Broken icon links in Manifest file when using assetPrefix

[ehannes]

Description

It seems that gatsby-plugin-manifest does not care about assetPrefix.

Steps to reproduce

1. Create a new Gatsby project
2. Add an assetPrefix
3. Run gatsby build --prefix-paths and compare the icon links in public/index.html with the ones in manifest.webmanifest. Those in index.html are prefixed, while the ones in the manifest are not.

Se this repo: https://github.com/ehannes/broken-icon-links-in-manifest, and compare icon links in public/index.html with public/manifest.webmanifest.

Expected result

Icon links in webmanifest should be prefixed with assetPrefix, as they are in the built index.html.

Actual result

Gatsby prefixes the icons correctly, for instance href="/assets/icons/icon-48x48.png?v=4b11ef345c95e35b68f0d09fdabdc428"/>. But in the manifest, the links are missing the asset prefix: "src": "icons/icon-48x48.png?v=4b11ef345c95e35b68f0d09fdabdc428". This leads to the following error in the browser console:
Error while trying to use the following icon from the Manifest: http://localhost:9000/icons/icon-144x144.png?v=4b11ef345c95e35b68f0d09fdabdc428 (Download error or resource isn't a valid image).

This is probably connected to this change: cdd800f, where the manifest file were no longer prefixed.

Environment

$ gatsby info --clipboard

  System:
    OS: Linux 4.15 Pop!_OS 18.04 LTS
    CPU: (12) x64 Intel(R) Core(TM) i7-8750H CPU @ 2.20GHz
    Shell: 4.4.20 - /bin/bash
  Languages:
    Python: 2.7.15+ - /usr/bin/python
  Browsers:
    Chrome: 77.0.3865.90
    Firefox: 69.0.1
  npmPackages:
    gatsby: ^2.15.35 => 2.15.35
    gatsby-image: ^2.2.27 => 2.2.27
    gatsby-plugin-manifest: ^2.2.21 => 2.2.21
    gatsby-plugin-offline: ^3.0.14 => 3.0.14
    gatsby-plugin-react-helmet: ^3.1.11 => 3.1.11
    gatsby-plugin-sharp: ^2.2.29 => 2.2.29
    gatsby-source-filesystem: ^2.1.31 => 2.1.31
    gatsby-transformer-sharp: ^2.2.21 => 2.2.21

[ehannes]

I guess it's gatsby-plugin-manifest/src/common.js that should take assetPrefix into consideration.

[LekoArts]

We'd be happy to receive a PR fixing this!

[moonmeister]

So did a quick look on this. I initially tired adding prefixing to the common.js file. this way when the defaults were fetched they'd have the prefixes. However, because this isn't happening before gatsby is bootstrapping itself it breaks looking for the __PATH_PREFIX___ global variable.

It'd be simple enough to add a loop into the gatsby-node.js code to prefix the icons. However, this would possibly affect manually defined paths when working in "manual", and "hybrid" modes.

What do y'all think, should this only affect the default icon set in automatic mode, or should this also prefix developer defined paths? I can see positives of both, and downsides to both but am leaning towards prefixing everything.

The downsides to prefixing everything is well, developer puts in the full path and it gets prefixed again. The benefit is the prefix is always handled by config, developer puts in the short path and it gets prefixed, if the prefix ever changes the developer only changes the build/config.

Thoughts?

[Santos-Luis]

The issue is also happening with me. We have a separated cdn and we used 12128 to solve that problem. Although, the solution implemented does not work with the gatsby-plugin-manifest, since the in the sw.js file the array __precacheManifest has all the objects with the attribute url without the assetPrefix

[femesq]

Is it working for anyone using with assetPrefix and gatsby build --prefix-assets?

Tried this code on gatsby-node.js:

exports.onPostBootstrap = async ({ basePath }) => {
  console.log("onPostBootstrap: ", basePath);
};

and basePath is '' - used here.

Thanks for any help on this!

[moonmeister]

@femesq Is your problem related to #25207 ?

[femesq]

@moonmeister Yes! Thanks for pointing me to there... will keep track for updates in that issue.