串行异步网络请求的简单实现

//仅列出关键代码

@property (strong, nonatomic) NSArarry *datasArray;

- (void)beginUploadData {
[self uploadDataToServer:self.datasArray[0] index:0];
}

- (void)uploadDataToServer:(id)data index:(NSUInteger)index {
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager POST:@"url"
parameters:@{@"data":data}
success:^(AFHTTPRequestOperation *operation, id responseObject) {
if(index == self.datasArray.count - 1) {
//最后一条数据上传成功
}
else {
//上传下一条数据
[self uploadDataToServer:self.datasArray[index + 1] index:index + 1];
}
}
failure:^(AFHTTPRequestOperation *operation,NSError *error)  {
//提示错误
];
}
view rawdemo.m hosted with ❤ by GitHub

//用了表示是否有异步请求正在执行
@property (assign, atomic) BOOL excuting;
@property (strong, nonatomic) NSArray *datasArray;
@property (strong, nonatomic) NSOperationQueue *operationQueue;

- (void)ViewDidLoad {
[super viewDidLoad];
self.excuting = NO;
self.operationQueue = [[NSOperationQueue alloc] init];
[self.operationQueue setMaxConcurrentOperationCount:1];
NSInvocationOperation *previousOperation = nil;
for(id data in datasArray) {
NSInvocationOperation *operation = [[NSInvocationOperation alloc]
initWithTarget:self
selector:@selector(uploadDataToServer:)
object:data];
if(previousOperation) {
[operation addDependency:previousOperation]
}
[self.operationQueue addOperation:operation];
previousOperation = operation;
}
}

- (void)uploadDataToServer:(id)data {
NSURL *url = [NSURL URLWithString:@"https://api/"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"POST"];
[request setTimeoutInterval:60];
[request setHTTPBody:data];
NSURLSessionDataTask *dataTask = [[NSURLSession sharedSession]
dataTaskWithRequest:request
completionHandler:^(NSData * _Nullable data,
NSURLResponse * _Nullable response,
NSError * _Nullable error) {
if (error) {
//该任务执行有错误，取消后续任务
[self.operationQueue cancelAllOperations];
}
else {
self.excuting = false;
}
}];
//如果有其他任务正在执行，则阻塞当前任务
while(self.excuting) {

}

//开始当前任务
[dataTask resume];
self.excuting = YES;
}