Bug where route path component contains both parameter and constant

[ehyche]

I am implementing a Swift Package Registry Service using swift-openapi-vapor. This service contains (among others) these two endpoints:

• fetchReleaseMetadata GET /{scope}/{name}/{version}
• downloadSourceArchive GET /{scope}/{name}/{version}.zip

The OpenAPI spec for this service can be found here.

The bug is: the VaporTransport cannot distinguish between these two routes. When I hit the my server with the following URL:

http://127.0.0.1:8080/pointfreeco/swift-clocks/1.0.6.zip

then this gets parsed as a fetchReleaseMetadata route rather than a downloadSourceArchive route.

I believe the bug is here in VaporTransport.swift:

extension [Vapor.PathComponent] {
    init(_ path: String) {
        self = path.split(
            separator: "/",
            omittingEmptySubsequences: true
        ).map { parameter in
            if parameter.first == "{", parameter.last == "}" {
                return .parameter(String(parameter.dropFirst().dropLast()))
            } else {
                return .constant(String(parameter))
            }
        }
    }
}

Currently the OpenAPI path /{scope}/{name}/{version}.zip is getting parsed as:

[
    .parameter("scope"),
    .parameter("name"),
    .constant("{version}.zip")
]

I would assume that the OpenAPI path /{scope}/{name}/{version}.zip should get parsed as:

    .parameter("scope"),
    .parameter("name"),
    .parameter("version"),
    .constant(".zip"),

Is this a correct assumption?

If so, then I will put up a PR which accomplishes this.

[MahdiBM]

@0xTim WDYT? Admittedly I haven't had to add path-parameters where they're not surrounded between /s.
Can/Does Vapor support this?

[0xTim]

So yes this is probably a bug, the issue is that Vapor's router doesn't currently support partially constant path parameters. So I suspect what you'll need to do is use the same handler and check in the handler if the path ends on .zip.

As an aside, having a fully dynamic path and a partially dynamic path is going to be ambiguous at best. We want to be able to support partially dynamic parameters in Vapor 5 but will need to consider the precedence of different path components because from a high level GET /{scope}/{name}/{version} would match just fine with /pointfreeco/swift-clocks/1.0.6.zip since there's no spec for 'Version'. So we will need to be careful not to tank performance in the router with whatever solution we come up with