Add functionality to Visual Recognition to update a classifier (watso…

…n-developer-cloud#399)

* Adding code for updating a classifier.

* Adding tests for updateClassifier

* Update formatting for updateClassifier function

* Add faster test for updateClassifier

Source/VisualRecognitionV3/Tests/VisualRecognitionTests.swift

@@ -271,6 +271,231 @@ class VisualRecognitionTests: XCTestCase {
         waitForExpectations()
     }
 
+    /** Update the trained classifier. */
+    func testUpdateClassifier() {
+        let description = "Update the trained classifier."
+        let expectation = expectationWithDescription(description)
+
+        let car = Class(name: "car", examples: examplesCars)
+        visualRecognition.updateClassifier(classifierID!, positiveExamples: [car], negativeExamples: examplesTrucks, failure: failWithError) {
+            classifier in
+            XCTAssertEqual(classifier.name, self.classifierName)
+            expectation.fulfill()
+        }
+        waitForExpectations()
+    }
+
+    /** Update the classifier with a positive example. */
+    func testUpdateClassifierWithPositiveExample() {
+        let description1 = "Train a new classifier with positive examples."
+        let expectation1 = expectationWithDescription(description1)
+
+        let name = "swift-sdk-unit-test-positive-update"
+        let cars = Class(name: "car", examples: examplesCars)
+        let trucks = Class(name: "truck", examples: examplesTrucks)
+
+        var classifierID: String?
+        visualRecognition.createClassifier(
+            name,
+            positiveExamples: [cars],
+            negativeExamples: examplesBaseball,
+            failure: failWithError) { classifier in
+                XCTAssertEqual(classifier.name, name)
+                XCTAssertEqual(classifier.classes.count, 1)
+                classifierID = classifier.classifierID
+                expectation1.fulfill()
+        }
+        waitForExpectations()
+
+        var trained = false
+        var tries = 0
+        while(!trained) {
+            tries += 1
+            let description = "Get the new classifier."
+            let expectation = expectationWithDescription(description)
+            visualRecognition.getClassifier(classifierID!, failure: failWithError) {
+                classifier in
+
+                if classifier.status == "ready" {
+                    trained = true
+                }
+                expectation.fulfill()
+            }
+            waitForExpectations()
+
+            if tries > 5 {
+                let description = "Delete the new classifier."
+                let expectation = expectationWithDescription(description)
+
+                visualRecognition.deleteClassifier(classifierID!, failure: failWithError) {
+                    expectation.fulfill()
+                }
+                waitForExpectations()
+
+                XCTFail("Could not train a new classifier. Try again later.")
+            }
+
+            sleep(5)
+        }
+
+        let description2 = "Update the classifier with a positive example."
+        let expectation2 = expectationWithDescription(description2)
+
+        visualRecognition.updateClassifier(
+            classifierID!,
+            positiveExamples: [trucks],
+            failure: failWithError) { classifier in
+                XCTAssertEqual(classifier.name, name)
+                expectation2.fulfill()
+        }
+        waitForExpectations()
+
+        trained = false
+        tries = 0
+        while(!trained) {
+            tries += 1
+            let description = "Get the updated classifier and make sure there are 2 classes."
+            let expectation = expectationWithDescription(description)
+            visualRecognition.getClassifier(classifierID!, failure: failWithError) {
+                classifier in
+
+                if classifier.status == "ready" {
+                    XCTAssertEqual(classifier.classes.count, 2)
+                    trained = true
+                }
+                expectation.fulfill()
+            }
+            waitForExpectations()
+
+            if tries > 5 {
+                let description = "Delete the new classifier."
+                let expectation = expectationWithDescription(description)
+
+                visualRecognition.deleteClassifier(classifierID!, failure: failWithError) {
+                    expectation.fulfill()
+                }
+                waitForExpectations()
+
+                XCTFail("Could not update the classifier. Try again later.")
+            }
+
+            sleep(5)
+        }
+
+        let description4 = "Delete the custom classifier."
+        let expectation4 = expectationWithDescription(description4)
+
+        visualRecognition.deleteClassifier(classifierID!, failure: failWithError) {
+            expectation4.fulfill()
+        }
+        waitForExpectations()
+    }
+
+    /** Update the classifier with a negative example. */
+    func testUpdateClassifierWithNegativeExample() {
+        let description1 = "Train a new classifier with positive examples."
+        let expectation1 = expectationWithDescription(description1)
+
+        let name = "swift-sdk-unit-test-negative-update"
+        let cars = Class(name: "car", examples: examplesCars)
+        let classes = [cars]
+
+        var classifierID: String?
+        visualRecognition.createClassifier(
+            name,
+            positiveExamples: classes,
+            negativeExamples: examplesTrucks,
+            failure: failWithError) { classifier in
+                XCTAssertEqual(classifier.name, name)
+                XCTAssertEqual(classifier.classes.count, 1)
+                classifierID = classifier.classifierID
+                expectation1.fulfill()
+        }
+        waitForExpectations()
+
+        var trained = false
+        var tries = 0
+        while(!trained) {
+            tries += 1
+            let description = "Get the new classifier."
+            let expectation = expectationWithDescription(description)
+            visualRecognition.getClassifier(classifierID!, failure: failWithError) {
+                classifier in
+
+                if classifier.status == "ready" {
+                    trained = true
+                }
+                expectation.fulfill()
+            }
+            waitForExpectations()
+
+            if tries > 5 {
+                let description = "Delete the new classifier."
+                let expectation = expectationWithDescription(description)
+
+                visualRecognition.deleteClassifier(classifierID!, failure: failWithError) {
+                    expectation.fulfill()
+                }
+                waitForExpectations()
+
+                XCTFail("Could not train a new classifier. Try again later.")
+            }
+
+            sleep(5)
+        }
+
+        let description2 = "Update the classifier with a negative example."
+        let expectation2 = expectationWithDescription(description2)
+        visualRecognition.updateClassifier(
+            classifierID!,
+            negativeExamples: examplesBaseball,
+            failure: failWithError) { classifier in
+                XCTAssertEqual(classifier.name, name)
+                expectation2.fulfill()
+        }
+        waitForExpectations()
+
+        trained = false
+        tries = 0
+        while(!trained) {
+            tries += 1
+            let description = "Get the updated classifier and make sure there is 1 class."
+            let expectation = expectationWithDescription(description)
+            visualRecognition.getClassifier(classifierID!, failure: failWithError) {
+                classifier in
+
+                if classifier.status == "ready" {
+                    XCTAssertEqual(classifier.classes.count, 1)
+                    trained = true
+                }
+                expectation.fulfill()
+            }
+            waitForExpectations()
+
+            if tries > 5 {
+                let description = "Delete the new classifier."
+                let expectation = expectationWithDescription(description)
+
+                visualRecognition.deleteClassifier(classifierID!, failure: failWithError) {
+                    expectation.fulfill()
+                }
+                waitForExpectations()
+
+                XCTFail("Could not update the classifier. Try again later.")
+            }
+
+            sleep(5)
+        }
+
+        let description4 = "Delete the custom classifier."
+        let expectation4 = expectationWithDescription(description4)
+
+        visualRecognition.deleteClassifier(classifierID!, failure: failWithError) {
+            expectation4.fulfill()
+        }
+        waitForExpectations()
+    }
+
     /** Classify an image by URL using the default classifier and all default parameters. */
     func testClassifyByURL1() {
         let description = "Classify an image by URL using the default classifier."

Source/VisualRecognitionV3/VisualRecognition.swift

@@ -277,6 +277,91 @@ public class VisualRecognition {
             }
     }
 
+    /**
+     Update an existing classifier by adding new classes or by adding new images to existing 
+     classes. At least one compressed file must be passed in.
+
+     - parameter classifierID: The ID of the classifier you want to update.
+     - parameter positiveExamples: An array of classes, each with a name and a zip archive file of
+        images that prominently depict the visual subject of the class. Each class requires a
+        minimum of 10 images. If you specify multiple classes, the system will learn to classify
+        each category.
+     - parameter negativeExamples: A zip archive file of images that *do not* prominently depict the
+        visual subject of *any* of the classes being trained. Must contain a minimum of 10
+        images.
+     - parameter failure: A function executed if an error occurs.
+     - parameter success: A function executed with information about the updated classifier.
+     */
+    public func updateClassifier(
+        classifierID: String,
+        positiveExamples: [Class]? = nil,
+        negativeExamples: NSURL? = nil,
+        failure: (NSError -> Void)? = nil,
+        success: Classifier -> Void)
+    {
+        // ensure there is at least one compressed file
+        guard (positiveExamples != nil) || (negativeExamples != nil) else {
+            let failureReason = "To update a classifier, you must provide at least one " +
+                "compressed file of either positive or negative examples."
+            let userInfo = [NSLocalizedFailureReasonErrorKey: failureReason]
+            let error = NSError(domain: domain, code: 0, userInfo: userInfo)
+            failure?(error)
+            return
+        }
+
+        // construct query parameters
+        var queryParameters = [NSURLQueryItem]()
+        queryParameters.append(NSURLQueryItem(name: "api_key", value: apiKey))
+        queryParameters.append(NSURLQueryItem(name: "version", value: version))
+
+        // construct REST request
+        let request = RestRequest(
+            method: .POST,
+            url: serviceURL + "/v3/classifiers/\(classifierID)",
+            acceptType: "application/json",
+            userAgent: userAgent,
+            queryParameters: queryParameters
+        )
+
+        // execute REST request
+        Alamofire.upload(request,
+            multipartFormData: { multipartFormData in
+                if let positiveExamples = positiveExamples {
+                    for positiveExample in positiveExamples {
+                        let name = positiveExample.name + "_positive_examples"
+                        if let examples = positiveExample.examples {
+                            multipartFormData.appendBodyPart(fileURL: examples, name: name)
+                        }
+                    }                    
+                }
+                if let negativeExamples = negativeExamples {
+                    let examples = negativeExamples
+                    let name = "negative_examples"
+                    multipartFormData.appendBodyPart(fileURL: examples, name: name)
+                }
+            },
+            encodingCompletion: { encodingResult in
+                switch encodingResult {
+                case .Success(let upload, _, _):
+                    upload.responseObject(dataToError: self.dataToError) {
+                        (response: Response<Classifier, NSError>) in
+                        switch response.result {
+                        case .Success(let classifier): success(classifier)
+                        case .Failure(let error): failure?(error)
+                        }
+                    }
+                case .Failure:
+                    let failureReason = "Provided file(s) could not be encoded as form data."
+                    let userInfo = [NSLocalizedFailureReasonErrorKey: failureReason]
+                    let error = NSError(domain: self.domain, code: 0, userInfo: userInfo)
+                    failure?(error)
+                    return
+                }
+            }
+        )
+
+    }
+
     /**
      Classify images by URL. The supported image formats include .jpg, .png, and .gif.