Added truly asynchronous support to GCDWebServerStreamedResponse

GCDWebServer/Responses/GCDWebServerStreamedResponse.h

@@ -34,6 +34,19 @@
  */
 typedef NSData* (^GCDWebServerStreamBlock)(NSError** error);
 
+/**
+ *  The GCDWebServerAsyncStreamBlock works like the GCDWebServerStreamBlock
+ *  except the streamed data can be returned at a later time allowing for
+ *  truly asynchronous generation of the data.
+ *
+ *  The block must return empty NSData when done or nil on error and set the
+ *  "error" argument which is guaranteed to be non-NULL.
+ *
+ *  The block must eventually call "completionBlock" passing the streamed data
+ *  if any and the error if applicable.
+ */
+typedef void (^GCDWebServerAsyncStreamBlock)(GCDWebServerBodyReaderCompletionBlock completionBlock);
+
 /**
  *  The GCDWebServerStreamedResponse subclass of GCDWebServerResponse streams
  *  the body of the HTTP response using a GCD block.
@@ -46,8 +59,18 @@ typedef NSData* (^GCDWebServerStreamBlock)(NSError** error);
 + (instancetype)responseWithContentType:(NSString*)type streamBlock:(GCDWebServerStreamBlock)block;
 
 /**
- *  This method is the designated initializer for the class.
+ *  Creates a response with async streamed data and a given content type.
+ */
++ (instancetype)responseWithContentType:(NSString*)type asyncStreamBlock:(GCDWebServerAsyncStreamBlock)block;
+
+/**
+ *  Initializes a response with streamed data and a given content type.
  */
 - (instancetype)initWithContentType:(NSString*)type streamBlock:(GCDWebServerStreamBlock)block;
 
+/**
+ *  This method is the designated initializer for the class.
+ */
+- (instancetype)initWithContentType:(NSString*)type asyncStreamBlock:(GCDWebServerAsyncStreamBlock)block;
+
 @end

GCDWebServer/Responses/GCDWebServerStreamedResponse.m

@@ -29,7 +29,7 @@
 
 @interface GCDWebServerStreamedResponse () {
 @private
-  GCDWebServerStreamBlock _block;
+  GCDWebServerAsyncStreamBlock _block;
 }
 @end
 
@@ -39,7 +39,21 @@
   return ARC_AUTORELEASE([[[self class] alloc] initWithContentType:type streamBlock:block]);
 }
 
++ (instancetype)responseWithContentType:(NSString*)type asyncStreamBlock:(GCDWebServerAsyncStreamBlock)block {
+  return ARC_AUTORELEASE([[[self class] alloc] initWithContentType:type asyncStreamBlock:block]);
+}
+
 - (instancetype)initWithContentType:(NSString*)type streamBlock:(GCDWebServerStreamBlock)block {
+  return [self initWithContentType:type asyncStreamBlock:^(GCDWebServerBodyReaderCompletionBlock completionBlock) {
+    
+    NSError* error = nil;
+    NSData* data = block(&error);
+    completionBlock(data, error);
+    
+  }];
+}
+
+- (instancetype)initWithContentType:(NSString*)type asyncStreamBlock:(GCDWebServerAsyncStreamBlock)block {
   if ((self = [super init])) {
     _block = [block copy];
     
@@ -54,8 +68,8 @@
   ARC_DEALLOC(super);
 }
 
-- (NSData*)readData:(NSError**)error {
-  return _block(error);
+- (void)asyncReadDataWithCompletion:(GCDWebServerBodyReaderCompletionBlock)block {
+  _block(block);
 }
 
 - (NSString*)description {