I write simple software to download image file from specific url. I using libcurl, i have this code:
#define CURL_STATICLIB
#include <stdio.h>
#include <curl/curl.h>
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;
}
int downloadFile() {
CURL *curl;
FILE *fp;
CURLcode res;
char *url = "http://www.example.eu/12.jpg";
char outfilename[FILENAME_MAX] = "D:\\12.jpg";
curl = curl_easy_init();
if (curl) {
fp = fopen(outfilename, "wb");
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(fp);
}
}
int main(void) {
downloadFile();
return 0;
}
When i build project i need copy dll file to project directory, because without him i have error. Is there any way to build an exe file with a built-in library? so to have the exe itself without having to attach another file?
I count on the fact that the file will be larger but for me it is a lot easier if I have 1 file, not a few, because as I add some files now I will have 1 exe and many dll files.
Related
I want to download a zip of a GitHub repository that does not have a zip. It is only folders and files. If I navigate to the URL in my web browser it will download a zip and if I use wget url it will download a zip, but executing the below C script will not download a zip file for me.
Why will this script not download the zip file?
#include <stdio.h>
#include <curl/curl.h>
int main(void)
{
CURL *curl;
CURLcode res;
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "https://github.com/miketheknight2016/SXOS_Cheats/archive/master.zip");
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
curl_easy_perform(curl);
res = curl_easy_perform(curl);
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));
curl_easy_cleanup(curl);
}
curl_global_cleanup();
return 0;
}
If you don't tell curl where to save the file it downloads, it will print it out in the console. What you're seeing is a zip file printed out in the console.
If you want it to save the output to a file, you have to create a function that writes a bunch of data to the file, and tell curl to use that function using CURL_OPT_WRITEFUNCTION and CURL_OPT_WRITEDATA:
// before main
static size_t write_data_to_file(void *ptr, size_t size, size_t nmemb, void *stream)
{
return fwrite(ptr, size, nmemb, (FILE *)stream);
}
// in main before curl_easy_perform
FILE *file = fopen("myfile.zip", "wb");
// you should probably check if file is null here - that would mean it failed to open the file
curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, file);
// in main after curl_easy_perform
fclose(file);
Don't ask me how this counts as "easy".
I am developing on Linux platform. I am using libcurl and able to receive json response and saving it to file. Below is the code.
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
#include <string.h>
#define URL "http://www.joes-hardware.com/tools.html"
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;
}
int main(void) {
CURL *curl;
FILE *fp;
CURLcode res;
//const char url[] = "http://www.joes-hardware.com/tools.html";
char *url= URL;
char outfilename[FILENAME_MAX] = "./json";
curl = curl_easy_init();
if (curl) {
fp = fopen(outfilename,"wb");
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(fp);
}
return 0;
}
Now I need to fetch a zip file from the server. Suppose the URL is of the format shown below:
#define URL "https://Server/File.zip"
For such URL, the code is not able to save the zip file.
How to achieve this?
I resolved the issue. The problem was with HTTPS connection. I had to add certificates for HTTPS.
Based on below links:
Can't connect to HTTPS site using cURL. Returns 0 length content instead
Getting no content from a HTTPS connection using CURL
#define CURL_STATICLIB
#include <stdio.h>
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
#include <string.h>
#include <stdlib.h>
#define false 0
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;
}
int main(void) {
CURL *curl;
FILE *fp;
CURLcode res;
const char url[] = "https://example.com/filename.zip";
const char outfilename[FILENAME_MAX] = "./json.zip";
curl_version_info_data * vinfo = curl_version_info(CURLVERSION_NOW);
if(vinfo->features & CURL_VERSION_SSL){
printf("CURL: SSL enabled\n");
}else{
printf("CURL: SSL not enabled\n");
}
curl = curl_easy_init();
if (curl) {
fp = fopen(outfilename,"wb");
/* Setup the https:// verification options. Note we */
/* do this on all requests as there may be a redirect */
/* from http to https and we still want to verify */
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_CAINFO, "./ca-bundle.crt");
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, false);
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, false);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
int i=fclose(fp);
if( i==0)
system("unzip -j json.zip");
}
return 0;
}
I am trying to write a program in C to download some files.
The source code:
#include <stdio.h>
#include <string.h>
#include <curl/curl.h>
#include <curl/easy.h>
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;
}
int main(){
if(curl_global_init(CURL_GLOBAL_ALL)){
printf("curl error. Exiting.\n");
return 1;
}
char links[3][100] = {
"http://download.freeroms.com/nes_roms/08/big_nose_the_caveman.zip",
"http://download.freeroms.com/nes_roms/02/contra.zip",
"http://download.freeroms.com/nes_roms/08/super_mario_bros._(usajapan).zip"};
int n = 0, k = 0;
char *lastslash;
char* name;
CURL *handle = curl_easy_init();
CURLcode res;
FILE *file;
while(n<3){
lastslash = strrchr(links[n], '/');
name = lastslash ? lastslash + 1 : links[n];
printf("\nURL: %s\n", links[n]);
printf("Filename: %s\n", name);
curl_easy_setopt(handle, CURLOPT_URL, links[n]);
curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, write_data);
file = fopen(name, "wb");
res = curl_easy_perform(handle);
fclose(file);
n++;
}
curl_easy_cleanup(handle);
return 0;
}
I can compile it, but this is the output when I run it :
URL: http://download.freeroms.com/nes_roms/08/big_nose_the_caveman.zip
Filename: big_nose_the_caveman.zip
Segmentation fault (core dumped)
My compiler setting:
gcc dl.c -lcurl -o dl
I found out that the problem occurs when it tries to execute curl_easy_perform(), but I don't know what to do with it.
try this coding.
#include <stdio.h>
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
#include <string>
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {
size_t written = fwrite(ptr, size, nmemb, stream);
return written;
}
int main(void) {
CURL *curl;
FILE *fp;
CURLcode res;
char *url = "http://localhost/aaa.txt";
char outfilename[FILENAME_MAX] = "C:\\bbb.txt";
curl = curl_easy_init();
if (curl) {
fp = fopen(outfilename,"wb");
curl_easy_setopt(curl, CURLOPT_URL, "http://localhost/aaa.txt");
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
/* always cleanup */
curl_easy_cleanup(curl);
fclose(fp);
}
return 0;
}
You need to open the file before you set the callback data. The FILE* is stored by value, not reference.
file = fopen(name, "wb");
curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
#define CURL_STATICLIB
#include <stdio.h>
#include <curl/curl.h>
#include <curl/types.h>
#include <curl/easy.h>
#include <string>
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;
}
int main(void) {
CURL *curl;
FILE *fp;
CURLcode res;
char *url = "http://localhost/aaa.txt";
char outfilename[FILENAME_MAX] = "C:\\bbb.txt";
curl = curl_easy_init();
if (curl) {
fp = fopen(outfilename,"wb");
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(fp);
}
return 0;
}
Some one has posted this code for a question. But on execution of this file the downloaded file is not saving in C drive rather a new txt file will be generating with name "C:\cat.txt"... I want the downloaded file will be stored in my desired location in hard drive.. can any one help me...
First, the default CURLOPT_WRITEFUNCTION accepts a FILE * and uses fwrite using whatever's been set with CURLOPT_WRITEDATA, so you don't need to override the function unless you're using curl as a Win32 DLL.
Also, you aren't checking the return from fopen, which may fail.
I suspect in this case that you either aren't recompiling your code, or are running a different binary from the one you built
I am building an application (on windows using Dev-C++) and I want it to download a file. I am doing this using libcurl (I have already installed the source code using packman). I found a working example (http://siddhantahuja.wordpress.com/2009/04/12/how-to-download-a-file-from-a-url-and-save-onto-local-directory-in-c-using-libcurl/) but it doesn't close the file after download is complete. I would like an example of how to download a file in C.
The example you are using is wrong. See the man page for easy_setopt. In the example write_data uses its own FILE, *outfile, and not the fp that was specified in CURLOPT_WRITEDATA. That's why closing fp causes problems - it's not even opened.
This is more or less what it should look like (no libcurl available here to test)
#include <stdio.h>
#include <curl/curl.h>
/* For older cURL versions you will also need
#include <curl/types.h>
#include <curl/easy.h>
*/
#include <string>
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {
size_t written = fwrite(ptr, size, nmemb, stream);
return written;
}
int main(void) {
CURL *curl;
FILE *fp;
CURLcode res;
char *url = "http://localhost/aaa.txt";
char outfilename[FILENAME_MAX] = "C:\\bbb.txt";
curl = curl_easy_init();
if (curl) {
fp = fopen(outfilename,"wb");
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
/* always cleanup */
curl_easy_cleanup(curl);
fclose(fp);
}
return 0;
}
Updated: as suggested by #rsethc types.h and easy.h aren't present in current cURL versions anymore.
Just for those interested you can avoid writing custom function by passing NULL as last parameter (if you do not intend to do extra processing of returned data).
In this case default internal function is used.
Details
http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTWRITEDATA
Example
#include <stdio.h>
#include <curl/curl.h>
int main(void)
{
CURL *curl;
FILE *fp;
CURLcode res;
char *url = "http://stackoverflow.com";
char outfilename[FILENAME_MAX] = "page.html";
curl = curl_easy_init();
if (curl)
{
fp = fopen(outfilename,"wb");
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, NULL);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(fp);
}
return 0;
}