Allow injection of values

Sources/Sanitizable+Request.swift

@@ -12,12 +12,31 @@ extension Request {
     /// 
     /// - Returns: The extracted, sanitized `Model`.
     public func extractModel<M: Model>() throws -> M where M: Sanitizable {
+        return try extractModel(injecting: .null)
+    }
+
+
+    /// Extracts a `Model` from the Request's JSON, first by adding/overriding
+    /// the given values and next stripping sensitive fields.
+    ///
+    /// - Parameter values: Values to set before sanitizing.
+    /// - Returns: The extracted, sanitized `Model`.
+    /// - Throws:
+    ///     - badRequest: Thrown when the request doesn't have a JSON body.
+    ///     - updateErrorThrown: `Sanitizable` models have the ability to override
+    ///         the error thrown when a model fails to instantiate.
+    public func extractModel<M: Model>(injecting values: Node) throws -> M where M: Sanitizable {
         guard let json = self.json else {
             throw Abort.badRequest
         }
-
-        let sanitized = json.permit(M.permitted)
-
+
+        var node = json.makeNode()
+        values.nodeObject?.forEach { key, value in
+            node[key] = value
+        }
+
+        let sanitized = try JSON(node: node).permit(M.permitted)
+
         try M.preValidate(data: sanitized)
 
         let model: M

Tests/SanitizedTests/SanitizedTests.swift

@@ -13,7 +13,10 @@ class SanitizedTests: XCTestCase {
         ("testPermitted", testPermitted),
         ("testEmptyPermitted", testEmptyPermitted),
     ]
-
+
+
+    // MARK: - Extraction.
+
     func testBasic() {
         let request = buildRequest(body: [
             "id": 1,
@@ -28,14 +31,71 @@ class SanitizedTests: XCTestCase {
             XCTAssertEqual(model.email, "[email protected]")
         }
     }
-
+
+
     func testBasicFailed() {
         let request = buildInvalidRequest()
         expect(toThrow: Abort.badRequest) {
             let _: TestModel = try request.extractModel()
         }
     }
-
+
+
+    // MARK: - Injection.
+
+    func testInjectingNewKeys() {
+        let request = buildRequest(body: [
+            "id": 1,
+            "name": "Brett"
+        ])
+
+        expectNoThrow() {
+            let model: TestModel = try request.extractModel(
+                injecting: ["email": "[email protected]"]
+            )
+            XCTAssertNil(model.id)
+            XCTAssertEqual(model.name, "Brett")
+            XCTAssertEqual(model.email, "[email protected]")
+        }
+    }
+
+    func testOverridingKeys() {
+        let request = buildRequest(body: [
+            "id": 1,
+            "name": "Brett",
+            "email": "[email protected]"
+        ])
+
+        expectNoThrow() {
+            let model: TestModel = try request.extractModel(
+                injecting: ["email": "[email protected]"]
+            )
+            XCTAssertNil(model.id)
+            XCTAssertEqual(model.name, "Brett")
+            XCTAssertEqual(model.email, "[email protected]")
+        }
+    }
+
+    func testInjectingSanitizedKeys() {
+        let request = buildRequest(body: [
+            "id": 1,
+            "name": "Brett",
+            "email": "[email protected]"
+        ])
+
+        expectNoThrow() {
+            let model: TestModel = try request.extractModel(
+                injecting: ["id": 1337]
+            )
+            XCTAssertNil(model.id)
+            XCTAssertEqual(model.name, "Brett")
+            XCTAssertEqual(model.email, "[email protected]")
+        }
+    }
+
+
+    // MARK: - Validation.
+
     func testPreValidateError() {
         let request = buildRequest(body: [
             "email": "[email protected]"
@@ -62,7 +122,10 @@ class SanitizedTests: XCTestCase {
             let _: TestModel = try request.extractModel()
         }
     }
-
+
+
+    // MARK: - Permitted fields.
+
     func testPermitted() {
         let json = JSON([
             "id": 1,
@@ -88,7 +151,10 @@ class SanitizedTests: XCTestCase {
         XCTAssertNil(result["name"])
         XCTAssertNil(result["email"])
     }
-
+
+
+    // MARK: - Patching.
+
     func testPatchBasic() {
         let model = try! TestModel(node: [
             "id": 15,