Linux support

[fwcd]

Is your feature request related to a problem? Please describe. It would be nice to have the library available on Linux too, e.g. to use the GraphQL client in server-sided applications.

Describe the solution you'd like Add support for Linux by...

• dropping dependencies on Apple-specific frameworks (like Combine)
• adding conditional FoundationNetworking imports, since URLSession is not part of the cross-platform Foundation anymore
• migrating to an open-source WebSocket client framework (e.g. websocket-kit), since URLSessionWebSocketTask is only available on Apple platforms
• adding LinuxMain.swift and XCTestManifests.swift to the test modules so the unit tests run on Linux too (an example of the test module structure can be found here)

[Amzd]

We could make the Selection.serialize function public so people can use SwiftGraphQL on their own network layer.

[maticzav]

@fwcd would that make integrating the library with apple code more complicated (i.e. would it require additional steps to include custom frameworks as compared to now)?

[shaps80]

I've actually been looking into platform support this past week. I recognise this is an old issue, but I also think we might have some options that would enable this.

To address @maticzav's concern, I agree we don't want to do that. But I think there could be options depending on how we structure packages.

I don't know the internals well enough yet, but as a broad idea, I believe we could include platform-agnostic code in a Core library. Then have the  platforms code in a library similar to what we have now, but automatically depending on the new core.

Linux libraries could then be added that build on core.

I also like this idea even for  platforms. I'd prefer to have "convenience" but still have options for injecting my own network stack since when integrating with an existing app for example, it would be common to already have a lot established networking layer, caching, logging, etc... that would be thus easier to integrate with.

I'd like to close this issue for now. But I'll start a new discussion so we can continue to discuss requirements and options there. This would likely be planned for v6 anyway, so a larger discussion makes more sense imo 👍