Using curl in php with client certificate and private key in separate files

Question

I need some assistance rewriting this PHP curl code that uses *.pem (CA cert), Client cert and private key in one file:

curl_setopt($curl, CURLOPT_URL, $this->url);
curl_setopt($curl, CURLOPT_HEADER, 0);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($curl, CURLOPT_SSLCERT, $this->keystore);
curl_setopt($curl, CURLOPT_CAINFO, $this->keystore);
curl_setopt($curl, CURLOPT_SSLKEYPASSWD, $this->keystorepassword);
curl_setopt($curl, CURLOPT_POSTFIELDS, $post);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

So it could use CA certificate, Client Certificate and Private Key in separate files.

As in this command-line example:

curl -d "var1=value1&var2=value2&..." -G -v --key key.pem --cacert ca.pem --cert client.pem:xxxxxx https://www.somesite.com/page

Answer 1

Here is a PHP script with a literal translation of your command line call:

<?php

  $data = "var1=value1&var2=value2&...";
  $url = "https://www.somesite.com/page";


  $keyFile = "key.pem";
  $caFile = "ca.pem";
  $certFile = "client.pem";
  $certPass = "xxxxxx";

  // Initialise cURL
  $ch = curl_init($actualUrl);

  // The -d option is equivalent to CURLOPT_POSTFIELDS. But...
  // PHP's libcurl interface does not implement the -G flag - instead you would
  // append $data to $url like this:
  $actualUrl = $url.'?'.$data;
  curl_setopt($ch, CURLOPT_URL, $actualUrl);

  // The -v flag only makes sense at the command line, but it can be enabled
  // with CURLOPT_VERBOSE - in this case the information will be written to
  // STDERR, or the file specified by CURLOPT_STDERR. I will ignore this for
  // now, but if you would like a demonstration let me know.

  // The --key option - If your key file has a password, you will need to set
  // this with CURLOPT_SSLKEYPASSWD
  curl_setopt($ch, CURLOPT_SSLKEY, $keyFile);

  // The --cacert option
  curl_setopt($ch, CURLOPT_CAINFO, $caFile);

  // The --cert option
  curl_setopt($ch, CURLOPT_SSLCERT, $certFile);
  curl_setopt($ch, CURLOPT_SSLCERTPASSWD, $certPass);

  /*
    Now we should get an identical request to the one created by your command
    line string, let's have a look at some of the other options you set...
  */

  // CURLOPT_HEADER is disabled by default, there's no need for this unless you
  // enabled it earlier
  //curl_setopt($ch, CURLOPT_HEADER, 0);

  // Your command line string forces a GET request with the -G option, are you
  // trying to POST or GET?
  //curl_setopt($ch, CURLOPT_POST, true);

  // We don't need body data with a GET request
  //curl_setopt($ch, CURLOPT_POSTFIELDS, $post);

  // Since we've gone to all the trouble of supplying CS information, we might
  // as well validate it!
  //curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);