Tcp request node issue

General
1

I am using node-red to do a low code flow development. When I use the below flow to implement the request, something unexpected happens.

http in > tcp request > http response

the tcp request will call another remote server to retrieve the data. The single test is fine with this flow. But when I use the Jmeter to do the performance tests, I found the request data can't map to the response data, and some of the requests will hang utill the timeout. It looks like this:
request 1 arrives > my flow send the data A to remote tcp server > request 2 arrives >my flow send the data B to remote tcp server > remote tcp server returns data A and close the tcp stream > return data A to request 2 > request 1 hang until timeout.

I am using the time type tcp request with 0ms setting. I am not good at nodejs, I can't figure out the deep reason for this behavior.

Anyone can help me with this?

2

something wrong with the tcp request node when handling lots of concurrent requests at one time. I used a function node to create a new net.Socket for each request to avoid the issue for now.

3

Can you provide a demo flow. Select the nodes to export them press ctrl+e. Paste the flow JSON in your reply.

5 
[
    {
        "id": "cb3b6c2a41cf72f0",
        "type": "tcp in",
        "z": "1282c65dbdf9f53c",
        "name": "监听11111",
        "server": "server",
        "host": "",
        "port": "11111",
        "datamode": "stream",
        "datatype": "buffer",
        "newline": "",
        "topic": "",
        "trim": false,
        "base64": false,
        "tls": "",
        "x": 240,
        "y": 180,
        "wires": [
            [
                "697533c7825e1ced",
                "03818d515d781ad3"
            ]
        ]
    },
    {
        "id": "388fba5269805c57",
        "type": "tcp out",
        "z": "1282c65dbdf9f53c",
        "name": "",
        "host": "",
        "port": "",
        "beserver": "reply",
        "base64": false,
        "end": false,
        "tls": "",
        "x": 570,
        "y": 180,
        "wires": []
    },
    {
        "id": "887d3185952d99a9",
        "type": "change",
        "z": "1282c65dbdf9f53c",
        "name": "",
        "rules": [
            {
                "t": "set",
                "p": "flag",
                "pt": "msg",
                "to": "",
                "tot": "date"
            }
        ],
        "action": "",
        "property": "",
        "from": "",
        "to": "",
        "reg": false,
        "x": 260,
        "y": 400,
        "wires": [
            [
                "8c5fa82733fd8f02"
            ]
        ]
    },
    {
        "id": "2e2d787232b8ef60",
        "type": "http in",
        "z": "1282c65dbdf9f53c",
        "name": "",
        "url": "/test",
        "method": "post",
        "upload": false,
        "swaggerDoc": "",
        "x": 100,
        "y": 460,
        "wires": [
            [
                "887d3185952d99a9"
            ]
        ]
    },
    {
        "id": "2dfcbf03c16f805b",
        "type": "http response",
        "z": "1282c65dbdf9f53c",
        "name": "",
        "statusCode": "",
        "headers": {},
        "x": 710,
        "y": 420,
        "wires": []
    },
    {
        "id": "2828b02abccf1a4f",
        "type": "tcp request",
        "z": "1282c65dbdf9f53c",
        "name": "",
        "server": "localhost",
        "port": "11111",
        "out": "time",
        "ret": "buffer",
        "splitc": "0",
        "newline": "",
        "trim": false,
        "tls": "",
        "x": 470,
        "y": 480,
        "wires": [
            [
                "672f219c956939e4"
            ]
        ]
    },
    {
        "id": "8c5fa82733fd8f02",
        "type": "function",
        "z": "1282c65dbdf9f53c",
        "name": "print request",
        "func": "node.log(\"flag:\" + msg.flag + \",payload:\" + msg.payload);\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [
            {
                "var": "net",
                "module": "net"
            }
        ],
        "x": 290,
        "y": 480,
        "wires": [
            [
                "2828b02abccf1a4f"
            ]
        ]
    },
    {
        "id": "672f219c956939e4",
        "type": "function",
        "z": "1282c65dbdf9f53c",
        "name": "print response",
        "func": "node.log(\"flag:\" + msg.flag + \",payload:\" + msg.payload);\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 660,
        "y": 480,
        "wires": [
            [
                "2dfcbf03c16f805b"
            ]
        ]
    },
    {
        "id": "697533c7825e1ced",
        "type": "function",
        "z": "1282c65dbdf9f53c",
        "name": "模拟返回",
        "func": "// 函数实现，参数 delay 单位 毫秒 ；\nfunction sleep(delay) {\n    var start = (new Date()).getTime();\n    while ((new Date()).getTime() - start < delay) {\n        // 使用  continue 实现；\n        continue;\n    }\n}\n\n// 调用方法，同步执行，阻塞后续程序的执行；\nsleep(Math.random());\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 420,
        "y": 180,
        "wires": [
            [
                "388fba5269805c57"
            ]
        ]
    },
    {
        "id": "03818d515d781ad3",
        "type": "debug",
        "z": "1282c65dbdf9f53c",
        "name": "debug 5",
        "active": false,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "",
        "statusType": "auto",
        "x": 540,
        "y": 80,
        "wires": []
    },
    {
        "id": "94d7958c51762c37",
        "type": "inject",
        "z": "1282c65dbdf9f53c",
        "name": "",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "",
        "payloadType": "date",
        "x": 90,
        "y": 380,
        "wires": [
            [
                "887d3185952d99a9"
            ]
        ]
    }
]
6

the flow is a simple request & resonse demo.

Once you use jmeter to test the /test with a random payload, you will find logs like below:

 573 25 Jul 12:53:28 - [info] [function:function 4] flag:1658724808303,payload:325726721
 574 25 Jul 12:53:28 - [info] [function:function 4] flag:1658724808304,payload:694579152
 575 25 Jul 12:53:28 - [info] [function:function 5] flag:1658724808304,payload:325726721694579152

which indicates the tcp request node content was incorrect.

7

ok, 2 things.

  1. JavaScript / NodeJS is an event driven async runtime - do not try to introduce a delay with a while loop - you will block the event loop. Instead, use the built in delay node
  2. It seems the TCP node does not graciously handle concurrent requests. Off the top of my head, you could limit the TCP Request node to one transaction using something like the semaphore node would be ideal (or a DIY fifo that you can push/peak/shift)

Here is a demo using built in nodes. NOTE: The data must have a \n newline for the TCP node to know when to emit otherwise fast operations will cause multiple repsonses to be concatenated ...

[
    {
        "id": "2e2d787232b8ef60",
        "type": "http in",
        "z": "53d61a606f3a5b66",
        "name": "",
        "url": "/test",
        "method": "post",
        "upload": false,
        "swaggerDoc": "",
        "x": 740,
        "y": 620,
        "wires": [
            [
                "8c5fa82733fd8f02"
            ]
        ]
    },
    {
        "id": "2828b02abccf1a4f",
        "type": "tcp request",
        "z": "53d61a606f3a5b66",
        "name": "",
        "server": "localhost",
        "port": "11111",
        "out": "sit",
        "ret": "string",
        "splitc": " ",
        "newline": "\\n",
        "trim": false,
        "tls": "",
        "x": 1270,
        "y": 620,
        "wires": [
            [
                "672f219c956939e4",
                "7ee1f6c07bdd0146"
            ]
        ]
    },
    {
        "id": "8c5fa82733fd8f02",
        "type": "function",
        "z": "53d61a606f3a5b66",
        "name": "add flag",
        "func": "msg.flag = RED.util.generateId()\nnode.log(\"flag:\" + msg.flag + \",payload:\" + msg.payload);\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [
            {
                "var": "crypto",
                "module": "crypto"
            }
        ],
        "x": 900,
        "y": 620,
        "wires": [
            [
                "2eeb96fd0e4f4d91",
                "93bf7d2106a6e741"
            ]
        ]
    },
    {
        "id": "672f219c956939e4",
        "type": "function",
        "z": "53d61a606f3a5b66",
        "name": "print response",
        "func": "node.log(\"flag:\" + msg.flag + \",payload:\" + msg.payload);\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1480,
        "y": 620,
        "wires": [
            [
                "f34b20e3b48bf779"
            ]
        ]
    },
    {
        "id": "e57a3876b7e6f0fc",
        "type": "inject",
        "z": "53d61a606f3a5b66",
        "name": "test 3",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "3",
        "payloadType": "num",
        "x": 810,
        "y": 820,
        "wires": [
            [
                "9c397614b000e13e"
            ]
        ]
    },
    {
        "id": "9c397614b000e13e",
        "type": "function",
        "z": "53d61a606f3a5b66",
        "name": "make multiple messages",
        "func": "for (let index = 0; index < msg.payload; index++) {\n    const m = {\n        payload: \"*\" + Date.now() + \"*\\n\",\n        requestTimeout: 5000\n    }\n    node.send(m);\n}\n",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1010,
        "y": 800,
        "wires": [
            [
                "9647b5cb32858609"
            ]
        ]
    },
    {
        "id": "9647b5cb32858609",
        "type": "http request",
        "z": "53d61a606f3a5b66",
        "name": "",
        "method": "POST",
        "ret": "txt",
        "paytoqs": "ignore",
        "url": "http://192.168.1.61:1880/test",
        "tls": "",
        "persist": false,
        "proxy": "",
        "authType": "",
        "senderr": false,
        "headers": [],
        "x": 1230,
        "y": 800,
        "wires": [
            [
                "559855fe09055156"
            ]
        ]
    },
    {
        "id": "559855fe09055156",
        "type": "debug",
        "z": "53d61a606f3a5b66",
        "name": "done (4)",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 1420,
        "y": 800,
        "wires": []
    },
    {
        "id": "daf26c52e601f08f",
        "type": "inject",
        "z": "53d61a606f3a5b66",
        "name": "test 1",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "1",
        "payloadType": "num",
        "x": 810,
        "y": 780,
        "wires": [
            [
                "9c397614b000e13e"
            ]
        ]
    },
    {
        "id": "1583264947bb0274",
        "type": "inject",
        "z": "53d61a606f3a5b66",
        "name": "test 50",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "50",
        "payloadType": "num",
        "x": 810,
        "y": 860,
        "wires": [
            [
                "9c397614b000e13e"
            ]
        ]
    },
    {
        "id": "d5f96f761e5259be",
        "type": "catch",
        "z": "53d61a606f3a5b66",
        "name": "",
        "scope": [
            "9647b5cb32858609"
        ],
        "uncaught": false,
        "x": 1050,
        "y": 900,
        "wires": [
            [
                "d8efe97e5f3574ee",
                "ebcce6b128a29a4f"
            ]
        ]
    },
    {
        "id": "d8efe97e5f3574ee",
        "type": "debug",
        "z": "53d61a606f3a5b66",
        "name": "err",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 1210,
        "y": 960,
        "wires": []
    },
    {
        "id": "c42ffa50e3bfe661",
        "type": "inject",
        "z": "53d61a606f3a5b66",
        "name": "clear",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "",
        "payloadType": "date",
        "x": 810,
        "y": 1040,
        "wires": [
            [
                "e0cc99a96593c366"
            ]
        ]
    },
    {
        "id": "2eeb96fd0e4f4d91",
        "type": "link call",
        "z": "53d61a606f3a5b66",
        "name": "",
        "links": [
            "2f6841c7c64868c8"
        ],
        "linkType": "static",
        "timeout": "30",
        "x": 1080,
        "y": 620,
        "wires": [
            [
                "2828b02abccf1a4f"
            ]
        ]
    },
    {
        "id": "f34b20e3b48bf779",
        "type": "link call",
        "z": "53d61a606f3a5b66",
        "name": "",
        "links": [
            "84d8551b17812c30"
        ],
        "linkType": "static",
        "timeout": "30",
        "x": 1710,
        "y": 620,
        "wires": [
            [
                "2dfcbf03c16f805b"
            ]
        ]
    },
    {
        "id": "7ee1f6c07bdd0146",
        "type": "debug",
        "z": "53d61a606f3a5b66",
        "name": "3",
        "active": false,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "",
        "statusType": "auto",
        "x": 1470,
        "y": 560,
        "wires": []
    },
    {
        "id": "93bf7d2106a6e741",
        "type": "debug",
        "z": "53d61a606f3a5b66",
        "name": "1",
        "active": false,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "payload",
        "targetType": "msg",
        "statusVal": "",
        "statusType": "auto",
        "x": 1050,
        "y": 560,
        "wires": []
    },
    {
        "id": "e0cc99a96593c366",
        "type": "link call",
        "z": "53d61a606f3a5b66",
        "name": "",
        "links": [
            "eea944fcfdf24a06"
        ],
        "linkType": "static",
        "timeout": "30",
        "x": 990,
        "y": 1040,
        "wires": [
            []
        ]
    },
    {
        "id": "ebcce6b128a29a4f",
        "type": "link call",
        "z": "53d61a606f3a5b66",
        "name": "",
        "links": [
            "84d8551b17812c30"
        ],
        "linkType": "static",
        "timeout": "30",
        "x": 1250,
        "y": 900,
        "wires": [
            []
        ]
    },
    {
        "id": "2937e3e3e75775f3",
        "type": "catch",
        "z": "53d61a606f3a5b66",
        "name": "",
        "scope": [
            "2e2d787232b8ef60",
            "8c5fa82733fd8f02",
            "2828b02abccf1a4f",
            "672f219c956939e4"
        ],
        "uncaught": false,
        "x": 1510,
        "y": 680,
        "wires": [
            [
                "c486a51ba28cdf47",
                "92ac7ce68a747a4b"
            ]
        ]
    },
    {
        "id": "92ac7ce68a747a4b",
        "type": "change",
        "z": "53d61a606f3a5b66",
        "name": "",
        "rules": [
            {
                "t": "set",
                "p": "statusCode",
                "pt": "msg",
                "to": "500",
                "tot": "num"
            }
        ],
        "action": "",
        "property": "",
        "from": "",
        "to": "",
        "reg": false,
        "x": 1720,
        "y": 680,
        "wires": [
            [
                "2dfcbf03c16f805b"
            ]
        ]
    },
    {
        "id": "c486a51ba28cdf47",
        "type": "debug",
        "z": "53d61a606f3a5b66",
        "name": "err",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 1670,
        "y": 740,
        "wires": []
    },
    {
        "id": "2dfcbf03c16f805b",
        "type": "http response",
        "z": "53d61a606f3a5b66",
        "name": "",
        "statusCode": "",
        "headers": {},
        "x": 1950,
        "y": 640,
        "wires": []
    },
    {
        "id": "a4f8f71434887c90",
        "type": "group",
        "z": "53d61a606f3a5b66",
        "style": {
            "stroke": "#999999",
            "stroke-opacity": "1",
            "fill": "none",
            "fill-opacity": "1",
            "label": true,
            "label-position": "nw",
            "color": "#a4a4a4"
        },
        "nodes": [
            "cb3b6c2a41cf72f0",
            "388fba5269805c57",
            "03818d515d781ad3",
            "42d9edb4e0b8039a"
        ],
        "x": 934,
        "y": 339,
        "w": 492,
        "h": 142
    },
    {
        "id": "cb3b6c2a41cf72f0",
        "type": "tcp in",
        "z": "53d61a606f3a5b66",
        "g": "a4f8f71434887c90",
        "name": "监听11111",
        "server": "server",
        "host": "",
        "port": "11111",
        "datamode": "stream",
        "datatype": "utf8",
        "newline": "\\n",
        "topic": "",
        "trim": true,
        "base64": false,
        "tls": "",
        "x": 1020,
        "y": 440,
        "wires": [
            [
                "03818d515d781ad3",
                "42d9edb4e0b8039a"
            ]
        ]
    },
    {
        "id": "388fba5269805c57",
        "type": "tcp out",
        "z": "53d61a606f3a5b66",
        "g": "a4f8f71434887c90",
        "name": "",
        "host": "",
        "port": "",
        "beserver": "reply",
        "base64": false,
        "end": false,
        "tls": "",
        "x": 1350,
        "y": 440,
        "wires": []
    },
    {
        "id": "03818d515d781ad3",
        "type": "debug",
        "z": "53d61a606f3a5b66",
        "g": "a4f8f71434887c90",
        "name": "2",
        "active": false,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 1170,
        "y": 380,
        "wires": []
    },
    {
        "id": "42d9edb4e0b8039a",
        "type": "delay",
        "z": "53d61a606f3a5b66",
        "g": "a4f8f71434887c90",
        "name": "",
        "pauseType": "delay",
        "timeout": "15",
        "timeoutUnits": "milliseconds",
        "rate": "1",
        "nbRateUnits": "1",
        "rateUnits": "second",
        "randomFirst": "1",
        "randomLast": "5",
        "randomUnits": "seconds",
        "drop": false,
        "allowrate": false,
        "outputs": 1,
        "x": 1190,
        "y": 440,
        "wires": [
            [
                "388fba5269805c57"
            ]
        ]
    },
    {
        "id": "a24078b37786ab11",
        "type": "group",
        "z": "53d61a606f3a5b66",
        "name": "Semaphore",
        "style": {
            "label": true,
            "fill": "#ffffbf",
            "label-position": "n",
            "color": "#000000"
        },
        "nodes": [
            "2681cf6bfa3573b5",
            "2f6841c7c64868c8",
            "0e926bcd5e075db3",
            "84d8551b17812c30",
            "814d5508332656f4",
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        "y": 139,
        "w": 692,
        "h": 162
    },
    {
        "id": "2681cf6bfa3573b5",
        "type": "function",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "semaphore",
        "func": "\n\nconst semaphore = context.get(\"semaphore\") || Semaphore(1);\ncontext.set(\"semaphore\", semaphore)\n\nif (msg.action === \"take\") {\n    const qmsg = RED.util.cloneMessage(msg)\n    delete qmsg.action\n    semaphore.take(qmsg, node.send)\n    updateStatus()\n} else if (msg.action === \"leave\") {\n    semaphore.leave()\n    node.send(msg);\n} else if (msg.action === \"clear\") {\n    semaphore.clear()\n}\n\nupdateStatus()\n\nreturn\n\nfunction updateStatus() {\n    if (semaphore.queue.length == 0) {\n        node.status({ fill: \"green\", shape: \"dot\", text: `empty` });\n    } else {\n        node.status({ fill: \"yellow\", shape: \"dot\", text: `Holding ${semaphore.queue.length}`});\n    }\n}\n\nfunction Semaphore(capacity) {\n    var nextTick = function (fn) { setTimeout(fn, 0); }\n    if (typeof process != 'undefined' && process && typeof process.nextTick == 'function') {\n        nextTick = process.nextTick;\n    }\n    var semaphore = {\n        capacity: capacity || 1,\n        queue: [],\n        take: function (data, callback) {\n            // node.warn([\"take\", semaphore])\n\n            var item = {\n                sent: false,\n                pos: semaphore.queue.length + 1,\n                task: function() {\n                    if(!item.sent) {\n                        callback(data)\n                        item.sent = true\n                    }\n                }\n            }\n            semaphore.queue.push(item);\n            if (item.pos <= semaphore.capacity) {\n                nextTick(semaphore.leave)\n            }\n        },\n\n        leave: function () {\n            if (!semaphore.queue.length) {\n                 return;\n            }\n            let item = semaphore.queue[0];\n            if (item) {\n                if(item.sent) {\n                    // node.warn([\"leave - shifting item\", item])\n                    semaphore.queue.shift()\n                    nextTick(semaphore.leave)\n                } else {\n                    // node.warn([\"leave - queing next execution task\", item])\n                    nextTick(item.task)\n                }\n            }            \n        },\n\n        clear: function () {\n            // node.warn([\"clear\", semaphore])\n            semaphore.queue = []\n            semaphore.current = 0\n        },\n\n        available: function (n) {\n            n = n || 1;\n            return (semaphore.current + n <= semaphore.capacity);\n        }\n    };\n\n    return semaphore;\n};\n\n",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1310,
        "y": 200,
        "wires": [
            [
                "835bdced53074bb6"
            ]
        ]
    },
    {
        "id": "2f6841c7c64868c8",
        "type": "link in",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "semaphore take",
        "links": [],
        "x": 900,
        "y": 180,
        "wires": [
            [
                "0e926bcd5e075db3"
            ]
        ],
        "l": true
    },
    {
        "id": "0e926bcd5e075db3",
        "type": "change",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "",
        "rules": [
            {
                "t": "set",
                "p": "action",
                "pt": "msg",
                "to": "take",
                "tot": "str"
            }
        ],
        "action": "",
        "property": "",
        "from": "",
        "to": "",
        "reg": false,
        "x": 1100,
        "y": 180,
        "wires": [
            [
                "2681cf6bfa3573b5"
            ]
        ]
    },
    {
        "id": "84d8551b17812c30",
        "type": "link in",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "semaphore leave",
        "links": [],
        "x": 900,
        "y": 220,
        "wires": [
            [
                "814d5508332656f4"
            ]
        ],
        "l": true
    },
    {
        "id": "814d5508332656f4",
        "type": "change",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "",
        "rules": [
            {
                "t": "set",
                "p": "action",
                "pt": "msg",
                "to": "leave",
                "tot": "str"
            }
        ],
        "action": "",
        "property": "",
        "from": "",
        "to": "",
        "reg": false,
        "x": 1100,
        "y": 220,
        "wires": [
            [
                "2681cf6bfa3573b5"
            ]
        ]
    },
    {
        "id": "835bdced53074bb6",
        "type": "link out",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "semaphore return",
        "mode": "return",
        "links": [],
        "x": 1445,
        "y": 200,
        "wires": []
    },
    {
        "id": "eea944fcfdf24a06",
        "type": "link in",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "semaphore clear",
        "links": [],
        "x": 900,
        "y": 260,
        "wires": [
            [
                "0afaf1f1096ceca4"
            ]
        ],
        "l": true
    },
    {
        "id": "0afaf1f1096ceca4",
        "type": "change",
        "z": "53d61a606f3a5b66",
        "g": "a24078b37786ab11",
        "name": "",
        "rules": [
            {
                "t": "set",
                "p": "action",
                "pt": "msg",
                "to": "clear",
                "tot": "str"
            }
        ],
        "action": "",
        "property": "",
        "from": "",
        "to": "",
        "reg": false,
        "x": 1100,
        "y": 260,
        "wires": [
            [
                "2681cf6bfa3573b5"
            ]
        ]
    }
]
8

Thanks for your comment. Even though I didn't test your demo, it looks not quite appropriate for my case. Although it is a good idea in other situations :slight_smile:

In my case, the TCP server closes the TCP connection once it returns the response immediately, so I can't separate the message with a special character. So the best option is to implement the net.Socket in function node to make sure each request will create a new TCP connection. Please advise me if my workaround has any concerns, thanks!

9

If you need it to close, a slight tweak resolves that...

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msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1480,"y":620,"wires":[["f34b20e3b48bf779"]]},{"id":"e57a3876b7e6f0fc","type":"inject","z":"53d61a606f3a5b66","name":"test 3","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"3","payloadType":"num","x":810,"y":820,"wires":[["9c397614b000e13e"]]},{"id":"9c397614b000e13e","type":"function","z":"53d61a606f3a5b66","name":"make multiple messages","func":"for (let index = 0; index < msg.payload; index++) {\n    const m = {\n        payload: \"*\" + Date.now() + \"*\",\n        requestTimeout: 5000\n    }\n    node.send(m);\n}\n","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1010,"y":800,"wires":[["9647b5cb32858609"]]},{"id":"9647b5cb32858609","type":"http request","z":"53d61a606f3a5b66","name":"","method":"POST","ret":"txt","paytoqs":"ignore","url":"http://192.168.1.61:1880/test","tls":"","persist":false,"proxy":"","authType":"","senderr":false,"headers":[],"x":1230,"y":800,"wires":[["559855fe09055156"]]},{"id":"559855fe09055156","type":"debug","z":"53d61a606f3a5b66","name":"done (4)","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":1420,"y":800,"wires":[]},{"id":"daf26c52e601f08f","type":"inject","z":"53d61a606f3a5b66","name":"test 1","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"1","payloadType":"num","x":810,"y":780,"wires":[["9c397614b000e13e"]]},{"id":"1583264947bb0274","type":"inject","z":"53d61a606f3a5b66","name":"test 50","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"50","payloadType":"num","x":810,"y":860,"wires":[["9c397614b000e13e"]]},{"id":"d5f96f761e5259be","type":"catch","z":"53d61a606f3a5b66","name":"","scope":["9647b5cb32858609"],"uncaught":false,"x":1050,"y":900,"wires":[["d8efe97e5f3574ee","ebcce6b128a29a4f"]]},{"id":"d8efe97e5f3574ee","type":"debug","z":"53d61a606f3a5b66","name":"err","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":1210,"y":960,"wires":[]},{"id":"c42ffa50e3bfe661","type":"inject","z":"53d61a606f3a5b66","name":"clear","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":810,"y":1040,"wires":[["e0cc99a96593c366"]]},{"id":"2eeb96fd0e4f4d91","type":"link 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chrome_BFKPPKKmvu

10

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