Inherits from NSOperation
Conforms to NSCoding
NSCopying
NSURLConnectionDataDelegate
NSURLConnectionDelegate
Declared in AFURLConnectionOperation.h

Overview

AFURLConnectionOperation is a subclass of NSOperation that implements NSURLConnection delegate methods.

Subclassing Notes

This is the base class of all network request operations. You may wish to create your own subclass in order to implement additional NSURLConnection delegate methods (see “NSURLConnection Delegate Methods” below), or to provide additional properties and/or class constructors.

If you are creating a subclass that communicates over the HTTP or HTTPS protocols, you may want to consider subclassing AFHTTPRequestOperation instead, as it supports specifying acceptable content types or status codes.

NSURLConnection Delegate Methods

AFURLConnectionOperation implements the following NSURLConnection delegate methods:

  • connection:didReceiveResponse:
  • connection:didReceiveData:
  • connectionDidFinishLoading:
  • connection:didFailWithError:
  • connection:didSendBodyData:totalBytesWritten:totalBytesExpectedToWrite:
  • connection:willCacheResponse:
  • connection:canAuthenticateAgainstProtectionSpace:
  • connection:didReceiveAuthenticationChallenge:

If any of these methods are overridden in a subclass, they must call the super implementation first.

Class Constructors

Class constructors, or methods that return an unowned instance, are the preferred way for subclasses to encapsulate any particular logic for handling the setup or parsing of response data. For instance, AFJSONRequestOperation provides JSONRequestOperationWithRequest:success:failure:, which takes block arguments, whose parameter on for a successful request is the JSON object initialized from the response data.

Callbacks and Completion Blocks

The built-in completionBlock provided by NSOperation allows for custom behavior to be executed after the request finishes. It is a common pattern for class constructors in subclasses to take callback block parameters, and execute them conditionally in the body of its completionBlock. Make sure to handle cancelled operations appropriately when setting a completionBlock (i.e. returning early before parsing response data). See the implementation of any of the AFHTTPRequestOperation subclasses for an example of this.

Subclasses are strongly discouraged from overriding setCompletionBlock:, as AFURLConnectionOperation’s implementation includes a workaround to mitigate retain cycles, and what Apple rather ominously refers to as “The Deallocation Problem”.

NSCoding & NSCopying Conformance

AFURLConnectionOperation conforms to the NSCoding and NSCopying protocols, allowing operations to be archived to disk, and copied in memory, respectively. However, because of the intrinsic limitations of capturing the exact state of an operation at a particular moment, there are some important caveats to keep in mind:

NSCoding Caveats

  • Encoded operations do not include any block or stream properties. Be sure to set completionBlock, outputStream, and any callback blocks as necessary when using -initWithCoder: or NSKeyedUnarchiver.
  • Operations are paused on encodeWithCoder:. If the operation was encoded while paused or still executing, its archived state will return YES for isReady. Otherwise, the state of an operation when encoding will remain unchanged.

NSCopying Caveats

  • -copy and -copyWithZone: return a new operation with the NSURLRequest of the original. So rather than an exact copy of the operation at that particular instant, the copying mechanism returns a completely new instance, which can be useful for retrying operations.
  • A copy of an operation will not include the outputStream of the original.
  • Operation copies do not include completionBlock. completionBlock often strongly captures a reference to self, which would otherwise have the unintuitive side-effect of pointing to the original operation when copied.

Tasks

Accessing Run Loop Modes

  •   runLoopModes

    The run loop modes in which the operation will run on the network thread. By default, this is a single-member set containing NSRunLoopCommonModes.

    property

Getting URL Connection Information

  •   request

    The request used by the operation’s connection.

    property
  •   response

    The last response received by the operation’s connection.

    property
  •   error

    The error, if any, that occurred in the lifecycle of the request.

    property

Getting Response Data

Accessing Streams

Managing Request Operation Information

  •   userInfo

    The user info dictionary for the receiver.

    property

Initializing an AFURLConnectionOperation Object

  • – initWithRequest:

    Initializes and returns a newly allocated operation object with a url connection configured with the specified url request.

Pausing / Resuming Requests

Configuring Backgrounding Task Behavior

Setting Progress Callbacks

Setting NSURLConnection Delegate Callbacks

  • – setAuthenticationAgainstProtectionSpaceBlock:

    Sets a block to be executed to determine whether the connection should be able to respond to a protection space’s form of authentication, as handled by the NSURLConnectionDelegate method connection:canAuthenticateAgainstProtectionSpace:.

  • – setAuthenticationChallengeBlock:

    Sets a block to be executed when the connection must authenticate a challenge in order to download its request, as handled by the NSURLConnectionDelegate method connection:didReceiveAuthenticationChallenge:.

  • – setRedirectResponseBlock:

    Sets a block to be executed when the server redirects the request from one URL to another URL, or when the request URL changed by the NSURLProtocol subclass handling the request in order to standardize its format, as handled by the NSURLConnectionDelegate method connection:willSendRequest:redirectResponse:.

  • – setCacheResponseBlock:

    Sets a block to be executed to modify the response a connection will cache, if any, as handled by the NSURLConnectionDelegate method connection:willCacheResponse:.

Properties

error

The error, if any, that occurred in the lifecycle of the request.

@property (readonly, nonatomic, strong) NSError *error

Discussion

The error, if any, that occurred in the lifecycle of the request.

Declared In

AFURLConnectionOperation.h

inputStream

The input stream used to read data to be sent during the request.

@property (nonatomic, strong) NSInputStream *inputStream

Discussion

The input stream used to read data to be sent during the request.

@discussion This property acts as a proxy to the HTTPBodyStream property of request.

Declared In

AFURLConnectionOperation.h

outputStream

The output stream that is used to write data received until the request is finished.

@property (nonatomic, strong) NSOutputStream *outputStream

Discussion

The output stream that is used to write data received until the request is finished.

@discussion By default, data is accumulated into a buffer that is stored into responseData upon completion of the request. When outputStream is set, the data will not be accumulated into an internal buffer, and as a result, the responseData property of the completed request will be nil. The output stream will be scheduled in the network thread runloop upon being set.

Declared In

AFURLConnectionOperation.h

request

The request used by the operation’s connection.

@property (readonly, nonatomic, strong) NSURLRequest *request

Discussion

The request used by the operation’s connection.

Declared In

AFURLConnectionOperation.h

response

The last response received by the operation’s connection.

@property (readonly, nonatomic, strong) NSURLResponse *response

Discussion

The last response received by the operation’s connection.

Declared In

AFURLConnectionOperation.h

responseData

The data received during the request.

@property (readonly, nonatomic, strong) NSData *responseData

Discussion

The data received during the request.

Declared In

AFURLConnectionOperation.h

responseString

The string representation of the response data.

@property (readonly, nonatomic, copy) NSString *responseString

Discussion

The string representation of the response data.

Declared In

AFURLConnectionOperation.h

responseStringEncoding

The string encoding of the response.

@property (readonly, nonatomic, assign) NSStringEncoding responseStringEncoding

Discussion

The string encoding of the response.

@discussion If the response does not specify a valid string encoding, responseStringEncoding will return NSUTF8StringEncoding.

Declared In

AFURLConnectionOperation.h

runLoopModes

The run loop modes in which the operation will run on the network thread. By default, this is a single-member set containing NSRunLoopCommonModes.

@property (nonatomic, strong) NSSet *runLoopModes

Discussion

The run loop modes in which the operation will run on the network thread. By default, this is a single-member set containing NSRunLoopCommonModes.

Declared In

AFURLConnectionOperation.h

userInfo

The user info dictionary for the receiver.

@property (nonatomic, strong) NSDictionary *userInfo

Discussion

The user info dictionary for the receiver.

Declared In

AFURLConnectionOperation.h

Instance Methods

initWithRequest:

Initializes and returns a newly allocated operation object with a url connection configured with the specified url request.

- (id)initWithRequest:(NSURLRequest *)urlRequest

Parameters

urlRequest

The request object to be used by the operation connection.

@discussion This is the designated initializer.

Discussion

Initializes and returns a newly allocated operation object with a url connection configured with the specified url request.

Declared In

AFURLConnectionOperation.h

isPaused

Whether the request operation is currently paused.

- (BOOL)isPaused

Return Value

YES if the operation is currently paused, otherwise NO.

Discussion

Whether the request operation is currently paused.

Declared In

AFURLConnectionOperation.h

pause

Pauses the execution of the request operation.

- (void)pause

Discussion

Pauses the execution of the request operation.

@discussion A paused operation returns NO for -isReady, -isExecuting, and -isFinished. As such, it will remain in an NSOperationQueue until it is either cancelled or resumed. Pausing a finished, cancelled, or paused operation has no effect.

Declared In

AFURLConnectionOperation.h

resume

Resumes the execution of the paused request operation.

- (void)resume

Discussion

Resumes the execution of the paused request operation.

@discussion Pause/Resume behavior varies depending on the underlying implementation for the operation class. In its base implementation, resuming a paused requests restarts the original request. However, since HTTP defines a specification for how to request a specific content range, AFHTTPRequestOperation will resume downloading the request from where it left off, instead of restarting the original request.

Declared In

AFURLConnectionOperation.h

setAuthenticationAgainstProtectionSpaceBlock:

Sets a block to be executed to determine whether the connection should be able to respond to a protection space’s form of authentication, as handled by the NSURLConnectionDelegate method connection:canAuthenticateAgainstProtectionSpace:.

- (void)setAuthenticationAgainstProtectionSpaceBlock:(BOOL ( ^ ) ( NSURLConnection *connection , NSURLProtectionSpace *protectionSpace ))block

Parameters

block

A block object to be executed to determine whether the connection should be able to respond to a protection space’s form of authentication. The block has a BOOL return type and takes two arguments: the URL connection object, and the protection space to authenticate against.

@discussion If _AFNETWORKING_ALLOW_INVALID_SSL_CERTIFICATES_ is defined, connection:canAuthenticateAgainstProtectionSpace: will accept invalid SSL certificates, returning YES if the protection space authentication method is NSURLAuthenticationMethodServerTrust.

Discussion

Sets a block to be executed to determine whether the connection should be able to respond to a protection space’s form of authentication, as handled by the NSURLConnectionDelegate method connection:canAuthenticateAgainstProtectionSpace:.

Declared In

AFURLConnectionOperation.h

setAuthenticationChallengeBlock:

Sets a block to be executed when the connection must authenticate a challenge in order to download its request, as handled by the NSURLConnectionDelegate method connection:didReceiveAuthenticationChallenge:.

- (void)setAuthenticationChallengeBlock:(void ( ^ ) ( NSURLConnection *connection , NSURLAuthenticationChallenge *challenge ))block

Parameters

block

A block object to be executed when the connection must authenticate a challenge in order to download its request. The block has no return type and takes two arguments: the URL connection object, and the challenge that must be authenticated.

@discussion If _AFNETWORKING_ALLOW_INVALID_SSL_CERTIFICATES_ is defined, connection:didReceiveAuthenticationChallenge: will attempt to have the challenge sender use credentials with invalid SSL certificates.

Discussion

Sets a block to be executed when the connection must authenticate a challenge in order to download its request, as handled by the NSURLConnectionDelegate method connection:didReceiveAuthenticationChallenge:.

Declared In

AFURLConnectionOperation.h

setCacheResponseBlock:

Sets a block to be executed to modify the response a connection will cache, if any, as handled by the NSURLConnectionDelegate method connection:willCacheResponse:.

- (void)setCacheResponseBlock:(NSCachedURLResponse *( ^ ) ( NSURLConnection *connection , NSCachedURLResponse *cachedResponse ))block

Parameters

block

A block object to be executed to determine what response a connection will cache, if any. The block returns an NSCachedURLResponse object, the cached response to store in memory or nil to prevent the response from being cached, and takes two arguments: the URL connection object, and the cached response provided for the request.

Discussion

Sets a block to be executed to modify the response a connection will cache, if any, as handled by the NSURLConnectionDelegate method connection:willCacheResponse:.

Declared In

AFURLConnectionOperation.h

setDownloadProgressBlock:

Sets a callback to be called when an undetermined number of bytes have been downloaded from the server.

- (void)setDownloadProgressBlock:(void ( ^ ) ( NSUInteger bytesRead , long long totalBytesRead , long long totalBytesExpectedToRead ))block

Parameters

block

A block object to be called when an undetermined number of bytes have been downloaded from the server. This block has no return value and takes three arguments: the number of bytes read since the last time the download progress block was called, the total bytes read, and the total bytes expected to be read during the request, as initially determined by the expected content size of the NSHTTPURLResponse object. This block may be called multiple times, and will execute on the main thread.

Discussion

Sets a callback to be called when an undetermined number of bytes have been downloaded from the server.

Declared In

AFURLConnectionOperation.h

setRedirectResponseBlock:

Sets a block to be executed when the server redirects the request from one URL to another URL, or when the request URL changed by the NSURLProtocol subclass handling the request in order to standardize its format, as handled by the NSURLConnectionDelegate method connection:willSendRequest:redirectResponse:.

- (void)setRedirectResponseBlock:(NSURLRequest *( ^ ) ( NSURLConnection *connection , NSURLRequest *request , NSURLResponse *redirectResponse ))block

Parameters

block

A block object to be executed when the request URL was changed. The block returns an NSURLRequest object, the URL request to redirect, and takes three arguments: the URL connection object, the the proposed redirected request, and the URL response that caused the redirect.

Discussion

Sets a block to be executed when the server redirects the request from one URL to another URL, or when the request URL changed by the NSURLProtocol subclass handling the request in order to standardize its format, as handled by the NSURLConnectionDelegate method connection:willSendRequest:redirectResponse:.

Declared In

AFURLConnectionOperation.h

setShouldExecuteAsBackgroundTaskWithExpirationHandler:

Specifies that the operation should continue execution after the app has entered the background, and the expiration handler for that background task.

- (void)setShouldExecuteAsBackgroundTaskWithExpirationHandler:(void ( ^ ) ( void ))handler

Parameters

handler

A handler to be called shortly before the application’s remaining background time reaches 0. The handler is wrapped in a block that cancels the operation, and cleans up and marks the end of execution, unlike the handler parameter in UIApplication -beginBackgroundTaskWithExpirationHandler:, which expects this to be done in the handler itself. The handler is called synchronously on the main thread, thus blocking the application’s suspension momentarily while the application is notified.

Discussion

Specifies that the operation should continue execution after the app has entered the background, and the expiration handler for that background task.

Declared In

AFURLConnectionOperation.h

setUploadProgressBlock:

Sets a callback to be called when an undetermined number of bytes have been uploaded to the server.

- (void)setUploadProgressBlock:(void ( ^ ) ( NSUInteger bytesWritten , long long totalBytesWritten , long long totalBytesExpectedToWrite ))block

Parameters

block

A block object to be called when an undetermined number of bytes have been uploaded to the server. This block has no return value and takes three arguments: the number of bytes written since the last time the upload progress block was called, the total bytes written, and the total bytes expected to be written during the request, as initially determined by the length of the HTTP body. This block may be called multiple times, and will execute on the main thread.

Discussion

Sets a callback to be called when an undetermined number of bytes have been uploaded to the server.

Declared In

AFURLConnectionOperation.h