IOS网络请求框架AFNetworking和ASIHttpRequest对比

ASI基于CFNetwork框架开发，而AFN基于NSURL.

ASI更底层，请求使用创建CFHTTPMessageRef进行，使用NSOperationQueue进行管理，ASIHTTPRequest就是NSOpration的子类，并实现了NSCopy协议。使用static NSOperationQueue *sharedQueue，在ASIHTTPRequest执行网络请求时把自己加进去queue。

AFN基于NSURL，请求使用NSURLRequest作为参数传入NSURlconnection进行。使用NSOperationQueue进行管理，通过初始化AFHTTPRquestOperationManager进行多线程管理。

更多可以参考对比IOS网络组件

2.优缺点对比

选自: AFNetworking、MKNetworkKit和ASIHTTPRequest对比

ASI开发者已于2012年10月宣布暂停该开源库的更新.

AFN的活跃维护者比较多。

3.使用

1.ASI的大概实现

ASIHTTPRequest是NSOperation的子类。在ASIHTTPRequest有个初始方法：

- (id)initWithURL:(NSURL *)newURL
{
    self = [self init];
    [self setRequestMethod:@"GET"];
 
    [self setRunLoopMode:NSDefaultRunLoopMode];
    [self setShouldAttemptPersistentConnection:YES];
    [self setPersistentConnectionTimeoutSeconds:60.0];
    [self setShouldPresentCredentialsBeforeChallenge:YES];
    [self setShouldRedirect:YES];
    [self setShowAccurateProgress:YES];
    [self setShouldResetDownloadProgress:YES];
    [self setShouldResetUploadProgress:YES];
    [self setAllowCompressedResponse:YES];
    [self setShouldWaitToInflateCompressedResponses:YES];
    [self setDefaultResponseEncoding:NSISOLatin1StringEncoding];
    [self setShouldPresentProxyAuthenticationDialog:YES];
 
    [self setTimeOutSeconds:[ASIHTTPRequest defaultTimeOutSeconds]];
    [self setUseSessionPersistence:YES];
    [self setUseCookiePersistence:YES];
    [self setValidatesSecureCertificate:YES];
    [self setRequestCookies:[[[NSMutableArray alloc] init] autorelease]];
    [self setDidStartSelector:@selector(requestStarted:)];
    [self setDidReceiveResponseHeadersSelector:@selector(request:didReceiveResponseHeaders:)];
    [self setWillRedirectSelector:@selector(request:willRedirectToURL:)];
    [self setDidFinishSelector:@selector(requestFinished:)];
    [self setDidFailSelector:@selector(requestFailed:)];
    [self setDidReceiveDataSelector:@selector(request:didReceiveData:)];
    [self setURL:newURL];
    [self setCancelledLock:[[[NSRecursiveLock alloc] init] autorelease]];
    [self setDownloadCache:[[self class] defaultCache]];
    return self;
}

然后在执行异步网络访问时，把自己扔进shareQueue进行管理。

- (void)startAsynchronous
{
#if DEBUG_REQUEST_STATUS || DEBUG_THROTTLING
    ASI_DEBUG_LOG(@"[STATUS] Starting asynchronous request %@",self);
#endif
    [sharedQueue addOperation:self];
}

执行同步访问时更直接。注意[self main]. main方法里面执行了CFNetwork的操作。

- (void)startSynchronous
{
#if DEBUG_REQUEST_STATUS || DEBUG_THROTTLING
    ASI_DEBUG_LOG(@"[STATUS] Starting synchronous request %@",self);
#endif
    [self setSynchronous:YES];
    [self setRunLoopMode:ASIHTTPRequestRunLoopMode];
    [self setInProgress:YES];
 
    if (![self isCancelled] && ![self complete]) {
        [self main];
        while (!complete) {
            [[NSRunLoop currentRunLoop] runMode:[self runLoopMode] beforeDate:[NSDate distantFuture]];
        }
    }
 
    [self setInProgress:NO];
}

2.ASI基本使用

ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:@"XXXXX"]];
[request setDelegate:self];   //ASIHTTPRequestDelegate
[request startAsynchronous];

不用进行很多配置，是因为ASIHTTPRequest的requestWithURL方法有默认配置，可以在实例化后自己再修改。如下(还有更多的自己阅读源码)：

[self setRequestMethod:@"GET"];   //访问方法
 
[self setRunLoopMode:NSDefaultRunLoopMode];   //默认runloop
[self setShouldAttemptPersistentConnection:YES];   //设置持久连接,重用request时用节约
[self setPersistentConnectionTimeoutSeconds:60.0];
[self setShouldPresentCredentialsBeforeChallenge:YES];  //是否要证书验证
[self setShouldRedirect:YES];
[self setShowAccurateProgress:YES];   //进度
[self setShouldResetDownloadProgress:YES];
[self setShouldResetUploadProgress:YES];
[self setAllowCompressedResponse:YES];
[self setShouldWaitToInflateCompressedResponses:YES];
[self setDefaultResponseEncoding:NSISOLatin1StringEncoding];
[self setShouldPresentProxyAuthenticationDialog:YES];
 
[self setTimeOutSeconds:[ASIHTTPRequest defaultTimeOutSeconds]];   //请求的网络等待时长
[self setUseSessionPersistence:YES];    //保持session
[self setUseCookiePersistence:YES];     //保持cookie
[self setValidatesSecureCertificate:YES];
[self setRequestCookies:[[[NSMutableArray alloc] init] autorelease]];
[self setDidStartSelector:@selector(requestStarted:)];   //请求开始
[self setDidReceiveResponseHeadersSelector:@selector(request:didReceiveResponseHeaders:)];        //获取到ResponseHeader
[self setWillRedirectSelector:@selector(request:willRedirectToURL:)];
[self setDidFinishSelector:@selector(requestFinished:)];    //请求完成
[self setDidFailSelector:@selector(requestFailed:)];      //请求失败
[self setDidReceiveDataSelector:@selector(request:didReceiveData:)];   //获取到data，多次
[self setURL:newURL];      //设置URL
[self setCancelledLock:[[[NSRecursiveLock alloc] init] autorelease]];
[self setDownloadCache:[[self class] defaultCache]];

ASIHTTPRequestDelegate的代理：

- (void)requestStarted:(ASIHTTPRequest *)request;
- (void)request:(ASIHTTPRequest *)request didReceiveResponseHeaders:(NSDictionary *)responseHeaders;
- (void)request:(ASIHTTPRequest *)request willRedirectToURL:(NSURL *)newURL;
- (void)requestFinished:(ASIHTTPRequest *)request;
- (void)requestFailed:(ASIHTTPRequest *)request;
- (void)requestRedirected:(ASIHTTPRequest *)request;
 
- (void)request:(ASIHTTPRequest *)request didReceiveData:(NSData *)data;
 
- (void)authenticationNeededForRequest:(ASIHTTPRequest *)request;
- (void)proxyAuthenticationNeededForRequest:(ASIHTTPRequest *)request;

2.AFN基本使用

1.实现基本原理:

先看看AFHTTPRquestOperationManager的默认初始化方法：可以看出默认的request为二进制，reponse为json解析。可以根据业务进行修改。

- (instancetype)initWithBaseURL:(NSURL *)url {
    self = [super init];
    if (!self) {
        return nil;
    }
 
    // Ensure terminal slash for baseURL path, so that NSURL +URLWithString:relativeToURL: works as expected
    if ([[url path] length] >  && ![[url absoluteString] hasSuffix:@"/"]) {
        url = [url URLByAppendingPathComponent:@""];
    }
 
    self.baseURL = url;     //初始化了baseurl，比如你的访问地址是http://192.168.0.100/login.action . 初始化baseUrl为http://192.168.0.100/ , 以后manager GET:@"login.action"即可。
 
    self.requestSerializer = [AFHTTPRequestSerializer serializer];
    self.responseSerializer = [AFJSONResponseSerializer serializer];
 
    self.securityPolicy = [AFSecurityPolicy defaultPolicy]; //AFSSLPinningModeNone无隐私要求
 
    self.reachabilityManager = [AFNetworkReachabilityManager sharedManager];
 
    self.operationQueue = [[NSOperationQueue alloc] init];
 
    self.shouldUseCredentialStorage = YES;
 
    return self;
}

再看看其中一个方法GET方法。

AFHTTPRequestOperation 是 AFURLConnectionOperation的子类，AFURLConnectionOperation的子类是NSOperation的子类，并实现了NSURLConnectionDelegate等网络协议。

@interface AFURLConnectionOperation : NSOperation <NSURLConnectionDelegate, NSURLConnectionDataDelegate, NSSecureCoding, NSCopying>

是使用刚才manager初始化生成的operationQueue进行多线程管理，所以一个项目有一个manager然后用来管理网络请求就行了。多线程已经由AFN内部处理了。

- (AFHTTPRequestOperation *)GET:(NSString *)URLString
                     parameters:(id)parameters
                        success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
                        failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
    AFHTTPRequestOperation *operation = [self HTTPRequestOperationWithHTTPMethod:@"GET" URLString:URLString parameters:parameters success:success failure:failure];
 
    [self.operationQueue addOperation:operation];
    return operation;
}

AFHTTPRequestOperation的生成，复用了很多manager的属性：

- (AFHTTPRequestOperation *)HTTPRequestOperationWithRequest:(NSURLRequest *)request
                                                    success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
                                                    failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    operation.responseSerializer = self.responseSerializer;
    operation.shouldUseCredentialStorage = self.shouldUseCredentialStorage;
    operation.credential = self.credential;
    operation.securityPolicy = self.securityPolicy;
 
    [operation setCompletionBlockWithSuccess:success failure:failure];  //注意这个地方
    operation.completionQueue = self.completionQueue;
    operation.completionGroup = self.completionGroup;
 
    return operation;
}

最后的回调，AFN是使用了NSOperation自己的block，难怪在协议找了好久没找到

- (void)setCompletionBlock:(void (^)(void))block {
    [self.lock lock];
    if (!block) {
        [super setCompletionBlock:nil];
    } else {
        __weak __typeof(self)weakSelf = self;
        [super setCompletionBlock:^ {
            __strong __typeof(weakSelf)strongSelf = weakSelf;
 
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wgnu"
            dispatch_group_t group = strongSelf.completionGroup ?: url_request_operation_completion_group();
            dispatch_queue_t queue = strongSelf.completionQueue ?: dispatch_get_main_queue();
#pragma clang diagnostic pop
 
            dispatch_group_async(group, queue, ^{
                block();
            });
 
            dispatch_group_notify(group, url_request_operation_completion_queue(), ^{
                [strongSelf setCompletionBlock:nil];
            });
        }];
    }
    [self.lock unlock];
}

2.基本GET

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    [manager GET:@"http://example.com/resources.json" parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"JSON: %@", responseObject);
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];

3.下载一个文件

NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];
 
NSURL *URL = [NSURL URLWithString:@"http://example.com/download.zip"];
NSURLRequest *request = [NSURLRequest requestWithURL:URL];
 
NSURLSessionDownloadTask *downloadTask = [manager downloadTaskWithRequest:request progress:nil destination:^NSURL *(NSURL *targetPath, NSURLResponse *response) {
    NSURL *documentsDirectoryURL = [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:NO error:nil];
    return [documentsDirectoryURL URLByAppendingPathComponent:[response suggestedFilename]];
} completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error) {
    NSLog(@"File downloaded to: %@", filePath);
}];
[downloadTask resume];