PHP fopen and fwrite throws no error, but the files aren't written to or created. Why?

Question

I am simply trying to pass some information to a PHP script using jquery $.post() and then write that information to a text file. The post is working just fine. No errors are thrown, as far as I know...but the files aren't created and when I put the file there it isn't written to. Am I missing something? Here's my code.

JavaScript

  var ajaxData = { IGC: JSON.stringify(containerObj), filename: newFilePath };
  $.post( "../php/generateIGC.php", ajaxData, function(data) {
        $('#generated_textarea').val(data)
  })

Originally I tried to interpret what was being sent and write it to the file.

PHP

<?php
  $data = json_decode(stripslashes($_POST['IGC']), true);
  $myFile = $_POST['filename'];
  $handle = fopen($myFile, 'w'); //or die('Cannot open file:  '.$myFile); 
  fwrite($handle,$data);
  fclose($handle);
  echo "File successfully created";
?>

Then I gave up and just tried to write to a file that I created for testing, and even this won't work.

<?php

  $data = 'dfjlsdkfsdlfkj';
  $handle = fopen('test.txt', 'w'); //or die('Cannot open file:  '.$myFile); 
  fwrite($handle,$data);
  fclose($handle);

 ?>

I'm not getting any error in the browser, and the post succeeds. The only indication I have that something isn't working is the file not being written to or created, and when I access (data) I just get a string of the php script. What am I doing wrong here?

UPDATE:

I changed the php script to this

<?php
 $data = json_decode(stripslashes($_POST['IGC']), true);
 $myFile = $_POST['filename']
 $handle = fopen('test.txt', 'w') or die('Cannot open file:  '.$myFile); 
 fwrite($handle,$data);
 fclose($handle);
 return $data;
 ?>

and now I get the error:

kCFErrorDomainCFNetwork error 1.)

Here is the post function if it helps

    function genCode() {
  var path = $('#path_to_image').val();
  var index = path.length
  for (var i = 1; i<=3; i++) {
    index = path.lastIndexOf('/',index-1)
  }
  var fileToCreate = path.substring(path.lastIndexOf('/')+1,path.lastIndexOf('.'))+'.igc'
  var newFilePath = path.substring(0,path.lastIndexOf('.'))+'.igc'
  containerObj["target_container"] = $('#target_container').val();
  containerObj["img_path"] = path.substring(index+1);
  containerObj["img_dims"] = {x: w, y: h};
  containerObj["mode"] = $('#number_of_axes').val();
  containerObj["sd"] = {x1: $('#sd_x1').val(), y1: $('#sd_y1').val(), x2: $('#sd_x2').val(), y2: $('#sd_y2').val()};
  containerObj["number_of_graphs"] = $('#number_of_graphs').val();
  var show_waypoints = false;
  containerObj["show_waypoints"] = false;
  //$('#generated_textarea').val("attachGraph.addGraph(" + JSON.stringify(containerObj, null, '\t') + ");");
  var ajaxData = { IGC: JSON.stringify(containerObj), filename: newFilePath };
 /*   $.ajax({
      type: "POST",
      url: "../php/generateIGC.php",
      data: ajaxData,
      success: function() {
        $('#generated_textarea').val("File created.")
      }
      })
    })
   */ $.post( "../php/generateIGC.php", ajaxData, function(data) {
        $('#generated_textarea').val(data)
    } )
}

Answer 1

It can me a lot of things, you should be aware of the path you are trying to write and also you should tweak the configuration of PHP to show errors since all file operations produce a WARNING that does not halt your script.

<?php
ini_set('display_errors', 1); // show errors
error_reporting(-1); // of all levels
date_default_timezone_set('UTC'); // PHP will complain about on this error level

if (!isset($_POST['IGC'])) { // Test if this was posted
    echo "IGC not defined";
    exit;
}

if (!isset($_POST['filename'])) { // Test if this was posted too
    echo "filename not defined."
    exit;
}
$data = json_decode(stripslashes($_POST['IGC']), true);
$myFile = $_POST['filename'];
$fileToWrite = 'test.txt';
if (!is_writable($fileToWrite)) { // Test if the file is writable
    echo "Cannot write to {$fileToWrite}";
    exit;
}

$handle = fopen($fileToWrite, 'w');
if (!is_resource($handle)) { // Test if PHP could open the file
    echo "Could not open {$fileToWrite} for writting."
    exit;
}

fwrite($handle,$data);
fclose($handle);
echo "File successfully created";
?>

This script as your upload PHP script should give you better details on your problem. The only thing you would have to be sure is where the file you are editing is, and if PHP has permission to write to it.

If you do not use an absolute path on the filename, PHP will try to write in the directory of the script.

Answer 2

Finally "solved" this problem. I had been accidentally running the html page locally, and not through the apache server, so the php couldn't run. Additionally, the txt files didn't have write access and there were some errors in my code originally. All pretty silly though.