resume.c

 1 //采用CURLOPT_RESUME_FROM_LARGE 实现文件断点续传功能
 2 #include <stdlib.h>
 3 #include <stdio.h>
 4 #include <sys/stat.h>
 5 #include <curl/curl.h>
 6 //这个函数为CURLOPT_HEADERFUNCTION 参数构造
 7 /*从http 头部获取文件size*/
 8 size_t getcontentlengthfunc(void *ptr, size_t size, size_t nmemb, void *stream) {
 9 int r;
10 long len = 0;
11 /* _snscanf() is Win32 specific */
12 // r = _snscanf(ptr, size * nmemb, "Content-Length: %ld
", &len);
13 r = sscanf(ptr, "Content-Length: %ld
", &len);
14 if (r) /* Microsoft: we don't read the specs */
15 *((long *) stream) = len;
16 return size * nmemb;
17 }
18 /*保存下载文件*/
19 size_t wirtefunc(void *ptr, size_t size, size_t nmemb, void *stream)
20 {
21 return fwrite(ptr, size, nmemb, stream);
22 }
23 /*读取上传文件*/
24 size_t readfunc(void *ptr, size_t size, size_t nmemb, void *stream)
25 {
26 FILE *f = stream;
27 size_t n;
28 if (ferror(f))
29 return CURL_READFUNC_ABORT;
30 n = fread(ptr, size, nmemb, f) * size;
31 return n;
32 }
33 //下载或者上传文件函数
34 int download(CURL *curlhandle, const char * remotepath, const char * localpath,
35 long timeout, long tries)
36 {
37 FILE *f;
38 curl_off_t local_file_len = -1 ;
39 long filesize =0 ;
40 CURLcode r = CURLE_GOT_NOTHING;
41 int c;
42 struct stat file_info;
43 int use_resume = 0;
44 /*得到本地文件大小*/
45 //if(access(localpath,F_OK) ==0)
46 if(stat(localpath, &file_info) == 0)
47 {
48 local_file_len = file_info.st_size;
49 use_resume = 1;
50 }
51 //采用追加方式打开文件，便于实现文件断点续传工作
52 f = fopen(localpath, "ab+");
53 if (f == NULL) {
54 perror(NULL);
55 return 0;
56 }
57 //curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L);
58 curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);
59 curl_easy_setopt(curlhandle, CURLOPT_CONNECTTIMEOUT,
60 timeout); //设置连接超时，单位秒
61 //设置http 头部处理函数
62 curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION,
63 getcontentlengthfunc);
64 curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &filesize);
65 //设置文件续传的位置给libcurl
66 curl_easy_setopt(curlhandle, CURLOPT_RESUME_FROM_LARGE,
67 use_resume?local_file_len:0);
68 curl_easy_setopt(curlhandle, CURLOPT_WRITEDATA, f);
69 curl_easy_setopt(curlhandle, CURLOPT_WRITEFUNCTION, wirtefunc);
70 //curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);
71 //curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);
72 curl_easy_setopt(curlhandle, CURLOPT_NOPROGRESS, 1L);
73 curl_easy_setopt(curlhandle, CURLOPT_VERBOSE, 1L);
74 r = curl_easy_perform(curlhandle);
75 fclose(f);
76 if (r == CURLE_OK)
77 return 1;
78 else {
79 fprintf(stderr, "%s
", curl_easy_strerror(r));
80 return 0;
81 }
82 }
83 int main(int c, char **argv) {
84 CURL *curlhandle = NULL;                //定义一个指针
85 curl_global_init(CURL_GLOBAL_ALL);        //初始化libcurl库
86 curlhandle = curl_easy_init();            //获得指针
87 //download(curlhandle, "ftp://user:pass@host/path/file", "C:\file", 0, 3);
88 download(curlhandle , "http://software.skyunion.cn/index.asp","/work/index.asp",1,3);
89 curl_easy_cleanup(curlhandle);
90 curl_global_cleanup();
91 return 0;
92 }