added support for refreshing an access token

Package.swift

@@ -7,11 +7,11 @@ let package = Package(
 			name: "OAuth2"),
 		],
     dependencies: [
-		.Package(url: "https://github.com/PerfectlySoft/PerfectLib.git", majorVersion: 2),
-		.Package(url: "https://github.com/PerfectlySoft/Perfect-HTTP.git", majorVersion: 2),
-		.Package(url: "https://github.com/PerfectlySoft/Perfect-Logger.git", majorVersion: 1),
-		.Package(url: "https://github.com/iamjono/SwiftString.git", majorVersion: 1),
-		.Package(url: "https://github.com/PerfectlySoft/Perfect-Session.git", majorVersion: 1),
+		.Package(url: "https://github.com/PerfectlySoft/PerfectLib.git", majorVersion: 3),
+		.Package(url: "https://github.com/PerfectlySoft/Perfect-HTTP.git", majorVersion: 3),
+		.Package(url: "https://github.com/PerfectlySoft/Perfect-Logger.git", majorVersion: 3),
+		.Package(url: "https://github.com/iamjono/SwiftString.git", majorVersion: 2),
+		.Package(url: "https://github.com/PerfectlySoft/Perfect-Session.git", majorVersion: 3),
 		]
 
 )

Sources/OAuth2/OAuth2.swift

@@ -92,7 +92,47 @@ open class OAuth2 {
         return try exchange(authorizationCode: AuthorizationCode(code: code, redirectURL: redirectURL))
     }
 
-    // TODO: add refresh token support
+
+    /// Renew Access token by using the previously fetched refresh token
+    /// - Parameters:
+    ///     - refreshToken: the refresh token used to renew the access token
+    ///     - needSecret: Some providers do not need a client secret (i.e. Microsoft)
+    ///     - scopes: the scopes used with the original access token (optional)
+    /// - Throws:
+    ///     - InvalidAPIResponse(): if the server does not respond in a way we expect
+    ///     - OAuth2Error() if the oauth server calls back with an error
+
+    func refresh(refreshToken: String, needSecret: Bool = false, scopes: [String] = []) throws -> OAuth2Token {
+
+        var postBody = ["grant_type": "refresh_token",
+                        "client_id": clientID,
+                        "refresh_token": refreshToken]
+
+        if !scopes.isEmpty {
+            postBody["scope"] = scopes.joined(separator: " ")
+        }
+
+        if needSecret {
+            postBody["client_secret"] = clientSecret
+        }
+
+        var httpBody = URLComponents()
+        httpBody.queryItems = postBody.map { key, value in
+            return URLQueryItem(name: key, value: value)
+        }
+
+        let data = makeRequest(.post, tokenURL, body: httpBody.percentEncodedQuery!, encoding: "form")
+        guard let token = OAuth2Token(json: data) else {
+            if let error = OAuth2Error(json: data) {
+                throw error
+            } else {
+                throw InvalidAPIResponse()
+            }
+        }
+        return token
+
+    }
+
 }
 
 extension URLComponents {

Sources/OAuth2/OAuth2Error.swift

@@ -24,7 +24,7 @@ public struct OAuth2Error: Error {
     }
 
     /// Convenience initializer from JSON
-    init?(json: [String: Any]) {
+    public init?(json: [String: Any]) {
         guard let errorCode = json["error"] as? String,
               let code = OAuth2ErrorCode(rawValue: errorCode) else {
                 return nil

Sources/OAuth2/makeRequest.swift

@@ -23,7 +23,7 @@ extension OAuth2 {
 	/// - body: The JSON formatted sring to sent to the server
 	/// Response:
 	/// (HTTPResponseStatus, "data" - [String:Any], "raw response" - [String:Any], HTTPHeaderParser)
-	func makeRequest(
+	open func makeRequest(
 		_ method: HTTPMethod,
 		_ url: String,
 		body: String = "",

Tests/AuthTests/AuthProvidersTests.swift

@@ -1,5 +1,5 @@
 import XCTest
-@testable import AuthProviders
+@testable import OAuth2
 
 class AuthProvidersTests: XCTestCase {