基於libevent2.0的ministored的http框架--server端

將Ministored從libevent1.4升級到2.0以後，花了兩天額外的時間來做調試這個http的框架。

 

按照開發的設想，這個ministored支持四個基本的操作put、get、delete、status；在經過幾個版本的改動以後，協議如下：

1）數據通過post的方式提交

2）各個基本操作通過一個自定義的Http的頭method來區分。而client和server之間的傳送的二進制數據通過base64編碼以後的字符串發送。數據附加在post操作提交的字符緩衝區中。

     2.1 put操作需要的數據key value,解碼以後，按照key和value的大小直接二進制拷貝，server並不關心數據的具體類型

     2.2 get操作接收client發送的key,解碼，取出對應的數據以後，base64編碼，發送給client

     2.3 delete操作接收client發送的key,解碼，刪除數據

     2.4 status操作直接返回當前Ministore狀態的描述字符串

3）各個操作的結果通過自定義的響應頭"result"返回

 

下面是部分的代碼，限於篇幅，就不完全展開了。

 

#include <event2/event.h> #include <event2/buffer.h> #include <event2/http.h> #include <event2/http_struct.h> #include <event2/keyvalq_struct.h> #include "base64.h" struct ministored_handler_param{ int key_size; int value_size; }; void ministored_handler(struct evhttp_request *req, void *arg){ struct ministored_handler_param *param = (struct ministored_handler_param *) arg; struct evbuffer * buf; buf = evbuffer_new(); const char * ministored_input_opt = evhttp_find_header(req->input_headers,"method"); fprintf(stdout,"method from client,%s/n",ministored_input_opt); evhttp_add_header(req->output_headers,"Content-Type","text/plain"); evhttp_add_header(req->output_headers,"Connection","keep-alive"); evhttp_add_header(req->output_headers,"Cache_Control","no-cache"); if( NULL != ministored_input_opt ){ if( strcmp(ministored_input_opt,"put") == 0 ){ int buffer_data_len; buffer_data_len = evbuffer_get_length(req->input_buffer); if( buffer_data_len > 0 ){ char * buffer_data = (char * ) malloc(buffer_data_len + 1); memset(buffer_data,'/0',buffer_data_len + 1); evbuffer_copyout(req->input_buffer,buffer_data,buffer_data_len); fprintf(stdout,"data:%s/n",buffer_data); fprintf(stdout,"length:%d/n",buffer_data_len); char *decoded_data = (char*) malloc (sizeof(char) * 200); int decoded_len = decode(buffer_data,buffer_data_len,decoded_data); if( NULL != decoded_data){ char * ministored_key = (char*) malloc( sizeof( char) * (param->key_size + 1) ); memset(ministored_key,'/0',param->key_size + 1); memcpy(ministored_key, decoded_data, param->key_size); char *ministored_value = (char*)malloc( sizeof(char) * (param->value_size + 1) ); memset(ministored_value,'/0', param->value_size + 1); memcpy(ministored_value, decoded_data + param->value_size, param->value_size); //todo,put into ministore long key,value; memcpy(&key,ministored_key,8); memcpy(&value,ministored_value,8); printf("key:%ld/tvaleu:%ld/n",key,value); free( ministored_key ); free( ministored_value ); evhttp_add_header(req->output_headers,"result","MINISTORED_OK"); }else{ evhttp_add_header(req->output_headers,"result","MINISTORED_INTENAL_ERROR"); } free(buffer_data); free(decoded_data); }else{ evhttp_add_header(req->output_headers,"result","MINISTORED_NO_DATA"); } } if(strcmp(ministored_input_opt,"get")== 0 ){ ... ...; } if(strcmp(ministored_input_opt,"delete")== 0 ){ ... ...; } if( strcmp(ministored_input_opt,"status" ) == 0){ int size; int used; evbuffer_add_printf(buf,"Ministored Simple Service"); evbuffer_add_printf(buf,"--------------------------"); evbuffer_add_printf(buf,"size:%d",size); evbuffer_add_printf(buf,"used:%d",used); } evhttp_send_reply(req,HTTP_OK,"OK",buf); evbuffer_free(buf); } } void kill_signal(const int sig){ exit(0); } void show_help(){ char *b ="-----------------------------------------" "HTTP SIMPLE MiniStore Service /n" "-l <ip_addr> IP Address/n" "-p <num> TCP Port/n" "-d run as a daemon/n"; fprintf(stderr,b,strlen(b)); } int main(int argc,char **argv){ char * ministored_listen_ip ="0.0,0.0"; int ministored_listen_port = 1314; bool ministored_daemon = false; int ministored_time_out = 3; char * ministored_shm_path = "/var/log/temp"; int ministored_mem_size = 100*1024*1024; float ministored_mem_capacity= 0.8; int ministored_key_size = 8; int ministored_value_size = 8; int ministore_work_mode = 1; int c; while ((c = getopt(argc, argv, "l:p:x:t:s:c:m:i:d:h:k:v")) != -1) { switch (c) { case 'l': ministored_listen_ip = strdup(optarg); break; case 'p': ministored_listen_port = atoi(optarg); break; case 'd': ministored_daemon=true; break; case 't': ministored_time_out = atoi(optarg); break; case 'k': ministored_key_size = atoi(optarg); break; case 'v': ministored_value_size = atoi(optarg); break; case 'h': default: show_help(); } } // run as deamon if( ministored_daemon ){ pid_t pid; pid =fork(); if( pid < 0 ){ exit(-1); } if(pid > 0){ exit(0); } } signal(SIGPIPE,SIG_IGN); signal(SIGINT,kill_signal); signal(SIGKILL,kill_signal); signal(SIGQUIT,kill_signal); signal(SIGTERM,kill_signal); signal(SIGHUP,kill_signal); struct event_base *base; struct evhttp *httpd; struct evhttp_bound_socket *handle; base = event_base_new(); if (!base) { fprintf(stderr, "Couldn't create an event_base: exiting/n"); return 1; } /* Create a new evhttp object to handle requests. */ httpd = evhttp_new(base); if (!httpd) { fprintf(stderr, "couldn't create evhttp. Exiting./n"); return 1; } evhttp_set_timeout(httpd,ministored_time_out); struct ministored_handler_param *param = (struct ministored_handler_param*) malloc(sizeof(struct ministored_handler_param)); param->key_size = ministored_key_size; param->value_size = ministored_value_size; // set the call back function evhttp_set_gencb(httpd,ministored_handler,param); /* Now we tell the evhttp what port to listen on */ handle = evhttp_bind_socket_with_handle(httpd,ministored_listen_ip , ministored_listen_port); if (!handle) { fprintf(stderr, "couldn't bind to port %d. Exiting./n", (int)ministored_listen_port); return 1; } event_base_dispatch(base); evhttp_free(httpd); return 0; }

這個server框架不僅適用ministored，可以將它搭配任意的存儲工具來做網絡端的存儲。比如BDB、tokyo cabinet來做一個定製的大容量的緩存。