Swift - 二次封装AFN（无网络走缓存基本原理）

Q:AFN网络框架怎么会跟缓存有一腿呢？缓存不是FMDB的事吗?两脸愣比

A: 了解URL缓存机制

0.1 AFNetworking使用NSURLConnection，它利用了原生的缓存机制NSURLCache
0.2 NSURLCache缓存了从服务器返回的NSURLResponse对象
0.3 NSURLCache的默认配置只是缓存在内存并没有写到硬盘

---

   import YYCache

// YYCache配合缓存用
1.1 从内存中读，有就直接拿来用
1.2 没有再从磁盘读，有就拿来用，并写入内存中
1.3 仍然没有就返回空

   import AFNetworking
   // CocoaSecurity将字符串转换为MD5工具
   import CocoaSecurity
   enum AFNRequestMethod {
   case GET
   case POST
   }
class NetworkTools: AFHTTPSessionManager {

/** 
  *  @param method        请求方式 
  *  @param parameters    请求参数
  *  @param finished      完成回调
  */  
func request(method:AFNRequestMethod,URLString:String,parameters:[Any],finished:@escaping (_ data:Any?,_ error:Error?)->()){


   //2.1发起网络请求时进来通过URL到磁盘查找是否存在已缓存有的
   if let responseByCache = NetworkTools.cacheJsonWithURL(URLString: URLString) {    
   finished(responseByCache, nil)
   return
 }

    //成功回调
 let success_block:((URLSessionDataTask, Any?) -> Swift.Void) = { (task, anyValue)->Void in        
      finished(anyValue, nil)
      // 2.2 调用保存请求响应文件
     NetworkTools.saveResponseToCacheFile(jsonResponse: anyValue, andURL: URLString)
    }
     //失败回调
   let failure_block:((URLSessionDataTask?, Error) -> Swift.Void) = { (task,err)->Void in
      finished(nil, err)
 }
 
 if method == AFNRequestMethod.GET{       

  get(URLString, parameters: parameters, progress: nil, success: success_block, failure: failure_block)

  } else if method == AFNRequestMethod.POST{

  post(URLString, parameters: parameters, progress: nil, success: success_block, failure: failure_block)
   
  }

  }

extension NetworkTools{
// 查找是否存在缓存处理
class func cacheJsonWithURL(URLString:String) ->(Any?){
// path_md5 通过CocoaSecurity用URL字符串返回MD5
let path_md5:String = self.returnCompletionPathByMd5(URLString: URLString)
// 创建YYCache会在path_md5沙盒路径下自动创建文件夹
let cache = YYCache.init(path: path_md5)

let isContains  = cache?.containsObject(forKey: URLString) ?? false

 if isContains {

 return cache?.object(forKey:URLString)
 }
 return nil
 }

 //保存过程处理
class func saveResponseToCacheFile(jsonResponse:Any?,andURL URLString:String){
let path = self.returnCompletionPathByMd5(URLString: URLString)

let cache = YYCache.init(path: path)
guard jsonResponse != nil else {
return
}
let isExist:Bool =  cache?.containsObject(forKey: URLString) ?? false
cache?.setObject(jsonResponse as! NSCoding, forKey: URLString)
if isExist {
print("保存[\(URLString)]成功")
}
}
}