From a5a19fd672bc0b8113d620669b557f17dccd343a Mon Sep 17 00:00:00 2001
From: Christian Schneider
Date: Thu, 26 Oct 2006 13:35:12 +0000
Subject: Moved itools to live branch

---
 urlcache/urlcache.class | 225 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 225 insertions(+)
 create mode 100644 urlcache/urlcache.class

(limited to 'urlcache/urlcache.class')

diff --git a/urlcache/urlcache.class b/urlcache/urlcache.class
new file mode 100644
index 0000000..790efa4
--- /dev/null
+++ b/urlcache/urlcache.class
@@ -0,0 +1,225 @@
+<?php
+/*
+**	$Id$
+**
+**	Relog Internet Tools 3 Library ("ITOOLS3")     
+**
+**	it_urlcache.class - Interface to URL content cache in DB
+**
+**	This class relies on a DB table with the following scheme:
+**	url		CHAR(255)	NOT NULL,
+**	updateinterval	INT		NOT NULL,
+**	lastupdate	INT		NOT NULL,
+**	nextupdate	INT		NOT NULL,
+**	contentmd5	CHAR(32)	NOT NULL,
+**	content		TEXT		NOT NULL,
+**	PRIMARY KEY	(url),
+**	KEY		(nextupdate)
+**
+**	$Log$
+**	Revision 1.2  2002/01/22 17:42:14  weber
+**	Changed set_socket_blocking() to socekt_set_blocking()
+**
+**	Revision 1.1  2000/01/28 02:37:55  cschneid
+**	Added URL cache class and simple script to be put into crontab
+**	
+*/
+
+/* PRIVATE */
+define("_IT_URLCACHE_DEFAULT_INTERVAL", 300);
+define("_IT_URLCACHE_MAX_CONNECTIONS", 30);
+
+class it_urlcache extends it_db_record
+{
+	/* PRIVATE */
+	var $default_interval = _IT_URLCACHE_DEFAULT_INTERVAL;
+	var $max_connections = _IT_URLCACHE_MAX_CONNECTIONS;
+
+function set_default_interval($default_interval)
+{
+	$this->default_interval = $default_interval;
+}
+
+
+function set_max_connections($max_connections)
+{
+	$this->max_connections = $max_connections;
+}
+
+
+/*
+ * Register an URL to be fetched by background process.
+ * Note: get() will return an empty string until the url is fetched for the
+ * first time
+ */
+function register($url)
+{
+	if (!$this->read($url))
+	{
+		$tags = array("url" => $url, "updateinterval" => $this->default_interval);
+		$this->create($tags);
+	}
+}
+
+
+/*
+ * Removes the url from the cache. It won't be fetched again until register()
+ * is called again.
+ */
+function unregister($url)
+{
+	if ($this->read($url))
+		$this->delete();
+}
+
+
+/*
+ * Get content of url. Returns empty string if it was never successfully
+ * fetched.
+ */
+function get_content($url)
+{
+	$this->read($url);
+	return $this->data['content'];
+}
+
+
+/*
+ * Try to refetch all URLs in the database.
+ * Note: This is intented for background process use only as it may take
+ * a while to finish...
+ */
+function update_cache()
+{
+	$now = time();
+	$pages = array();
+
+	$result = $this->table->safe_sql_select("WHERE nextupdate < $now", "url");
+
+	while (list($url) = $this->table->db->fetch_array($result))
+		$pages[] = $url;
+
+	$this->table->db->free($result);
+
+	$this->_fetch_urls($pages, $now);
+}
+
+
+/* PRIVATE */
+function _update_cache($url, $content, $now)
+{
+	$contentmd5 = md5($content);
+
+	if ($this->read($url))
+	{
+		$interval = $this->data['updateinterval'];
+		$age = $now - $this->data['lastupdate'];
+
+		if ($this->data['contentmd5'] == $contentmd5)
+		{
+			if ($age > ($interval * 2))
+				$interval = $interval * 1.5;
+
+			$tags = array("updateinterval" => $interval, "nextupdate" => $now + $interval);
+		}
+		else
+		{
+			if ($age < ($interval / 2))
+				$interval = $interval / 1.5;
+
+			if ($interval < $this->default_interval)
+				$interval = $this->default_interval;
+
+			$tags = array("updateinterval" => $interval, "lastupdate" => $now, "nextupdate" => $now + $interval, "contentmd5" => $contentmd5, "content" => $content);
+		}
+
+		$this->update($tags);
+	}
+	else
+	{
+		$tags = array("url" => $url, "updateinterval" => $this->default_interval, "lastupdate" => $now, "nextupdate" => $now + $this->default_interval, "contentmd5" => $contentmd5, "content" => $content);
+		$this->create($tags);
+	}
+}
+
+
+/*
+ * PRIVATE
+ * Fetch URL in array $urls and store update cache database accordingly
+ */
+function _fetch_urls($pages, $now)
+{
+	$pos = 0;
+	$fds = array();
+	$urls = array();
+	$content = array();
+	$count = 0;
+
+	for ($pos = 0; ($pos < count($pages)) && ($pos < $this->max_connections); $pos++)
+	{
+		debug("Opening $pages[$pos]", 10);
+
+		if ($fd = fopen($pages[$pos], "r"))
+		{
+			socket_set_blocking($fd, false);
+			$fds[] = $fd;
+			$urls[] = $pages[$pos];
+			$content[] = "";
+			$count++;
+			debug("Opened $pages[$pos]", 10);
+		}
+	}
+
+	while ($count > 0)
+	{
+		$read = 0;
+
+		for ($i = 0; $i < count($fds); $i++)
+		{
+			if ($fds[$i])
+			{
+				if (!feof($fds[$i]))
+				{
+					$data = fread($fds[$i], 4096);
+					$content[$i] .= $data;
+					$read += strlen($data);
+					debug("Read " . strlen($data) . " from $urls[$i]", 10);
+				}
+
+				if (feof($fds[$i]))
+				{
+					fclose($fds[$i]);
+					$fds[$i] = 0;
+					$count--;
+					$this->_update_cache($urls[$i], $content[$i], $now);
+					debug("Finished $urls[$i]: " . strlen($content[$i]) . " bytes", 10);
+
+					/* Schedule next url for retrieval */
+					if ($pos < count($pages))
+					{
+						if ($fd = fopen($pages[$pos], "r"))
+						{
+							socket_set_blocking($fd, false);
+							$fds[$i] = $fd;
+							$urls[$i] = $pages[$pos];
+							$content[$i] = "";
+							$count++;
+							debug("Opened $pages[$pos]", 10);
+						}
+
+						$pos++;
+					}
+				}
+			}
+		}
+
+		/* We are in non-blocking mode, be nice */
+		if (($count > 0) && ($read == 0))
+		{
+			sleep(1);
+			debug("Sleeping...", 10);
+		}
+	}
+}
+
+} /* End class it_urlcache */
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