General Curl Helper Function for PHP scripts

curl_helper.php

<?php


/**
 * @author Will Woodlief
 * @license MIT
 * 
 * General Curl Helper. Its multipurpose. Used it in the transcription project and now improved it
 * @example curl_helper('cnn.com',null,$code)
 *          curl_helper('enri.ch',['var1'=>4],$code)
 * @param $url string the url
 * @param $fields array|null the params to pass
 * @param &$http_code integer , will be set to the integer return code of the server. Its only an output variable
 * @param $b_post boolean , default true . POST is true, GET is false
 * @param  $format string (json|xml|text) default json <p>
 *      Tells how the response is formatted, text means no conversion
 * </p>
 * @param $b_verbose boolean, default false. If set to true will print to screen the connection process
 * @param $b_header_only boolean, default false <p>
 *  if true then no body is downloaded, and the return the headers
 * </>
 * @return array|string|int|null depends on the format and option
 * @throws \Exception <p>
 *      if curl cannot connect or has error,
 *      if the site gives a response of 0 or greater than 500 (if $b_header_only is false)
 *      if the format is json and the the conversion has errors
 *      if the format is xml and the conversion has errors
 *
 */
function curl_helper($url, array $fields = null, &$http_code, $b_post=true , $format = 'json', $b_verbose=false, $b_header_only = false)
{
    $ch = curl_init();
    try {
        curl_setopt_array($ch, [
            CURLOPT_RETURNTRANSFER => true,
        ]);

        //curl will not print verbose info to the html browser screen. So we have to capture it and replay it
        $verbose = null;
        if ($b_verbose) {
            $verbose = fopen('php://temp', 'w+');
            curl_setopt($ch, CURLOPT_STDERR, $verbose);
            curl_setopt($ch, CURLOPT_VERBOSE, true);
        }

        if ($b_header_only) {
            curl_setopt($ch, CURLOPT_HEADER, true);    // we want headers
            curl_setopt($ch, CURLOPT_NOBODY, true);    // we don't need body
        }

        //if testing on localhost and url is https, then this gets around it because some localhost do not have ssl certs

        if (isset($_SERVER['REMOTE_ADDR'])) {
            if( in_array( $_SERVER['REMOTE_ADDR'], array( '127.0.0.1', '::1' ) ) ) {
                curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
            }
        }


        if ($b_post) {
            curl_setopt($ch, CURLOPT_POST, 1);
            if ($fields) {
                curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
            }

        } else {
            if ($fields) {
                $query = http_build_query($fields);
                $url = $url . '?' . $query;
            }
        }

        curl_setopt($ch, CURLOPT_URL, $url);

        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);




        $curl_output = curl_exec($ch);

        if ($b_verbose) {
            rewind($verbose);
            $verboseLog = stream_get_contents($verbose);
            echo "Verbose information:\n<pre>", htmlspecialchars($verboseLog), "</pre>\n";
        }



        $http_code = intval(curl_getinfo($ch, CURLINFO_HTTP_CODE));

        if (curl_errno($ch)) {
            throw new \Exception("could not open url: $url because of curl error: " . curl_error($ch));
        } else {
            curl_close($ch);
        }

        if ($b_header_only) {

            $header_array=array();
            $data=explode("\n",$curl_output);
            $header_array['status']=$data[0];
            array_shift($data);
            foreach($data as $part){
                $middle=explode(":",$part);
                $header_array[trim($middle[0])] = trim($middle[1]);
            }

            return $header_array; //journey ends here with just the headers
        }

        if ($http_code == 0 || $http_code >= 500) {
            throw new \Exception("Could not send data to $url, response was " . $http_code);
        }

        if (!is_string($curl_output) || !strlen($curl_output)) {
            throw new \Exception("could not get contents from : $url  ");
        }

        //makes it easy to skip formatting
        if ($format === true || !$format) {
            $format = 'none';
        }
        switch ($format) {
            case 'json':
                //** @link https://gist.github.com/willwoodlief/9c431fbb55b376982b28cd20dc29d29f */
                $header_array = JsonHelpers::fromString($curl_output);
                break;
            case 'xml':
                $header_array = simplexml_load_string($curl_output);
                if ($header_array === null) {
                    throw new \Exception("failed to decode as xml: $curl_output");
                }
                break;
            default: {
                $header_array = $curl_output;
            }
        }


        return $header_array;
    }
    finally {
        //always close curl, in case we need to do a lot of this. Its a limited resource
        curl_close ($ch);
    }
}