Twitter stream as a feed in Atom format (using oauth)

twitterfeed.php

<?
/**
 * twitterfeed.php
 *
 * A single file script which serves an authenticated personal Twitter timeline as an Atom feed.
 * 
 * To use: 
 * 	1) Go to https://dev.twitter.com/apps and create a new App
 * 	2) Use the Authentication button to create the tokens/secrets needed
 * 	3) Copy the results into the appropriate spots below
 * 	4) Add your screen name and full name. 
 * 	5) Serve chilled with a peanut butter and jelly sandwich
 * 
 * 
 * @author Russell Beattie <russ@russellbeattie.com>
 * @version 0.001
 * @license 100% FREE TO COPY/USE FOR ANY PURPOSE, BUT DON'T BUG ME ABOUT IT, EVER.
 *
 * 16 October 2012
 */

	date_default_timezone_set('America/Los_Angeles');
	ini_set('display_errors', 0);

	$user_screen_name = 'CHANGE_ME';
	$user_full_name = 'CHANGE ME TOO';


// Twitter App Settings (https://dev.twitter.com/apps): 

	$settings = array(
	  'consumer_key' => '',
	  'consumer_secret' => '',
	  'access_token' => '',
	  'access_token_secret' => ''
	);


// API: https://dev.twitter.com/docs/api/1.1/get/statuses/home_timeline

	$api_url = 'https://api.twitter.com/1.1/statuses/home_timeline.json';

	$api_params = array(
		'count' => 40,
		'contributor_details' => 'false',
		'include_entities' => 'false'
	);

// OAuth: 

	function oauth_encode($data){
		if(is_array($data)){
			return array_map('oauth_encode', $data);
		} else if(is_scalar($data)) {
			return str_ireplace(array('+', '%7E'), array(' ', '~'), rawurlencode($data));
		} else {
			return '';
		}
	}

// OAuth base settings

	$oauth_params = array(
		'oauth_consumer_key' => $settings['consumer_key'],
		'oauth_nonce' => md5(microtime() . mt_rand()),
		'oauth_signature_method' => 'HMAC-SHA1',
		'oauth_timestamp' => time(),
		'oauth_token' => $settings['access_token'],
		'oauth_version' => '1.0',
	);

// Sign OAuth params

	$sign_params = array_merge($oauth_params, $api_params);

	uksort($sign_params, 'strcmp');

	foreach ($sign_params as $k => $v) {
		$sparam[] = oauth_encode($k) . '=' . oauth_encode($v);
	}
		
	$sparams = implode('&', $sparam);

	$base_string = 'GET&' . oauth_encode($api_url) . '&' . oauth_encode($sparams);

	$signing_key = oauth_encode($settings['consumer_secret']) . '&' . oauth_encode($settings['access_token_secret']);

	$oauth_params['oauth_signature'] = oauth_encode(base64_encode(hash_hmac('sha1', $base_string, $signing_key, TRUE)));


// Set Authorization header: 

	uksort($oauth_params, 'strcmp');

	foreach ($oauth_params as $k => $v) {
	  $hparam[] = $k . '="' . $v . '"';
	}

	$hparams = implode(', ', $hparam);

	$headers = array();
	$headers['Expect'] = '';
	$headers['Authorization'] = 'OAuth ' . $hparams; 

	foreach ($headers as $k => $v) {
		$curlheaders[] = trim($k . ': ' . $v);
	}

// Format params: 

	foreach ($api_params as $k => $v) {
		$rparam[] = $k . '=' . $v;
	}
	
	$rparams = implode('&', $rparam);


 // echo "curl --get '" . $api_url . "' --data '" . $rparams . "' --header 'Authorization: OAuth " . $hparams . "' --verbose" . PHP_EOL;


// GET:

	$ch = curl_init();    
	curl_setopt($ch, CURLOPT_URL, $api_url . '?' . $rparams);
	curl_setopt($ch, CURLOPT_HTTPHEADER, $curlheaders);
	curl_setopt($ch, CURLOPT_HEADER, false);
	curl_setopt($ch, CURLINFO_HEADER_OUT, true);
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
	curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
	curl_setopt($ch, CURLOPT_TIMEOUT, 10 );

	$response = curl_exec($ch);
	$code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
	$info = curl_getinfo($ch);
	$error = curl_error($ch);
	$errno = curl_errno($ch);
	
	curl_close($ch);

	if($code != 200){

		echo 'Error' . PHP_EOL;
		echo $code . PHP_EOL;
		print_r($response);
		print_r($info);

	} else {

		$all = json_decode($response, true);

		$updated = date(DATE_ATOM, strtotime($all[0]['created_at']));

		header('Content-type: application/atom+xml; charset=UTF-8', true);

		echo '<?xml version="1.0" encoding="utf-8"?' . '>' . PHP_EOL;

?>
<feed xml:lang="en-US" xmlns="http://www.w3.org/2005/Atom">
<title>Twitter / <?=$user_screen_name?></title>
<id>tag:twitter.com,2007:Status</id>
<link type="text/html" rel="alternate" href="http://twitter.com/<?=$user_screen_name?>"/>
<link type="application/atom+xml" rel="self" href="http://<?=$_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"]?>"></link>
<updated><?=$updated?></updated>
<subtitle>Twitter updates from <?=$user_full_name?>.</subtitle>
<?

		foreach($all as $row){

			$id = $row['id_str'];
			$text = $row['text'];
			$name = htmlspecialchars($row['user']['name']);
			$screen_name = $row['user']['screen_name'];
			$url = $row['user']['url'];
			$profile_image_url = $row['user']['profile_image_url'];
			$source = htmlspecialchars($row['source']);
			
			$created = date(DATE_ATOM, strtotime($row['created_at']));

			$entry = htmlspecialchars($row['user']['screen_name'] . ': ' . $row['text']);

?>
	<entry>
	<title><?=$entry?></title>
	<content type="html"><?=$entry?></content>
	<id>tag:twitter.com,2007:http://twitter.com/<?=$screen_name?>/status/<?=$id?></id>
	<published><?=$created?></published>
	<updated><?=$created?></updated>
	<link type="text/html" rel="alternate" href="http://twitter.com/<?=$screen_name?>/status/<?=$id?>"/>
	<link type="image/png" rel="image" href="<?=$profile_image_url?>"/>
	<author>
	<name><?=$name?></name>
	<uri><?=$url?></uri>
	</author>
	</entry>
<?
		}
?>
</feed>
<?
		

		exit();

	}