gfontenot · February 5, 2015 19:25 · Feb 5, 2015
diff --git a/requests.swift b/requests.swift
@@ -0,0 +1,68 @@
+import Foundation
+
+infix operator >>- { associativity left precedence 150 }
+public func >>-<T, U>(a: T?, f: T -> U?) -> U? {
+    return a.flatMap(f)
+}
+
+extension Optional {
+    func flatMap<U>(f: T -> U?) -> U? {
+        switch self {
+        case let .Some(x): return f(x)
+        default: return .None
+        }
+    }
+}
+
+protocol RequestType { }
+
+struct Request<T: RequestType> {
+    let request: NSMutableURLRequest
+}
+
+struct GET: RequestType { }
+struct POST: RequestType { }
+struct Authenticated: RequestType { }
+struct Payload: RequestType { }
+
+func addPayload<T: RequestType>(json: AnyObject)(request: Request<T>) -> Request<Payload>? {
+    let req = request.request
+    req.setValue("application/json", forHTTPHeaderField: "Content-Type")
+    req.HTTPBody = NSJSONSerialization.dataWithJSONObject(json, options: NSJSONWritingOptions(0), error: nil)
+    return Request(request: req)
+}
+
+func postRequest(request: Request<GET>) -> Request<POST>? {
+    let req = request.request
+    req.HTTPMethod = "POST"
+    return Request(request: req)
+}
+
+func authenticateRequest<T: RequestType>(request: Request<T>) -> Request<Authenticated>? {
+    if let token = getToken() {
+        let req = request.request
+        req.setValue("Token token=\(token)", forHTTPHeaderField: "Authorization")
+        return Request(request: req)
+    }
+
+    return .None
+}
+
+func getToken() -> String? {
+    return "foo"
+}
+
+
+func mutableRequestForPath(path: String) -> Request<GET>? {
+    let url = NSURL(string: path)
+
+    if let request = url.map({ NSMutableURLRequest(URL: $0) }) {
+        request.setValue("application/vnd.circus+json; version=foobar", forHTTPHeaderField: "Accept")
+        request.setValue("gzip;q=1.0,compress;q=0.5", forHTTPHeaderField: "Accept-Encoding")
+        return Request(request: request)
+    }
+
+    return .None
+}
+
+let request = mutableRequestForPath("foo") >>- postRequest >>- addPayload([]) >>- authenticateRequest