1.实现原理

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。
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3.使用

1.ASI的大概实现

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

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	- (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。

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- (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

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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):

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[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:

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- (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。

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- (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] > 0 && ![[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。

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	- (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

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- (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

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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

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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];