resume.c

resume.c

　　

 //采用CURLOPT_RESUME_FROM_LARGE 实现文件断点续传功能
 #include <stdlib.h>
 #include <stdio.h>
 #include <sys/stat.h>
 #include <curl/curl.h>
 //这个函数为CURLOPT_HEADERFUNCTION 参数构造
 /*从http 头部获取文件size*/
 size_t getcontentlengthfunc(void *ptr, size_t size, size_t nmemb, void *stream) {
 int r;
 long len = ;
 /* _snscanf() is Win32 specific */
 // r = _snscanf(ptr, size * nmemb, "Content-Length: %ld\n", &len);
 r = sscanf(ptr, "Content-Length: %ld\n", &len);
 if (r) /* Microsoft: we don't read the specs */
 *((long *) stream) = len;
 return size * nmemb;
 }
 /*保存下载文件*/
 size_t wirtefunc(void *ptr, size_t size, size_t nmemb, void *stream)
 {
 return fwrite(ptr, size, nmemb, stream);
 }
 /*读取上传文件*/
 size_t readfunc(void *ptr, size_t size, size_t nmemb, void *stream)
 {
 FILE *f = stream;
 size_t n;
 if (ferror(f))
 return CURL_READFUNC_ABORT;
 n = fread(ptr, size, nmemb, f) * size;
 return n;
 }
 //下载或者上传文件函数
 int download(CURL *curlhandle, const char * remotepath, const char * localpath,
 long timeout, long tries)
 {
 FILE *f;
 curl_off_t local_file_len = - ;
 long filesize = ;
 CURLcode r = CURLE_GOT_NOTHING;
 int c;
 struct stat file_info;
 int use_resume = ;
 /*得到本地文件大小*/
 //if(access(localpath,F_OK) ==0)
 if(stat(localpath, &file_info) == )
 {
 local_file_len = file_info.st_size;
 use_resume = ;
 }
 //采用追加方式打开文件，便于实现文件断点续传工作
 f = fopen(localpath, "ab+");
 if (f == NULL) {
 perror(NULL);
 return ;
 }
 //curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L);
 curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);
 curl_easy_setopt(curlhandle, CURLOPT_CONNECTTIMEOUT,
 timeout); //设置连接超时，单位秒
 //设置http 头部处理函数
 curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION,
 getcontentlengthfunc);
 curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &filesize);
 //设置文件续传的位置给libcurl
 curl_easy_setopt(curlhandle, CURLOPT_RESUME_FROM_LARGE,
 use_resume?local_file_len:);
 curl_easy_setopt(curlhandle, CURLOPT_WRITEDATA, f);
 curl_easy_setopt(curlhandle, CURLOPT_WRITEFUNCTION, wirtefunc);
 //curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);
 //curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);
 curl_easy_setopt(curlhandle, CURLOPT_NOPROGRESS, 1L);
 curl_easy_setopt(curlhandle, CURLOPT_VERBOSE, 1L);
 r = curl_easy_perform(curlhandle);
 fclose(f);
 if (r == CURLE_OK)
 return ;
 else {
 fprintf(stderr, "%s\n", curl_easy_strerror(r));
 return ;
 }
 }
 int main(int c, char **argv) {
 CURL *curlhandle = NULL;                //定义一个指针
 curl_global_init(CURL_GLOBAL_ALL);        //初始化libcurl库
 curlhandle = curl_easy_init();            //获得指针
 //download(curlhandle, "ftp://user:pass@host/path/file", "C:\\file", 0, 3);
 download(curlhandle , "http://software.skyunion.cn/index.asp","/work/index.asp",,);
 curl_easy_cleanup(curlhandle);
 curl_global_cleanup();
 return ;
 }