昨天考慮好了IM傳送圖檔的方式，用的是FTP做緩存來傳遞圖檔，以減少聊天伺服器的壓力，用的是libcurl庫，自己下載下傳了一個Server-U 伺服器，下面是測試程式，上傳和下載下傳都跑通了，剩下的就是在程式中寫邏輯來實作具體的功能了。
上傳代碼：
//ftp上傳執行個體
// 伺服器位址：192.168.0.185 賬号：spider 密碼：spider
// 在伺服器路徑 a上建立一個a.txt ，本地檔案是test.txt
// 指令行參數192.168.0.185 spider spider a a.txt D:/test.txt
//#include <stdlib.h>
//#include <stdio.h>
//#include <curl/curl.h>
//#include <string.h>
//
//int debugFun(CURL* curl, curl_infotype type, char* str, size_t len, void* stream)
//{
// //隻列印CURLINFO_TEXT類型的資訊
// if(type == CURLINFO_TEXT)
// {
// fwrite(str, 1, len, (FILE*)stream);
// }
// return 0;
//}
//
//int main(int argc, char** argv)
//{
// CURL* curl;
// CURLcode res;
// char errorBuf[CURL_ERROR_SIZE];
// FILE *sendFile, *debugFile;
// char ftpurl[256 + 1];
// char usrpasswd[64 + 1];
//
// curl_slist *slist=NULL;
//
// if(argc != 7)
// {
// printf("Usage:\n\t./ftp ip username password ftpPath destFileName srcFile");
// return -1;
// }
//
// //将相關的調試資訊列印到dubugFile.txt中
// if(NULL == (debugFile = fopen("debugFile.txt", "a+")))
// return -1;
//
// //打開ftp上傳的源檔案
// if(NULL == (sendFile = fopen(argv[6], "r")))
// {
// fclose(debugFile);
// return -1;
// }
//
// //擷取需要發送檔案的大小
// fseek(sendFile, 0, SEEK_END);
// int sendSize = ftell(sendFile);
// if(sendSize < 0)
// {
// fclose(debugFile);
// fclose(sendFile);
// return -1;
// }
// fseek(sendFile, 0L, SEEK_SET);
//
// if((res = curl_global_init(CURL_GLOBAL_ALL)) != 0)
// {
// fclose(debugFile);
// fclose(sendFile);
// return -1;
// }
// if((curl = curl_easy_init()) == NULL)
// {
// fclose(debugFile);
// fclose(sendFile);
// curl_global_cleanup();
// return -1;
// }
//
// if(argv[4][strlen(argv[4]) - 1] != '/')
// sprintf(ftpurl, "ftp://%s/%s/%s", argv[1], argv[4], argv[5]);
// else
// sprintf(ftpurl, "ftp://%s/%s%s", argv[1], argv[4], argv[5]);
// curl_easy_setopt(curl, CURLOPT_URL, ftpurl);
// //設定ftp上傳url,組成如下的URL
// //ftp://192.168.31.145//root/subdir/curl/testftp.txt
//
// sprintf(usrpasswd, "%s:%s", argv[2], argv[3]);
// curl_easy_setopt(curl, CURLOPT_USERPWD, usrpasswd);
//
// curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
// curl_easy_setopt(curl, CURLOPT_DEBUGDATA, debugFile);
//
// curl_easy_setopt(curl, CURLOPT_READDATA, sendFile);
// curl_easy_setopt(curl, CURLOPT_UPLOAD, 1);
// curl_easy_setopt(curl, CURLOPT_INFILESIZE, sendSize);
// curl_easy_setopt(curl, CURLOPT_FTP_CREATE_MISSING_DIRS, 1);
//
// curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, debugFun);
//
// res = curl_easy_perform(curl);
// if(0 != res)
// {
// fclose(sendFile);
// fclose(debugFile);
// curl_easy_cleanup(curl);
// curl_global_cleanup();
// return -1;
// }
//
// curl_easy_cleanup(curl);
// fclose(sendFile);
// fclose(debugFile);
// curl_global_cleanup();
// getchar();
// return 0;
//} 下載下傳代碼如下：
//ftp下載下傳執行個體
#include <stdio.h>;
#include <curl/curl.h>;
#include <curl/types.h>;
#include <curl/easy.h>;
struct FtpFile //定義一個結構為了傳遞給my_fwrite函數.可用curl_easy_setopt的CURLOPT_WRITEDATA選項傳遞
{
char *filename;
FILE *stream;
};
int my_fwrite(void *buffer, size_t size, size_t nmemb, void *stream)
{
struct FtpFile *out=(struct FtpFile *)stream; // stream指針其實就是指向struct FtpFile ftpfile的
if(out && !out->stream)
{
out->stream=fopen(out->filename, "wb"); //沒有這個流的話就建立一個名字是out->filename.
if(!out->stream)
return -1;
}
return fwrite(buffer, size, nmemb, out->stream);
}
int main(int argc, char *argv[])
{
CURL *curl;
CURLcode res;
struct FtpFile ftpfile={"D:/Success.txt",NULL}; //初始化一個FtpFile結構
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl)
{
curl_easy_setopt(curl, CURLOPT_URL,"ftp://192.168.0.185/a/a.txt");
curl_easy_setopt(curl, CURLOPT_USERPWD,"spider:spider");
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, my_fwrite);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &ftpfile); //給相關函數的第四個參數傳遞一個結構體的指針
curl_easy_setopt(curl, CURLOPT_VERBOSE, TRUE);//CURLOPT_VERBOSE 這個選項很常用用來在螢幕上顯示對伺服器相關操作傳回的資訊
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
if(CURLE_OK != res)
fprintf(stderr, "curl told us %d\n", res);
}
if(ftpfile.stream)
fclose(ftpfile.stream);
curl_global_cleanup();
return 0;
} 最後記錄一個比較好用的：
#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;
}
}
// 下載下傳
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;
//擷取本地檔案大小資訊
if(stat(localpath, &file_info) == 0)
{
local_file_len = file_info.st_size;
use_resume = 1;
}
//追加方式打開檔案，實作斷點續傳
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");
//連接配接逾時設定
curl_easy_setopt(curlhandle, CURLOPT_CONNECTTIMEOUT, timeout);
//設定頭處理函數
curl_easy_setopt(curlhandle, CURLOPT_HEADERFUNCTION, getcontentlengthfunc);
curl_easy_setopt(curlhandle, CURLOPT_HEADERDATA, &filesize);
// 設定斷點續傳
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;
}