CODEWITHSUNDEEP
phpfileupdating
Supreme Dolphin
Supreme Dolphin

Reputation: 2584

How to update files in PHP

I have some PHP function that requires the line number of a CSV file used as database. Once it has line, it navigates to the specific value that needs to be changed, changes it and rewrites the whole files. Here is my code:

<?php
function update($file, $id, $field, $value)
 {
 //$id is the line number
  $contents = explode("\n", file_get_contents($file));
  $fh = fopen($file, "w");
  $lines = array();
  foreach($contents as $line)
   {
    if($line == "")
      continue;
  $fields = explode("|", $line);
  if($fields[0] == $id)
    {
     $line = null;
    for($i = 0; $i<count($fields); $i++)
       {
       if($i == $field)
        $fields[$i] = $value;
      if($i != count($fields)-1)
       $line .= $fields[$i]."|";
      else
       $line .= $fields[$i];
      }
   }
 $line .= "\n";
 fwrite($fh, $line);
}
fclose($fh);
$contents = null;
 return true;
}

$id = $_SESSION['id'];
$uid = $_GET['p'];
$myfile = "myfile.txt";

if(update($myfile, 12, 14, "somevalue"))
  echo "updated!";
?>

I am unable to find the problem because whenever I run the code, it outputs "updated!" just as it should but when check the file, I find it has not been updated. I do not know why, but it always remains the same! Thanks.

Upvotes: 2

Views: 2452

Answers (2)

Supreme Dolphin
Supreme Dolphin

Reputation: 2584

I found out what the problem was.

$id = $_SESSION['id'];
$uid = $_GET['p'];
$myfile = "myfile.txt";

if(update($myfile, 12, 14, "somevalue"))

The line number pointed to the previous line, which made it impossible to update the first line of the file. So all I had to do was

$line ++;

Upvotes: 0

Frank
Frank

Reputation: 664

Check that fwrite() is not failing.

Do something like this:

...
    $writeSuccess = (fwrite($fh, $line) !== false);
}
fclose($fh);
$contents = null;
return $writeSuccess;
}
...

If it is failing, check that your filesystem permissions are correctly set. The Apache user needs to have write access to whatever file/folder you are writing the file to.

Upvotes: 1

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