Send If-Modified-Since header on crawling and indexing

3 files changed, 40 insertions, 13 deletions

diff --git a/bin/index.php b/bin/index.php
index d110423..5a55427 100755
--- a/bin/index.php
+++ b/bin/index.php
@@ -24,27 +24,38 @@ function removeTags($doc, $tag) {
     }
 }
 
-$es = new Elasticsearch($GLOBALS['phinde']['elasticsearch']);
-
 $url = $argv[1];
-$existingDoc = $es->get($url);
-if ($existingDoc && $existingDoc->status == 'indexed') {
-    echo "URL already indexed: $url\n";
-    exit(0);
-}
-//FIXME: size limit
-//FIXME: sourcetitle, sourcelink
 
 $req = new \HTTP_Request2($url);
 $req->setConfig('follow_redirects', true);
 $req->setConfig('connect_timeout', 5);
 $req->setConfig('timeout', 10);
 $req->setConfig('ssl_verify_peer', false);
+//FIXME: size limit
+
+$es = new Elasticsearch($GLOBALS['phinde']['elasticsearch']);
+$existingDoc = $es->get($url);
+if ($existingDoc && $existingDoc->status == 'indexed') {
+    $nMoDate     = strtotime($existingDoc->modate);
+    $refreshtime = $GLOBALS['phinde']['refreshtime'];
+    if (time() - $nMoDate < $refreshtime) {
+        echo "URL already indexed less than $refreshtime seconds ago: $url\n";
+        exit(0);
+    }
+
+    $req->setHeader('If-Modified-Since: ' . date('r', $nMoDate));
+}
+//FIXME: sourcetitle, sourcelink
+
 $res = $req->send();
 //FIXME: try-catch
 
-//FIXME: delete if 401 gone or 404 when updating
-if ($res->getStatus() !== 200) {
+if ($res->getStatus() === 304) {
+    //not modified since last time
+    //FIXME: store "last try" time
+    exit(0);
+} else if ($res->getStatus() !== 200) {
+    //FIXME: delete if 401 gone or 404 when updating
     echo "Response code is not 200 but " . $res->getStatus() . ", stopping\n";
     //FIXME: update status
     exit(3);
diff --git a/data/config.php.dist b/data/config.php.dist
index 7eb8ccf..b4d7d5c 100644
--- a/data/config.php.dist
+++ b/data/config.php.dist
@@ -13,5 +13,7 @@ $GLOBALS['phinde'] = array(
     'subscriptions' => array(
         'http://www.example.org/feed',
     ),
+    //time in seconds after which URLs may be re-indexed
+    'refreshtime' => 86400,
 );
 ?>
\ No newline at end of file
diff --git a/src/phinde/Crawler.php b/src/phinde/Crawler.php
index 9b14878..43d9459 100644
--- a/src/phinde/Crawler.php
+++ b/src/phinde/Crawler.php
@@ -25,7 +25,11 @@ class Crawler
 
     public function crawl($url)
     {
-        $res       = $this->fetch($url);
+        $res = $this->fetch($url);
+        if ($res === false) {
+            return;
+        }
+
         $linkInfos = $this->extractLinks($res);
         if ($this->showLinksOnly) {
             $this->showLinks($linkInfos);
@@ -36,13 +40,23 @@ class Crawler
 
     protected function fetch($url)
     {
+        $existingDoc = $this->es->get($url);
+
         $req = new HttpRequest($url);
         $req->setHeader(
             'accept',
             implode(',', array_keys(static::$supportedIndexTypes))
         );
+        if ($existingDoc) {
+            $nMoDate = strtotime($existingDoc->modate);
+            $req->setHeader('If-Modified-Since: ' . date('r', $nMoDate));
+        }
+
         $res = $req->send();
-        if ($res->getStatus() !== 200) {
+        if ($res->getStatus() === 304) {
+            //not modified since last time, so don't crawl again
+            return false;
+        } else if ($res->getStatus() !== 200) {
             throw new \Exception(
                 "Response code is not 200 but "
                 . $res->getStatus() . ", stopping"