[Swift] Improve server protocol to prepare for C(R)UD

Swift/FHIRResource.swift

@@ -8,6 +8,9 @@
 
 import Foundation
 
+/// The block signature for most server interaction callbacks
+public typealias FHIRResourceErrorCallback = ((resource: FHIRResource?, error: NSError?) -> Void)
+
 
 /**
  *  Abstract superclass for all FHIR resource models.
@@ -95,7 +98,7 @@ public class FHIRResource: FHIRElement
 	/**
 		Reads the resource with the given id from the given server.
 	 */
-	public class func read(id: String, server: FHIRServer, callback: ((resource: FHIRResource?, error: NSError?) -> ())) {
+	public class func read(id: String, server: FHIRServer, callback: FHIRResourceErrorCallback) {
 		let path = "\(resourceName)/\(id)"
 		readFrom(path, server: server) { resource, error in
 			if let res = resource {
@@ -108,13 +111,13 @@ public class FHIRResource: FHIRElement
 	/**
 		Reads the resource from the given path on the given server.
 	 */
-	public class func readFrom(path: String, server: FHIRServer, callback: ((resource: FHIRResource?, error: NSError?) -> ())) {
-		server.requestJSON(path) { json, error in
-			if nil != error {
-				callback(resource: nil, error: error)
+	public class func readFrom(path: String, server: FHIRServer, callback: FHIRResourceErrorCallback) {
+		server.getJSON(path) { response, error in
+			if nil != error || nil != response?.error {
+				callback(resource: nil, error: error ?? response!.error!)
 			}
 			else {
-				let resource = self(json: json)
+				let resource = self(json: response?.body)
 				resource._server = server
 				callback(resource: resource, error: nil)
 			}
@@ -180,22 +183,3 @@ public class FHIRResourceMeta: FHIRElement
 	}
 }
 
-
-/**
- *  Protocol for server objects to be used by `FHIRResource` and subclasses.
- */
-public protocol FHIRServer
-{
-	/** A server object must always have a base URL. */
-	var baseURL: NSURL { get }
-
-	/**
-		Instance method that takes a path, which is relative to `baseURL`, retrieves data from that URL and returns a
-		decoded JSONDictionary - or an error - in the callback.
-
-		:param: path The REST path to request, relative to the server's base URL
-		:param: callback The callback to call when the request ends (success or failure)
-	 */
-	func requestJSON(path: String, callback: ((json: JSONDictionary?, error: NSError?) -> Void))
-}
-

Swift/FHIRSearch.swift

@@ -75,12 +75,12 @@ public class FHIRSearch
 			return
 		}
 
-		server.requestJSON(construct()) { json, error in
+		server.getJSON(construct()) { response, error in
 			if nil != error {
 				callback(bundle: nil, error: error)
 			}
 			else {
-				callback(bundle: Bundle(json: json), error: nil)
+				callback(bundle: Bundle(json: response?.body), error: nil)
 			}
 		}
 	}

Swift/FHIRServer.swift

@@ -0,0 +1,131 @@
+//
+//  FHIRReference.swift
+//  SMART-on-FHIR
+//
+//  Created by Pascal Pfiffner on 01/24/15.
+//  2015, SMART Platforms.
+//
+
+import Foundation
+
+
+/// Callback from server methods
+public typealias FHIRServerJSONCallback = ((response: FHIRServerJSONResponse?, error: NSError?) -> Void)
+
+/// The FHIR server error domain
+public let FHIRServerErrorDomain = "FHIRServerError"
+
+
+/**
+	Encapsulates a server response.
+ */
+public class FHIRServerResponse
+{
+	/// The HTTP status code
+	public let status: Int = 0
+
+	/// Response headers
+	public let headers: [String: String]
+
+	/// An NSError, generated from status code unless it was explicitly assigned.
+	public var error: NSError?
+
+	public required init(status: Int, headers: [String: String]) {
+		self.status = status
+		self.headers = headers
+
+		if status >= 400 {
+			let errstr = NSHTTPURLResponse.localizedStringForStatusCode(status)
+			error = NSError(domain: FHIRServerErrorDomain, code: status, userInfo: [NSLocalizedDescriptionKey: errstr])
+		}
+	}
+
+
+	/** Instantiate a FHIRServerJSONResponse from an NS(HTTP)URLResponse. */
+	public class func from(# response: NSURLResponse) -> Self {
+		var status = 0
+		var headers = [String: String]()
+
+		if let http = response as? NSHTTPURLResponse {
+			status = http.statusCode
+			for (key, val) in http.allHeaderFields {
+				if let keystr = key as? String {
+					if let valstr = val as? String {
+						headers[keystr] = valstr
+					}
+					else {
+						println("DEBUG: Not a string in location headers: \(val) (for \(keystr))")
+					}
+				}
+			}
+		}
+
+		return self(status: status, headers: headers)
+	}
+}
+
+
+/**
+	Encapsulates a server response with JSON response body, if any.
+ */
+public class FHIRServerJSONResponse: FHIRServerResponse
+{
+	/// The response body, decoded into a JSONDictionary
+	public var body: JSONDictionary?
+
+	public required init(status: Int, headers: [String: String]) {
+		super.init(status: status, headers: headers)
+	}
+
+	/** Instantiate a FHIRServerJSONResponse from an NS(HTTP)URLResponse and NSData. */
+	public class func from(# response: NSURLResponse, data inData: NSData?) -> Self {
+		let sup = super.from(response: response)
+		let res = self(status: sup.status, headers: sup.headers)		// TODO: figure out how to make super work with "Self"
+
+		if let data = inData {
+			var error: NSError? = nil
+			if let json = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: &error) as? JSONDictionary {
+				res.body = json
+			}
+			else {
+				let errstr = "Failed to deserialize JSON into a dictionary: \(error?.localizedDescription)\n"
+				             "\(NSString(data: data, encoding: NSUTF8StringEncoding))"
+				res.error = NSError(domain: FHIRServerErrorDomain, code: res.status, userInfo: [NSLocalizedDescriptionKey: errstr])
+			}
+		}
+
+		return res
+	}
+}
+
+
+/**
+	Protocol for server objects to be used by `FHIRResource` and subclasses.
+ */
+public protocol FHIRServer
+{
+	/** A server object must always have a base URL. */
+	var baseURL: NSURL { get }
+
+	/**
+		Instance method that takes a path, which is relative to `baseURL`, executes a GET request from that URL and
+		returns a decoded JSONDictionary - or an error - in the callback.
+
+		:param: path The REST path to request, relative to the server's base URL
+		:param: callback The callback to call when the request ends (success or failure)
+	 */
+	func getJSON(path: String, callback: FHIRServerJSONCallback)
+
+	/**
+		Instance method that takes a path, which is relative to `baseURL`, executes a PUT request at that URL and
+		returns a decoded JSONDictionary - or an error - in the callback.
+
+		:param: path The REST path to request, relative to the server's base URL
+		:param: body The request body data as JSONDictionary
+		:param: callback The callback to call when the request ends (success or failure)
+	*/
+	func putJSON(path: String, body: JSONDictionary, callback: FHIRServerJSONCallback)
+
+	func postJSON(path: String, body: JSONDictionary, callback: FHIRServerJSONCallback)
+}
+

Swift/settings.py

@@ -30,6 +30,7 @@
         'date', 'dateTime', 'time', 'instant',
     ]),
     ('Swift/JSON-extensions.swift', None, []),
+    ('Swift/FHIRServer.swift', None, []),
 ]
 
 # factory methods