libcurl+ncurses 分段range批量下载和进度条显示源码实例

这个例子来自参考文献[1], 那里有很多小bug，我都做了修改，在这里不一一说明了。ncurse界面编程比较容易入门，就是几个接口，网上资料很多，这里不详述了。

//gcc -g mget.c -o mget -lcurl -lncurses -lm//#include <stdio.h>#include <stdlib.h>#include <string.h>#include <math.h>#include <ncurses.h>#include <time.h>#include <curl/curl.h>WINDOW *win;int width, height;WINDOW *create_newwin (int height, int width, int starty, int startx);void destroy_win (WINDOW * local_win);typedef struct progress{    char byteInterval[64]; //下载分段的字节范围int handle; //文件编号或索引double totalDownloaded; //累计下载double segmentSize;//片段总长字节double currentTime;//当前时间戳double startTime;//开始时间戳} *dl_progress;size_t write_data (void *ptr, size_t size, size_t nmemb, FILE * stream){size_t written;written = fwrite (ptr, size, nmemb, stream);return written;}static size_t get_size_struct (void *ptr, size_t size, size_t nmemb, void *data){(void) ptr;(void) data;// return only the size, dump the restreturn (size_t) (size * nmemb);}int display_progress (dl_progress pgr){int i = pgr->handle;    int totalDots = 80; //进度条的长度是80, 剩余的长度是160-80=80    double totalDownloaded = pgr->totalDownloaded; //已下载片段大小    time_t diffTime = pgr->currentTime - pgr->startTime;    double segmentSize = pgr->segmentSize; //总片段大小    double averageSpeed = pgr->totalDownloaded / diffTime; //平均下载速度    double fractionDownloaded = totalDownloaded / segmentSize; //下载百分比    int dots = round (fractionDownloaded * totalDots); //用几个点来表示?    // create the meter    mvwprintw (win, i + 3, 2, "%3.0f%% [%2d] [", fractionDownloaded * 100, i);    int ii = 0;    for (; ii < dots; ii++)        mvwprintw (win, i + 3, 13 + ii, "="); //8    for (; ii < totalDots; ii++)        mvwprintw (win, i + 3, 13 + ii, " ");    mvwprintw (win, i + 3, totalDots + 13, "]");//注意间隔是40    // display some download info    mvwprintw (win, i + 3, totalDots + 15, "[%s]", pgr->byteInterval);    mvwprintw (win, i + 3, totalDots + 45, "%03.2f KB/s", averageSpeed / 1024);    mvwprintw (win, i + 3, width - 18, "%0.2f / %0.2f MB", totalDownloaded / 1024 / 1024, segmentSize / 1024 / 1024);wrefresh (win);return 0;}int progress_func (dl_progress ptr, double totalToDownload, double nowDownloaded, double totalToUpload, double nowUploaded){time_t seconds;seconds = time (NULL);ptr->totalDownloaded = nowDownloaded;ptr->currentTime = seconds;return display_progress (ptr);}static double get_download_size (char *url){CURL *curl;CURLcode res;double size = 0.0;curl = curl_easy_init ();curl_easy_setopt (curl, CURLOPT_URL, url);curl_easy_setopt (curl, CURLOPT_NOBODY, 1L);curl_easy_setopt (curl, CURLOPT_HEADERFUNCTION, get_size_struct);curl_easy_setopt (curl, CURLOPT_FOLLOWLOCATION, 1L);res = curl_easy_perform (curl);res = curl_easy_getinfo (curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &size);if (res != CURLE_OK){fprintf (stderr, "curl_easy_getinfo() failed: %s\n", curl_easy_strerror (res));}curl_easy_cleanup (curl);return size;}int main (int argc, char *argv[]){if (argc != 3){printf ("Incorrect parameters\nUsage: %s <num_parts> <url>\n", argv[0]);return -1;}// setup the start time for average download speed later when we have finishedtime_t startTime;startTime = time (NULL);// number of partsint parts = strtol (argv[1], &argv[1], 10);// base 10    struct progress *MyProgress = malloc(sizeof(struct progress) * parts);    memset(MyProgress, 0 , sizeof(struct progress) * parts);// create the windowinitscr ();height = parts + 5;width = 160; //这里窗口的宽度是160    intstarty = (LINES - height) / 2;int startx = (COLS - width) / 2;refresh ();win = create_newwin (height, width, starty, startx);// setup our varsconst char *outputfile;char *url = argv[2];double partSize = 0;double segLocation = 0;int still_running;int i;// get file nameoutputfile = strrchr ((const char *) url, '/') + 1;// get file sizedouble size = get_download_size (argv[2]);partSize = size / parts;    mvwprintw (win, 0, 10, "Downloading %dx%0.2f MB segments (%0.2f MB)  %s", parts, size / parts / 1024 / 1024, size / 1024 / 1024, outputfile);// setup curl varsFILE *fileparts[parts];CURL *single_handles[parts];CURLM *multi_handle;CURLMsg *msg;int msgs_left;int error;curl_global_init (CURL_GLOBAL_ALL);for (i = 0; i < parts; i++){time_t seconds;seconds = time (NULL);        memset(MyProgress[i].byteInterval, 0, sizeof(MyProgress[i].byteInterval));MyProgress[i].startTime = seconds;MyProgress[i].handle = i;MyProgress[i].segmentSize = partSize;MyProgress[i].totalDownloaded = 0;// setup our output filenamechar filename[50] = { 0 };snprintf (filename, sizeof (filename), "%s.part.%0d", outputfile, i);// allocate curl handle for each segmentsingle_handles[i] = curl_easy_init ();fileparts[i] = fopen (filename, "w");double nextPart = 0;if (i == parts - 1){nextPart = size;}else{nextPart = segLocation + partSize - 1;}char range[64] = { 0 };snprintf (range, sizeof (range), "%12.0f-%12.0f", segLocation, nextPart);        memcpy(MyProgress[i].byteInterval, range, strlen(range));// set some curl options.curl_easy_setopt (single_handles[i], CURLOPT_URL, url);curl_easy_setopt (single_handles[i], CURLOPT_RANGE, range);  //设置range请求curl_easy_setopt (single_handles[i], CURLOPT_FOLLOWLOCATION, 1L);curl_easy_setopt (single_handles[i], CURLOPT_WRITEFUNCTION, write_data);//设置接收到文件内容回调curl_easy_setopt (single_handles[i], CURLOPT_WRITEDATA, fileparts[i]); //写数据回调的最后一个参数curl_easy_setopt (single_handles[i], CURLOPT_NOPROGRESS, 0); //设置进度回调功能curl_easy_setopt (single_handles[i], CURLOPT_PROGRESSFUNCTION, progress_func); //设置进度回调函数curl_easy_setopt (single_handles[i], CURLOPT_PROGRESSDATA, &MyProgress[i]); //设置进度回调函数的第一个参数segLocation += partSize;}multi_handle = curl_multi_init ();// add all individual transfers to the stackfor (i = 0; i < parts; i++){curl_multi_add_handle (multi_handle, single_handles[i]);}curl_multi_perform (multi_handle, &still_running);do{struct timeval timeout;int rc;// return codefd_set fdread;fd_set fdwrite;fd_set fdexcep;// file descriptor exceptionint maxfd = -1;long curl_timeo = -1;FD_ZERO (&fdread);FD_ZERO (&fdwrite);FD_ZERO (&fdexcep);// set a suitable timeout to play withtimeout.tv_sec = 100 * 1000;timeout.tv_usec = 0;curl_multi_timeout (multi_handle, &curl_timeo);if (curl_timeo >= 0){timeout.tv_sec = curl_timeo / 1000;if (timeout.tv_sec > 1){timeout.tv_sec = 1;}else{timeout.tv_usec = (curl_timeo % 1000) * 1000;}}curl_multi_fdset (multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);rc = select (maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);switch (rc){case -1:fprintf (stderr, "Could not select the error\n");break;case 0:/* timeout */default:curl_multi_perform (multi_handle, &still_running);break;}}while (still_running);while ((msg = curl_multi_info_read (multi_handle, &msgs_left))){if (msg->msg == CURLMSG_DONE){int index, found = 0;for (index = 0; index < parts; index++){found = (msg->easy_handle == single_handles[index]);if (found)break;}}}// clean up our multi handlecurl_multi_cleanup (multi_handle);// free up the curl handlesfor (i = 0; i < parts; i++){curl_easy_cleanup (single_handles[i]);}// close ncurses window    destroy_win(win);endwin ();    free(MyProgress);// send some output to the console for records sake.time_t endTime;endTime = time (NULL);printf ("Downloaded %0.2f MB in %ld seconds\n", partSize * parts / 1024 / 1024, endTime - startTime);printf ("%0.2f KB/s (average)\n", (partSize * parts / (endTime - startTime) / 1024));return 0;}WINDOW *create_newwin (int height, int width, int starty, int startx){WINDOW *local_win;local_win = newwin (height, width, starty, startx);box (local_win, 0, 0);wrefresh (local_win);return local_win;}void destroy_win (WINDOW * local_win){/* box(local_win, ' ', ' '); : This won't produce the desired * result of erasing the window. It will leave it's four corners * and so an ugly remnant of window. */wborder (local_win, '|', '|', '-', '-', '+', '+', '+', '+');/* The parameters taken are * 1. win: the window on which to operate * 2. ls: character to be used for the left side of the window * 3. rs: character to be used for the right side of the window * 4. ts: character to be used for the top side of the window * 5. bs: character to be used for the bottom side of the window * 6. tl: character to be used for the top left corner of the window * 7. tr: character to be used for the top right corner of the window * 8. bl: character to be used for the bottom left corner of the window * 9. br: character to be used for the bottom right corner of the window */wrefresh (local_win);delwin (local_win);}

运行方法

需要两个参数，第一个参数是，分段个数，第二个参数是大文件的链接。默认是大文件下载，上G的文件，可以分为几十兆一个分段，并行异步下载（注意是单线程异步批量，不是多线程），效果还可以。

./mget 20 "http://cdimage.ubuntu.com/releases/14.04/release/ubuntu-14.04-desktop-amd64+mac.iso"
Downloaded 962.00 MB in 867 seconds
1136.20 KB/s (average)

运行截图

附加说明

设计UI界面是个费时费力的细致活, 需要根据屏幕分辨率设计好. 我的ThinkPad是720P的屏，当前的效果给出的是80宽度的框, 进度条使用"="表示, 宽度是40, 高度是文件个数,加上5行空白, 上面是3, 下面是2.一般的笔记本通常没有高的分辨率，建议框的宽度是40就可以，其他的调整按照参考文献[1]设置就够用了。

待解决的问题

如何将这几个文件的即时速度的和统计出来?我暂时没有找到较好的方法.希望大牛指点.

参考文献

[1].https://github.com/logikaljay/mget