Perform feed discovery correctly; fixes #118

lib/Database.php

@@ -411,13 +411,19 @@ class Database {
             throw new User\ExceptionAuthz("notAuthorized", ["action" => __FUNCTION__, "user" => $user]);
         }
         // check to see if the feed exists
-        $feedID = $this->db->prepare("SELECT id from arsse_feeds where url is ? and username is ? and password is ?", "str", "str", "str")->run($url, $fetchUser, $fetchPassword)->getValue();
+        $check = $this->db->prepare("SELECT id from arsse_feeds where url is ? and username is ? and password is ?", "str", "str", "str");
+        $feedID = $check->run($url, $fetchUser, $fetchPassword)->getValue();
+        if ($discover && is_null($feedID)) {
+            // if the feed doesn't exist, first perform discovery if requested and check for the existence of that URL
+            $url = Feed::discover($url, $fetchUser, $fetchPassword);
+            $feedID = $check->run($url, $fetchUser, $fetchPassword)->getValue();
+        }
         if (is_null($feedID)) {
-            // if the feed doesn't exist add it to the database; we do this unconditionally so as to lock SQLite databases for as little time as possible
+            // if the feed still doesn't exist in the database, add it to the database; we do this unconditionally so as to lock SQLite databases for as little time as possible
             $feedID = $this->db->prepare('INSERT INTO arsse_feeds(url,username,password) values(?,?,?)', 'str', 'str', 'str')->run($url, $fetchUser, $fetchPassword)->lastId();
             try {
                 // perform an initial update on the newly added feed
-                $this->feedUpdate($feedID, true, $discover);
+                $this->feedUpdate($feedID, true);
             } catch (\Throwable $e) {
                 // if the update fails, delete the feed we just added
                 $this->db->prepare('DELETE from arsse_feeds where id is ?', 'int')->run($feedID);
@@ -548,7 +554,7 @@ class Database {
         return array_column($feeds, 'id');
     }
     
-    public function feedUpdate($feedID, bool $throwError = false, bool $discover = false): bool {
+    public function feedUpdate($feedID, bool $throwError = false): bool {
         $tr = $this->db->begin();
         // check to make sure the feed exists
         if (!ValueInfo::id($feedID)) {
@@ -564,7 +570,7 @@ class Database {
         // here. When an exception is thrown it should update the database with the
         // error instead of failing; if other exceptions are thrown, we should simply roll back
         try {
-            $feed = new Feed((int) $feedID, $f['url'], (string) Date::transform($f['modified'], "http", "sql"), $f['etag'], $f['username'], $f['password'], $scrape, $discover);
+            $feed = new Feed((int) $feedID, $f['url'], (string) Date::transform($f['modified'], "http", "sql"), $f['etag'], $f['username'], $f['password'], $scrape);
             if (!$feed->modified) {
                 // if the feed hasn't changed, just compute the next fetch time and record it
                 $this->db->prepare("UPDATE arsse_feeds SET updated = CURRENT_TIMESTAMP, next_fetch = ? WHERE id is ?", 'datetime', 'int')->run($feed->nextFetch, $feedID);

lib/Feed.php

@@ -5,6 +5,7 @@ namespace JKingWeb\Arsse;
 use JKingWeb\Arsse\Misc\Date;
 use PicoFeed\PicoFeedException;
 use PicoFeed\Config\Config;
+use PicoFeed\Client\Client;
 use PicoFeed\Reader\Reader;
 use PicoFeed\Reader\Favicon;
 use PicoFeed\Scraper\Scraper;
@@ -12,31 +13,37 @@ use PicoFeed\Scraper\Scraper;
 class Feed {
     public $data = null;
     public $favicon;
-    public $parser;
-    public $reader;
     public $resource;
     public $modified = false;
     public $lastModified;
     public $nextFetch;
     public $newItems = [];
     public $changedItems = [];
+
+    public static function discover(string $url, string $username = '', string $password = ''): string {
+        // fetch the candidate feed
+        $f = self::download($url, "", "", $username, $password);
+        if ($f->reader->detectFormat($f->getContent())) {
+            // if the prospective URL is a feed, use it
+            $out = $url;
+        } else {
+            $links = $f->reader->find($f->getUrl(), $f->getContent());
+            if (!$links) {
+                // work around a PicoFeed memory leak FIXME: remove this hack (or not) once PicoFeed stops leaking memory
+                libxml_use_internal_errors(false);
+                throw new Feed\Exception($url, new \PicoFeed\Reader\SubscriptionNotFoundException('Unable to find a subscription'));
+            } else {
+                $out = $links[0];
+            }
+        }
+        // work around a PicoFeed memory leak FIXME: remove this hack (or not) once PicoFeed stops leaking memory
+        libxml_use_internal_errors(false);
+        return $out;
+    }
     
-    public function __construct(int $feedID = null, string $url, string $lastModified = '', string $etag = '', string $username = '', string $password = '', bool $scrape = false, bool $discover = false) {
+    public function __construct(int $feedID = null, string $url, string $lastModified = '', string $etag = '', string $username = '', string $password = '', bool $scrape = false) {
-        // set the configuration
-        $userAgent = Arsse::$conf->fetchUserAgentString ?? sprintf('Arsse/%s (%s %s; %s; https://code.jkingweb.ca/jking/arsse) PicoFeed (https://github.com/fguillot/picoFeed)',
-            Arsse::VERSION, // Arsse version
-            php_uname('s'), // OS
-            php_uname('r'), // OS version
-            php_uname('m') // platform architecture
-        );
-        $this->config = new Config;
-        $this->config->setMaxBodySize(Arsse::$conf->fetchSizeLimit);
-        $this->config->setClientTimeout(Arsse::$conf->fetchTimeout);
-        $this->config->setGrabberTimeout(Arsse::$conf->fetchTimeout);
-        $this->config->setClientUserAgent($userAgent);
-        $this->config->setGrabberUserAgent($userAgent);
         // fetch the feed
-        $this->download($url, $lastModified, $etag, $username, $password, $discover);
+        $this->resource = self::download($url, $lastModified, $etag, $username, $password);
         // format the HTTP Last-Modified date returned
         $lastMod = $this->resource->getLastModified();
         if (strlen($lastMod)) {
@@ -65,26 +72,40 @@ class Feed {
         $this->nextFetch = $this->computeNextFetch();
     }
 
-    protected function download(string $url, string $lastModified, string $etag, string $username, string $password, bool $discover): bool {
+    protected static function configure(): Config {
-        $action = $discover ? "discover" : "download";
+        $userAgent = Arsse::$conf->fetchUserAgentString ?? sprintf('Arsse/%s (%s %s; %s; https://thearsse.com/) PicoFeed (https://github.com/miniflux/picoFeed)',
+            Arsse::VERSION, // Arsse version
+            php_uname('s'), // OS
+            php_uname('r'), // OS version
+            php_uname('m') // platform architecture
+        );
+        $config = new Config;
+        $config->setMaxBodySize(Arsse::$conf->fetchSizeLimit);
+        $config->setClientTimeout(Arsse::$conf->fetchTimeout);
+        $config->setGrabberTimeout(Arsse::$conf->fetchTimeout);
+        $config->setClientUserAgent($userAgent);
+        $config->setGrabberUserAgent($userAgent);
+        return $config;
+    }
+
+    protected static function download(string $url, string $lastModified, string $etag, string $username, string $password): Client {
         try {
-            $this->reader = new Reader($this->config);
+            $reader = new Reader(self::configure());
-            $this->resource = $this->reader->$action($url, $lastModified, $etag, $username, $password);
+            $client = $reader->download($url, $lastModified, $etag, $username, $password);
+            $client->reader = $reader;
+            return $client;
         } catch (PicoFeedException $e) {
             throw new Feed\Exception($url, $e);
         }
-        return true;
     }
 
     protected function parse(): bool {
         try {
-            $this->parser = $this->reader->getParser(
+            $feed = $this->resource->reader->getParser(
                 $this->resource->getUrl(),
                 $this->resource->getContent(),
                 $this->resource->getEncoding()
-            );
+            )->execute();
-            $feed = $this->parser->execute();
-            
             // Grab the favicon for the feed; returns an empty string if it cannot find one.
             // Some feeds might use a different domain (eg: feedburner), so the site url is
             // used instead of the feed's url.
@@ -388,7 +409,7 @@ class Feed {
     }
 
     protected function scrape(): bool {
-        $scraper = new Scraper($this->config);
+        $scraper = new Scraper(self::configure());
         foreach (array_merge($this->newItems, $this->changedItems) as $item) {
             $scraper->setUrl($item->url);
             $scraper->execute();

tests/Feed/TestFeed.php

@@ -134,12 +134,13 @@ class TestFeed extends Test\AbstractTest {
     }
 
     public function testDiscoverAFeedSuccessfully() {
-        $this->assertInstanceOf(Feed::class, new Feed(null, $this->base."Discovery/Valid", "", "", "", "", false, true));
+        $this->assertSame($this->base."Discovery/Feed", Feed::discover($this->base."Discovery/Valid"));
+        $this->assertSame($this->base."Discovery/Feed", Feed::discover($this->base."Discovery/Feed"));
     }
 
     public function testDiscoverAFeedUnsuccessfully() {
         $this->assertException("subscriptionNotFound", "Feed");
-        new Feed(null, $this->base."Discovery/Invalid", "", "", "", "", false, true);
+        Feed::discover($this->base."Discovery/Invalid");
     }
 
     public function testParseEntityExpansionAttack() {

tests/lib/Database/SeriesSubscription.php

@@ -133,9 +133,9 @@ trait SeriesSubscription {
         $feedID = $this->nextID("arsse_feeds");
         $subID = $this->nextID("arsse_subscriptions");
         Phake::when(Arsse::$db)->feedUpdate->thenReturn(true);
-        $this->assertSame($subID, Arsse::$db->subscriptionAdd($this->user, $url));
+        $this->assertSame($subID, Arsse::$db->subscriptionAdd($this->user, $url, "", "", false));
         Phake::verify(Arsse::$user)->authorize($this->user, "subscriptionAdd");
-        Phake::verify(Arsse::$db)->feedUpdate($feedID, true, true);
+        Phake::verify(Arsse::$db)->feedUpdate($feedID, true);
         $state = $this->primeExpectations($this->data, [
             'arsse_feeds'         => ['id','url','username','password'],
             'arsse_subscriptions' => ['id','owner','feed'],
@@ -145,15 +145,33 @@ trait SeriesSubscription {
         $this->compareExpectations($state);
     }
 
+    public function testAddASubscriptionToANewFeedViaDiscovery() {
+        $url = "http://localhost:8000/Feed/Discovery/Valid";
+        $discovered = "http://localhost:8000/Feed/Discovery/Feed";
+        $feedID = $this->nextID("arsse_feeds");
+        $subID = $this->nextID("arsse_subscriptions");
+        Phake::when(Arsse::$db)->feedUpdate->thenReturn(true);
+        $this->assertSame($subID, Arsse::$db->subscriptionAdd($this->user, $url, "", "", true));
+        Phake::verify(Arsse::$user)->authorize($this->user, "subscriptionAdd");
+        Phake::verify(Arsse::$db)->feedUpdate($feedID, true);
+        $state = $this->primeExpectations($this->data, [
+            'arsse_feeds'         => ['id','url','username','password'],
+            'arsse_subscriptions' => ['id','owner','feed'],
+        ]);
+        $state['arsse_feeds']['rows'][] = [$feedID,$discovered,"",""];
+        $state['arsse_subscriptions']['rows'][] = [$subID,$this->user,$feedID];
+        $this->compareExpectations($state);
+    }
+
     public function testAddASubscriptionToAnInvalidFeed() {
         $url = "http://example.org/feed1";
         $feedID = $this->nextID("arsse_feeds");
         Phake::when(Arsse::$db)->feedUpdate->thenThrow(new FeedException($url, new \PicoFeed\Client\InvalidUrlException()));
         try {
-            Arsse::$db->subscriptionAdd($this->user, $url);
+            Arsse::$db->subscriptionAdd($this->user, $url, "", "", false);
         } catch (FeedException $e) {
             Phake::verify(Arsse::$user)->authorize($this->user, "subscriptionAdd");
-            Phake::verify(Arsse::$db)->feedUpdate($feedID, true, true);
+            Phake::verify(Arsse::$db)->feedUpdate($feedID, true);
             $state = $this->primeExpectations($this->data, [
                 'arsse_feeds'         => ['id','url','username','password'],
                 'arsse_subscriptions' => ['id','owner','feed'],