Multimc5: Add "Install Fabric" Button

[nift4]

System Information

MultiMC version: 0.6.5-stable

Operating System: Ubuntu GNU/Linux 19.04 Linux 5.0.0

Summary of the issue or suggestion:

Please add a "Install Fabric" button like "Install Forge".

What should happen:

??

Steps to reproduce the issue (Add more if needed):

1. Open MultiMC

2. Edit an instance.

3. No "Install Fabric" button available.

Suspected cause:

Feature not added.

Logs/Screenshots:

Additional Info:

Fabric has a MultiMC instance "generator" that generates URLs like this: https://fabricmc.net/download/multimc?yarn=1.14+build.6&loader=0.4.6+build.141

And if you add &format=patchJson you get a patch json. (No idea what this is ;))

[Dolphin2Point1]

You are using the BUG template. You do not need this template for a feature. However, I support this idea.

[asiekierka]

@peterix There are two routes that can be undertaken to support this, now that we have finally moved the "Yarn version issue" (with one mapping version per game version) greatly simplifying the user-side experience:

• Use the Fabric Meta API to both query versions and get the installer JSON data, with MultiMC building the resulting patch .JSON,
• Use the Fabric Meta API to query versions and the fabricmc.net API to download a prebuilt patch .JSON in MultiMC's format.

Which one would you side with?

[peterix]

Basically neither, but possibly either of them applied to https://github.com/MultiMC/meta instead.

[peterix]

In MultiMC, it should just be one more button that adds a fabric component to the instance.

[asiekierka]

The only problem I see in practice is that there are two components: one provides the mappings (Intermediary, there is only one version of it per Minecraft version), and one provides the mod loader (which is not dependent on a Minecraft version).

In effect, how MultiMC would have to act, to avoid an O(n^2) scalability for the data, is query the list of Intermediary mapping versions to figure out if a version of Minecraft is supported, then just list the compatible (for now - all) Loader versions and attach the correct Intermediary mapping for a given version of Minecraft.

EDIT: Note that the Intermediary package's version is always a 1:1 match with how Minecraft refers to the version in their manifests, for this reason. This might help.

[asiekierka]

Further progress depends on https://github.com/MultiMC/meta/pull/1

[peterix]

Aand this should land in develop soon :)