在开发BT客户端时候，考虑获取TrackerServer的Peers信息时，使用自己之前开发的HTTPDownload类，偶尔失败。究其原因，无时间追踪。开始考虑封装使用Curl来实现。
等有时间，再来分析一下Curl的功能，的确很强大，对HTTP,FTP,SSL等协议都封装的非常好。他日定可以派上大用场。

代码使用如下：
string server = "http://doserver.net"; string _url = "aboutme.htm"; TTracker t; t.SetURL(server + "/" + _url); t.Do(pb->s_infohash,write_data_1);

类代码如下：

TTracker.h
/* * File:   TTracker.h * Author: huzhangyou * Copyright: HZY_CP * Site: http://doserver.net * Mail: huzhangyou2002<at>gmail.com * Created on February 1, 2009, 4:50 PM */ #ifndef _TTRACKER_H #define  _TTRACKER_H #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <curl/curl.h> #include <curl/types.h> #include <curl/easy.h> #include <string> #include <iostream> using namespace std; typedef size_t (*func)(void *ptr, size_t size, size_t nmemb, void *stream); class TTracker{ public:     TTracker();     ~TTracker();     void SetURL(const string& _url){         url = _url;     }     bool Do(const string& _file,func fun); public:     CURL *curl;     string url; }; #endif  /* _TTRACKER_H */

实现代码TTracker.c

#include "TTracker.h" #include "globalconfig.h"   //这里定义了一个 extern FILE *fp; /* * File:   TTracker.h * Author: huzhangyou * Copyright: HZY_CP * Site: http://doserver.net * Mail: huzhangyou2002<at>gmail.com * Created on February 1, 2009, 4:50 PM */ extern FILE *fp; TTracker::TTracker(){     //     curl_global_init(CURL_GLOBAL_ALL);     curl=curl_easy_init(); } TTracker::~TTracker(){     //     curl_easy_cleanup(curl); } bool TTracker::Do(const string& _file,func fun){     string s_filename = _file + ".hash";     if((fp=fopen(s_filename.c_str(),"w"))==NULL){         cout << "error " <<  endl;         return false;     }     curl_easy_setopt(curl, CURLOPT_URL, url.c_str());     curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fun);     curl_easy_perform(curl);     fclose(fp);     return true; } size_t write_data_1(void *ptr, size_t size, size_t nmemb, void *stream) {     int written = fwrite(ptr, size, nmemb, (FILE *)fp);     return written; }