Question

So I have a file called cache, which stores traffic analysis of a site, using multidimensional arrays.

cache.php

$traffic_array=array("date_ip_uniqueNU"=>array("pageviews"=>34,"time_enteredOnsite"=>"12:00"),"date_ip_uniqueNU"=>array("pageviews"=>34,"time_enteredOnsite"=>"12:00"));//ect ect

Now, I need to somehow append to the array above.

I could simply just read the whole file, go through and rebuild the array in a foreach loop, and then just re-write the whole file, something like this:

include('cache.php');

foreach($traffic_array as $mainKey){

$rebuild_contents.="array("something"=>array("pageviews"=>".$mainKey['pageviews'].","time_enteredOnsite"=>".$mainKey['time_enteredOnsite'].");"//so I'm just building a string containing all the code to re-write the file.

} 

//then write to the file

$file="cache.php";

$content_to_put"\<? \$traffic_array=\"$rebuild_content\";"

file_put_contents($file,$content_to_put);

//NOTE: I just quickly wrote this up now, so expect syntax errors.

So do you see what I’ve done above – Simply rebuild the array contents into a string, and then write that string into the cache file.

But, I’m sure there is a much better approach to this, so can someone help me out?

Thank you! xD

EDIT: Also a problem with the method above, If this process was to happen multiple times, at the EXACT same millisecond – something would mess up, right?

Answer 1

It’s very, hm, strange method of caching.
Let suppose that you wish to change some php code in the file.

file_put_contents have ability to append the data to end of file, call this method with flag FILE_APPEND (details).
You may change method of defining array to like this:

$traffic_array[new key 1] = array(new data 1);
$traffic_array[new key 2] = array(new data 2);
...

And then you just add content to end of file like this

file_put_contents($file, '$traffic_array[your new key] = array(data for adding);', FILE_APPEND);

But if you may not change method of defining the array traffic_array then file_put_contents not for you. Use fopen() with flag ‘r+’, use fseek() for move a pointer to to correct place for put new data at the file, fwrite() for write only new data, and fclose().

// Content of file: <?php $a = array('k' => array(), 'k2' => array());\n
$f = fopen('file', 'r+');
fseek($f, -3, SEEK_END); // place the pointer after last value of array, before ");\n"; cont from end
fwrite($f, ", 'k3' => array('f'=>'a'));\n"); // put new data, also add overwrited data ");\n"
fclose($f);
//now content of file: <?php $a = array('k' => array(), 'k2' => array(), 'k3' => array('f'=>'a'));\n

Changing of input file can cause huge problems.

Also a problem with the method above, If this process was to happen multiple times, at the EXACT same millisecond – something would mess up, right?

Right, read about file locking.