如何在 WebSocket 中代理到多个服务器

Question

我有一个用 ballerina 编程的代理，它接收用户对网络套接字的请求，并通过另一个网络套接字将其发送到处理它的服务。当前，当服务向我发送响应时，芭蕾舞脚本 return 会响应用户。我想这样做，一旦我收到来自该服务的响应，它就会被发送到另一个服务以执行第二次处理，当该服务响应时，return 将它发送给用户。

我有以下代码：

import ballerina/http;
import ballerina/log;


final string ASSOCIATED_CONNECTION = "EXTRACTOR CONNECTION";
final string EXTRACTOR = "ws://192.168.10.248:8081";



@http:WebSocketServiceConfig {
    path: "/api/ws"
}

service RequestService on new http:Listener(9091) {

  resource function onOpen(http:WebSocketCaller caller) {

        http:WebSocketClient wsClientEp = new(
            EXTRACTOR,
            {callbackService: ClientService,
            readyOnConnect: false,
            maxFrameSize: 2147483648
        });

        wsClientEp.setAttribute(ASSOCIATED_CONNECTION, caller);
        caller.setAttribute(ASSOCIATED_CONNECTION, wsClientEp);

        var err = wsClientEp->ready();
        if (err is http:WebSocketError) {
            log:printError("Error calling ready on client", err);
        }
    }

    resource function onText(http:WebSocketCaller caller, string text, boolean finalFrame) {

        http:WebSocketClient clientEp = getAssociatedClientEndpoint(caller);
        var err = clientEp->pushText(text, finalFrame);
        if (err is http:WebSocketError) {
            log:printError("Error occurred when sending text message", err);
        }
    }


    resource function onError(http:WebSocketCaller caller, error err) {

       http:WebSocketClient clientEp = getAssociatedClientEndpoint(caller);
       var e = clientEp->close(statusCode = 1011, reason = "Unexpected condition");
       if (e is http:WebSocketError) {
           log:printError("Error occurred when closing the connection", e);
       }
       _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
       log:printError("Unexpected error hence closing the connection", err);
   }

   resource function onClose(http:WebSocketCaller caller, int statusCode, string reason) {

       http:WebSocketClient clientEp = getAssociatedClientEndpoint(caller);
       var err = clientEp->close(statusCode = statusCode, reason = reason);
       if (err is http:WebSocketError) {
           log:printError("Error occurred when closing the connection", err);
       }
       _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
   }
}

service ClientService = @http:WebSocketServiceConfig {} service {

    resource function onText(http:WebSocketClient caller, string text, boolean finalFrame) {
        http:WebSocketCaller serverEp = getAssociatedServerEndpoint(caller);
        var err = serverEp->pushText(text, finalFrame);
        if (err is http:WebSocketError) {
            log:printError("Error occurred when sending text message", err);
        }
    }

    resource function onError(http:WebSocketClient caller, error err) {
        http:WebSocketCaller serverEp = getAssociatedServerEndpoint(caller);
        var e = serverEp->close(statusCode = 1011, reason = "Unexpected condition");
        if (e is http:WebSocketError) {
            log:printError("Error occurred when closing the connection", err = e);
        }
        _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
        log:printError("Unexpected error hense closing the connection", err);
    }

    resource function onClose(http:WebSocketClient caller, int statusCode, string reason) {
        http:WebSocketCaller serverEp = getAssociatedServerEndpoint(caller);
        var err = serverEp->close(statusCode = statusCode, reason = reason);
            if (err is http:WebSocketError) {
                log:printError("Error occurred when closing the connection", err);
            }
        _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
    }
};

function getAssociatedClientEndpoint(http:WebSocketCaller ep) returns (http:WebSocketClient) {
    http:WebSocketClient wsClient = <http:WebSocketClient>ep.getAttribute(ASSOCIATED_CONNECTION);
    return wsClient;
}

function getAssociatedServerEndpoint(http:WebSocketClient ep) returns (http:WebSocketCaller) {
    http:WebSocketCaller wsEndpoint = <http:WebSocketCaller>ep.getAttribute(ASSOCIATED_CONNECTION);
    return wsEndpoint;
}

我制作了以下管道：客户端 --> Ballerina 代理 --> Service1 --> Ballerina 代理 --> 客户端

我想要：客户端 --> Ballerina 代理 --> Service1 --> Ballerina 代理 --> Service2 --> Ballerina 代理 --> 客户端

Answer 1

我们可以链接关联的连接

caller has wsClientEp
wsClientEp has wsClientEp2
wsClientEp2 has caller

我写了一些粗略的代码我认为下面的代码应该可以工作。确保更改变量名称：

import ballerina/http;
import ballerina/log;


final string ASSOCIATED_CONNECTION = "EXTRACTOR CONNECTION";
final string EXTRACTOR = "ws://localhost:9090/basic";
final string EXTRACTOR2 = "ws://localhost:9091/basic";



@http:WebSocketServiceConfig {
    path: "/api/ws"
}

service RequestService on new http:Listener(9092) {

  resource function onOpen(http:WebSocketCaller caller) {

        http:WebSocketClient wsClientEp = new(
            EXTRACTOR,
            {callbackService: ClientService1,
            readyOnConnect: false,
            maxFrameSize: 2147483648
        });
        http:WebSocketClient wsClientEp2 = new(
            EXTRACTOR2,
            {callbackService: ClientService2,
            readyOnConnect: false,
            maxFrameSize: 2147483648
        });

        caller.setAttribute(ASSOCIATED_CONNECTION, wsClientEp);
        wsClientEp.setAttribute(ASSOCIATED_CONNECTION, wsClientEp2);
        wsClientEp2.setAttribute(ASSOCIATED_CONNECTION, caller);

        var err = wsClientEp->ready();
        if (err is http:WebSocketError) {
            log:printError("Error calling ready on client 1", err);
        }

        err = wsClientEp2->ready();
        if (err is http:WebSocketError) {
            log:printError("Error calling ready on client 2", err);
        }
    }

    resource function onText(http:WebSocketCaller caller, string text, boolean finalFrame) {

        http:WebSocketClient clientEp = getAssociatedClientEndpoint(caller);
        var err = clientEp->pushText(text, finalFrame);
        if (err is http:WebSocketError) {
            log:printError("Error occurred when sending text message", err);
        }
    }


    resource function onError(http:WebSocketCaller caller, error err) {

       http:WebSocketClient clientEp = getAssociatedClientEndpoint(caller);
       var e = clientEp->close(statusCode = 1011, reason = "Unexpected condition");
       if (e is http:WebSocketError) {
           log:printError("Error occurred when closing the connection", e);
       }
       _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
       log:printError("Unexpected error hence closing the connection", err);
   }

   resource function onClose(http:WebSocketCaller caller, int statusCode, string reason) {

       http:WebSocketClient clientEp = getAssociatedClientEndpoint(caller);
       var err = clientEp->close(statusCode = statusCode, reason = reason);
       if (err is http:WebSocketError) {
           log:printError("Error occurred when closing the connection", err);
       }
       _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
   }
}

service ClientService1 = @http:WebSocketServiceConfig {} service {

    resource function onText(http:WebSocketClient caller, string text, boolean finalFrame) {
        http:WebSocketClient clientEp2 = getAssociatedClientEndpointFromClient(caller);
        var err = clientEp2->pushText(text, finalFrame);
        if (err is http:WebSocketError) {
            log:printError("Error occurred when sending text message", err);
        }
    }

    resource function onError(http:WebSocketClient caller, error err) {
        http:WebSocketClient clientEp2 = getAssociatedClientEndpointFromClient(caller);
        var e = clientEp2->close(statusCode = 1011, reason = "Unexpected condition");
        if (e is http:WebSocketError) {
            log:printError("Error occurred when closing the connection", err = e);
        }
        _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
        log:printError("Unexpected error hense closing the connection", err);
    }

    resource function onClose(http:WebSocketClient caller, int statusCode, string reason) {
        http:WebSocketClient clientEp2 = getAssociatedClientEndpointFromClient(caller);
        var err = clientEp2->close(statusCode = statusCode, reason = reason);
            if (err is http:WebSocketError) {
                log:printError("Error occurred when closing the connection", err);
            }
        _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
    }
};

service ClientService2 = @http:WebSocketServiceConfig {} service {

    resource function onText(http:WebSocketClient caller, string text, boolean finalFrame) {
        http:WebSocketCaller serverEp = getAssociatedServerEndpoint(caller);
        var err = serverEp->pushText(text, finalFrame);
        if (err is http:WebSocketError) {
            log:printError("Error occurred when sending text message", err);
        }
    }

    resource function onError(http:WebSocketClient caller, error err) {
        http:WebSocketCaller serverEp = getAssociatedServerEndpoint(caller);
        var e = serverEp->close(statusCode = 1011, reason = "Unexpected condition");
        if (e is http:WebSocketError) {
            log:printError("Error occurred when closing the connection", err = e);
        }
        _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
        log:printError("Unexpected error hense closing the connection", err);
    }

    resource function onClose(http:WebSocketClient caller, int statusCode, string reason) {
        http:WebSocketCaller serverEp = getAssociatedServerEndpoint(caller);
        var err = serverEp->close(statusCode = statusCode, reason = reason);
            if (err is http:WebSocketError) {
                log:printError("Error occurred when closing the connection", err);
            }
        _ = caller.removeAttribute(ASSOCIATED_CONNECTION);
    }
};

function getAssociatedClientEndpoint(http:WebSocketCaller ep) returns (http:WebSocketClient) {
    http:WebSocketClient wsClient = <http:WebSocketClient>ep.getAttribute(ASSOCIATED_CONNECTION);
    return wsClient;
}

function getAssociatedServerEndpoint(http:WebSocketClient ep) returns (http:WebSocketCaller) {
    http:WebSocketCaller wsEndpoint = <http:WebSocketCaller>ep.getAttribute(ASSOCIATED_CONNECTION);
    return wsEndpoint;
}

function getAssociatedClientEndpointFromClient(http:WebSocketClient ep) returns (http:WebSocketClient) {
    http:WebSocketClient wsEndpoint = <http:WebSocketClient>ep.getAttribute(ASSOCIATED_CONNECTION);
    return wsEndpoint;
}

请注意，我已经稍微更改了 url 以进行测试。

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