我必须在 c 中使用 FTP 协议和 libcurl 传输文件。它工作正常,但我有一些问题。
1)如果开始传输,但在某个时刻我断开了网络连接,我的程序仍然在 libcurl 函数中,速度变为 0,我不能做任何其他事情。我试图设置超时(CURLOPT_TIMEOUT),但这只是传输时间的超时。
2)我遇到的第二个问题,与第一个问题有关,我怎么知道转移是否成功完成?
我的转移代码是:
struct FtpFile {
const char *filename;
FILE *stream;
};
long int size;
static size_t my_fwrite(void *buffer, size_t size, size_t nmemb, void *stream)
{
struct FtpFile *out=(struct FtpFile *)stream;
if(out && !out->stream) {
/* open file for writing */
out->stream=fopen(out->filename, "ab");
if(!out->stream)
return -1; /* failure, can't open file to write */
}
return fwrite(buffer, size, nmemb, out->stream);
}
int sz;
int main(void)
{
CURL *curl;
CURLcode res;
char prova;
struct stat statbuf;
FILE *stream;
/* apro il file per leggere la dimensione*/
if ((stream = fopen("Pdf.pdf", "rb"))
== NULL)
{
fprintf(stderr, "Nessun file da aprire, il download partirà da zero.\n");
}
else
{
/* Ricevo informazioni sul file */
fstat(fileno(stream), &statbuf);
fclose(stream);
size = statbuf.st_size;
printf("Dimensione del file in byte: %ld\n", size);
}
struct FtpFile ftpfile={
"Pdf.pdf", /* name to store the file as if succesful */
NULL
};
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "ftp://....");
/* Define our callback to get called when there's data to be written */
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, my_fwrite);
/* Set a pointer to our struct to pass to the callback */
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &ftpfile);
/* Switch on full protocol/debug output */
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
/*Pass a long as parameter. It contains the offset in number of bytes that you want the transfer to start from.
Set this option to 0 to make the transfer start from the beginning (effectively disabling resume). For FTP, set
this option to -1 to make the transfer start from the end of the target file (useful to continue an interrupted
upload).
When doing uploads with FTP, the resume position is where in the local/source file libcurl should try to resume
the upload from and it will then append the source file to the remote target file. */
if(stream == NULL)
{
curl_easy_setopt(curl, CURLOPT_RESUME_FROM, 0);
}
else
{
curl_easy_setopt(curl, CURLOPT_RESUME_FROM, size);
}
/*Used to show file progress*/
curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 0);
res = curl_easy_perform(curl);
/* always cleanup */
curl_easy_cleanup(curl);
if(CURLE_OK != res) {
/* we failed */
fprintf(stderr, "curl told us %d\n", res);
}
}
if(ftpfile.stream)
fclose(ftpfile.stream); /* close the local file */
curl_global_cleanup();
return 0;
}