Unable to build web app with ES client package

[discoos]

Unable to build web app with ES client package

[kengu]

Hi! Did it work earlier for web-targets? I would not think so based on the errors above. I haven't tested it myself on web-targets, but it seems like the MAX literal is not possible to represent as an integer i js. I'll investigate and come back to you.

[kengu]

Bug confirmed with flutter run -d chrome, investigating further

[kengu]

The X509Certificate errors are there because eventstore_client does not as of now support web, as shown here in the scoring section

I'm not sure how I will introduce support for web, probably following the pattern in the grpc package.

[kengu]

@robin-dojo I can't promise when web support is available, but I am working on it.

[kengu]

@robin-dojo gRPC-web is now supported in master. I'll release a new version to pub.dev soon.

NOTE
EventStoreDB does not support the gRPC-web protocol directly (in-process proxy). The EventStore team could add in-process proxy support using Grpc.AspNetCore.Web, but I doubt they will prioritize this because gRCP-web have limited streaming support (details below). If you plan to connect directly to EventStoreDB from a browser, you need to configure a gRCP-web proxy in front of EventStoreDB, that translates between native gRPC and gRPC-web protocols automatically (see official Google implementation of grpc-web).

IMPORTANT! gRPC-web have limited streaming support. Especially bidirectional streams (both RPC requests and responses are sent and received using streams) which EventStoreDB use for Append-operations, are not supported by the gRPC-web protocol. When browser-support for Streams is high enough (see global coverage), the gRCP-web protocol will become optional and web clients will also be able to use the native gRPC protocol.

Choices
You have three technical different options to choose from when connecting to EventStoreDB from a browser.

If you only need to read events, then one of these options is sufficient

• use Envoy as reverse proxy (official solution, Front + Sidecar Proxy, see conceptual example using AWS)
• use another reverse proxy from the community, see proxying gRPC-web with YARP from Microsoft (open source)
• implement an in-process proxy in EventStoreDB yourself

If you also need to support appending events from the browser, then you need to make a custom gRPC server between the gRCP-web proxy (Envoy or in-process) and EventStoreDB. This custom gRPC server must translate the bi-directional Append command exposed by EventStoreDB to a command exposed by the custom gRCP server that is supported by the gRPC-web protocol. You could do this by implementing an Append command with an unary request (all events in one request) that returns a stream of responses (same as the Append command exposed by EventStoreDB does). This command is supported by gRCP-web and should work (in theory, I have not tested it myself). You would need to repeat this for all EventStore gRPC service commands that are bidirectional, which is a big undertaking.

My advice
If you need Append-support from the browser, I think the better solution is to wait for the official support of native gRPC that use Streams. I don't know when this will happen, but the (global coverage) is ~94% now. See the roadmap for full streaming support for official information.

[robin-dojo]

Thanks, @kengu - will try out 0.7.0 when it is released.

For my needs, the web interface will not need to append streams directly as we have an API service for this, but other platforms will require it as they will not always interact with the API :)

[kengu]

Fixed in master. See flutter_echo_app for example of grpc-web protocol usage, and tool/grpc/bridge for example of how the infrastructure is set up locally for testing.