twitter_short.php

<?php
// based on https://stackoverflow.com/questions/12684765/twitter-api-returns-error-215-bad-authentication-data
define( 'ACCESS_TOKEN' , 'YOUR_ACCESS_TOKEN' );
define( 'ACCESS_TOKEN_SECRET' , 'YOUR_ACCESS_TOKEN_SECRET' );
define( 'CONSUMER_KEY' , 'YOUR_CONSUMER_KEY' );
define( 'CONSUMER_KEY_SECRET' , 'YOUR_CONSUMER_KEY_SECRET' );

// get the twitter ids of all followers of your account
$query = array(
    'screen_name' => 'YOUR_TWITTER_USERNAME',
    'stringify_ids' => true
);
$json = json_decode( twitterRequest( "https://api.twitter.com/1.1/followers/ids.json" , "GET" , $query ) );
var_dump( $json );

function twitterRequest( $url , $method , $query )
{
    // oauth parameters
    $oauth = array(
        'oauth_consumer_key' => CONSUMER_KEY,
        'oauth_token' => ACCESS_TOKEN,
        'oauth_nonce' => (string)mt_rand(),
        'oauth_timestamp' => time(),
        'oauth_signature_method' => 'HMAC-SHA1',
        'oauth_version' => '1.0'
    );

    // must be encoded before sorting
    $oauth = array_map( "rawurlencode" , $oauth ); 
    $query = array_map( "rawurlencode" , $query );

    $arr = array_merge( $oauth , $query ); // combine the values then sort
    asort( $arr ); // secondary sort (value)
    ksort( $arr ); // primary sort (key)

    // http_build_query automatically encodes, but the parameters are already encoded, and must be by this point, so we undo the encoding step
    $querystring = urldecode( http_build_query( $arr , '' , '&' ) );

    // mash everything together for the text to hash
    $base_string = $method."&".rawurlencode($url)."&".rawurlencode($querystring);

    // same with the key
    $key = rawurlencode(CONSUMER_KEY_SECRET)."&".rawurlencode(ACCESS_TOKEN_SECRET);

    // generate the hash, which is the oauth signature
    $oauth['oauth_signature'] = rawurlencode( base64_encode( hash_hmac( 'sha1' , $base_string , $key , true ) ) );

    // some query parameters include commas and they don't work when the parameter is urlencoded above, so decode it here and use it raw, WARNING: this may be a little hacky
    if ( $method == "GET" )
    {
        // build the GET parameters
        $url .= "?";
        while ( $element = current($query) )
        {
            $url .= key($query)."=".urldecode($element)."&";
            next($query);
        }
        $url = rtrim( $url , "&" );
    }
    else
    {
        // build the POST parameters
        $postParameters = "";
        while ( $element = current($query) )
        {
            $postParameters .= key($query)."=".urldecode($element)."&";
            next($query);
        }
        $postParameters = rtrim( $postParameters , "&" );
    }

    // this is the full value of the authorization line
    $auth = "OAuth ".urldecode( http_build_query( $oauth , '' , ', ' ) );

    // curl options
    $options = array( CURLOPT_HTTPHEADER => array("Authorization: $auth"),
                      CURLOPT_HEADER => false,
                      CURLOPT_URL => $url,
                      CURLOPT_RETURNTRANSFER => true,
                      CURLOPT_SSL_VERIFYPEER => false);

    // add the POST parameters
    if ( $method == "POST" )
    {
        $options[CURLOPT_POSTFIELDS] = $postParameters;
    }

    // curl
    $curl = curl_init();
    curl_setopt_array( $curl , $options );
    $result = curl_exec( $curl );
    curl_close( $curl );
    return $result;
}
?>