一、curl简介

 // 采用CURLOPT_WRITEFUNCTION 实现网页下载保存功能  

 #include <stdio.h>;  

 #include <stdlib.h>;  

 #include <unistd.h>;  

 #include <curl/curl.h>;  

 #include <curl/types.h>;  

 #include <curl/easy.h>;  

 FILE *fp;  // 定义FILE类型指针  

 //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 write_data(void *ptr, size_t size, size_t nmemb, void *stream)   

 {  

     int written = fwrite(ptr, size, nmemb, (FILE *)fp);  

     return written;  

 }  

 int main(int argc, char *argv[])  

 {  

     CURL *curl;  

     curl_global_init(CURL_GLOBAL_ALL);   

     curl=curl_easy_init();  

     curl_easy_setopt(curl, CURLOPT_URL, argv[]);   

     if((fp=fopen(argv[],"w"))==NULL)  

     {  

         curl_easy_cleanup(curl);  

         exit();  

     }  

 ////CURLOPT_WRITEFUNCTION 将后继的动作交给write_data函数处理  

     curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);   

     curl_easy_perform(curl);  

     curl_easy_cleanup(curl);  

     exit();  

 }  

 编译：

 #gcc  save_http.c  -o save_http –lcurl

 #./save_http www.baidu.com  /tmp/baidu

 // 采用CURLOPT_NOPROGRESS， CURLOPT_PROGRESSFUNCTION    CURLOPT_PROGRESSDATA 实现文件传输进度提示功能  

 //函数采用了gtk库，故编译时需指定gtk库  

 //函数启动专门的线程用于显示gtk 进度条bar  

 #include <stdio.h>

 #include <gtk/gtk.h>

 #include <curl/curl.h>

 #include <curl/types.h> /* new for v7 */

 #include <curl/easy.h> /* new for v7 */  

 GtkWidget *Bar;  

 ////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(GtkWidget *bar,  

                      double t, /* dltotal */

                      double d, /* dlnow */

                      double ultotal,

                      double ulnow)

 {

   /*  printf("%d / %d (%g %%)/n", d, t, d*100.0/t);*/

   gdk_threads_enter();

   gtk_progress_set_value(GTK_PROGRESS(bar), d*100.0/t);

   gdk_threads_leave();

   return ;

 }  

 void *my_thread(void *ptr)

 {

   CURL *curl;

   CURLcode res;

   FILE *outfile;

   gchar *url = ptr;

   curl = curl_easy_init();

   if(curl)

   {

     outfile = fopen("test.curl", "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)

 {  

   GtkWidget *Window, *Frame, *Frame2;  

   GtkAdjustment *adj;  

   /* Must initialize libcurl before any threads are started */  

   curl_global_init(CURL_GLOBAL_ALL);  

   /* Init thread */  

   g_thread_init(NULL);  

   gtk_init(&argc, &argv);  

   Window = gtk_window_new(GTK_WINDOW_TOPLEVEL);  

   Frame = gtk_frame_new(NULL);  

   gtk_frame_set_shadow_type(GTK_FRAME(Frame), GTK_SHADOW_OUT);  

   gtk_container_add(GTK_CONTAINER(Window), Frame);  

   Frame2 = gtk_frame_new(NULL);  

   gtk_frame_set_shadow_type(GTK_FRAME(Frame2), GTK_SHADOW_IN);  

   gtk_container_add(GTK_CONTAINER(Frame), Frame2);  

   gtk_container_set_border_width(GTK_CONTAINER(Frame2), );  

   adj = (GtkAdjustment*)gtk_adjustment_new(, , , , , );  

   Bar = gtk_progress_bar_new_with_adjustment(adj);  

   gtk_container_add(GTK_CONTAINER(Frame2), Bar);  

   gtk_widget_show_all(Window);  

   if (!g_thread_create(&my_thread, argv[], FALSE, NULL) != )  

     g_warning("can't create the thread");  

   gdk_threads_enter();  

   gtk_main();  

   gdk_threads_leave();  

   return ;  

 }  

 编译:

 #export PKG_CONFIG_PATH=/usr/lib/pkgconfig/

 #gcc progress.c –o progress ` pkg-config --libs –cflags gtk+-..` -lcurl –lgthread-2.0

 #./ progress  http://software.sky-union.cn/index.asp

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/n", &len);
13. r = sscanf(ptr, "Content-Length: %ld/n", &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, timeout);  // 设置连接超时，单位秒
60. //设置http 头部处理函数
61. curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION, getcontentlengthfunc);
62. curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &filesize);
63. // 设置文件续传的位置给libcurl
64. curl_easy_setopt(curlhandle, CURLOPT_RESUME_FROM_LARGE, use_resume?local_file_len:0);
65. curl_easy_setopt(curlhandle, CURLOPT_WRITEDATA, f);
66. curl_easy_setopt(curlhandle, CURLOPT_WRITEFUNCTION, wirtefunc);
67. //curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);
68. //curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);
69. curl_easy_setopt(curlhandle, CURLOPT_NOPROGRESS, 1L);
70. curl_easy_setopt(curlhandle, CURLOPT_VERBOSE, 1L);
71. r = curl_easy_perform(curlhandle);
72. fclose(f);
73. if (r == CURLE_OK)
74. return 1;
75. else {
76. fprintf(stderr, "%s/n", curl_easy_strerror(r));
77. return 0;
78. }
79. }
80. int main(int c, char **argv) {
81. CURL *curlhandle = NULL;
82. curl_global_init(CURL_GLOBAL_ALL);
83. curlhandle = curl_easy_init();
84. //download(curlhandle, "ftp://user:pass@host/path/file", "C://file", 0, 3);
85. download(curlhandle , "http://software.sky-union.cn/index.asp","/work/index.asp",1,3);
86. curl_easy_cleanup(curlhandle);
87. curl_global_cleanup();
88. return 0;
89. }