func channelRead()

in Sources/SwiftDocCUtilities/PreviewServer/PreviewHTTPHandler.swift [80:135]
38 lines of code
6 McCabe index (conditional complexity)

    func channelRead(context: ChannelHandlerContext, data: NIOAny) {
        let requestPart = unwrapInboundIn(data)
        
        switch (requestPart, state) {
        case (.head(let head), _):
            let handler: RequestHandlerFactory
            if FileRequestHandler.isAssetPath(head.uri) {
                // Serve a static asset file.
                handler = FileRequestHandler(rootURL: rootURL, fileIO: fileIO)
            } else {
                // Serve the fallback index file.
                handler = DefaultRequestHandler(rootURL: rootURL)
            }
            state = .requestInProgress(requestHead: head, handler: handler.create(channelHandler: self))
            
        case (.end, .requestInProgress(let head, let handler)):
            // In case the handler was initialized with user credentials,
            // do verify they match the sent "Authorization" header
            if let credentials = credentials {
                
                // Verify the user sent credentials over via the HTTP headers
                let authorizationHeaders = head.headers["Authorization"]
                guard !authorizationHeaders.isEmpty else {
                    error(context: context, requestPart: requestPart, head: head, status: .unauthorized, headers: [("WWW-Authenticate", "Basic realm=\"Preview server\"")])
                    return
                }
                
                let credentialsToken = [credentials.user, credentials.pass].joined(separator: ":")
                    .data(using: .utf8)!.base64EncodedString()
                
                guard authorizationHeaders[0] == "Basic \(credentialsToken)" else {
                    error(context: context, requestPart: requestPart, head: head, status: .forbidden)
                    return
                }
            }
            
            defer {
                // Complete the response to the client, reset ``state``
                completeResponse(context, trailers: nil, promise: nil)
            }
            
            // Call the pre-defined during the `head` context handler.
            do {
                try handler(context, head)
            } catch {
                let errorHandler = ErrorRequestHandler(error: error as? RequestError)
                    .create(channelHandler: self)
                
                // The error handler will never throw.
                try! errorHandler(context, head)
            }
            
        // Ignore other parts of a request, e.g. POST data or others.
        default: break
        }
    }