fix regression for template extensions ( A beta 16 breaking change)

Bug from change

Bug Report

Current Behavior Prior to beta 16 my extension (gpx preview) added a custom template to upload, worked great.

changes as part of beta 16 introduced hard-coded switch statement inclusive only of your 4 templates. And now my plugin is broke.

Steps to Reproduce

create extension with a "tag" not in the predefined switch
it defaults to a file URL

Expected Behavior It looks up tag based on the list of templates it has, and then asks the tag'd template for it's appropriate BBcode.

Screenshots

export default function fileToBBcode(file) {
    switch (file.tag()) {
        // File
        case 'file':
            return `[upl-file uuid=${file.uuid()} size=${file.humanSize()}]${file.baseName()}[/upl-file]`;

        // Image template
        case 'image':
            return `[upl-image uuid=${file.uuid()} size=${file.humanSize()} url=${file.url()}]${file.baseName()}[/upl-image]`;

        // Image preview
        case 'image-preview':
            return `[upl-image-preview url=${file.url()}]`;

        // 'just-url' or unknown
        default:
            return file.url();
    }
}

Environment

Flarum version: 0.0.1-beta16
Extension version: 0.14.0

Possible solution(s) A hard coded switch like this is generally a sign that some logic should be delegated to the child/component classes. We already have a list of all registered templates, and a lookup function.

We should shift interface of templates to (i think logically) include the BBCode (oh wait, they do!) they generate/ parse as well. This could be done in PHP where the collection of templates lived, and a "bbcode" attribute returned from the API on upload success for the frontend to use when placing the (also server generated) url into editor.

Additional Context I hacked the File class and overwrote with myown, fixed upload but display worked, so I think there weee other changes in a similar assumption of upload-only templates.

FriendsOfFlarum / upload

fix regression for template extensions ( A beta 16 breaking change) #281

Bug Report