Why might PHP be incorrectly detecting it is running a web (and

ghz 7months ago ⋅ 76 views

Why might PHP be incorrectly detecting it is running a web (and not a console) context?

I have a PHP script on a shared web host that reads a lot of log files and summarises data in JSON format. This script is run periodically via Cron. I do not control the server, but I have FTP access.

The cron entry for this script is thus:

0    1    *    *    *    php /home/username/public_html/example.com/minecraft-graph/src/process.php > /home/username/public_html/example.com/minecraft-graph/output-hourly.json

In other words, at 1am daily, the script is run and the JSON output is written to a JSON file. The JSON is loaded by a website front end and used to draw a graph.

Now, here's the odd thing. The JSON fetch in the web app recently broke, and I can see why. The JSON file, to which stdout is redirected, now looks like this:

X-Powered-By: PHP/7.3.33
Content-type: text/html; charset=UTF-8

{
    "averages": [
        {
            "year": 2023,
            "month": 1,
            "date": 15,
            "hour": 16,
            "average": 0
        },
        {

Obviously the headers here are going to make the JSON file invalid.

Since Apache is not involved here, PHP must be rendering those headers. Moreover, this script used to work fine, so I think the host owner has reconfigured something. (I should think they have some kind of CPanel system).

My initial thought to fix this is to do this in the code:

header_remove('X-Powered-By');
header_remove('Content-type');

However this is a bit yucky, and I wonder if there is a switch I can give to PHP to stop it rendering any headers. Something is making the judgement that it is running in a web context, and (being run from Cron on the console) it obviously isn't.

Updates

After trying new search terms, I've now found this question, and it recommends -q, but that appears to be deprecated since 5.2. I might try it though: on my local system it seems not to cause an error with a 7.x installation. (But also my local system does not render these headers, so it is hard to tell if this is the fix).

Also, one of the comments on this manual page suggests a hashbang might fix it. I might try that too, though I wonder if that would stop me running the script via the web for debugging.

Answers

It seems like the issue you're facing is due to PHP emitting headers even when running from the command line, which is causing the JSON output file to be invalid.

Here are a few potential solutions you can try:

  1. Use the -q option: As you mentioned, you can try using the -q option when running the PHP script from the command line. While this option is deprecated, it might still work in your case without causing errors.

    php -q /home/username/public_html/example.com/minecraft-graph/src/process.php > /home/username/public_html/example.com/minecraft-graph/output-hourly.json

  2. Use a hashbang: You can add a hashbang (shebang) line at the beginning of your PHP script to indicate the PHP interpreter to use. This might prevent PHP from emitting unnecessary headers.

    #!/usr/bin/php
<?php
// Your PHP script code here

    Make sure to give execute permission to the script file (chmod +x script.php), and you can run it directly from the command line.

  3. Explicitly remove headers: As you suggested, you can explicitly remove the unwanted headers within your PHP script. While this might seem a bit cumbersome, it ensures that the script behaves consistently across different environments.

    <?php
header_remove('X-Powered-By');
header_remove('Content-type');
// Your PHP script code here

  4. Check server configuration: If none of the above solutions work, there might be server configuration settings causing PHP to emit headers even in CLI mode. Unfortunately, since you don't have control over the server configuration, you may need to contact your hosting provider for assistance.

Try these solutions one by one and see which one works best for your situation. If you're still facing issues, feel free to provide more details, and I'll be happy to assist you further!

#php