Parte de Alexander y Kendrick PHP

reciver.php

 <?php
-	function read_and_delete_first_line($filename)
-	{
-		$file = file($filename);
-		array_shift($file);
-		file_put_contents($filename, $file);
-	}
-	$decoded_location  = json_decode(file_get_contents('php://input'));
-	$inTime = gmdate('H:i:s',time());
-	$file = 'db.txt';
-	$totalLines = intval(exec("wc -l '$file'"));
-	//echo $totalLines. "\n"; //For testing purposes
-	if($totalLines > 15)
-	{
-		read_and_delete_first_line("db.txt");
-	}
+        function read_and_delete_first_line($filename) // This function will delete the first line of db.txt.
+        {
+                $file = file($filename); //Makes the contents of db.txt into an array.
+                array_shift($file); //Removes the first element of the array.
+                file_put_contents($filename, $file); //Rewrites db.txt with the contents of the array.
+        }
+        $decoded_location  = json_decode(file_get_contents('php://input')); //Receives input from app and decodes the json recived.
+        $decoded_location->inTime = gmdate('H:i:s',time()); //Adds a new property to the object we get after decoding the json and stores the current time.
+	$encoded_location = json_encode($decoded_location); //Reencodes the object back into a json with the new inTime property.
+        $file = 'db.txt';
+        $totalLines = intval(exec("wc -l '$file'")); //Counts how many lines db.txt has.
+        //echo $totalLines. "\n"; //For testing purposes
+        if($totalLines > 15) //If db.txt has more than a specified amount of lines, it will delete the first line of db.txt.
+        {
+                read_and_delete_first_line("db.txt");
+        }
 
-	$db = fopen("db.txt","a") or die("FAILED TO ACCESS DATABASE");
-	fwrite($db,$decoded_location->latitude. "\t". $decoded_location->longitude. "\t". $inTime. "\n");
-	fclose($db);
-	//$totalLines = intval(exec("wc -l '$file'")); //For testing purposes
-	//echo $totalLines; //For testing purposes
+        $db = fopen("db.txt","a") or die("FAILED TO ACCESS DATABASE"); //Opens db.txt in append mode. If it somehow fails to open the database, an error message will be displayed.
+        fwrite($db,$encoded_location. "\n"); //Writes the newly encoded json into db.txt.
+        fclose($db); //Closes db.txt
+        //$totalLines = intval(exec("wc -l '$file'")); //For testing purposes
+        //echo $totalLines; //For testing purposes
 ?>