WordPress REST API query params not working properly on GAE Standard PHP7.2

[Patrick Steadman]

Issue on GitHub: https://github.com/GoogleCloudPlatform/php-docs-samples/issues/809

After following the instructions here for setting up a new WordPress installation on GAE standard 7.2, query params used for filtering content via the wp-json rest API included in WordPress do not behave as expected. 

Example 404 request of WordPress deployed on GAE: https://stock-dot-wordpress-test-222422.appspot.com/wp-json/wp/v2/pages?slug=sample-page

Expected behavior: http://demo.wp-api.org/wp-json/wp/v2/pages?slug=sample-page

Non-query param requests work fine: https://stock-dot-wordpress-test-222422.appspot.com/wp-json/wp/v2/pages

This issue seems to be the result of a change in how the GAE PHP 7.2 standard environment serves requests, as the `/pages?slug=` requests were working fine up until around December 22nd 2018, and redeploying WordPress to the GAE flex environment fixes the issue. (You can read more about the details of our headless setup [here](https://computerlab.io/2018/12/20/deploying-headless-wordpress-on-gcp/) if it's helpful.)

It would be very helpful to know if this is a bug in GAE PHP 7.2 standard environment, or an intentional change.

It'd also be helpful to know if there's a workaround / way to configure the service so that the wp-json API can be used on the standard environment.

[Tiago (Google Cloud Platform Support)]

Hello Patrick,

I see that you created a ticket in the Issue Tracker to further investigate this, as it seems that something might have changed on our side which caused the issue to appear as of Dec 22. The Issue Tracker is a better place to drive this to a resolution as its purpose is to make us aware of issues in our products, and as such I’ll follow up this discussion from there. 

Please also note that currently the PHP 7.2 runtime in the GAE Standard environment is in Beta, and consequently should not be used for production applications at this time.