Library-Distribution · maul-esel · Apr 6, 2013 · Apr 6, 2013 · Apr 6, 2013 · Apr 6, 2013
diff --git a/ContentNegotiator.php b/ContentNegotiator.php
@@ -0,0 +1,60 @@
+<?php
+require_once(dirname(__FILE__) . '/config/content-negotiation.php');
+require_once(dirname(__FILE__) . '/modules/HttpException/HttpException.php');
+
+require_once(dirname(__FILE__) . '/JsonConverter.php');
+require_once(dirname(__FILE__) . '/YamlConverter.php');
+
+class ContentNegotiator {
+	private static $output_handlers = array('application/json' => 'JsonConverter' /*, 'text/x-yaml' => 'YamlConverter'*/);
+
+	public static function SupportedMimeTypes() {
+		$mimes = array();
+		$instances = array();
+
+		foreach (self::$output_handlers AS $mime => $handler) {
+			if (!isset($instances[$handler])) {
+				if (!class_exists($handler)) {
+					continue;
+				}
+				$instances[$handler] = new $handler();
+				if (!($instances[$handler] instanceof OutputConverter)) {
+					throw new HttpException(500, NULL, 'Unsupported converter for mime type "' . $mime . '"!');
+				}
+			}
+
+			if ($instances[$handler]->canRun()) {
+				$mimes[] = $mime;
+			}
+		}
+
+		return $mimes;
+	}
+
+	public static function MimeType() {
+		$additional = func_get_args();
+		$mimes = array_unique(array_merge(self::SupportedMimeTypes(), $additional));
+
+		if (isset($_SERVER['HTTP_ACCEPT'])) {
+			foreach(explode(',', $_SERVER['HTTP_ACCEPT']) as $value) {
+				list($suggested_mime) = explode(';', $value);
+				if (in_array($suggested_mime, $mimes)) {
+					return $suggested_mime;
+				}
+			}
+			throw new HttpException(406, array('Content-Type' => implode($mimes, ',')));
+		}
+		return DEFAULT_MIME_TYPE;
+	}
+
+	public static function Output(array $data, $namespace) {
+		$mime = self::MimeType();
+		$conv = new self::$output_handlers[$mime]();
+		$content = $conv->convert($data, $namespace); # canRun() is checked by <SupportedMimeTypes> already
+
+		header('Content-Type: ' . $mime);
+		echo $content;
+		exit;
+	}
+}
+?>
diff --git a/JsonConverter.php b/JsonConverter.php
@@ -0,0 +1,13 @@
+<?php
+require_once(dirname(__FILE__) . '/OutputConverter.php');
+
+class JsonConverter implements OutputConverter {
+	public function canRun() {
+		return function_exists('json_encode');
+	}
+
+	public function convert($data, $namespace = NULL) {
+		return json_encode($data);
+	}
+}
+?>
diff --git a/OutputConverter.php b/OutputConverter.php
@@ -0,0 +1,6 @@
+<?php
+interface OutputConverter {
+	public function canRun();
+	public function convert($data, $namespace);
+}
+?>
diff --git a/YamlConverter.php b/YamlConverter.php
@@ -0,0 +1,13 @@
+<?php
+require_once(dirname(__FILE__) . '/OutputConverter.php');
+
+class YamlConverter implements OutputConverter {
+	public function canRun() {
+		return function_exists('yaml_emit');
+	}
+
+	public function convert($data, $namespace = NULL) {
+		return yaml_emit($data);
+	}
+}
+?>
diff --git a/config/content-negotiation.php b/config/content-negotiation.php
@@ -0,0 +1,10 @@
+<?php
+	# The default output content type if no Accept header is given
+	define('DEFAULT_MIME_TYPE', 'application/json');
+	# This content type should of course be supported. For supported
+	# content types, see the ContentNegotiator class.
+	# To add support for a new content type, you must do the following:
+	# 1) add a converter class that implements OutputConverter. for an example, see YamlConverter.php.
+	# 2) require() the class in ContentNegotiator.php
+	# 3) map it to the according content types in the ContentNegotiator class
+?>
diff --git a/items/describe.php b/items/describe.php
@@ -2,6 +2,7 @@
 	require_once("../modules/HttpException/HttpException.php");
 	require_once("../db.php");
 	require_once("../util.php");
+	require_once('../ContentNegotiator.php');
 	require_once("../Assert.php");
 	require_once("../modules/semver/semver.php");
 	require_once('../Item.php');
@@ -15,7 +16,7 @@
 		Assert::GetParameters("id", array("name", "version"));
 
 		# validate accept header of request
-		$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml", "application/x-ald-package"), "application/json");
+		$content_type = ContentNegotiator::MimeType('application/x-ald-package');
 
 		# connect to database server
 		$db_connection = db_ensure_connection();

diff --git a/items/list.php b/items/list.php
@@ -2,6 +2,7 @@
 	require_once("../modules/HttpException/HttpException.php");
 	require_once("../db.php");
 	require_once("../util.php");
+	require_once('../ContentNegotiator.php');
 	require_once('../SortHelper.php');
 	require_once('../FilterHelper.php');
 	require_once("../User.php");
@@ -18,7 +19,7 @@
 		Assert::RequestMethod(Assert::REQUEST_METHOD_GET); # only allow GET requests
 
 		# validate accept header of request
-		$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml"), "application/json");
+		$content_type = ContentNegotiator::MimeType();
 
 		# connect to database server
 		$db_connection = db_ensure_connection();

diff --git a/items/rating.php b/items/rating.php
@@ -3,6 +3,7 @@
 	require_once("../Item.php");
 	require_once("../Assert.php");
 	require_once("../util.php");
+	require_once('../ContentNegotiator.php');
 	require_once("../db.php");
 	require_once('../sql2array.php');
 	require_once("../config/rating.php"); # import config settings
@@ -60,7 +61,7 @@
 
 		} else if ($request_method == Assert::REQUEST_METHOD_GET) {
 			# validate accept header of request
-			$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml", "application/x-ald-package"), "application/json");
+			$content_type = ContentNegotiator::MimeType();
 
 			$db_query = 'SELECT name AS user, rating FROM ' . DB_TABLE_RATINGS . ', ' . DB_TABLE_USERS . ' WHERE item = UNHEX("' . $id . '") AND `user` = `id`';
 			$db_result = $db_connection->query($db_query);

diff --git a/items/tags.php b/items/tags.php
@@ -2,13 +2,14 @@
 require_once('../modules/HttpException/HttpException.php');
 require_once('../db.php');
 require_once('../util.php');
+require_once('../ContentNegotiator.php');
 require_once('../Assert.php');
 
 try {
 	Assert::RequestMethod(Assert::REQUEST_METHOD_GET); # only allow GET requests
 
 	# validate accept header of request
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	# connect to database server
 	$db_connection = db_ensure_connection();

diff --git a/items/types.php b/items/types.php
@@ -1,10 +1,10 @@
 <?php
-	require_once('../util.php');
+	require_once('../ContentNegotiator.php');
 	require_once('../Assert.php');
 	require_once('ItemType.php');
 
 	Assert::RequestMethod(Assert::REQUEST_METHOD_GET);
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	$types = ItemType::getAllNames();
 

diff --git a/stdlib/candidates/create.php b/stdlib/candidates/create.php
@@ -1,6 +1,7 @@
 <?php
 require_once('../../modules/HttpException/HttpException.php');
 require_once('../../util.php');
+require_once('../../ContentNegotiator.php');
 require_once('../../Assert.php');
 require_once('../../User.php');
 require_once('../../Item.php');
@@ -16,7 +17,7 @@
 	Assert::GetParameters('id', array('name', 'version'));
 	Assert::PostParameters('reason');
 
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	if (!isset($_GET['id'])) {
 		$item = Item::getId($_GET['name'], $_GET['version']);

diff --git a/stdlib/candidates/describe.php b/stdlib/candidates/describe.php
@@ -1,14 +1,15 @@
 <?php
 require_once('../../modules/HttpException/HttpException.php');
 require_once('../../util.php');
+require_once('../../ContentNegotiator.php');
 require_once('../../Assert.php');
 require_once('Candidate.php');
 
 try {
 	Assert::RequestMethod(Assert::REQUEST_METHOD_GET);
 	Assert::GetParameters('id');
 
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	$candidate = Candidate::describe($_GET['id']);
 

diff --git a/stdlib/candidates/list.php b/stdlib/candidates/list.php
@@ -1,6 +1,7 @@
 <?php
 require_once('../../modules/HttpException/HttpException.php');
 require_once('../../util.php');
+require_once('../../ContentNegotiator.php');
 require_once('../../Assert.php');
 require_once('../../SortHelper.php');
 require_once('../../FilterHelper.php');
@@ -9,7 +10,7 @@
 try {
 	Assert::RequestMethod(Assert::REQUEST_METHOD_GET);
 
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	$filters = FilterHelper::FromParams(array('user', 'item', 'created', 'created-after', 'created-before', 'approved', 'owner'));
 	$sort_list = SortHelper::getListFromParam(isset($_GET['sort']) ? $_GET['sort'] : '');

diff --git a/stdlib/candidates/voting.php b/stdlib/candidates/voting.php
@@ -1,6 +1,7 @@
 <?php
 require_once('../../modules/HttpException/HttpException.php');
 require_once('../../util.php');
+require_once('../../ContentNegotiator.php');
 require_once('../../Assert.php');
 require_once('../../SortHelper.php');
 require_once('../../User.php');
@@ -46,7 +47,7 @@
 
 	} else {
 		Assert::GetParameters('id');
-		$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+		$content_type = ContentNegotiator::MimeType();
 
 		$filters = FilterHelper::FromParams(array('user', 'final', 'accept', 'voted', 'voted-after', 'voted-before'));
 		$sort_list = SortHelper::getListFromParam(isset($_GET['sort']) ? $_GET['sort'] : '');

diff --git a/stdlib/items.php b/stdlib/items.php
@@ -1,6 +1,7 @@
 <?php
 require_once('../modules/HttpException/HttpException.php');
 require_once('../util.php');
+require_once('../ContentNegotiator.php');
 require_once('../sql2array.php');
 require_once('../db.php');
 require_once('../Assert.php');
@@ -9,7 +10,7 @@
 
 try {
 	Assert::RequestMethod(Assert::REQUEST_METHOD_GET);
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	$db_connection = db_ensure_connection();
 	$db_sort = '';

diff --git a/stdlib/pending/list.php b/stdlib/pending/list.php
@@ -1,14 +1,15 @@
 <?php
 require_once('../../modules/HttpException/HttpException.php');
 require_once('../../util.php');
+require_once('../../ContentNegotiator.php');
 require_once('../../Assert.php');
 require_once('../../UpdateType.php');
 require_once('../StdlibPending.php');
 require_once('../releases/StdlibRelease.php');
 
 try {
 	Assert::RequestMethod(Assert::REQUEST_METHOD_GET);
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	if (isset($_GET['action'])) {
 		$action = UpdateType::getCode($_GET['action'], UpdateType::USAGE_STDLIB);

diff --git a/stdlib/releases/create.php b/stdlib/releases/create.php
@@ -1,5 +1,6 @@
 <?php
 	require_once("../../util.php");
+	require_once('../../ContentNegotiator.php');
 	require_once("../../Assert.php");
 	require_once("../../modules/HttpException/HttpException.php");
 	require_once("../../UpdateType.php");
@@ -12,7 +13,7 @@
 		Assert::RequestMethod(Assert::REQUEST_METHOD_POST);
 		Assert::GetParameters("type");
 
-		$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml"), "application/json");
+		$content_type = ContentNegotiator::MimeType();
 
 		$publish_status = StdlibRelease::PUBLISHED_BOTH;
 		if (!empty($_GET["base"]))

diff --git a/stdlib/releases/describe.php b/stdlib/releases/describe.php
@@ -3,6 +3,7 @@
 	require_once("../../db.php");
 	require_once("../../sql2array.php");
 	require_once("../../util.php");
+	require_once('../../ContentNegotiator.php');
 	require_once("../../modules/semver/semver.php");
 	require_once("../../Assert.php");
 	require_once("../../User.php");
@@ -17,7 +18,7 @@
 		Assert::GetParameters("version");
 
 		# validate accept header of request
-		$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml"), "application/json");
+		$content_type = ContentNegotiator::MimeType();
 
 		$publish_status = StdlibRelease::PUBLISHED_YES;
 		if (isset($_SERVER["PHP_AUTH_USER"]) && isset($_SERVER["PHP_AUTH_PW"]))

diff --git a/stdlib/releases/list.php b/stdlib/releases/list.php
@@ -1,6 +1,7 @@
 <?php
 	require_once("../../modules/HttpException/HttpException.php");
 	require_once("../../util.php");
+	require_once('../../ContentNegotiator.php');
 	require_once("../../User.php");
 	require_once('../../SortHelper.php');
 	require_once("../../Assert.php");
@@ -11,7 +12,7 @@
 		Assert::RequestMethod(Assert::REQUEST_METHOD_GET);
 
 		# validate accept header of request
-		$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml"), "application/json");
+		$content_type = ContentNegotiator::MimeType();
 
 		$publish_status = StdlibRelease::PUBLISHED_YES;
 		if (!empty($_GET["published"]))

diff --git a/users/describe.php b/users/describe.php
@@ -2,6 +2,7 @@
 	require_once("../modules/HttpException/HttpException.php");
 	require_once("../db.php");
 	require_once("../util.php");
+	require_once('../ContentNegotiator.php');
 	require_once("../User.php");
 	require_once("../Assert.php");
 	require_once("Suspension.php");
@@ -13,7 +14,7 @@
 		Assert::GetParameters("name", "id");
 
 		# validate accept header of request
-		$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml"), "application/json");
+		$content_type = ContentNegotiator::MimeType();
 
 		# connect to database server
 		$db_connection = db_ensure_connection();

diff --git a/users/list.php b/users/list.php
@@ -1,7 +1,8 @@
 <?php
 	require_once("../modules/HttpException/HttpException.php");
 	require_once("../db.php");
-	require_once("../util.php");
+	require_once('../util.php');
+	require_once('../ContentNegotiator.php');
 	require_once('../SortHelper.php');
 	require_once('../sql2array.php');
 	require_once("../Assert.php");
@@ -12,7 +13,7 @@
 		Assert::RequestMethod(Assert::REQUEST_METHOD_GET); # only allow GET requests
 
 		# validate accept header of request
-		$content_type = get_preferred_mimetype(array("application/json", "text/xml", "application/xml"), "application/json");
+		$content_type = ContentNegotiator::MimeType();
 
 		# connect to database server
 		$db_connection = db_ensure_connection();

diff --git a/users/suspensions/list.php b/users/suspensions/list.php
@@ -2,6 +2,7 @@
 require_once('../../Assert.php');
 require_once('../../modules/HttpException/HttpException.php');
 require_once('../../util.php');
+require_once('../../ContentNegotiator.php');
 require_once('../../SortHelper.php');
 require_once('../../FilterHelper.php');
 require_once('../../User.php');
@@ -27,7 +28,7 @@
 	}
 
 	# validate accept header of request
-	$content_type = get_preferred_mimetype(array('application/json', 'text/xml', 'application/xml', 'application/x-ald-package'), 'application/json');
+	$content_type = ContentNegotiator::MimeType();
 
 	$filters = FilterHelper::FromParams(array('active', 'created', 'created-after', 'created-before', 'expires', 'expires-after', 'expires-before', 'infinite', 'restricted'));
 	$sort_list = SortHelper::getListFromParam(isset($_GET['sort']) ? $_GET['sort'] : '');