Implement NSCopying, NSCoding, able to remove event handlers

TRVSEventSource.xcodeproj/project.pbxproj

@@ -210,7 +210,7 @@
 				ORGANIZATIONNAME = "Travis Jeffery";
 				TargetAttributes = {
 					3275255018047A3B00CF5D6F = {
-						TestTargetID = 3275253518047A3A00CF5D6F;
+						TestTargetID = 3275253518047A3A00CF5D6F /* TRVSEventSource */;
 					};
 				};
 			};

TRVSEventSource/TRVSEventSource.h

@@ -14,9 +14,17 @@
 
 typedef void (^TRVSEventSourceEventHandler)(TRVSServerSentEvent *event, NSError *error);
 
-@interface TRVSEventSource : NSObject <NSURLSessionDelegate, NSURLSessionDataDelegate>
 
-// The URL that the event source receives events from.
+/**
+ `TRVSEventSource` is an Objective-C implementation of the EventSource DOM interface supported by modern browsers.
+ 
+ An event source opens an HTTP connection, and receives events as they are sent from the server. Each event is encoded as an `TRVSServerSentEvent` object, and dispatched to all listeners for that particular event type.
+ 
+ @see http://www.w3.org/TR/eventsource/
+ */
+@interface TRVSEventSource : NSObject <NSURLSessionDelegate, NSURLSessionDataDelegate, NSCopying, NSCoding>
+
+// The URL the event source receives events from.
 @property (nonatomic, strong, readonly) NSURL *URL;
 // The managed session.
 @property (nonatomic, strong, readonly) NSURLSession *URLSession;
@@ -29,23 +37,60 @@ typedef void (^TRVSEventSourceEventHandler)(TRVSServerSentEvent *event, NSError
 
 // @name connection state
 
+// The connection state can be in only one state at any given time.
 - (BOOL)isConnecting;
 - (BOOL)isOpen;
 - (BOOL)isClosed;
 - (BOOL)isClosing;
 
 // @name initializing an event source
 
+/**
+ *  Initializes an `TRVSEventSource` object with the specified URL. The event source will open only by calling -[TRVSEventSource open].
+ *
+ *  @param URL The url the event source will receive events from.
+ *
+ *  @return The newly-initialized event source.
+ */
 - (instancetype)initWithURL:(NSURL *)URL;
 
 // @name opening and closing an event source
 
+/**
+ *  Opens a connection to the `URL` to receive events. The request specifies an `Accept` HTTP header field value of `text/event-stream`.
+ */
 - (void)open;
+
+/**
+ *  Closes the connection.
+ */
 - (void)close;
 
 // @name listening for events
 
+/**
+ *  Adds a listener to the event source thats runs the `eventHandler` block whenever an event is received with the given `event` name.
+ *
+ *  @param event        The name of the event to listen for.
+ *  @param eventHandler The block to run when events with the given name are received.
+ *
+ *  @return The identifier associated with the listener for the specified event. Pass this to `-[TRVSEventSource removeEventListenerWithIdentifier:]` to remove the listener.
+ */
 - (NSUInteger)addListenerForEvent:(NSString *)event
                 usingEventHandler:(TRVSEventSourceEventHandler)eventHandler;
 
+/**
+ Removes the event listener with the given identifier
+ 
+ @param identifier The identifier associated with the event listener.
+ 
+ @discussion The event listener identifier is returned when added with `-[TRVSEventSource addListenerForEvent:usingBlock:]`.
+ */
+- (void)removeEventListenerWithIdentifier:(NSUInteger)identifier;
+
+/**
+ * Removes all listeners for events of the given type.
+ */
+- (void)removeAllListenersForEvent:(NSString *)event;
+
 @end

TRVSEventSource/TRVSEventSource.m

@@ -7,32 +7,28 @@
 //
 
 #import "TRVSEventSource.h"
-#import "TRVSServerSentEvent.h"
 
-
-NSString *const TRVSEventSourceErrorDomain = @"com.travisjeffery.TRVSEventSource";
-const NSInteger TRVSEventSourceErrorSourceClosed = 666;
 static NSUInteger const TRVSEventSourceListenersCapacity = 100;
 static char *const TRVSEventSourceSyncQueueLabel = "com.travisjeffery.TRVSEventSource.syncQueue";
 static NSString *const TRVSEventSourceOperationQueueName = @"com.travisjeffery.TRVSEventSource.operationQueue";
 
 static NSDictionary *TRVSServerSentEventFieldsFromData(NSData *data, NSError * __autoreleasing *error) {
     if (!data || [data length] == 0) return nil;
-    
+
     NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
     NSMutableDictionary *mutableFields = [NSMutableDictionary dictionary];
-    
+
     for (NSString *line in [string componentsSeparatedByCharactersInSet:[NSCharacterSet newlineCharacterSet]]) {
         if (!line || [line length] == 0 || [line hasPrefix:@":"]) continue;
-        
+
         @autoreleasepool {
             NSScanner *scanner = [[NSScanner alloc] initWithString:line];
             scanner.charactersToBeSkipped = [NSCharacterSet whitespaceCharacterSet];
             NSString *key, *value;
             [scanner scanUpToString:@":" intoString:&key];
             [scanner scanString:@":" intoString:nil];
             [scanner scanUpToString:@"\n" intoString:&value];
-            
+
             if (key && value) {
                 if (mutableFields[key]) {
                     mutableFields[key] = [mutableFields[key] stringByAppendingFormat:@"\n%@", value];
@@ -42,7 +38,7 @@
             }
         }
     }
-    
+
     return mutableFields;
 }
 
@@ -70,41 +66,54 @@ @implementation TRVSEventSource
 
 - (instancetype)initWithURL:(NSURL *)URL {
     if (!(self = [super init])) return nil;
+
     self.operationQueue = [[NSOperationQueue alloc] init];
     self.operationQueue.name = TRVSEventSourceOperationQueueName;
     self.URL = URL;
     self.listenersKeyedByEvent = [[NSMapTable alloc] initWithKeyOptions:NSPointerFunctionsCopyIn valueOptions:NSPointerFunctionsStrongMemory capacity:TRVSEventSourceListenersCapacity];
     self.URLSession = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration] delegate:self delegateQueue:self.operationQueue];
     self.syncQueue = dispatch_queue_create(TRVSEventSourceSyncQueueLabel, NULL);
+
     return self;
 }
 
 - (void)open {
-    __weak typeof(self) weakSelf = self;
-    dispatch_sync(self.syncQueue, ^{
-        [weakSelf transitionToConnecting];
-    });
+    [self transitionToConnecting];
 }
 
 - (void)close {
-    __weak typeof(self) weakSelf = self;
-    dispatch_sync(self.syncQueue, ^{
-        [weakSelf transitionToClosing];
-    });
+    [self transitionToClosing];
 }
 
 - (NSUInteger)addListenerForEvent:(NSString *)event usingEventHandler:(TRVSEventSourceEventHandler)eventHandler {
     NSMutableDictionary *mutableListenersKeyedByIdentifier = [self.listenersKeyedByEvent objectForKey:event];
     if (!mutableListenersKeyedByIdentifier) mutableListenersKeyedByIdentifier = [NSMutableDictionary dictionary];
-    
+
     NSUInteger identifier = [[NSUUID UUID] hash];
     mutableListenersKeyedByIdentifier[@(identifier)] = [eventHandler copy];
-    
+
     [self.listenersKeyedByEvent setObject:mutableListenersKeyedByIdentifier forKey:event];
-    
+
     return identifier;
 }
 
+- (void)removeEventListenerWithIdentifier:(NSUInteger)identifier {
+    NSEnumerator *enumerator = [self.listenersKeyedByEvent keyEnumerator];
+    id event = nil;
+    while ((event = [enumerator nextObject])) {
+        NSMutableDictionary *mutableListenersKeyedByIdentifier = [self.listenersKeyedByEvent objectForKey:event];
+        if ([mutableListenersKeyedByIdentifier objectForKey:@(identifier)]) {
+            [mutableListenersKeyedByIdentifier removeObjectForKey:@(identifier)];
+            [self.listenersKeyedByEvent setObject:mutableListenersKeyedByIdentifier forKey:event];
+            return;
+        }
+    }
+}
+
+- (void)removeAllListenersForEvent:(NSString *)event {
+    [self.listenersKeyedByEvent removeObjectForKey:event];
+}
+
 #pragma mark - State
 
 - (BOOL)isConnecting {
@@ -125,13 +134,13 @@ - (BOOL)isClosing {
 
 #pragma mark - NSURLSessionDelegate
 
-- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {    
+- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
     NSUInteger length = data.length;
     while (YES) {
         NSInteger totalNumberOfBytesWritten = 0;
         if (self.outputStream.hasSpaceAvailable) {
             const uint8_t *dataBuffer = (uint8_t *)[data bytes];
-            
+
             NSInteger numberOfBytesWritten = 0;
             while (totalNumberOfBytesWritten < (NSInteger)length) {
                 numberOfBytesWritten = [self.outputStream write:&dataBuffer[0] maxLength:length];
@@ -141,7 +150,7 @@ - (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)data
                     totalNumberOfBytesWritten += numberOfBytesWritten;
                 }
             }
-            
+
             break;
         }
     }
@@ -170,7 +179,7 @@ - (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode {
             NSError *error = nil;
             TRVSServerSentEvent *event = [TRVSServerSentEvent eventWithFields:TRVSServerSentEventFieldsFromData([data subdataWithRange:NSMakeRange(self.offset, [data length] - self.offset)], &error)];
             self.offset = [data length];
-            
+
             if (error) {
                 [self transitionToFailedWithError:error];
             }
@@ -179,7 +188,7 @@ - (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode {
                     [[self.listenersKeyedByEvent objectForKey:event.event] enumerateKeysAndObjectsUsingBlock:^(id _, TRVSEventSourceEventHandler eventHandler, BOOL *stop) {
                         eventHandler(event, nil);
                     }];
-                                        
+
                     if ([self.delegate respondsToSelector:@selector(eventSource:didReceiveEvent:)]) {
                         [self.delegate eventSource:self didReceiveEvent:event];
                     }
@@ -195,27 +204,36 @@ - (void)stream:(NSStream *)stream handleEvent:(NSStreamEvent)eventCode {
     }
 }
 
-#pragma mark - Private
+#pragma NSCoding
 
-- (void)setupOutputStream {
-    self.outputStream = [NSOutputStream outputStreamToMemory];
-    self.outputStream.delegate = self;
-    [self.outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
-    [self.outputStream open];
+- (id)initWithCoder:(NSCoder *)aDecoder {
+    NSURL *URL = [aDecoder decodeObjectForKey:@"URL"];
+    if (!(self = [self initWithURL:URL])) return nil;
+    return self;
 }
 
-- (void)closeOutputStream {
-    self.outputStream.delegate = nil;
-    [self.outputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
-    [self.outputStream close];
+- (void)encodeWithCoder:(NSCoder *)aCoder {
+    [aCoder encodeObject:self.URL forKey:@"URL"];
 }
 
+#pragma NSCopying
+
+- (id)copyWithZone:(NSZone *)zone {
+    return [[[self class] allocWithZone:zone] initWithURL:self.URL];
+}
+
+#pragma mark - Private
+
 - (void)transitionToOpenIfNeeded {
-    if (self.state != TRVSEventSourceConnecting) return;
-    self.state = TRVSEventSourceOpen;
-    if ([self.delegate respondsToSelector:@selector(eventSourceDidOpen:)]) {
-        [self.delegate eventSourceDidOpen:self];
-    }
+    __weak typeof(self) weakSelf = self;
+    dispatch_sync(self.syncQueue, ^{
+        __strong typeof(weakSelf) strongSelf = weakSelf;
+        if (strongSelf.state != TRVSEventSourceConnecting) return;
+        strongSelf.state = TRVSEventSourceOpen;
+        if ([strongSelf.delegate respondsToSelector:@selector(eventSourceDidOpen:)]) {
+            [strongSelf.delegate eventSourceDidOpen:self];
+        }
+    });
 }
 
 - (void)transitionToFailedWithError:(NSError *)error {
@@ -233,16 +251,37 @@ - (void)transitionToClosed {
 }
 
 - (void)transitionToConnecting {
-    self.state = TRVSEventSourceConnecting;
-    [self setupOutputStream];
-    self.URLSessionTask = [self.URLSession dataTaskWithURL:self.URL];
-    [self.URLSessionTask resume];
+    __weak typeof(self) weakSelf = self;
+    dispatch_sync(self.syncQueue, ^{
+        __strong typeof(weakSelf) strongSelf = weakSelf;
+        strongSelf.state = TRVSEventSourceConnecting;
+        [strongSelf setupOutputStream];
+        strongSelf.URLSessionTask = [strongSelf.URLSession dataTaskWithURL:strongSelf.URL];
+        [strongSelf.URLSessionTask resume];
+    });
 }
 
 - (void)transitionToClosing {
-    self.state = TRVSEventSourceClosing;
-    [self closeOutputStream];
-    [self.URLSession invalidateAndCancel];
+    __weak typeof(self) weakSelf = self;
+    dispatch_sync(self.syncQueue, ^{
+        __strong typeof(weakSelf) strongSelf = weakSelf;
+        strongSelf.state = TRVSEventSourceClosing;
+        [strongSelf closeOutputStream];
+        [strongSelf.URLSession invalidateAndCancel];
+    });
+}
+
+- (void)setupOutputStream {
+    self.outputStream = [NSOutputStream outputStreamToMemory];
+    self.outputStream.delegate = self;
+    [self.outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
+    [self.outputStream open];
+}
+
+- (void)closeOutputStream {
+    self.outputStream.delegate = nil;
+    [self.outputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
+    [self.outputStream close];
 }
 
 @end

TRVSEventSourceTests/TRVSEventSourceTests.m

@@ -21,12 +21,13 @@ @implementation TRVSEventSourceTests
 - (void)testEventSourceStreaming {
     // you must be running the local server. see README.md.
     TRVSEventSource *eventSource = [[TRVSEventSource alloc] initWithURL:[NSURL URLWithString:@"http://127.0.0.1:8000"]];
-
     __block TRVSMonitor *monitor = [[TRVSMonitor alloc] initWithExpectedSignalCount:3];
+
     [eventSource addListenerForEvent:@"message" usingEventHandler:^(TRVSServerSentEvent *event, NSError *error) {
+        NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:event.data options:0 error:NULL];
+
         XCTAssert(event);
         XCTAssertEqualObjects(@"message", event.event);
-        NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:event.data options:0 error:NULL];
         XCTAssertEqualObjects(@1, dictionary[@"author_id"]);
         XCTAssertEqualObjects(@1, dictionary[@"conversation_id"]);
         XCTAssert(dictionary[@"body"]);
@@ -56,8 +57,8 @@ - (void)testEventSourceOpening {
     }] eventSourceDidOpen:eventSource];
 
     [eventSource open];
-    XCTAssert(eventSource.isConnecting);
 
+    XCTAssert(eventSource.isConnecting);
     XCTAssert([monitor wait]);
     [delegate verify];
 }
@@ -80,14 +81,14 @@ - (void)testEventSourceClosing {
     [[[delegate stub] andDo:^(NSInvocation *invocation) {
         [monitor signal];
     }] eventSourceDidOpen:eventSource];
-
-    [eventSource open];
-
+
     [[[delegate stub] andDo:^(NSInvocation *invocation) {
         XCTAssert(eventSource.isClosed);
         [monitor signal];
     }] eventSourceDidClose:eventSource];
 
+    [eventSource open];
+
     XCTAssert([monitor wait]);
     [delegate verify];
 }