);
			ctx->meta.content_length=ctx->ref_tango_cache_result->tlength;
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache query hit: %s", ctx->url);
			break;
		case RESULT_TYPE_USERTAG:		
			cached_meta_set(&ctx->meta, RESULT_TYPE_USERTAG, ctx->ref_tango_cache_result->data_frag, ctx->ref_tango_cache_result->size);
			break;
		case RESULT_TYPE_MISS:
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache query miss: %s", ctx->url);
			//NOT break intentionally.
		case RESULT_TYPE_END:
			//last call.	
			ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERYING]));	
			promise_dettach_ctx(p);
			cache_query_ctx_free_cb(ctx);
			break;
		case RESULT_TYPE_BODY:
			ATOMIC_ADD(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERY_BYTES]), ctx->ref_tango_cache_result->size);
			break;
		default:
			break;
	}
	promise_success(p, ctx);

	return;
}
static void cache_query_obj_on_fail(enum e_future_error err, const char * what, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_query_context* ctx=(struct cache_query_context*)promise_dettach_ctx(p);
	promise_failed(p, err, what);	
	ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERYING]));	
	cache_query_ctx_free_cb(ctx);
	return;
}


struct cache_pending_context
{
	enum cache_pending_result status;
	int is_undefined_obj;
	char* req_if_none_match, *req_if_modified_since;
	const struct tfe_http_half * request;

	char* url;
	struct cached_meta cached_obj_meta;
	
	struct cache_handle* ref_handle;
	struct tango_cache_result* ref_tango_cache_result;
	struct future* f_tango_cache_fetch;
};
void cache_pending_ctx_free_cb(void* p)
{
	struct cache_pending_context* ctx=(struct cache_pending_context*)p;
	ctx->request=NULL;
	FREE(&(ctx->url));
	FREE(&(ctx->req_if_modified_since));
	FREE(&(ctx->req_if_none_match));
	if(ctx->f_tango_cache_fetch)
	{
		future_destroy(ctx->f_tango_cache_fetch);
	}
	FREE(&(ctx->cached_obj_meta.etag));
	FREE(&(ctx->cached_obj_meta.last_modified));
	FREE(&(ctx->cached_obj_meta.content_type));
	free(ctx);
	return;
}
const struct cached_meta* cache_pending_result_read_meta(future_result_t * result)
{
	struct cache_pending_context* ctx=(struct cache_pending_context*)result;
	if(ctx->status==PENDING_RESULT_MISS)
	{
		return NULL;
	}
	else
	{
		return &(ctx->cached_obj_meta);
	}
}

static void cache_query_meta_on_succ(future_result_t * result, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_pending_context* ctx=(struct cache_pending_context*)promise_get_ctx(p);
	struct tango_cache_result* _result=tango_cache_read_result(result);
	ctx->ref_tango_cache_result=_result;

	switch(_result->type)
	{
		case RESULT_TYPE_HEADER:
			ctx->cached_obj_meta.content_length=_result->tlength;
			cached_meta_set(&ctx->cached_obj_meta, RESULT_TYPE_HEADER, _result->data_frag, _result->size);
			ctx->status=PENDING_RESULT_REVALIDATE;
			break;
		case RESULT_TYPE_USERTAG:
			cached_meta_set(&ctx->cached_obj_meta, RESULT_TYPE_USERTAG, _result->data_frag, _result->size);
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache meta query hit: %s %s %s"
							, ctx->url
							, ctx->cached_obj_meta.last_modified ? ctx->cached_obj_meta.last_modified:"no_last_modify"
							, ctx->cached_obj_meta.etag ? ctx->cached_obj_meta.etag:"no_etag");
			break;
		case RESULT_TYPE_MISS:
			ctx->status=PENDING_RESULT_MISS;
			TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache meta query miss: %s", ctx->url);
			//NOT break intentionally.
		case RESULT_TYPE_END:
			//last call.	
			ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_PENDING]));	
			promise_dettach_ctx(p);		
			promise_success(p, ctx);
			cache_pending_ctx_free_cb(ctx);
			break;
		default:
			break;
	}

}
static void cache_query_meta_on_fail(enum e_future_error err, const char * what, void * user)
{
	struct promise * p = (struct promise *) user;
	struct cache_pending_context* ctx=(struct cache_pending_context*)promise_dettach_ctx(p);
	promise_failed(p, err, what);	
	ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_PENDING]));	
	cache_pending_ctx_free_cb(ctx);
	return;
}
struct cache_mid
{
	enum cache_pending_result result;
	struct request_freshness req_fresshness;
	char shall_bypass;
	char is_using_exception_param;
	char is_dyn_url;
	char has_cookie;
	char use_cnt;
	int cfg_id;
	char* cache_key;
	struct cache_param* param;
};
void cache_mid_clear(struct cache_mid **mid)
{
	if(*mid==NULL)
	{
		return;
	}
	if((*mid)->is_using_exception_param)
	{
		cache_param_free(0, NULL, NULL, (void**)&((*mid)->param), 0, NULL);
	}
	FREE(&((*mid)->cache_key));
	FREE(mid);
	return;
}

#define	CACHE_ACTION_BYPASS	0x80
enum cache_pending_result web_cache_async_pending(struct cache_handle* handle, unsigned int thread_id,
							const struct tfe_http_half * request, struct cache_mid** mid, struct future* f_revalidate)
{	
	enum cache_pending_result result=PENDING_RESULT_FOBIDDEN;
	int is_undefined_obj=0;
	struct Maat_rule_t cache_policy;
	struct cache_param* param=&(handle->default_cache_policy);
	MAAT_RULE_EX_DATA ex_data=NULL;
	scan_status_t scan_mid=NULL;
	int ret=0;
	const char* cookie=NULL;
	struct cache_mid* _mid=ALLOC(struct cache_mid, 1);
	*mid=_mid;
	cookie=tfe_http_std_field_read(request, TFE_HTTP_COOKIE);
	if(cookie)
	{
		_mid->has_cookie=1;
	}	
	_mid->is_dyn_url=is_dynamic_url(request->req_spec.url);
	if(handle->cache_policy_enabled)
	{
		ret=Maat_full_scan_string(handle->ref_feather, handle->table_url_constraint, CHARSET_UTF8,
								request->req_spec.url, strlen(request->req_spec.url),
								&cache_policy, NULL, 1, &scan_mid, thread_id);
		

		if(cookie && ret<=0)
		{
			ret=Maat_full_scan_string(handle->ref_feather, handle->table_cookie_constraint, CHARSET_UTF8,
									cookie, strlen(cookie),
									&cache_policy, NULL, 1, &scan_mid, thread_id);
		}
		Maat_clean_status(&scan_mid);

		if(ret>0)
		{
			ex_data=Maat_rule_get_ex_data(handle->ref_feather, &cache_policy, handle->cache_param_idx);
			if(ex_data!=NULL)
			{
				param=(struct cache_param*)ex_data;
				_mid->is_using_exception_param=1;
				_mid->param=param;
			}
			if(cache_policy.action==CACHE_ACTION_BYPASS)
			{
				_mid->shall_bypass=1;
			}
			_mid->cfg_id=cache_policy.config_id;
		}
		if(_mid->shall_bypass ||
			(!param->cache_dyn_url && _mid->is_dyn_url && param->key_descr.qs_num==0) ||
			(param->cache_cookied_cont && _mid->has_cookie) )
		{
			_mid->result=PENDING_RESULT_FOBIDDEN;
			return _mid->result;
		}
	}
	enum cache_pending_action get_action=tfe_cache_get_pending(request, &(_mid->req_fresshness));
	switch(get_action)
	{
		case UNDEFINED:
			if(!handle->query_undefined_obj_enabled)
			{
				ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_FORBIDDEN]));
				result=PENDING_RESULT_FOBIDDEN;
			}
			else
			{
				is_undefined_obj=1;
				ATOMIC_INC(&(handle->stat_val[STAT_CACHE_OVERRIDE_QUERY]));
				result=PENDING_RESULT_ALLOWED;
			}
			break;
		case FORBIDDEN:
			if(param->ignore_req_nocache || param->force_caching)
			{
				result=PENDING_RESULT_ALLOWED;
			}
			else
			{
				ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_FORBIDDEN]));
				result=PENDING_RESULT_FOBIDDEN;
			}
			break;
		case ALLOWED:
			result=PENDING_RESULT_ALLOWED;
			break;
		default:
			if(param->no_revalidate)
			{
				result=PENDING_RESULT_ALLOWED;
			}
			else
			{
				result=PENDING_RESULT_REVALIDATE;				
			}
			break;
	}
	if(result!=PENDING_RESULT_REVALIDATE)
	{
		_mid->result=result;
		return _mid->result;
	}
	
	struct tango_cache_meta_get meta;
	memset(&meta, 0, sizeof(meta));
	if(param->key_descr.is_not_empty)
	{
		_mid->cache_key=get_cache_key(request, &(param->key_descr));
		meta.url = _mid->cache_key;
	}
	else
	{
		meta.url = request->req_spec.url;
	}
	meta.get = _mid->req_fresshness;
	
	struct promise* p=future_to_promise(f_revalidate);
	struct cache_pending_context* ctx=ALLOC(struct cache_pending_context, 1);
	ctx->status=PENDING_RESULT_FOBIDDEN;	
	ctx->ref_handle=handle;
	ctx->url=tfe_strdup(request->req_spec.url);

	ctx->req_if_modified_since=tfe_strdup(tfe_http_std_field_read(request, TFE_HTTP_IF_MODIFIED_SINCE));
	ctx->req_if_none_match=tfe_strdup(tfe_http_std_field_read(request, TFE_HTTP_IF_NONE_MATCH));
	promise_set_ctx(p, ctx, cache_pending_ctx_free_cb);

	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_PENDING]));		
	ctx->f_tango_cache_fetch=future_create("_cache_pend", cache_query_meta_on_succ, cache_query_meta_on_fail, p);
	ret=tango_cache_head_object(handle->clients[thread_id], ctx->f_tango_cache_fetch, &meta);
	if(ret<0)
	{
		cache_pending_ctx_free_cb(ctx);
		_mid->result=PENDING_RESULT_FOBIDDEN;
		return _mid->result;
	}
	_mid->result=PENDING_RESULT_REVALIDATE;
	
	return _mid->result;
}
int web_cache_async_query(struct cache_handle* handle, unsigned int thread_id,
									const struct tfe_http_half * request, struct cache_mid** mid, struct future* f)
{
	enum cache_pending_action get_action;	
	struct cache_query_context* query_ctx=NULL;
	struct promise* p=NULL;
	struct future* _f=NULL;
	struct cache_mid* _mid=*mid;
	assert(_mid->result!=PENDING_RESULT_FOBIDDEN);
	
	if(ATOMIC_READ(&(handle->stat_val[STAT_CACHE_QUERYING])) > ATOMIC_READ(&(handle->put_concurrency_max)))
	{		
		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_ABANDON]));	
		return -1;
	}

	struct tango_cache_meta_get meta;
	memset(&meta, 0, sizeof(meta));
	meta.url=_mid->cache_key?_mid->cache_key:request->req_spec.url;
	meta.get=_mid->req_fresshness;
	query_ctx=ALLOC(struct cache_query_context, 1);
	query_ctx->ref_handle=handle;
	query_ctx->url=tfe_strdup(request->req_spec.url);

	p=future_to_promise(f);
	promise_set_ctx(p, query_ctx, cache_query_ctx_free_cb);
	
	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERYING]));	
	query_ctx->f_tango_cache_fetch=future_create("_cache_get", cache_query_obj_on_succ, cache_query_obj_on_fail, p);
	int ret=tango_cache_fetch_object(handle->clients[thread_id], query_ctx->f_tango_cache_fetch, &meta);
	if(ret<0)
	{
		cache_query_ctx_free_cb(query_ctx);
		return -1;
	}
	return 0;
}
struct wrap_cache_put_ctx
{
	char* url;
	time_t start;
	struct future* f;
	struct cache_handle* ref_handle;
};
void wrap_cache_put_ctx_free(struct wrap_cache_put_ctx* ctx)
{
	FREE(&(ctx->url));
	future_destroy(ctx->f);
	free(ctx);
}
static void wrap_cache_update_on_succ(future_result_t * result, void * user)
{
	struct wrap_cache_put_ctx* ctx=(struct wrap_cache_put_ctx*)user;
	TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache upload success: %s elapse: %d", ctx->url, time(NULL)-ctx->start);
	wrap_cache_put_ctx_free(ctx);
}
static void wrap_cache_update_on_fail(enum e_future_error err, const char * what, void * user)
{
	struct wrap_cache_put_ctx* ctx=(struct wrap_cache_put_ctx*)user;
	TFE_LOG_DEBUG(ctx->ref_handle->logger, "cache upload failed: %s %s lapse: %d", ctx->url, what, time(NULL)-ctx->start);
	wrap_cache_put_ctx_free(ctx);
}

struct cache_update_context* web_cache_update_start(struct cache_handle* handle, unsigned int thread_id, 
															const struct tfe_http_session * session, struct cache_mid **mid)
{
	struct cache_update_context* update_ctx=NULL;
	struct response_freshness resp_freshness;
	enum cache_pending_action put_action;
	struct tango_cache_ctx *write_ctx=NULL;
	char cont_type_str[TFE_STRING_MAX]={0}, user_tag_str[TFE_STRING_MAX]={0};
	const char* value=NULL;
	char *tmp=NULL;
	int i=0, is_undefined_obj=0;
	size_t content_len=0;
	const struct cache_param* param=NULL;	
	struct cache_mid* _mid=*mid;
	
	if(_mid!=NULL && _mid->is_using_exception_param)
	{
		param=_mid->param;
	}
	else
	{
		param=&(handle->default_cache_policy);
	}
	if(session->resp->resp_spec.content_length)
	{
		sscanf(session->resp->resp_spec.content_length, "%lu", &content_len);
	}
	
	put_action=tfe_cache_put_pending(session->resp, &resp_freshness);
	switch(put_action){
		case FORBIDDEN:
			if(!(param->ignore_res_nocache || param->force_caching))
			{
				ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_FORBIDEN]));
				TFE_LOG_DEBUG(handle->logger, "cache update forbiden: %s", session->req->req_spec.url);
				return NULL;	
			}
			break;
		case REVALIDATE:
		case ALLOWED:	
		case UNDEFINED:
			if(_mid->shall_bypass 
				|| content_len > param->max_cache_obj_size
				|| (!param->cache_cookied_cont && _mid->has_cookie) )
			{
				ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_BYPASS]));
				TFE_LOG_DEBUG(handle->logger, "cache update bypass: %d : %s", _mid->cfg_id, session->req->req_spec.url);
				return NULL;
			}
			break;
		default:
			assert(0);
			break;
	}
	if(ATOMIC_READ(&(handle->stat_val[STAT_CACHE_UPLOADING])) > handle->get_concurrency_max)
	{		
		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_ABANDON]));	
		return NULL;
	}
	const char* key=NULL;
	size_t key_len=0;
	if(param->min_use>0)
	{
		if(_mid->cache_key)
		{
			key=_mid->cache_key;
			key_len=strlen(_mid->cache_key);
		}
		else
		{
			key=session->req->req_spec.url;
			key_len=strlen(session->req->req_spec.url);
		}
		_mid->use_cnt=counting_bloom_check(handle->cache_key_bloom[thread_id].bloom, key, key_len);

		if(_mid->use_cnt<param->min_use)
		{
			counting_bloom_add(handle->cache_key_bloom[thread_id].bloom, key, key_len);
			return NULL;
		}
	}
	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOADING]));
	
	struct tango_cache_meta_put meta;
	memset(&meta, 0, sizeof(meta));
	meta.url=_mid->cache_key?_mid->cache_key:session->req->req_spec.url;
	i=0;

	snprintf(cont_type_str, sizeof(cont_type_str), "content-type:%s",session->resp->resp_spec.content_type);
	meta.std_hdr[i]=cont_type_str;
	i++;
	const char* etag=tfe_http_std_field_read(session->resp, TFE_HTTP_ETAG);
	const char* last_modified=tfe_http_std_field_read(session->resp, TFE_HTTP_LAST_MODIFIED);
	tmp=user_tag_str;
	if(etag) tmp+=snprintf(tmp, sizeof(user_tag_str)-(tmp-user_tag_str), "etag:%s\r\n", etag);
	if(last_modified) tmp+=snprintf(tmp, sizeof(user_tag_str)-(tmp-user_tag_str), "Last-modified:%s\r\n", last_modified);
	if(strlen(user_tag_str)>0)
	{
		meta.usertag=user_tag_str;
		meta.usertag_len=strlen(user_tag_str)+1;
	}
	meta.put=resp_freshness;
	meta.put.timeout=MAX(param->pinning_time_sec, resp_freshness.timeout);

	struct wrap_cache_put_ctx* _cache_put_ctx=ALLOC(struct wrap_cache_put_ctx, 1);
	_cache_put_ctx->url=tfe_strdup(session->req->req_spec.url);
	_cache_put_ctx->start=time(NULL);
	_cache_put_ctx->ref_handle=handle;
	_cache_put_ctx->f=future_create("cache_put", wrap_cache_update_on_succ, wrap_cache_update_on_fail, _cache_put_ctx);
	write_ctx=tango_cache_update_start(handle->clients[thread_id], _cache_put_ctx->f, &meta);
	if(write_ctx==NULL)//exceed maximum cache memory size.
	{
		wrap_cache_put_ctx_free(_cache_put_ctx);
		return NULL;
	}
	TFE_LOG_DEBUG(handle->logger, "cache upload allowed: %s", _cache_put_ctx->url);
	if(is_undefined_obj)
	{
		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_OVERRIDE]));
		FS_operate(handle->fs_handle,handle->fs_id[STAT_CACHE_OVERRIDE_UPLOAD_OBJ_SIZE], 0, FS_OP_SET, content_len/1024);
	}
	FS_operate(handle->fs_handle,handle->fs_id[STAT_CACHE_UPLOAD_OBJ_SIZE], 0, FS_OP_SET, content_len/1024);
	update_ctx=ALLOC(struct cache_update_context, 1);
	update_ctx->write_ctx=write_ctx;
	update_ctx->ref_cache_handle=handle;
	return update_ctx;

}
void web_cache_update(struct cache_update_context* ctx, const unsigned char * body_frag, size_t frag_size)
{
	tango_cache_update_frag_data(ctx->write_ctx, (const char*)body_frag, frag_size);
	ATOMIC_ADD(&(ctx->ref_cache_handle->stat_val[STAT_CACHE_UPLOAD_BYTES]), frag_size);
	return;
}
void web_cache_update_end(struct cache_update_context* ctx)
{

	tango_cache_update_end(ctx->write_ctx);
	ATOMIC_DEC(&(ctx->ref_cache_handle->stat_val[STAT_CACHE_UPLOADING]));

	ctx->write_ctx = NULL;
	ctx->ref_cache_handle = NULL;
	free(ctx);
	return;
}