Running the hello world snap locally fails.

[compojoom]

Hey guys!

I wanted to play around with snaps, but right now I cannot get past installing a local snap. It just doesn't work.

I the metamask changelog I see that there were few bugfixes related to the installation of snaps in version 10.17. However the versions of flask offered in the firefox and chrome app stores are 10.16?

When are you guys distributing the latest flask version in the app stores?

[compojoom]

Ok, so I built the metamask extension from sources and installed the generated firefox flask version. Now I'm with version: 10.17.0-flask.0

Unfortunately I was still not able to install my local snap.

So here is what I did. I followed the steps in the docs:
https://docs.metamask.io/guide/snaps.html#getting-started

I generated this repo: https://github.com/compojoom/mm-snap-trustlines from template-snap. Cloned it locally and ran:

yarn install && yarn build:clean && yarn serve

then I navigated to http://localhost:8080

I was able to click on connect and then I clicked on connect. No window was present afterwards.

Now I clicked on "say hello" and I receive: "Problem happened: The snap "local:http://localhost:8080/" is not installed. This is a bug, please report it."

The exact error in the terminal is:

MetaMask - RPC Error: The snap "local:http://localhost:8080/" is not installed. This is a bug, please report it. 
Object { code: -32600, message: "The snap \"local:http://localhost:8080/\" is not installed. This is a bug, please report it." }

Clicking on connect no longer opens metamask.

The deployed "hello world" example over here:
https://metamask.github.io/template-snap/
works fine.

The one difference with the localhost version I noticed is that after hitting "connect" - metamask opens again with a window asking me whether I want to install the snap.

[compojoom]

Ok, so I looked into the ff extension debugger and I found that:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:8080/snap.manifest.json. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). Status code: 200.

So I looked in the yarn serve command and it falls back to mm-snap serve which uses http. In my repository I'm with version 0.15.0 of mm-snap.

I hacked the source code and added a header Access-Control-Allow-Origin and now it works fine locally.

Will try updating to the latest mm-snap version and will report if it works or whether we need a PR.