libcurl

//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 = 0;
	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 = -1 ;
	long filesize =0 ;

	CURLcode r = CURLE_GOT_NOTHING;
	int c;
	struct stat file_info;
	int use_resume = 0;
	/* 得到本地文件大小 */
	//if(access(localpath,F_OK) ==0)
    if(stat(localpath, &file_info) == 0) 
    {
		local_file_len =  file_info.st_size;
        use_resume  = 1;
    }
  //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 0;
	}
 
	//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:0);

	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 1;
	else {
		fprintf(stderr, "%s\n", curl_easy_strerror(r));
		return 0;
	}
}
 
int main(int c, char **argv)
{
	CURL *curlhandle = NULL;
	curl_global_init(CURL_GLOBAL_ALL);
	curlhandle = curl_easy_init();

    //download(curlhandle, "ftp://user:pass@host/path/file", "C:\\file", 0, 3);
	download(curlhandle , "http://software.sky-union.cn/index.asp","/work/index.asp",1,3);
	curl_easy_cleanup(curlhandle);
	curl_global_cleanup();
	return 0;
}

// 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 0;
}
 
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), 5);
  adj = (GtkAdjustment*)gtk_adjustment_new(0, 0, 100, 0, 0, 0);
  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[1], FALSE, NULL) != 0)
    g_warning("can't create the thread");
 
 
  gdk_threads_enter();
  gtk_main();
  gdk_threads_leave();
  return 0;
}

FTP DOWNLOAD AND UPLOAD USE LIBCURL

#include <stdlib.h>
#include <stdio.h>
#include <curl/curl.h>
#include <sys/stat.h>
/* parse headers for Content-Length */
size_t getcontentlengthfunc(void *ptr, size_t size, size_t nmemb, void *stream) 
{
    int r;
    long len = 0;
    /* _snscanf() is Win32 specific */
    //r = _snscanf(ptr, size * nmemb, "Content-Length: %ld\n", &len);
    r = sscanf((const char*)ptr, "Content-Length: %ld\n", &len);
    if (r) /* Microsoft: we don't read the specs */
        *((long *) stream) = len;
    return size * nmemb;
}
/* discard downloaded data */
size_t discardfunc(void *ptr, size_t size, size_t nmemb, void *stream) 
{
    return size * nmemb;
}
//write data to upload
size_t writefunc(void *ptr, size_t size, size_t nmemb, void *stream)
{
    return fwrite(ptr, size, nmemb, (FILE*)stream);
}
/* read data to upload */
size_t readfunc(void *ptr, size_t size, size_t nmemb, void *stream)
{
    FILE *f = (FILE*)stream;
    size_t n;
    if (ferror(f))
        return CURL_READFUNC_ABORT;
    n = fread(ptr, size, nmemb, f) * size;
    return n;
}
int upload(CURL *curlhandle, const char * remotepath, const char * localpath, long timeout, long tries)
{
    FILE *f;
    long uploaded_len = 0;
    CURLcode r = CURLE_GOT_NOTHING;
    int c;
    f = fopen(localpath, "rb");
    if (f == NULL) {
        perror(NULL);
        return 0;
    }
    curl_easy_setopt(curlhandle, CURLOPT_UPLOAD, 1L);
    curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);
    curl_easy_setopt(curlhandle, CURLOPT_USERPWD, "spider:spider");   
    if (timeout)
        curl_easy_setopt(curlhandle, CURLOPT_FTP_RESPONSE_TIMEOUT, timeout);
    curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION, getcontentlengthfunc);
    curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &uploaded_len);
    curl_easy_setopt(curlhandle, CURLOPT_WRITEFUNCTION, discardfunc);
    curl_easy_setopt(curlhandle, CURLOPT_READFUNCTION, readfunc);
    curl_easy_setopt(curlhandle, CURLOPT_READDATA, f);
    curl_easy_setopt(curlhandle, CURLOPT_FTPPORT, "-"); /* disable passive mode */
    curl_easy_setopt(curlhandle, CURLOPT_FTP_CREATE_MISSING_DIRS, 1L);
    curl_easy_setopt(curlhandle, CURLOPT_VERBOSE, 1L);
    for (c = 0; (r != CURLE_OK) && (c < tries); c++) {
        /* are we resuming? */
        if (c) { /* yes */
            /* determine the length of the file already written */
            /*
            * With NOBODY and NOHEADER, libcurl will issue a SIZE
            * command, but the only way to retrieve the result is
            * to parse the returned Content-Length header. Thus,
            * getcontentlengthfunc(). We need discardfunc() above
            * because HEADER will dump the headers to stdout
            * without it.
            */
            curl_easy_setopt(curlhandle, CURLOPT_NOBODY, 1L);
            curl_easy_setopt(curlhandle, CURLOPT_HEADER, 1L);
            r = curl_easy_perform(curlhandle);
            if (r != CURLE_OK)
                continue;
            curl_easy_setopt(curlhandle, CURLOPT_NOBODY, 0L);
            curl_easy_setopt(curlhandle, CURLOPT_HEADER, 0L);
            fseek(f, uploaded_len, SEEK_SET);
            curl_easy_setopt(curlhandle, CURLOPT_APPEND, 1L);
        }
        else { /* no */
            curl_easy_setopt(curlhandle, CURLOPT_APPEND, 0L);
        }
        r = curl_easy_perform(curlhandle);
    }
    fclose(f);
    if (r == CURLE_OK)
        return 1;
    else {
        fprintf(stderr, "%s\n", curl_easy_strerror(r));
        return 0;
    }
}
// 下载
int download(CURL *curlhandle, const char * remotepath, const char * localpath, long timeout, long tries)
{
    FILE *f;
    curl_off_t local_file_len = -1 ;
    long filesize =0 ;
    CURLcode r = CURLE_GOT_NOTHING;
    struct stat file_info;
    int use_resume = 0;
    //获取本地文件大小信息
    if(stat(localpath, &file_info) == 0)
    {
        local_file_len = file_info.st_size; 
        use_resume = 1;
    }
    //追加方式打开文件，实现断点续传
    f = fopen(localpath, "ab+");
    if (f == NULL) {
        perror(NULL);
        return 0;
    }
    curl_easy_setopt(curlhandle, CURLOPT_URL, remotepath);
    curl_easy_setopt(curlhandle, CURLOPT_USERPWD, "spider:spider");   
    //连接超时设置
    curl_easy_setopt(curlhandle, CURLOPT_CONNECTTIMEOUT, timeout);
    //设置头处理函数
    curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION, getcontentlengthfunc);
    curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &filesize);
    // 设置断点续传
    curl_easy_setopt(curlhandle, CURLOPT_RESUME_FROM_LARGE, use_resume?local_file_len:0);
    curl_easy_setopt(curlhandle, CURLOPT_WRITEFUNCTION, writefunc);
    curl_easy_setopt(curlhandle, CURLOPT_WRITEDATA, 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 1;
    else {
        fprintf(stderr, "%s\n", curl_easy_strerror(r));
        return 0;
    }
}
int main(int c, char **argv) 
{
    CURL *curlhandle = NULL;
    CURL *curldwn = NULL;
    curl_global_init(CURL_GLOBAL_ALL);
    curlhandle = curl_easy_init();
    curldwn = curl_easy_init();
    upload(curlhandle, "ftp://192.168.0.185/a/success", "D:/abc.jpg", 1, 3);
    download(curldwn, "ftp://192.168.0.185/a/success", "D:/abc1.jpg", 1, 3);
    curl_easy_cleanup(curlhandle);
    curl_easy_cleanup(curldwn);
    curl_global_cleanup();
    return 0;
}