FaustWP: Image URLs in post content are sometimes relative instead of absolute

[ChrisWiegman]

Description

It’s possible under certain conditions for FaustWP to rewrite image URLs in post_content to be relative URLs instead of absolute URLs. When these are URLs to images stored in WP, it results in broken images on the JS site.

Reported here: https://wpengine.slack.com/archives/C01MQH51L14/p1702321472868279

Steps to Reproduce

• Configure Faust to NOT have a Front-end Site URL value
• Disable “Use the WordPress domain for media URLs in post content”
• Create a post, link to an image in the post content.
• Query the post in GraphiQL and notice the src URL is a relative URL like //wp-content/uploads/2023/12/file.jpg

Expected Behavior

[mindctrl]

The team discussed this and here are our thoughts:

• Configure Faust to NOT have a Front-end Site URL value
• Disable “Use the WordPress domain for media URLs in post content”

When Faust is configured this way, we cannot magically fix the situation. The user has the plugin configured to NOT use the WP domain, so we strip the WP domain from the media URLs. However, we have no front-end URL to replace it with, so it remains a relative URL. This should probably be considered a "misconfiguration", as it's basically an invalid state for the intended use cases for Faust.

We've only seen 1-2 reports of this type of configuration, and at this time we don't want to complicate things to cover every single edge case. It's also worth noting that when Faust is configured to not have a front-end URL, we show a warning on the settings page:

Front-end site URL is required to utilize url rewrites and previews.

It is highly recommended that you update it below to avoid unexpected behavior.

We're closing this as wontfix, but we're also considering enabling “Use the WordPress domain for media URLs in post content” by default, to improve the experience in general. See #1849. At some point in the future, we may consider ways to prevent "invalid" configurations like this, but it's not a big enough issue at this time.