I'm trying to use libcurl in D to download a page that requires logging in first. At the moment though, I can't even get the logging in working. I tried with curl.exe, got it working, and used the --libcurl command to export C code that I then turned into (I think) equivalent D code.

The problem is that when I POST the login form, curl.exe gets a HTTP 200 to the correct page, whereas libcurl gets a HTTP 302 back to the login page, which is the same behaviour I noticed when cookies weren't being saved/reused.

I've tried with the HTTP struct functions, and also setting curl options explicitly like the C code does. Is there something I've missed?

import std.file;
import std.net.curl;
import std.stdio;

void main() {
	getLogon();
	postLogon();
	getIndex();
}

void getLogon()
{
	auto http = HTTP();
	http.onReceive = (ubyte[] data) { /+ drop +/ std.file.write("logon1.html", data); /+writeln(cast(char[])(data)); stdout.flush;+/ return data.length; };
	
	http.handle.set(CurlOption.tcp_nodelay, 1);
	http.handle.set(CurlOption.buffersize, 102400);
	http.handle.set(CurlOption.noprogress, 1);
	//http.handle.set(CurlOption.useragent, "curl/7.57.0");
	http.handle.set(CurlOption.maxredirs, 50);
	//http.handle.set(CurlOption.cainfo, "C:\\Users\\Josh\\Downloads\\curl-7.57.0-win64-mingw\\bin\\curl-ca-bundle.crt");
	http.handle.set(CurlOption.cookiejar, "cookie.dat");
	http.handle.set(CurlOption.cookiefile, "cookie.dat");
	http.handle.set(CurlOption.verbose, 1);
	
	http.handle.set(CurlOption.url, "https://foo.com/logon.php");
	http.method(HTTP.Method.get);
	
	http.perform();
}

void doLogon()
{
	auto http = HTTP();
	http.onReceive = (ubyte[] data) { /+ drop +/ std.file.write("logon2.html", data); /+writeln(cast(char[])(data)); stdout.flush;+/ return data.length; };
	
	http.handle.set(CurlOption.tcp_nodelay, 1);
	http.handle.set(CurlOption.buffersize, 102400);
	http.handle.set(CurlOption.noprogress, 1);
	//http.handle.set(CurlOption.useragent, "curl/7.57.0");
	http.handle.set(CurlOption.maxredirs, 50);
	//http.handle.set(CurlOption.cainfo, "C:\\Users\\Josh\\Downloads\\curl-7.57.0-win64-mingw\\bin\\curl-ca-bundle.crt");
	http.handle.set(CurlOption.cookiejar, "cookie.dat");
	http.handle.set(CurlOption.cookiefile, "cookie.dat");
	http.handle.set(CurlOption.verbose, 1);
	
	http.handle.set(CurlOption.url, "https://foo.com/logon.php");
	http.handle.set(CurlOption.postfields, "username=user&password=pass&Logon=submit");
	http.handle.set(CurlOption.postfieldsize_large, 52);
	http.method(HTTP.Method.post);
	
	http.perform();
}

void getIndex()
{
	auto http = HTTP();
	http.onReceive = (ubyte[] data) { /+ drop +/ std.file.write("index.html", data); /+writeln(cast(char[])(data)); stdout.flush;+/ return data.length; };
	
	http.handle.set(CurlOption.tcp_nodelay, 1);
	http.handle.set(CurlOption.buffersize, 102400);
	http.handle.set(CurlOption.noprogress, 1);
	//http.handle.set(CurlOption.useragent, "curl/7.57.0");
	http.handle.set(CurlOption.maxredirs, 50);
	//http.handle.set(CurlOption.cainfo, "C:\\Users\\Josh\\Downloads\\curl-7.57.0-win64-mingw\\bin\\curl-ca-bundle.crt");
	http.handle.set(CurlOption.cookiejar, "cookie.dat");
	http.handle.set(CurlOption.cookiefile, "cookie.dat");
	http.handle.set(CurlOption.verbose, 1);
	
	http.handle.set(CurlOption.url, "https://foo.com/index.php");
	http.method(HTTP.Method.get);
	
	http.perform();
}

libcurl verbose dump: https://pastebin.com/Sq60CLHV
curl.exe verbose dump: https://pastebin.com/KBDDNq9k

Thanks,

Josh

The POST C code was:

/********* Sample code generated by the curl command line tool **********
 * All curl_easy_setopt() options are documented at:
 * https://curl.haxx.se/libcurl/c/curl_easy_setopt.html
 ************************************************************************/
#include <curl/curl.h>

int main(int argc, char *argv[])
{
  CURLcode ret;
  CURL *hnd;

  hnd = curl_easy_init();
  curl_easy_setopt(hnd, CURLOPT_BUFFERSIZE, 102400L);
  curl_easy_setopt(hnd, CURLOPT_URL, "https://foo.com/logon.php");
  curl_easy_setopt(hnd, CURLOPT_POSTFIELDS, "username=user&password=pass&Logon=submit");
  curl_easy_setopt(hnd, CURLOPT_POSTFIELDSIZE_LARGE, (curl_off_t)52);
  curl_easy_setopt(hnd, CURLOPT_USERAGENT, "curl/7.57.0");
  curl_easy_setopt(hnd, CURLOPT_MAXREDIRS, 50L);
  curl_easy_setopt(hnd, CURLOPT_HTTP_VERSION, (long)CURL_HTTP_VERSION_2TLS);
  curl_easy_setopt(hnd, CURLOPT_CAINFO, "C:\\Users\\Josh\\Downloads\\curl-7.57.0-win64-mingw\\bin\\curl-ca-bundle.crt");
  curl_easy_setopt(hnd, CURLOPT_SSH_KNOWNHOSTS, "C:\\Users\\Josh\\AppData\\Roaming/_ssh/known_hosts");
  curl_easy_setopt(hnd, CURLOPT_COOKIEFILE, "cookie.dat");
  curl_easy_setopt(hnd, CURLOPT_COOKIEJAR, "cookie.dat");
  curl_easy_setopt(hnd, CURLOPT_VERBOSE, 1L);
  curl_easy_setopt(hnd, CURLOPT_TCP_KEEPALIVE, 1L);

  /* Here is a list of options the curl code used that cannot get generated
     as source easily. You may select to either not use them or implement
     them yourself.

  CURLOPT_WRITEDATA set to a objectpointer
  CURLOPT_INTERLEAVEDATA set to a objectpointer
  CURLOPT_WRITEFUNCTION set to a functionpointer
  CURLOPT_READDATA set to a objectpointer
  CURLOPT_READFUNCTION set to a functionpointer
  CURLOPT_SEEKDATA set to a objectpointer
  CURLOPT_SEEKFUNCTION set to a functionpointer
  CURLOPT_ERRORBUFFER set to a objectpointer
  CURLOPT_STDERR set to a objectpointer
  CURLOPT_DEBUGFUNCTION set to a functionpointer
  CURLOPT_DEBUGDATA set to a objectpointer
  CURLOPT_HEADERFUNCTION set to a functionpointer
  CURLOPT_HEADERDATA set to a objectpointer

  */

  ret = curl_easy_perform(hnd);

  curl_easy_cleanup(hnd);
  hnd = NULL;

  return (int)ret;
}
/**** End of sample code ****/

On Monday, 11 December 2017 at 03:53:25 UTC, Josh wrote:
> The POST C code was:
>
> /********* Sample code generated by the curl command line tool **********
>  * All curl_easy_setopt() options are documented at:
>  * https://curl.haxx.se/libcurl/c/curl_easy_setopt.html

Maybe off-topic but you can try http://code.dlang.org/packages/requests.