From 744edcf2abaa5b567c0642277d9cdc29df7dc1d5 Mon Sep 17 00:00:00 2001
From: Mike Macgirvin <mike@macgirvin.com>
Date: Tue, 12 Oct 2010 16:50:12 -0700
Subject: [PATCH] modularise webfinger and make it service agnostic

---
 boot.php             | 122 +++++++++++++++++++++++++++----------------
 mod/dfrn_request.php |   2 +-
 2 files changed, 78 insertions(+), 46 deletions(-)

diff --git a/boot.php b/boot.php
index 4deafe317c..bd6d6cc867 100644
--- a/boot.php
+++ b/boot.php
@@ -833,57 +833,89 @@ function convert_xml_element_to_array($xml_element, &$recursion_depth=0) {
 // Return an empty string if email-style addresses but webfinger fails,
 // or if the resultant personal XRD doesn't contain a DFRN profile.
 
-if(! function_exists('webfinger')) {
-function webfinger($s) {
+if(! function_exists('webfinger_dfrn')) {
+function webfinger_dfrn($s) {
 	if(! strstr($s,'@')) {
 		return $s;
 	}
-	$host = substr($s,strpos($s,'@') + 1);
-	$url = 'http://' . $host . '/.well-known/host-meta' ;
-	$xml = fetch_url($url);
-	if (! $xml)
-		return '';
-	$h = simplexml_load_string($xml);
-	$arr = convert_xml_element_to_array($h);
-
-	if(! isset($arr['xrd']['link']))
-		return '';
-
-	$link = $arr['xrd']['link'];
-	if(! isset($link[0]))
-		$links = array($link);
-	else
-		$links = $link;
-
-	foreach($links as $link)
-		if($link['@attributes']['rel'] && $link['@attributes']['rel'] === 'lrdd')
-			$tpl = $link['@attributes']['template'];
-	if((empty($tpl)) || (! strpos($tpl, '{uri}')))
-		return '';
-
-	$pxrd = str_replace('{uri}', urlencode('acct://'.$s), $tpl);
-
-	$xml = fetch_url($pxrd);
-	if (! $xml)
-		return '';
-	$h = simplexml_load_string($xml);
-	$arr = convert_xml_element_to_array($h);
-
-	if(! isset($arr['xrd']['link']))
-		return '';
-
-	$link = $arr['xrd']['link'];
-	if(! isset($link[0]))
-		$links = array($link);
-	else
-		$links = $link;
-
-	foreach($links as $link)
-		if($link['@attributes']['rel'] == NAMESPACE_DFRN)
-			return $link['@attributes']['href'];
+	$links = webfinger($s);
+	if(count($links)) {
+		foreach($links as $link)
+			if($link['@attributes']['rel'] == NAMESPACE_DFRN)
+				return $link['@attributes']['href'];
+	}
 	return '';
 }}
 
+// Given an email style address, perform webfinger lookup and 
+// return the array of link attributes from the personal XRD file.
+// On error/failure return an empty array.
+
+
+if(! function_exists('webfinger')) {
+function webfinger($s) {
+	$host = '';
+	if(strstr($s,'@')) {
+		$host = substr($s,strpos($s,'@') + 1);
+	}
+	if(strlen($host)) {
+		$tpl = fetch_lrdd_template($host);
+		if(strlen($tpl)) {
+			$pxrd = str_replace('{uri}', urlencode('acct://'.$s), $tpl);
+			$links = fetch_xrd_links($pxrd);
+			if(! count($links)) {
+				// try without the double slashes
+				$pxrd = str_replace('{uri}', urlencode('acct:'.$s), $tpl);
+				$links = fetch_xrd_links($pxrd);
+			}
+			return $links;
+		}
+	}
+	return array();
+}}
+
+// Given a host name, locate the LRDD template from that
+// host. Returns the LRDD template or an empty string on
+// error/failure.
+
+if(! function_exists('fetch_lrdd_template')) {
+function fetch_lrdd_template($host) {
+	$tpl = '';
+	$url = 'http://' . $host . '/.well-known/host-meta' ;
+	$links = fetch_xrd_links($url);
+	if(count($links)) {
+		foreach($links as $link)
+			if($link['@attributes']['rel'] && $link['@attributes']['rel'] === 'lrdd')
+				$tpl = $link['@attributes']['template'];
+	}
+	if(! strpos($tpl,'{uri}'))
+		$tpl = '';
+	return $tpl;
+}}
+
+// Given a URL, retrieve the page as an XRD document.
+// Return an array of links.
+// on error/failure return empty array.
+
+if(! function_exists('fetch_xrd_links')) {
+function fetch_xrd_links($url) {
+
+	$xml = fetch_url($url);
+	if (! $xml)
+		return array();
+	$h = simplexml_load_string($xml);
+	$arr = convert_xml_element_to_array($h);
+
+	if(isset($arr['xrd']['link'])) {
+		$link = $arr['xrd']['link'];
+		if(! isset($link[0]))
+			$links = array($link);
+		else
+			$links = $link;
+		return $links;
+	}
+	return array();
+}}
 
 // Convert an ACL array to a storable string
 
diff --git a/mod/dfrn_request.php b/mod/dfrn_request.php
index 1458ba8e46..3cb2a16a4d 100644
--- a/mod/dfrn_request.php
+++ b/mod/dfrn_request.php
@@ -181,7 +181,7 @@ function dfrn_request_post(&$a) {
 
 		// Canonicalise email-style profile locator
 
-		$url = webfinger($url);
+		$url = webfinger_dfrn($url);
 
 		if(! strlen($url)) {
 			notice( t("Unable to resolve your name at the provided location.") . EOL);