WEEX + HTTPDNS iOS解决方案

WEEX + HTTPDNS iOS解决方案

由于WebView并未暴露处设置DNS的接口，因而在WebView场景下使用HttpDns存在很多无法限制，但如果接入WEEX,则可以较好地植入HTTPDNS，本文主要介绍在WEEX场景下接入HTTPDNS的方案细节。

在WEEX运行时环境下，所有的逻辑最终都会转换到Native Runtime中执行，网络请求也不例外。同时WEEX也提供了自定义相应实现的接口，通过重写网络请求适配器，我们可以较为简单地接入HTTPDNS。在WEEX运行环境中，主要有两种网络请求：

• 通过Stream进行的网络请求
• <image>标签指定的加载图片的网络请求

下面以 weex iOS 0.7.0 版本为例：

Stream网络请求 + HTTPDNS

Stream网络请求在 iOS 端最终会通过WXNetworkDefaultImpl完成，同时WEEX也提供了相应的接口自定义网络请求适配器。具体的逻辑如下：

第一步：创建自定义网络请求适配器，实现 WXNetworkHttpDnsImpl 接口

#import <WeexSDK/WeexSDK.h>
#import "WXNetworkDefaultImpl.h"

@interface WXNetworkHttpDnsImpl : NSObject<WXNetworkProtocol, WXModuleProtocol , NSURLSessionDelegate>

@end

第二步：在WEEX初始化时注册自定义网络适配器，替换默认适配器：

    [WXSDKEngine registerHandler:[WXNetworkHttpDnsImpl new] withProtocol:@protocol(WXNetworkProtocol)];

之后的网络请求都会通过WXNetworkHttpDnsImpl实现，所以只需要在WXNetworkHttpDnsImpl中植入 HTTPDNS 逻辑即可，具体逻辑可以参考如下代码：

#import "WXNetworkDefaultImpl.h"

@interface WXNetworkCallbackInfo : NSObject

@property (nonatomic, copy) void(^sendDataCallback)(int64_t, int64_t);
@property (nonatomic, copy) void(^responseCallback)(NSURLResponse *);
@property (nonatomic, copy) void(^receiveDataCallback)(NSData *);
@property (nonatomic, strong) NSMutableData *data;
@property (nonatomic, copy) void(^compeletionCallback)(NSData *, NSError *);

@end

@implementation WXNetworkCallbackInfo

@end

@implementation WXNetworkDefaultImpl
{
    NSMutableDictionary *_callbacks;
    NSURLSession *_session;
}

- (id)sendRequest:(NSURLRequest *)request withSendingData:(void (^)(int64_t, int64_t))sendDataCallback
                                             withResponse:(void (^)(NSURLResponse *))responseCallback
                                          withReceiveData:(void (^)(NSData *))receiveDataCallback
                                          withCompeletion:(void (^)(NSData *, NSError *))compeletionCallback
{
    WXNetworkCallbackInfo *info = [WXNetworkCallbackInfo new];
    info.sendDataCallback = sendDataCallback;
    info.responseCallback = responseCallback;
    info.receiveDataCallback = receiveDataCallback;
    info.compeletionCallback = compeletionCallback;
    
    if (!_session) {
        _session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]
                                                 delegate:self
                                            delegateQueue:[NSOperationQueue mainQueue]];
    }
    
    NSURLSessionDataTask *task = [_session dataTaskWithRequest:request];
    if (!_callbacks) {
        _callbacks = [NSMutableDictionary dictionary];
    }
    [_callbacks setObject:info forKey:task];
    [task resume];
    
    return task;
}

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task
                                didSendBodyData:(int64_t)bytesSent
                                 totalBytesSent:(int64_t)totalBytesSent
                       totalBytesExpectedToSend:(int64_t)totalBytesExpectedToSend
{
    WXNetworkCallbackInfo *info = [_callbacks objectForKey:task];
    if (info.sendDataCallback) {
        info.sendDataCallback(totalBytesSent, totalBytesExpectedToSend);
    }
}

- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)task
                                 didReceiveResponse:(NSURLResponse *)response
                                  completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
{
    WXNetworkCallbackInfo *info = [_callbacks objectForKey:task];
    if (info.responseCallback) {
        info.responseCallback(response);
    }
    completionHandler(NSURLSessionResponseAllow);
}

- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)task didReceiveData:(NSData *)data
{
    WXNetworkCallbackInfo *info = [_callbacks objectForKey:task];
    if (info.receiveDataCallback) {
        info.receiveDataCallback(data);
    }
    
    NSMutableData *mutableData = info.data;
    if (!mutableData) {
        mutableData = [NSMutableData new];
        info.data = mutableData;
    }
    
    [mutableData appendData:data];
}

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
{
    WXNetworkCallbackInfo *info = [_callbacks objectForKey:task];
    if (info.compeletionCallback) {
        info.compeletionCallback(info.data, error);
    }
    [_callbacks removeObjectForKey:task];
}

@end

1.2 <image>网络请求 + HTTPDNS

WEEX并没有提供默认的图片适配器实现，所以用户必须自行实现才能完成图片请求逻辑，具体步骤分为以下几步：

第一步：自定义图片请求适配器，实现IWXImgLoaderAdapter接口

#import "WXImgLoaderProtocol.h"

@interface WXImgLoaderDefaultImpl : NSObject<WXImgLoaderProtocol, WXModuleProtocol>
@end

第二步：在WEEX初始化时注册该图片适配器：

   [WXSDKEngine registerHandler:[WXImgLoaderDefaultImpl new] withProtocol:@protocol(WXImgLoaderProtocol)];

所以同WXNetworkHttpDnsImpl一样，我们只需在WXNetworkHttpDnsImpl植入HTTPDNS逻辑即可。