Handle relative icon urls in manifest

[friedger]

This PR

• uses the manifest url (if available) to resolve a relative icon url retrieved from the app manifest

• fixes Icon in app manifest are not resolved correctly #1783

This only comes into effect after stx-labs/stacks.js#629 is merged and the new version of blockstack.js is used - until then app developers need to specify absolute icon urls in their manifest.

Re image src (from MDN: https://developer.mozilla.org/en-US/docs/Web/Manifest#icons)
src The path to the image file. If src is a relative URL, the base URL will be the URL of the manifest.

[markmhendrickson]

@friedger is this ready for review by @aulneau ?

[friedger]

The PR mentioned in this issue is still open. But this is ready to review. It assumes that the manifest contains a reference to the url it was loaded from

[friedger]

I added a reference in the issue description to MDN for image src in the web manifest.

[timstackblock]

This still seems to serve broken image links for some apps, the fix doesn't seem to work everywhere.

It seems to be working for me with Zinc but not with IO chat. Please see the screenshots below.

[timstackblock]

It seems certain apps still do not display the icon with this change.

[timstackblock]

[friedger]

Have you tested with stx-labs/stacks.js#629?

[timstackblock]

Have you tested with blockstack/blockstack.js#629?

Just reran the test with #629 looks good

[hstove]

Because stx-labs/stacks.js#629 is not included in the local version of blockstack.js yet, I think we'll need to wait on that before merging this.

[hstove]

I'm closing this, but I merged your commit in #1922 , which includes the latest blockstack.js. Thanks!