From 0a3df5cbcfc10a0f18e9da311d887eb00fd6fbf1 Mon Sep 17 00:00:00 2001
From: Karl 'vollmerk' Vollmer <vollmer@ampache.org>
Date: Fri, 15 Jul 2005 06:50:58 +0000
Subject: added on the fly bandwidth management for downsampled users

---
 lib/stream.lib.php | 249 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 249 insertions(+)
 create mode 100644 lib/stream.lib.php

(limited to 'lib/stream.lib.php')

diff --git a/lib/stream.lib.php b/lib/stream.lib.php
new file mode 100644
index 00000000..a022b6da
--- /dev/null
+++ b/lib/stream.lib.php
@@ -0,0 +1,249 @@
+<?php
+/*
+
+ Copyright 2001 - 2005 Ampache.org
+ All Rights Reserved
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ as published by the Free Software Foundation; either version 2
+ of the License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+/**
+ * delete_now_playing
+ * This function checks to see if we should delete the last now playing entry now that it's
+ * finished streaming the song. Basicly this is an exception for WMP10
+ * @package General
+ * @catagory Now Playing
+ */
+function delete_now_playing($insert_id) { 
+
+        $user_agent = $_SERVER['HTTP_USER_AGENT'];
+
+        if (stristr($user_agent,"Windows-Media-Player")) {
+                // Commented out until I can figure out the
+                // trick to making this work
+                //return true;
+        }
+
+        
+        // Remove the song from the now_playing table
+        $sql = "DELETE FROM now_playing WHERE id = '$insert_id'";
+        $db_result = mysql_query($sql, dbh());
+
+} // delete_now_playing
+
+/** 
+ * gc_now_playing
+ * this is a garbage collection function for now playing this is called every time something
+ * is streamed
+ * @package General
+ * @catagory Now Playing
+ */
+function gc_now_playing() { 
+
+        $time = time();
+        $expire = $time - 1800;  // 86400 seconds = 1 day
+
+        $sql = "DELETE FROM now_playing WHERE start_time < $expire";
+        $db_result = mysql_query($sql, dbh());
+        
+} // gc_now_playing
+
+/**
+ * insert_now_playing
+ * This function takes care of inserting the now playing data
+ * we use this function because we need to do thing differently
+ * depending upon which play is actually streaming
+ * @package General
+ * @catagory Now Playing
+ */
+function insert_now_playing($song_id,$uid,$song_length) {
+
+        $user_agent = $_SERVER['HTTP_USER_AGENT'];
+        $time = time();
+
+        /* Windows Media Player is evil and it makes multiple requests per song */
+        if (stristr($user_agent,"NSPlayer")) { return false; }
+
+        /* Set the Expire Time */
+
+        // If they are using Windows media player
+        if (stristr($user_agent,"Windows-Media-Player")) {
+                // WMP does keep the session open so we need to cheat a little here
+                $expire = $time + $song_length;
+        }
+        else {
+                $expire = $time;
+        }
+
+        $sql = "INSERT INTO now_playing (`song_id`, `user`, `start_time`)" .
+                " VALUES ('$song_id', '$uid', '$expire')";
+
+        $db_result = mysql_query($sql, dbh());
+
+        $insert_id = mysql_insert_id(dbh());
+
+        return $insert_id;
+
+} // insert_now_playing
+
+/**
+ * check_lock_songs
+ * This checks to see if the song is already playing, if it is then it prevents the user
+ * from streaming it
+ * @package General
+ * @catagory Security
+ */
+function check_lock_songs($song_id) { 
+
+	$sql = "SELECT COUNT(*) FROM now_playing " . 
+		"WHERE song_id = '$song_id'";
+	$db_results = mysql_query($sql, dbh());
+
+	if (mysql_num_rows($db_results)) { 
+		return false;
+	}
+
+	return true;
+
+} // check_lock_songs
+
+/**
+ * start_downsample
+ * This is a rather complext function that starts the downsampling of a song and returns the 
+ * opened file handled
+ * @package General
+ * @catagory Downsample
+ * @param $song	The Song Object
+ */
+function start_downsample($song,$now_playing_id=0,$song_name=0) { 
+
+	/* Check to see if bitrates are set if so let's go ahead and optomize! */
+	$max_bitrate = conf('max_bitrate');
+	$min_bitrate = conf('min_bitrate');
+	$time = time();
+	$dbh = dbh();
+	$user_sample_rate = $GLOBALS['user']->prefs['sample_rate'];
+	$browser = new Browser();
+
+	if (!$song_name) { 
+		$song_name = $song->f_artist_full . " - " . $song->title . "." . $song->type;
+	}
+
+	if ($max_bitrate > 1 AND $min_bitrate < $max_bitrate) {   
+		$last_seen_time = $time - 1200; //20 min.
+
+		/**********************************
+		 * Commenting out the following, I'd rather have it slightly less accurate and avoid a 4 table join 
+      		// Count the users connected in the last 20 min using downsampling 
+		$sql = "SELECT COUNT(DISTINCT session.username) FROM session,user,user_preference,preferences " . 
+			"WHERE user.username = session.username AND session.expire > '$time' AND user.last_seen > $last_seen_time " . 
+			"AND preferences.name = 'play_type' AND user_preference.preference = preferences.id AND " . 
+			"user_preference.user = user.username AND user_preference.value='downsample'";
+		$db_result = mysql_query($sql, $dbh);
+		$results = mysql_fetch_row($db_result);
+
+		// The current number of connected users 
+		$current_users_count = $results[0];
+		************************************/
+		
+
+		$sql = "SELECT COUNT(*) FROM now_playing, user_preference, preferences" . 
+			"WHERE preferences.name = 'play_type' AND user_preference.preference = preferences.id " . 
+			"AND now_playing.user = user_preference.user AND user_preference.value='downsample'";
+		$db_results = mysql_query($sql,$dbh);
+		$results = mysql_fetch_row($db_result);
+
+		// Current number of active streams + 1 (the one we are starting)
+		$active_streams = $results[0] + 1;
+
+
+		/* If only one user, they'll get all available.  Otherwise split up equally. */
+		$sample_rate = floor($max_bitrate/$active_streams);
+
+		/* If min_bitrate is set, then we'll exit if the bandwidth would need to be split up smaller than the min. */
+		if ($min_bitrate > 1 AND ($max_bitrate/$active_streams) < $min_bitrate) {
+               
+			/* Log the failure */
+			if (conf('debug')) { 
+				log_event($user->username,' downsample ',"Error: Max bandwidith already allocated. $active_streams Active Streams"); 
+			}
+			
+			/* Toast the now playing entry, then tell em to try again later */
+			delete_now_playing($now_playing_id);
+			echo "Maximum bandwidth already allocated.  Try again later.";
+        	        exit();
+
+		}
+		else {
+               		$sample_rate = floor($max_bitrate/$active_streams);
+		} // end else
+      
+		/* Round to standard bitrates */
+		$sample_rate = 8*(floor($sample_rate/8));
+	
+		// Never go over the users sample rate 
+		if ($sample_rate > $user_sample_rate) { $sample_rate = $user_sample_rate; }	
+
+		if (conf('debug')) { 
+			log_event($GLOBALS['user']->username, ' downsample ',"Downsampled: $active_streams current active streams, downsampling to $sample_rate");
+		}
+
+	} // end if we've got bitrates
+
+	else { 
+		$sample_rate = $user_sample_rate;
+	}
+
+	/* Never Upsample a song */
+	if (($sample_rate*1000) > $song->bitrate) {
+		unset($sample_rate);
+	}
+
+	$sample_ratio = $sample_rate/($song->bitrate/1000);
+
+        $browser->downloadHeaders($song_name, $song->mime, false,$sample_ratio*$song->size);
+
+        /* Get Offset */
+	$offset = ( $start*$song->time )/( $sample_ratio*$song->size );
+        $offsetmm = floor($offset/60);
+        $offsetss = floor($offset-$offsetmm*60);
+        $offset   = sprintf("%02d.%02d",$offsetmm,$offsetss);
+
+        /* Get EOF */
+	$eofmm  = floor($song->time/60);
+        $eofss  = floor($song->time-$eofmm*60);
+        $eof    = sprintf("%02d.%02d",$eofmm,$eofss);
+
+        /* Replace Variables */
+        $downsample_command = conf('downsample_cmd');
+        $downsample_command = str_replace("%FILE%",$song->file,$downsample_command);
+        $downsample_command = str_replace("%OFFSET%",$offset,$downsample_command);
+        $downsample_command = str_replace("%EOF%",$eof,$downsample_command);
+        $downsample_command = str_replace("%SAMPLE%",$sample_rate,$downsample_command);
+
+        // If we are debugging log this event
+        if (conf('debug')) {
+		$message = "Start Downsample: $downsample_command";
+                log_event($GLOBALS['user']->username,' downsample ',$message);
+	} // if debug
+
+	$fp = @popen($downsample_command, 'r');
+
+	return ($fp);
+
+} // start_downsample
+
+?>
-- 
cgit