如何使用 apollo ios 客户端实现 graphql 订阅答案

【问题标题】：How to implement graphql subscription using apollo ios client如何使用 apollo ios 客户端实现 graphql 订阅
【发布时间】：2019-01-14 03:58:56
【问题描述】：

我正在尝试使用 apollo ios 客户端实现 graphql 订阅。但由于缺乏文档示例而无法弄清楚。阿波罗文档中给出的示例是：

let apollo: ApolloClient = {
  let configuration = URLSessionConfiguration.default
  // Add additional headers as needed
  configuration.httpAdditionalHeaders = ["Authorization": "Bearer <token>"] // Replace `<token>`

  let url = URL(string: "http://localhost:8080/graphql")!

  return ApolloClient(networkTransport: HTTPNetworkTransport(url: url, configuration: configuration))
}()

APOLLO IOS GUIDE: Creating a client

【问题讨论】：

标签： graphql apollo-ios

【解决方案1】：

按照以下步骤在 apollo ios graphql 客户端中实现订阅。

使用 cocoapods：
1. pod 'Apollo'
2. pod 'Apollo/WebSocket'
3. pod install
创建客户端以支持订阅和身份验证。在AppDelegate.swift中添加以下代码：
1. Websocket - 我们必须使用WebSocketTransport 和URLRequest
2. 身份验证 - 我们必须将连接参数connectingPayload 中的身份验证参数传递给服务器。对于 http，我们在问题 sn-p 中提到的标头中传递它。
3. SplitNetworkTransport- 结合 http 和 websocket 来创建客户端。我们必须使用httpNetworkTransport 和webSocketNetworkTransport


lazy var apollo: ApolloClient = {
    let authPayloads = [
        "Authorization": "Bearer "
    ]
    let configuration = URLSessionConfiguration.default
    configuration.httpAdditionalHeaders = authPayloads

let map: GraphQLMap = authPayloads 
let wsEndpointURL = URL(string: "ws://localhost:8080/subscriptions")!
let endpointURL = URL(string: "http://localhost:8080/api")!
let websocket = WebSocketTransport(request: URLRequest(url: wsEndpointURL), connectingPayload: map)
let splitNetworkTransport = SplitNetworkTransport(
    httpNetworkTransport: HTTPNetworkTransport(
        url: endpointURL,
        configuration: configuration
    ), 
    webSocketNetworkTransport: websocket
)
return ApolloClient(networkTransport: splitNetworkTransport)


}()

【讨论】：

从哪里获得 wsEndpointURL？下一步我需要做什么来更新 UI？
你能帮帮我吗

【解决方案2】：

我快到了。我因在 Websocket 升级中没有正确的标头而被拒绝。我最终不得不直接在URLRequest 对象上设置它们。

    var apollo: ApolloClient? {
        let authHeaders = ["X-Hasura-Access-Key": "<my_Key>", "Content-Type": "application/json"]

        let configuration = URLSessionConfiguration.default
        // Add additional headers as needed
        configuration.httpAdditionalHeaders = authHeaders

        //The string to my graph QL Server run by Hasure on AWS RDS.
        let graphQLEndpoint = "http://<my_host>/v1alpha1/graphql"
        let graphQLSubscriptionEndpoint = "ws://<my_host>/v1alpha1/graphql"
        //Take my Ec2 Server string and make a URL for the graph QL and subscriptions
        guard let httpURL = URL(string: graphQLEndpoint), let webSocketURL = URL(string: graphQLSubscriptionEndpoint) else {
            return nil
        }

        let httpTransport = HTTPNetworkTransport(url: httpURL, configuration: configuration, sendOperationIdentifiers: false)

        var request = URLRequest(url: webSocketURL)

        request.setValue("<my_key>", forHTTPHeaderField: "X-Hasura-Access-Key")

        request.setValue("application/json", forHTTPHeaderField: "Content-Type")

        let webSocketTransport = WebSocketTransport(request: request, sendOperationIdentifiers: false, connectingPayload: nil)

        let splitTransport = SplitNetworkTransport(httpNetworkTransport: httpTransport, webSocketNetworkTransport: webSocketTransport)

        //Initalize the APolloClient with that URL.
        return ApolloClient(networkTransport: splitTransport)
    }

在那之后升级工作了。

【讨论】：

【解决方案3】：

这是我的 ApolloClient 设置，仅用于 Web 套接字传输客户端：

let connectingPayload = ["authToken": accessToken]
let urlRequest = URLRequest(url: baseURL)
let webSocketTransport = WebSocketTransport(request: urlRequest, sendOperationIdentifiers: false, connectingPayload: connectingPayload)

let apollo = ApolloClient(networkTransport: webSocketTransport)

【讨论】：