Alamofire 嵌套 JSON 序列化器
Posted
技术标签:
【中文标题】Alamofire 嵌套 JSON 序列化器【英文标题】：Alamofire Nested JSON Serializer 【发布时间】：2015-02-12 23:52:14 【问题描述】：我正在使用 Alamofire 向 JSON API 发出请求。我正在尝试序列化 Post 对象的集合，其中包含一个作者对象和一个 cmets 数组。
Click to see the hosted JSON
我做了以下事情：
第 1 步：按照步骤操作
扩展Alamofire.Request 对象并添加ResponseObjectSerializer 和ResponseCollectionSerializer，如Generic Response Object Serialization 下的文档中所述
第 2 步：添加以下模型
Post.swift
final class Post : ResponseObjectSerializable, ResponseCollectionSerializable
let id: Int
let title: String
let body: String
let author: Author
let comments: [Comment]
required init?(response: NSHTTPURLResponse, representation: AnyObject)
self.id = representation.valueForKeyPath("id") as Int
self.body = representation.valueForKeyPath("body") as String
self.title = representation.valueForKeyPath("title") as String
// What do I do with the author object
var authorObj: AnyObject? = representation.valueForKeyPath("author")
if (authorObj != nil)
self.author = Author(response: response, representation: authorObj!)!
// What do I do with the comments Array?
self.comments = Comment.collection(response: response, representation: representation.valueForKeyPath("comments")!)
class func collection(#response: NSHTTPURLResponse, representation: AnyObject) -> [Post]
var postList:[Post] = []
for p in representation as [AnyObject]
postList.append(Post(response: response, representation: p)!)
return postList
Comment.swift
final class Comment : ResponseObjectSerializable, ResponseCollectionSerializable
let id: Int
let body: String
required init?(response: NSHTTPURLResponse, representation: AnyObject)
self.id = representation.valueForKeyPath("id") as Int
self.body = representation.valueForKeyPath("body") as String
class func collection(#response: NSHTTPURLResponse, representation: AnyObject) -> [Comment]
var commentList:[Comment] = []
var commentArray = representation as [AnyObject]
for c in commentArray
commentList.append(Comment(response: response, representation: c)!)
return commentList
作者.swift
final class Author : ResponseObjectSerializable
let id: Int
let name: String
required init?(response: NSHTTPURLResponse, representation: AnyObject)
self.id = representation.valueForKeyPath("id") as Int
self.name = representation.valueForKeyPath("name") as String
第 3 步：表示是 Builtin.RawPointer
(lldb) po representation
(instance_type = Builtin.RawPointer = 0x00007f8b9ae1d290 -> 0x000000010c7f4c88 (void *)0x000000010c7f4dc8: __NSArrayI)
有什么建议吗？
第 4 步：这是我调用代码的方式
class NetworkPostProvider
typealias RequestsCollectionResponse = (NSError?, [Post]?) -> Void
class func all(onCompletion: RequestsCollectionResponse)
var manager = Alamofire.Manager.sharedInstance
manager.session.configuration.HTTPAdditionalHeaders = [
"Authorization": NSUserDefaults.standardUserDefaults().valueForKey(DEFAULTS_TOKEN) as String
]
manager.request(.GET, BASE_URL + "/alamofire/nested")
.validate()
.responseCollection( (req, res, requests:[Post]?, error) -> Void in
println("Request:")
println(req)
println("Response:")
println(res)
println(requests)
)
【问题讨论】：
如果您发布您如何使用 Alamofire 调用它会有所帮助。 @cnoon 这有帮助吗？ 【参考方案1】：您的解析逻辑肯定存在一些问题（主要是安全性）。我尽我所能重新创建了你的场景，并重新设计了看起来有问题的部分。我已经设法修复了您的解析，我很确定这是问题所在。从 Alamofire 的角度来看，您似乎正确地调用了所有内容。
import Foundation
import Alamofire
@objc public protocol ResponseObjectSerializable
init?(response: NSHTTPURLResponse, representation: AnyObject)
@objc public protocol ResponseCollectionSerializable
class func collection(#response: NSHTTPURLResponse, representation: AnyObject) -> [Self]
extension Alamofire.Request
public func responseObject<T: ResponseObjectSerializable>(completionHandler: (NSURLRequest, NSHTTPURLResponse?, T?, NSError?) -> Void) -> Self
let serializer: Serializer = (request, response, data) in
let JSONSerializer = Request.JSONResponseSerializer(options: .AllowFragments)
let (JSON: AnyObject?, serializationError) = JSONSerializer(request, response, data)
if response != nil && JSON != nil
return (T(response: response!, representation: JSON!), nil)
else
return (nil, serializationError)
return response(serializer: serializer, completionHandler: (request, response, object, error) in
completionHandler(request, response, object as? T, error)
)
public func responseCollection<T: ResponseCollectionSerializable>(completionHandler: (NSURLRequest, NSHTTPURLResponse?, [T]?, NSError?) -> Void) -> Self
let serializer: Serializer = (request, response, data) in
let JSONSerializer = Request.JSONResponseSerializer(options: .AllowFragments)
let (JSON: AnyObject?, serializationError) = JSONSerializer(request, response, data)
if response != nil && JSON != nil
return (T.collection(response: response!, representation: JSON!), nil)
else
return (nil, serializationError)
return response(serializer: serializer, completionHandler: (request, response, object, error) in
completionHandler(request, response, object as? [T], error)
)
final class Post : ResponseObjectSerializable, ResponseCollectionSerializable, Printable
let id: Int
let title: String
let body: String
let author: Author
let comments: [Comment]
var description: String
return "Post id = \(self.id), title = \(self.title), body = \(self.body), author = \(self.author), comments = \(self.comments)"
required init?(response: NSHTTPURLResponse, representation: AnyObject)
let id = representation.valueForKeyPath("id") as? Int
let title = representation.valueForKeyPath("title") as? String
let body = representation.valueForKeyPath("body") as? String
var author: Author?
if let authorObject: AnyObject = representation.valueForKeyPath("author")
author = Author(response: response, representation: authorObject)
var comments: [Comment]?
if let commentsObject: AnyObject = representation.valueForKeyPath("comments")
comments = Comment.collection(response: response, representation: commentsObject)
if id != nil && body != nil && title != nil && author != nil && comments != nil
self.id = id!
self.title = title!
self.body = body!
self.author = author!
self.comments = comments!
else
self.id = 0
self.title = ""
self.body = ""
self.author = Author(id: 0, name: "")
self.comments = [Comment]()
return nil
class func collection(#response: NSHTTPURLResponse, representation: AnyObject) -> [Post]
var postList = [Post]()
for p in representation as [AnyObject]
if let post = Post(response: response, representation: p)
postList.append(post)
return postList
final class Comment : ResponseObjectSerializable, ResponseCollectionSerializable, Printable
let id: Int
let body: String
var description: String
return "Comment id = \(self.id), name = \(self.body)"
init(id: Int, body: String)
self.id = id
self.body = body
required init?(response: NSHTTPURLResponse, representation: AnyObject)
let id = representation.valueForKeyPath("id") as? Int
let body = representation.valueForKeyPath("body") as? String
if id != nil && body != nil
self.id = id!
self.body = body!
else
self.id = 0
self.body = ""
return nil
class func collection(#response: NSHTTPURLResponse, representation: AnyObject) -> [Comment]
var commentList = [Comment]()
var commentArray = representation as [AnyObject]
for c in commentArray
if let comment = Comment(response: response, representation: c)
commentList.append(comment)
return commentList
final class Author : ResponseObjectSerializable, Printable
let id: Int
let name: String
var description: String
return "Author id = \(self.id), name = \(self.name)"
init(id: Int, name: String)
self.id = id
self.name = name
required init?(response: NSHTTPURLResponse, representation: AnyObject)
let id = representation.valueForKeyPath("id") as? Int
let name = representation.valueForKeyPath("name") as? String
if id != nil && name != nil
self.id = id!
self.name = name!
else
self.id = 0
self.name = ""
return nil
class NetworkPostProvider
typealias RequestsCollectionResponse = (NSError?, [Post]?) -> Void
class func all(onCompletion: RequestsCollectionResponse)
var manager = Alamofire.Manager.sharedInstance
manager.session.configuration.HTTPAdditionalHeaders = [
"Authorization": NSUserDefaults.standardUserDefaults().valueForKey("12345678") as String
]
let request = manager.request(.GET, "Some base url" + "/alamofire/nested")
request.validate()
request.responseCollection (req, res, requests: [Post]?, error) in
println("Request:")
println(req)
println("Response:")
println(res)
println(requests)
class func forceLoadJSON()
let path = NSBundle.mainBundle().pathForResource("stacked", ofType: "json")!
let data = NSData(contentsOfFile: path)!
if let json: AnyObject = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.AllowFragments, error: nil)
println(json)
let fakeResponse = NSHTTPURLResponse(URL: NSURL(string: "")!, statusCode: 200, HTTPVersion: nil, headerFields: nil)!
let posts = Post.collection(response: fakeResponse, representation: json)
println("Posts: \(posts)")
else
println("Failed to load the posts")
forceloadJSON 方法重新创建一旦请求从服务器返回，Alamofire 将触发的所有内容。问题是我实际上不能调用你的服务器 b/c 你没有提供必要的凭据或 URL 来实际调用它。如果您希望我进一步调试它，我将需要该信息。尽管我对Post、Comment 和Author 类所做的所有更改都已经解决了您的问题，但我几乎是肯定的。
我建议的另一个改变是使用结构而不是类。目前在 Swift 1.1 编译器中有一个 bug 不允许您在类内的可失败初始化程序中使用 return nil。这很可能在 Swift 1.2 中得到修复，但我还没有检查过。
我要更改的最后一件事是修改 ResponseCollectionSerializable 函数 collection 以便能够返回可选数组或可选数组。这是因为您的集合方法可能无法创建实例，因为它正在调用可失败的初始化程序。目前它正在掩埋这些错误，您不知道解析是否失败。你以前会在那种情况下崩溃（也许这就是你想要的）。我对其进行了修改，使其不会崩溃，但错误随后被掩埋。
【讨论】：
以上是关于Alamofire 嵌套 JSON 序列化器的主要内容，如果未能解决你的问题，请参考以下文章
为我可以用来操作 JSON 的 Alamofire 创建回调
AlamoFire 4.0 + SwiftyJSON 展开深度嵌套的 JSON