Question

I’m a .NET guy attempting a PHP thing here, so am totally out of my comfort zone right now. What I THINK I want to do is to have 3 files:

• download.php:

  (a) contains a lookup of IDs to filenames (so download.php?file=11 querystring tells me I should host abc.zip)

  (b) Some code to log this download to stats.log

  (c) A couple header() calls and a readfile() call, similar to the answer to this question

• stats.log: A simple log file that might look like the following example. This allows for logging to be accomplished by simply appending a line of text yet allows me to condense it from time to time.

---

abc.zip 1234
xyz.zip 4321
abc.zip 1
abc.zip 1
abc.zip 1
xyz.zip 1
abc.zip 1

---

• stats.php: This is ultimately the PHP file that serves the stats. They can be real-time or near real-time, perhaps re-reading the file every minute and caching it or whatever. I don’t really care and this won’t be hit all that often but I do need to make sure that this isn’t a stupidly expensive operation. This need not be a pretty page. Something so a human can easily read it is all that matters, so no fancy requirements there. For the above example of stats.log, I’d like this to serve something like the following:

---

abc.zip: 1238 downloads
xyz.zip: 4322 downloads

---

Ultimately, I don’t want a database or any other systems involved in this. I only have FTP access to the server, so I can’t really do much other than place scripts into the directory. I realize that I’ll need to make sure that the script has write permissions to stats.txt, which is fine.

So my questions. I have a number of them but I believe they’re all quite easy for somebody who knows PHP.

1. I think I have the hosting portion of download.php understood by setting headers and using readfile. However, how could I have a collection of key/value pairs representing file ids and filenames? If I were in .NET, I could do something like: var foo = new Dictionary<int, string> {{11, "abc.zip"}, {12, "xyz.zip"}} but I don’t have a clue what this looks like in PHP.
2. How do I get querystrings? I need to pull from the URL “stuff/download.php?file=11” and take the 11 to grab my “abc.zip” out of my lookup collection.
3. How do I write the newline to my stats.log file?
4. How do I loop through my stats.log file in my stats.php script to count up and host these stats?
5. Bonus question: How do I cache the results from step 4 and only read the file once every minute/hour/or whatever?

I can probably fill in some gaps if somebody can answer at least most of these questions, but help sure would be appreciated! 🙂

Answer 1

1- You are looking for array e.g.

 $files=array(11=>'abc.zip',
             12=>'xyz.zip');

2- The Query String is accessed by the super global $_GET, so in your case $_GET['file'] holds that data you are interested in.

3,4,5
I would recommend storing the information JSON encoded. e.g.

$rawInfo=file_get_contents('stats.log');
$Info=json_decode($rawInfo,true);
if(isset($Info[$_GET['file']])){
    $Info[$_GET['file']]++;
}else{
    $Info[$_GET['file']]=1;
}
$rawInfo=json_encode($Info);
$h=fopen('stats.log','c');// If $h is false, you couldn't open the file
flock($h,LOCK_EX);// lock the file
$b=fwrite($h,$rawInfo);// if $b is not greater than 0, nothing was written
flock($h,LOCK_UN);
fclose($h);
//And then actually serve the file requested

This has the advantage of storing the information already in a useful format.

Whenever you fetch out the json_decodeed data, it is in the format of an array, which you will need to know how to handle.

stats.php might look something like this:

$rStats=file_get_contents('stats.log');
$Stats=json_decode($rStats,true);
foreach($Stats as $k=>$v){
   echo $k.': '.$v.' download'.($v==1?'':'s');
}