Respond to different requests in Vapor

VaporRespond.swift

public func respond(to request: Request, with responses: [ContentType : ResponseRepresentable]) throws -> ResponseRepresentable {
    let contentType: ContentType
    let _ = request.accept.prefers("html")
    if let header = request.accept.first {
        var requestedContentType = ContentType.from(string: header.mediaType)
        if requestedContentType == .any {
            if let requestContentType = request.contentType {
                requestedContentType = ContentType.from(string: requestContentType)
            }
            else {
                requestedContentType = .html
            }
        }
        contentType = requestedContentType
    }
    else {
        contentType = ContentType.html
    }

    guard let response = responses[contentType] else { throw Abort.badRequest }
    return response
}