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 ;
}