对AFNetworking的一个简单封装

背景

在MVC的架构下，我们习惯于在Controller里做很多的逻辑操作，例如发起网络请求并解析返回数据。这么做固然不错，但我个人认为将网络请求抽离出去更好一些，让Controller不去在乎那些细节，也更符合面向对象编程的理念。

现有的AFNetworking已将网络请求封装的很好，使用起来也很方便。但是还是要在Controller里指定URL、parameters、GET/POST等参数，还要在成功之后解析结果，Controller本不应该关心这些事，Controller应该只是拿到最终的model添加到DataSource里面。因此对AFNetworking做一个简单的封装。

具体实现

//LLBaseRequest.h

typedef NS_ENUM(NSUInteger, LLRequestType) {
    LLRequestTypeGet,
    LLRequestTypePost,
};
@class LLBaseResponse;
@interface LLBaseRequest : NSObject

@property (nonatomic, copy) NSString *url;
@property (nonatomic, copy) NSDictionary *parameters;
@property (nonatomic, assign) LLRequestType requestType;

+ (instancetype)sharedInstance;

- (instancetype)init NS_UNAVAILABLE;

- (Class)responseClass;
- (void)loadDataSuccess:(nullable void (^)(__kindof LLBaseResponse  * _Nullable response))success
                failure:(nullable void (^)(NSString * _Nullable errorMessage))failure;
@end

//LLBaseRequest.m

#import <AFNetworking/AFNetworking.h>

@implementation LLBaseRequest

+ (instancetype)sharedInstance {
    static LLBaseRequest *sharedInstance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [[self alloc] init];
    });
    return sharedInstance;
}

- (instancetype)init
{
    self = [super init];
    if (self) {
        _url = @"";
        _parameters = @{};
        _requestType = LLRequestTypeGet;
    }
    return self;
}

- (Class)responseClass {
    return [LLBaseResponse class];
}

- (void)loadDataSuccess:(void (^)(__kindof LLBaseResponse * _Nullable))success failure:(void (^)(NSString * _Nullable))failure {
    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    switch ([self requestType]) {
        case LLRequestTypeGet:
        {
            [manager GET:self.url parameters:self.parameters progress:^(NSProgress * _Nonnull downloadProgress) {
                
            } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
                NSLog(@"------response object------\n%@ : %@", [self class], responseObject);
                if (success) {
                    success([[self responseClass] yy_modelWithDictionary:responseObject]);
                }
            } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
                NSLog(@"------request error------\n%@ : %@", [self class], [error localizedDescription]);
                if (failure) {
                    failure([error localizedDescription]);
                }
            }];
        }
            break;
            
        case LLRequestTypePost:
        {
            [manager POST:self.url parameters:self.parameters progress:^(NSProgress * _Nonnull uploadProgress) {
                
            } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
                NSLog(@"------response object------\n%@ : %@", [self class], responseObject);
                if (success) {
                    success([[self responseClass] yy_modelWithDictionary:responseObject]);
                }
            } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
                NSLog(@"------request error------\n%@ : %@", [self class], [error localizedDescription]);
                if (failure) {
                    failure([error localizedDescription]);
                }
            }];
        }
            break;
            
        default:
            break;
    }
}

@end

• 采用单例模式
• 子类实现url、parameters、requestType
• 子类指定返回的model

子类继承LLBaseRequest，实现对应方法

@implementation LLHomeRecommendRequest

- (NSString *)url {
    ···
}

- (NSDictionary *)parameters {
    ···
}

- (Class)responseClass {
    return [LLHomeRecommendResponse class];
}

- (LLRequestType)requestType {
    return LLRequestTypePost;
}

@end

这样在Controller中只用实例化一个request对象，调用一个方法，即可拿到最终的model

LLHomeRecommendRequest *request = [LLHomeRecommendRequest sharedInstance];
__weak typeof(self) weakSelf = self;
[request loadDataSuccess:^(LLHomeRecommendResponse * _Nullable response) {
    __strong typeof(weakSelf) strongSelf = weakSelf;
    [strongSelf.collectionView.mj_header endRefreshing];
    for (LLDiscoverRecommendData *data in response.feedDataGroup.dataList) {
        LLBaseComponent *component = [LLBaseComponent componentWithCollectionView:strongSelf.collectionView data:data];
        if (component) {
            [strongSelf.components addObject:component];
        }
    }
    [strongSelf.collectionView reloadData];
} failure:^(NSString * _Nullable errorMessage) {
    __strong typeof(weakSelf) strongSelf = weakSelf;
    [strongSelf.collectionView.mj_header endRefreshing];
}];

思考总结

对于从C语言来的同学，应该尽快摆脱之前的编码思维，尽快理解面向对象编程的含义，这样写出来的代码才更易维护，更灵活。