Nodejs 无法 TCP/解析长 JSON 文件

Question

我有一个如下的 JSON 文件。虽然文件本身对于一个例子来说似乎不必要地长，但我包含它是有原因的。基本上，在我看来，我的文件太大而无法通过 TCP 到达我的实时站点。

{
    "FormatNumber": 1,
    "Team_Types": [{
            "Teams": "EmmersonCod",
            "Channels": [{
                    "Team_Name": "Tanaka",
                    "Team_Members": 1,
                    "Team_Mascot": "Dolphin"
                },
                {
                    "Team_Name": "Drago",
                    "Team_Members": 2,
                    "Team_Mascot": "Lundgren"
                },
                {
                    "Team_Name": "Apollo",
                    "Team_Members": 3,
                    "Team_Mascot": "Crews"
                },
                {
                    "Team_Name": "Cobra",
                    "Team_Members": 4,
                    "Team_Mascot": "Kai"
                }
            ]
        },
        {
            "Teams": "Candy",
            "Channels": [{
                    "Team_Name": "Simson",
                    "Team_Members": 1,
                    "Team_Mascot": "The"
                },
                {
                    "Team_Name": "Rick",
                    "Team_Members": 2,
                    "Team_Mascot": "Sanchez"
                }
            ]
        },
        {
            "Teams": "FoxNews",
            "Channels": [{
                    "Team_Name": "David",
                    "Team_Members": 1,
                    "Team_Mascot": "Bannon"
                },
                {
                    "Team_Name": "Rickety",
                    "Team_Members": 2,
                    "Team_Mascot": "Crickett"
                },
                {
                    "Team_Name": "Lady",
                    "Team_Members": 3,
                    "Team_Mascot": "Madam"
                },
                {
                    "Team_Name": "Random",
                    "Team_Members": 4,
                    "Team_Mascot": "Words"
                },
                {
                    "Team_Name": "Put",
                    "Team_Members": 5,
                    "Team_Mascot": "Together"
                },
                {
                    "Team_Name": "To",
                    "Team_Members": 6,
                    "Team_Mascot": "Fill"
                },
                {
                    "Team_Name": "These",
                    "Team_Members": 7,
                    "Team_Mascot": "Blanks"
                },
                {
                    "Team_Name": "And",
                    "Team_Members": 8,
                    "Team_Mascot": "Illustrate"
                },
                {
                    "Team_Name": "The",
                    "Team_Members": 9,
                    "Team_Mascot": "Issues"
                },
                {
                    "Team_Name": "We",
                    "Team_Members": 10,
                    "Team_Mascot": "Are"
                },
                {
                    "Team_Name": "Going",
                    "Team_Members": 11,
                    "Team_Mascot": "Through"
                },
                {
                    "Team_Name": "At",
                    "Team_Members": 12,
                    "Team_Mascot": "This"
                },
                {
                    "Team_Name": "Very",
                    "Team_Members": 13,
                    "Team_Mascot": "Moment"
                },
                {
                    "Team_Name": "The",
                    "Team_Members": 14,
                    "Team_Mascot": "JSON"
                },
                {
                    "Team_Name": "Is",
                    "Team_Members": 15,
                    "Team_Mascot": "Too"
                },
                {
                    "Team_Name": "Long",
                    "Team_Members": 16,
                    "Team_Mascot": "For"
                },
                {
                    "Channl_Name": "My",
                    "Team_Members": 17,
                    "Team_Mascot": "TCP"
                },
                {
                    "Team_Name": "To",
                    "Team_Members": 18,
                    "Team_Mascot": "Go"
                }
            ]
        }
    ]
}

我用来解析的 Node.js 代码如下：

var express = require('express');
var net = require("net");
var fs = require("fs");
var request = require('request');
var app = express();
var server = net.createServer();
var pack;

app.use(function(req, res, next){
    res.header("Access-Control-Allow-Origin", "*");
    next();
});

server.on("connection", function(socket){
    pack = "";
    socket.setEncoding('utf8');
        socket.on("data", function(d){
            pack = JSON.parse(d);
            console.log(pack.Timestamp.LocalTimestamp);
            app.set('dee', d);
                app.get("/"+pack.FormatNumber, function(req, res){
                    res.writeHead(200, {'Content-Type': 'text/plain'});
                    res.write(req.app.get('dee'));
                    res.end();
                });
        });
        socket.once("close", function(){
            console.log("connection closed");
        });
});

server.on("error", function(){
    console.log("connection error");
});

server.listen(9000, function(){
    console.log("Server Listening to Port 9000");
});

app.listen(8081, function(){

});

这个 JSON 文件作为 TCP 数据包发送到我的 Node 服务器，然后由它解析它。代码和功能在我的本地主机环境中完美运行。但是，当尝试将我的 JSON 文件推送到我的 Digitalocean Node.js 服务器时，我收到以下错误。

undefined:57
                                        "Cha
                                         ^

SyntaxError: Unexpected token C
    at Object.parse (native)
    at Socket.<anonymous> 
    at emitOne (events.js:77:13)
    at Socket.emit (events.js:169:7)
    at readableAddChunk (_stream_readable.js:146:16)
    at Socket.Readable.push (_stream_readable.js:110:10)
    at TCP.onread (net.js:523:20)

如果我减少我的 JSON 数组中的对象数量，那么将它传递到我的实时服务器会按预期工作。我不清楚这是为什么。 TCP 数据包仅通过较小的 JSON 文件进行解析。

Answer 1

TCP provides a stream of bytes, not messages.

尽管 TCP 通过 IP 数据包发送数据，但 TCP 不是数据包协议。 TCP 套接字只是数据的流。因此，将data 事件视为逻辑消息 是不正确的。换句话说，一端的一个socket.write 不等于另一端的一个data 事件。单个data 事件可能包含多个 消息、单个消息或仅消息的一部分。

好消息是这个问题已经解决了很多次。我会推荐：

• 使用 a library 表示通过 TCP 传递 JSON 消息。
• 使用 redis 之类的东西作为发布-订阅消息解决方案（此选项使您的应用更易于扩展）
• 如果您知道您的两个应用程序将始终在同一台机器上运行，您应该使用节点的built-in IPC mechanism。