feat: make `shorebird` easier to use by developers in China

[eseidel]

Update Sept 11, 2024: We know of at least some developers using Shorebird successfully from China today.
Users should be able to download published patches through our CDN (without needing to do anything special):
https://shorebird.dev/blog/improved-patch-delivery/
However the updater client also talks to api.shorebird.dev which is hosted in Google Cloud and thus may not be accessible.

Developers may also still need to find a way to reach Google Cloud for using shorebird tooling such as using a VPN.

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The directions for using Shorebird in china include setting FLUTTER_STORAGE_BASE_URL:
https://docs.flutter.dev/community/china

This environment variable is ignored by shorebird, since shorebird itself uses FLUTTER_STORAGE_BASE_URL to pass download.shorebird.dev to flutter.

The larger issue for developers in China is that Shorebird currently uses Google Cloud as our infrastructure provider and Google Cloud is not reliably reachable across China.

We could implement a proxy within china for download.shorebird.dev and either then make it possible to use FLUTTER_STORAGE_BASE_URL to point to such, or some other environment variable.

However we would still need to make access to api.shorebird.dev more reliable for Shorebird to work for Developers without them needing to modify their network.

Regardless, Shorebird works seems to work for some users in china (the api.shorebird.dev request sometimes fails, but if it succeeds patch installs otherwise seem to work fine in China). Developers who cannot reach api.shorebird.dev will still have trouble actually uploading the patches.

[xster]

I suspect it's not as simple as setting an alternate URL. The mirror URLs pointed to in https://docs.flutter.dev/community/china physically host the actual bytes to the Flutter engine etc. You'll need to find a partner (who can register a https://en.wikipedia.org/wiki/ICP_license) who can host the app bits being pushed to point the CLI to.

[AlexV525]

Hi guys, just noticed this issue when I was browsing new stuff. I can answer the questions above since I'm also a maintainer to flutter.cn .

I'm not sure if download.shorebird.dev is accessible from China?

Currently, it's available. If you can provide an exact artifact destination then we can test if the connection is stable enough (download.shorebird.dev returns Unrecognized artifact path).

I'm also not sure how we would tell download.shorebird.dev (possibly in the headers?) what proxy to proxy too?

About how our mirror works: We host our service with a local services provider, mirroring requests with the same path of googleapis, marking artifacts that need to be cached by CDN, and resolving them into buckets.

In order to make our mirror work with shorebird, we'll need another domain or subdomain for it, and create another service that is different from the Flutter one.

So to summarize this, I don't think we'll need a new mirror service for now since everything is working as expected. Let me know if I missed something.

[eseidel]

Thanks Alex. That sounds like an excellent option. I don't think we're quite ready to set this up yet, but if you reach out via email eric@, happy to discuss further when we get there!

[liu731]

another way is to support private deployment.

[eseidel]

We also just got a report that Google OAuth may not work in China (may not connect to oauth2.googleapis.com). So we likely need to support #335 too.

Recommended alternatives included WeChat or QQ OAuth.
Also just having Shorebird support its own accounts (e.g. with email auth).

[956569686]

When will this problem be solved?

[eseidel]

We don't have a specific date. We're quite busy with other customers at the moment and have not yet sat down to try and understand what work remains to be done for Shorebird to be usable within China.

[956569686]

I hope the team can support Chinese developers as soon as possible. A large number of Chinese flutter developers hope to use this tool.