多个子协议Websocket Javascript客户端和Libwebsockets服务器无法正常工作

Question

我正在尝试为演示创建一个简单的两个协议客户端和服务器。但是当我在websocket的客户端初始化中指定两个子协议时，我总是在服务器端获得此消息：

[1363089953:1535] ERR: Req protocol SIGN_IN_OUT_REQUEST_PROTOCOL, GET_REQUEST_PROTOCOL not supported

客户端Javascript代码：

    var host = 'ws://10.0.96.32:9000';
var webSocket = {};
var websocketStatus = {};

$(function() {

        function webSocketSupported() {
            if(window.MozWebSocket) {
                window.WebSocket = window.MozWebSocket;
            }
            return (window.webSocket != null);
        }

        if(!webSocketSupported) { 
           $(document).simpledialog2({
               mode: 'blank',
               headerClose: true,
               blankContent :
                       "<p>Websockets not supported by this browser. How about <a href='http://www.google.com/chrome'>Google Chrome</a>?</p>"+
                       "<a rel='close' data-role='button' href='#'>Close</a>"         
           }); 
        } else {

            $("#login_form").validate({
               rules:{
                   username: {required: true, minlength: 2},
                   password: {required: true, minlength: 4}
               },
               messages:{
                   username: {required: "Username is required",
                              minlength: "Username must be atleast 2 characters"},
                   password: {required: "Password is required",
                              minlength: "Password must be atleast 4 characters"}
               } 
            });

            /** Setting up WebSocket **/
            webSocket = new WebSocket(host, 'SIGN_IN_OUT_REQUEST_PROTOCOL', 'GET_REQUEST_PROTOCOL');
            webSocket.binaryType = "arraybuffer";
            webSocket.onopen = onopen;
            webSocket.onmessage = onmessage;
            webSocket.onclose = onclose;
            webSocket.onerror = onerror;           
        }
});

function onopen() {
    $('#connectionStatus').text("Connected");
    $('#connectionStatus').buttonMarkup({theme: 'b'});
    $("#connectionStatus").data('icon', 'check'); 
    $("#connectionStatus .ui-icon").addClass("ui-icon-check").removeClass("ui-icon-alert");
    $('#login_info').append("Sub-protocol: "+webSocket.protocol+"\n");
}

function onmessage(event) {
    var data = new DataView(event.data);
    if(data.getUint8(data.byteLength - 1) == 1) {
        $('#login_info').append("Login Attempt Successful");
        $.mobile.loadPage("mobileApp.html");
        $.mobile.changePage("mobileApp.html")
    }
    else {
        $('#login_info').append("Login Attempt Unsuccessful");
        $('#username').val("");
        $('#password').val("");
    }
}

function onclose() {
    $('#connectionStatus').text("Connection Closed");
    $('#connectionStatus').buttonMarkup({theme: 'a'});
    $("#connectionStatus").data('icon', 'alert'); 
    $("#connectionStatus .ui-icon").addClass("ui-icon-alert").removeClass("ui-icon-alert");
}

function onerror() {
    $('#connectionStatus').text("Connection Error");
    $('#connectionStatus').buttonMarkup({theme: 'a'});
    $("#connectionStatus").data('icon', 'alert'); 
    $("#connectionStatus .ui-icon").addClass("ui-icon-alert").removeClass("ui-icon-alert");
}

function initialize() {
    $('#login_info').val("");
    $('#username').val("");
    $('#password').val("");
    $('#connectionStatus').text("Connection Closed");
    $('#connectionStatus').buttonMarkup({theme: 'a'});
    $("#connectionStatus").data('icon', 'alert'); 
    $("#connectionStatus .ui-icon").addClass("ui-icon-alert").removeClass("ui-icon-alert");
}

function sendLoginRequest(event) {
    var i = 0;
    event.preventDefault();
    if($("#login_form").valid()) {
        var username = $("#username").val();
        var password = $("#password").val();
        var loginRequest = new Uint8Array(calculateBufferLength());
        loginRequest[i++] = 0x13; //User Accounts IP
        loginRequest[i++] = 0x13; //Sign In/Sign Out Request
        loginRequest[i++] = 0x07; //Sign In
        loginRequest[i++] = username.length;
        loginRequest[i++] = password.length;

        //Pushing username
        for(var j=0; j < username.length; j++) {
            loginRequest[i++] = username.charCodeAt(j);
        }

        //Pushing password
        for(var j=0; j < password.length; j++) {
            loginRequest[i++] = password.charCodeAt(j);
        }

        webSocket.send(loginRequest.buffer);
        $("#login_info").append("Login request sent with\nUsername: "+username+"\nPassword: "+password+"\n");
    }
}

function calculateBufferLength() {
    var opIPLength = 1;
    var modeLength = 1;
    var subModeLength = 1;
    var UserNamePasswordlengths = 2;
    var userNameLength = $("#username").val().length;
    var passwordLength = $("#password").val().length;
    return (opIPLength + modeLength + subModeLength + UserNamePasswordlengths + userNameLength + passwordLength);
}

服务器C / C ++代码（Libwebsockets）

    #include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string>
#include <vector>
#include <libwebsockets.h>

using namespace std;

typedef enum {
    USER_ACCOUNTS_IP_REQUEST,
    MODE,
    SUB_MODE,
    USER_NAME_LENGTH,
    PASSWORD_LENGTH
}user_accounts_ip_request_t;

typedef enum {
    USER_ACCOUNTS_IP_RESPONSE,
    RESPONSE_IP
}user_accounts_ip_response_t;

int Hex_to_Dec(unsigned char *array, int size);
void sendLoginResponse(struct libwebsocket *wsi, void *in_buffer, size_t bufferlen, struct per_session_data__binary *out_buffer);
void printSocketInfo(struct libwebsocket *wsi, struct libwebsocket_context *currentContext);

struct per_session_data__binary
{
    unsigned int len;
    unsigned char buf[sizeof(LWS_SEND_BUFFER_PRE_PADDING) + 1024 + sizeof(LWS_SEND_BUFFER_POST_PADDING)];
};

static int callback_http(struct libwebsocket_context *currentContext,
                         struct libwebsocket *wsi,
                         enum libwebsocket_callback_reasons reason, void *user,
                         void *in, size_t len)
{
    return 0;
}

static int callback_sign_in_out_request(struct libwebsocket_context *currentContext,
                                   struct libwebsocket *wsi,
                                   enum libwebsocket_callback_reasons reason,
                                   void *user, void *in, size_t len)
{
    struct per_session_data__binary *psb = (per_session_data__binary *)user;   ////////

    switch (reason) {
        case LWS_CALLBACK_ESTABLISHED: // just log message that someone is connecting
            printf("connection established\n");
            break;
        case LWS_CALLBACK_PROTOCOL_INIT:
            printf("LWS_CALLBACK_PROTOCOL_INIT\n");
            break;
        case LWS_CALLBACK_CLIENT_CONNECTION_ERROR:
            printf("LWS_CALLBACK_CLIENT_CONNECTION_ERROR\n");
            break;
        case LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH:
            printf("LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH\n");
            break;
        case LWS_CALLBACK_RECEIVE: {
            printf("Binary frame received decoding packet...\n");
            sendLoginResponse(wsi, in, len, psb);
        }
            break;
        default:
                    break;
    }
        return 0;
}

static int callback_get_request(struct libwebsocket_context *currentContext,
        struct libwebsocket *wsi,
        enum libwebsocket_callback_reasons reason,
        void *user, void *in, size_t len)
{
    return 0;
}

static struct libwebsocket_protocols protocols[] = {
    /* first protocol must always be HTTP handler */
    {
        "http-only",   // name
        callback_http, // callback
        0              // per_session_data_size
    },
    {
        "SIGN_IN_OUT_REQUEST_PROTOCOL", // protocol name - very important!
        callback_sign_in_out_request,   // callback
        sizeof(struct per_session_data__binary)              // we don't use any per session data
    },
    {
        "GET_REQUEST_PROTOCOL",
        callback_get_request,
        sizeof(struct per_session_data__binary)
    },
    {
        NULL, NULL, 0   /* End of list */
    }
};

int main(void) {
        // server url will be http://localhost:9000
        int port = 9000;
        const char *interface = NULL;
        struct libwebsocket_context *context;
        struct lws_context_creation_info info;
        // we're not using ssl
        const char *cert_path = NULL;
        const char *key_path = NULL;
        // no special options
        int opts = 0;

    info.port = port;
    info.iface = interface;
    info.protocols = protocols;
    info.extensions = libwebsocket_get_internal_extensions();
    info.ssl_cert_filepath = cert_path;
    info.ssl_private_key_filepath = key_path;
    info.ssl_ca_filepath = NULL;
    info.gid = -1;
    info.uid = -1;
    info.options = opts;
    info.user = NULL;
    //info.ka_time = 0;
    //info.ka_probes = 100;
    //info.ka_interval= 60;

    context = libwebsocket_create_context(&info);

        if (context == NULL) {
            fprintf(stderr, "libwebsocket init failed\n");
            return -1;
    }

        printf("starting server...\n");

    // infinite loop, to end this server send SIGTERM. (CTRL+C)
    while (1) {
            libwebsocket_service(context, 50);
        //printf("after service\n");
            // libwebsocket_service will process all waiting events with their
            // callback functions and then wait 50 ms.
            // (this is a single threaded webserver and this will keep our server
            // from generating load while there are not requests to process)
    }
        libwebsocket_context_destroy(context);

        return 0;
}

void sendLoginResponse(struct libwebsocket *wsi, void *in_buffer, size_t bufferlen, struct per_session_data__binary *out_buffer)
{
    vector<string> userNames, passwords;
    string userName, password;
    bool loginValid = false;
    int usernameLength, passwordLength;
    int usernamePos, passwordPos;


    userNames.push_back("Nautel");
    passwords.push_back("password");

    //Print Login Request Data
    char* loginRequest = (char*) in_buffer;
    usernameLength = loginRequest[USER_NAME_LENGTH];
    passwordLength = loginRequest[PASSWORD_LENGTH];
    usernamePos = PASSWORD_LENGTH + 1;
    passwordPos = usernamePos + usernameLength;

    //Get Username
    for(int i=usernamePos; i < (usernamePos+usernameLength); i++) {
        userName.push_back(loginRequest[i]);
    }

    //Get Password
    for(int i=passwordPos; i < (passwordPos + passwordLength); i++) {
        password.push_back(loginRequest[i]);
    }

    printf("Username: %s Password: %s\n", userName.c_str(), password.c_str());

    for(int i=0; i < userNames.size(); i++) {
        loginValid = (!userName.compare(userNames[i]) && !password.compare(passwords[i]));
        if(loginValid) break;
    }

    out_buffer->buf[USER_ACCOUNTS_IP_RESPONSE] = 0x13;
    out_buffer->buf[RESPONSE_IP] = (loginValid) ? 0x01 : 0x00;
    out_buffer->len = 2;
    libwebsocket_write(wsi, out_buffer->buf,  out_buffer->len, LWS_WRITE_BINARY);
}

void printSocketInfo(struct libwebsocket *wsi, struct libwebsocket_context *currentContext){
    char name[128];
    int name_len=sizeof(name);
    char rip[16];
    int rip_len= sizeof(rip);
    int fd;

    fd = libwebsocket_get_socket_fd(wsi);
    libwebsockets_get_peer_addresses (currentContext, wsi, fd, name, name_len, rip, rip_len);

    printf("Name: %s, IP: %s\n", name, rip);
}

是否可以让客户端具有单个服务器支持的多个子协议，反之亦然。或者我是否需要从客户端到服务器的多个websocket连接以用于不同的协议。

此致 Shreyas

Answer 1

WebSocket客户端可以宣布支持多个WebSocket子协议，但服务器必须从客户端公布的列表中选择一个子协议（它支持）。

Answer 2

在握手期间，支持的子协议服务器端列表将发送到客户端。客户端也发送其列表。 他们必须至少有一个共同的子协议。

您可以实施自己的子协议或使用现有的ones。

例如，对于使用libwebsockets库（C / C ++）和javascript websocket客户端的websocket服务器，如果您实现自己的子协议：

服务器端：

static struct libwebsocket_protocols protocols[] = {
    {
        "http-only",
        callback_http, 
        0              
    },
    {
        "MySubProtocol",
        dedicated_callback_function,
        sizeof(struct per_session_data__binary)              
    }
}

客户端：

var exampleSocket = new WebSocket("ws://www.example.com/socketserver", "MySubProtocol");

更多信息here和here