libcurl

一、libcurl

主要功能就是用不同的协议连接和沟通不同的服务器~也就是相当封装了的sockPHP 支持libcurl（允许你用不同的协议连接和沟通不同的服务器）。, libcurl当前支持http, https, ftp, gopher, telnet, dict, file, 和ldap 协议。libcurl同样支持HTTPS证书授权，HTTP POST, HTTP PUT, FTP 上传（当然你也可以使用PHP的ftp扩展）, HTTP基本表单上传，代理，cookies,和用户认证。

二、利用libcurl 下载文件代码例程

#include <stdio.h>
#include <curl/curl.h>
//#include <curl/types.h> /* new for v7 */
#include <curl/easy.h> /* new for v7 */
  
 ////这个函数是为了符合CURLOPT_WRITEFUNCTION而构造的
 //完成数据保存功能
 size_t my_write_func(void *ptr, size_t size, size_t nmemb, FILE *stream)
 {
   return fwrite(ptr, size, nmemb, stream);
 }
 //这个函数是为了符合CURLOPT_READFUNCTION而构造的
 //数据上传时使用
 size_t my_read_func(void *ptr, size_t size, size_t nmemb, FILE *stream)
 {
   return fread(ptr, size, nmemb, stream);
 }
 //这个函数是为了符合CURLOPT_PROGRESSFUNCTION而构造的
 //显示文件传输进度，t代表文件大小，d代表传 输已经完成部分
 int my_progress_func(void *bar,
                      double t, /* dltotal */
                      double d, /* dlnow */
                      double ultotal,
                      double ulnow)
 {
   printf("%f / %f (%g %%)
", d, t, d*100.0/t);
   //printf("
33[?25l%f / %f (%g %%)33[?25h", d, t, d*100.0/t);
   return 0;
 }
  
 void *my_thread(void *ptr)
 {
   CURL *curl;
   CURLcode res;
   FILE *outfile;
   char *url = ptr;
  
   curl = curl_easy_init();
   if(curl)
   {
     outfile = fopen("test.zip", "w");
  
     curl_easy_setopt(curl, CURLOPT_URL, url);
     curl_easy_setopt(curl, CURLOPT_WRITEDATA, outfile);
     curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, my_write_func);
     curl_easy_setopt(curl, CURLOPT_READFUNCTION, my_read_func);
     curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 0L);
     curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, my_progress_func);
    // curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, Bar);
  
     res = curl_easy_perform(curl);
  
     fclose(outfile);
     /* always cleanup */
     curl_easy_cleanup(curl);
   }
  
   return NULL;
 }
  
 int main(int argc, char **argv)
 {
  
   /* Must initialize libcurl before any threads are started */
   curl_global_init(CURL_GLOBAL_ALL);

   //if (!g_thread_create(&my_thread, argv[1], false, NULL) != 0)
     //g_warning("can't create the thread");
   my_thread(argv[1]);
   while(1) {
       sleep(2);
   }
   return 0;
 }

 三、curl_easy_perform(curl) 返回值

CURLE_OK = 0, 0: no error  
CURLE_UNSUPPORTED_PROTOCOL, 1: unsupported protocol  
CURLE_FAILED_INIT, 2: failed init  
CURLE_URL_MALFORMAT, 3: URL using bad/illegal format or missing URL  
CURLE_URL_MALFORMAT_USER, 4: unknown error  
CURLE_COULDNT_RESOLVE_PROXY, 5: couldn’t resolve proxy name  
CURLE_COULDNT_RESOLVE_HOST, 6: couldn’t resolve host name  
CURLE_COULDNT_CONNECT, 7: couldn’t connect to server  
CURLE_FTP_WEIRD_SERVER_REPLY, 8: FTP: weird server reply  
CURLE_FTP_ACCESS_DENIED,9  
CURLE_FTP_USER_PASSWORD_INCORRECT, 10: unknown error  
CURLE_FTP_WEIRD_PASS_REPLY, 11: FTP: unknown PASS reply  
CURLE_FTP_WEIRD_USER_REPLY, 12: FTP: unknown USER reply  
CURLE_FTP_WEIRD_PASV_REPLY, 13: FTP: unknown PASV reply  
CURLE_FTP_WEIRD_227_FORMAT, 14: FTP: unknown 227 response format  
CURLE_FTP_CANT_GET_HOST, 15: FTP: can’t figure out the host in the PASV response  
CURLE_FTP_CANT_RECONNECT, 16: FTP: can’t connect to server the response code is unknown  
CURLE_FTP_COULDNT_SET_BINARY, 17: FTP: couldn’t set binary mode  
CURLE_PARTIAL_FILE, 18: Transferred a partial file  
CURLE_FTP_COULDNT_RETR_FILE, 19: FTP: couldn’t retrieve (RETR failed) the specified file  
CURLE_FTP_WRITE_ERROR, 20: FTP: the post-transfer acknowledge response was not OK  
CURLE_FTP_QUOTE_ERROR, 21: FTP: a quote command returned error  
CURLE_HTTP_RETURNED_ERROR, 22: HTTP response code said error  
CURLE_WRITE_ERROR, 23: failed writing received data to disk/application  
CURLE_MALFORMAT_USER, 24: unknown error  
CURLE_UPLOAD_FAILED, 25: upload failed (at start/before it took off)  
CURLE_READ_ERROR, 26: failed to open/read local data from file/application  
CURLE_OUT_OF_MEMORY, 27: out of memory  
CURLE_OPERATION_TIMEOUTED, 28: a timeout was reached  
CURLE_FTP_COULDNT_SET_ASCII, 29: FTP could not set ASCII mode (TYPE A)  
CURLE_FTP_PORT_FAILED, 30: FTP command PORT failed  
CURLE_FTP_COULDNT_USE_REST, 31: FTP command REST failed  
CURLE_FTP_COULDNT_GET_SIZE, 32: FTP command SIZE failed  
CURLE_HTTP_RANGE_ERROR, 33: a range was requested but the server did not deliver it  
CURLE_HTTP_POST_ERROR, 34: internal problem setting up the POST  
CURLE_SSL_CONNECT_ERROR, 35: SSL connect error  
CURLE_BAD_DOWNLOAD_RESUME, 36: couldn’t resume download  
CURLE_FILE_COULDNT_READ_FILE, 37: couldn’t read a file
CURLE_LDAP_CANNOT_BIND, 38: LDAP: cannot bind  
CURLE_LDAP_SEARCH_FAILED, 39: LDAP: search failed  
CURLE_LIBRARY_NOT_FOUND, 40: a required shared library was not found