Inherits from NSOperation
Conforms to NSCopying
NSSecureCoding
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:
  • connectionShouldUseCredentialStorage:
  • connection:needNewBodyStream:
  • connection:willSendRequestForAuthenticationChallenge:

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

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”.

SSL Pinning

Relying on the CA trust model to validate SSL certificates exposes your app to security vulnerabilities, such as man-in-the-middle attacks. For applications that connect to known servers, SSL certificate pinning provides an increased level of security, by checking server certificate validity against those specified in the app bundle.

SSL with certificate pinning is strongly recommended for any application that transmits sensitive information to an external webservice.

Connections will be validated on all matching certificates with a .cer extension in the bundle root.

App Extensions

When using AFNetworking in an App Extension, #define AF_APP_EXTENSIONS to avoid using unavailable APIs.

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, as it 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

Managing URL Credentials

  •   shouldUseCredentialStorage

    Whether the URL connection should consult the credential storage for authenticating the connection. YES by default.

    property
  •   credential

    The credential used for authentication challenges in -connection:didReceiveAuthenticationChallenge:.

    property

Managing Security Policy

  •   securityPolicy

    The security policy used to evaluate server trust for secure connections.

    property

Accessing Streams

Managing Callback Queues

  •   completionQueue

    The dispatch queue for completionBlock. If NULL (default), the main queue is used.

    property
  •   completionGroup

    The dispatch group for completionBlock. If NULL (default), a private dispatch group is used.

    property

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

Properties

completionGroup

@property (nonatomic, strong) dispatch_group_t completionGroup
Discussion

The dispatch group for completionBlock. If NULL (default), a private dispatch group is used.

Declared In

AFURLConnectionOperation.h

completionQueue

@property (nonatomic, strong) dispatch_queue_t completionQueue
Discussion

The dispatch queue for completionBlock. If NULL (default), the main queue is used.

Declared In

AFURLConnectionOperation.h

credential

@property (nonatomic, strong) NSURLCredential *credential
Discussion

The credential used for authentication challenges in -connection:didReceiveAuthenticationChallenge:.

This will be overridden by any shared credentials that exist for the username or password of the request URL, if present.

Declared In

AFURLConnectionOperation.h

error

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

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

Declared In

AFURLConnectionOperation.h

inputStream

@property (nonatomic, strong) NSInputStream *inputStream
Discussion

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

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

Declared In

AFURLConnectionOperation.h

outputStream

@property (nonatomic, strong) NSOutputStream *outputStream
Discussion

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

By default, data is accumulated into a buffer that is stored into responseData upon completion of the request, with the intermediary outputStream property set to nil. 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

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

The request used by the operation’s connection.

Declared In

AFURLConnectionOperation.h

response

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

The last response received by the operation’s connection.

Declared In

AFURLConnectionOperation.h

responseData

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

The data received during the request.

Declared In

AFURLConnectionOperation.h

responseString

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

The string representation of the response data.

Declared In

AFURLConnectionOperation.h

responseStringEncoding

@property (readonly, nonatomic, assign) NSStringEncoding responseStringEncoding
Discussion

The string encoding of the response.

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

Declared In

AFURLConnectionOperation.h

runLoopModes

@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

securityPolicy

@property (nonatomic, strong) AFSecurityPolicy *securityPolicy
Discussion

The security policy used to evaluate server trust for secure connections.

Declared In

AFURLConnectionOperation.h

shouldUseCredentialStorage

@property (nonatomic, assign) BOOL shouldUseCredentialStorage
Discussion

Whether the URL connection should consult the credential storage for authenticating the connection. YES by default.

This is the value that is returned in the NSURLConnectionDelegate method -connectionShouldUseCredentialStorage:.

Declared In

AFURLConnectionOperation.h

userInfo

@property (nonatomic, strong) NSDictionary *userInfo
Discussion

The user info dictionary for the receiver.

Declared In

AFURLConnectionOperation.h

Class Methods

batchOfRequestOperations:progressBlock:completionBlock:

+ (NSArray *)batchOfRequestOperations:(NSArray *)operations progressBlock:(void ( ^ ) ( NSUInteger numberOfFinishedOperations , NSUInteger totalNumberOfOperations ))progressBlock completionBlock:(void ( ^ ) ( NSArray *operations ))completionBlock

Declared In

AFURLConnectionOperation.h

Instance Methods

initWithRequest:

- (instancetype)initWithRequest:(NSURLRequest *)urlRequest
Discussion

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

This is the designated initializer.

Parameters

urlRequest

The request object to be used by the operation connection.

Declared In

AFURLConnectionOperation.h

isPaused

- (BOOL)isPaused
Discussion

Whether the request operation is currently paused.

Return Value

YES if the operation is currently paused, otherwise NO.

Declared In

AFURLConnectionOperation.h

pause

- (void)pause
Discussion

Pauses the execution of the request operation.

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

- (void)resume
Discussion

Resumes the execution of the paused request operation.

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

setCacheResponseBlock:

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

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.

Declared In

AFURLConnectionOperation.h

setDownloadProgressBlock:

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

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

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.

Declared In

AFURLConnectionOperation.h

setRedirectResponseBlock:

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

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.

Declared In

AFURLConnectionOperation.h

setShouldExecuteAsBackgroundTaskWithExpirationHandler:

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

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

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.

Declared In

AFURLConnectionOperation.h

setUploadProgressBlock:

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

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

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.

Declared In

AFURLConnectionOperation.h

setWillSendRequestForAuthenticationChallengeBlock:

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

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

Parameters

block

A block object to be executed when the connection will 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. This block must invoke one of the challenge-responder methods (NSURLAuthenticationChallengeSender protocol).

If allowsInvalidSSLCertificate is set to YES, connection:willSendRequestForAuthenticationChallenge: will attempt to have the challenge sender use credentials with invalid SSL certificates.

Declared In

AFURLConnectionOperation.h