I created my own FIFO node with support from community here .... the FIFO will handle msg.payload and treats it as object.. in my use-case I show a history of "Offline" device events and have added the msg.payload.timestamp for each message object.
The FIFO can be configured on how many Objects you want to store (20 by default). The FIFO stores them as an array of a clocal Flow-Variable
[
{
"id": "069fdecd535f40a9",
"type": "subflow",
"name": "FIFO (object)",
"info": "# FIFO\n## First in First Out subflow\nThis flow receives a series of msg.payloads and builds a queue using FIFO (First in First out) method. The LIFO size is configurabe through subflow enviroment variables.\n\n### Input\n`msg.topic == put`\nWill add the `msg.payload` to the end of the array. Everytime a new item is received the second output sends the complete queue.\n\n`msg.topic == get`\nWill remove the first item of the stack and will send it in the first output\n\n`msg.topic == list`\nSends the complete list on the second output.\n\n### Output 1\nThe first item on the top of the stack. It is sent only when `msg.topic == get`.\n\n### Output 2\nThe complete queue in Array format. It is sent everytime a new item is added, removed or when `msg.topic == list`\n\n### Status\nAlways show the queue size.\n\n### Enviroment Variables\n`Buffer_Size` defines the size of the queue. If a new item arrives and the queue is full, the oldest item will be removed.",
"category": "",
"in": [
{
"x": 100,
"y": 120,
"wires": [
{
"id": "b81a11f776547198"
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}
],
"out": [
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"y": 60,
"wires": [
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"wires": [
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"env": [
{
"name": "Buffer_Size",
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"value": "6"
}
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"meta": {},
"color": "#DDAA99",
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}
},
{
"id": "7880590df76f9ff6",
"type": "switch",
"z": "069fdecd535f40a9",
"name": "Topic",
"property": "topic",
"propertyType": "msg",
"rules": [
{
"t": "eq",
"v": "get",
"vt": "str"
},
{
"t": "eq",
"v": "put",
"vt": "str"
},
{
"t": "eq",
"v": "list",
"vt": "str"
},
{
"t": "eq",
"v": "clear",
"vt": "str"
},
{
"t": "else"
}
],
"checkall": "true",
"repair": false,
"outputs": 5,
"x": 390,
"y": 120,
"wires": [
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],
[
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[
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],
[]
]
},
{
"id": "4b83edbae5bc0152",
"type": "function",
"z": "069fdecd535f40a9",
"name": "get",
"func": "let xxx = flow.get(\"queue\");\nvar item;\n\nif (!Array.isArray(xxx)){\n //queue = [];\n //queue.length=0;\n xxx.splice(0, xxx.length);\n}else\n{\n item = xxx.pop();\n}\n\n\nflow.set(\"queue\", xxx)\nmsg.payload = item;\n\nreturn msg;",
"outputs": 1,
"timeout": "",
"noerr": 0,
"initialize": "",
"finalize": "",
"libs": [],
"x": 550,
"y": 60,
"wires": [
[
"7bbf04dc8fcbf342"
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]
},
{
"id": "fe1d80d74279a747",
"type": "change",
"z": "069fdecd535f40a9",
"name": "Count",
"rules": [
{
"t": "set",
"p": "payload",
"pt": "msg",
"to": "$count(msg.payload)\t",
"tot": "jsonata"
}
],
"action": "",
"property": "",
"from": "",
"to": "",
"reg": false,
"x": 730,
"y": 140,
"wires": [
[]
]
},
{
"id": "e0cceea26f7697e5",
"type": "change",
"z": "069fdecd535f40a9",
"name": "",
"rules": [
{
"t": "delete",
"p": "queue",
"pt": "flow"
},
{
"t": "set",
"p": "payload",
"pt": "msg",
"to": "queue",
"tot": "flow"
}
],
"action": "",
"property": "",
"from": "",
"to": "",
"reg": false,
"x": 580,
"y": 180,
"wires": [
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},
{
"id": "6c3572fe40d33be6",
"type": "change",
"z": "069fdecd535f40a9",
"name": "queue",
"rules": [
{
"t": "set",
"p": "payload",
"pt": "msg",
"to": "queue",
"tot": "flow"
}
],
"action": "",
"property": "",
"from": "",
"to": "",
"reg": false,
"x": 550,
"y": 140,
"wires": [
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]
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},
{
"id": "be1f1850c37acf5f",
"type": "function",
"z": "069fdecd535f40a9",
"name": "put",
"func": "var queue = flow.get(\"queue\")\n\n\nif (!Array.isArray(queue)){\n queue = [];\n}else if ( queue.length >= env.get(\"Buffer_Size\") ){\n queue.pop(1);\n}\n\nqueue.unshift(msg.payload);\n\nflow.set(\"queue\", queue);\nmsg.payload = queue;\n\nreturn msg;",
"outputs": 1,
"noerr": 0,
"x": 550,
"y": 100,
"wires": [
[
"3113b971abd47d00"
]
]
},
{
"id": "b81a11f776547198",
"type": "json",
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"name": "",
"property": "payload",
"action": "str",
"pretty": false,
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"y": 120,
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"type": "split",
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"name": "",
"splt": "\\n",
"spltType": "str",
"arraySplt": 1,
"arraySpltType": "len",
"stream": false,
"addname": "",
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"y": 100,
"wires": [
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"wires": [
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{
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"type": "join",
"z": "069fdecd535f40a9",
"name": "",
"mode": "auto",
"build": "object",
"property": "payload",
"propertyType": "msg",
"key": "topic",
"joiner": "\\n",
"joinerType": "str",
"accumulate": "false",
"timeout": "",
"count": "",
"reduceRight": false,
"x": 990,
"y": 100,
"wires": [
[]
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{
"id": "7bbf04dc8fcbf342",
"type": "split",
"z": "069fdecd535f40a9",
"name": "",
"splt": "\\n",
"spltType": "str",
"arraySplt": 1,
"arraySpltType": "len",
"stream": false,
"addname": "",
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"build": "object",
"property": "payload",
"propertyType": "msg",
"key": "topic",
"joiner": "\\n",
"joinerType": "str",
"accumulate": "false",
"timeout": "",
"count": "",
"reduceRight": false,
"x": 990,
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"wires": [
[]
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},
{
"id": "9c954bb2fdeb06b4",
"type": "catch",
"z": "069fdecd535f40a9",
"name": "",
"scope": null,
"uncaught": false,
"x": 800,
"y": 180,
"wires": [
[]
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"type": "junction",
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"y": 100,
"wires": [
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},
{
"id": "930cdb15beb07106",
"type": "moment",
"z": "1b4901acc4991304",
"g": "950ed30da8e3c242",
"name": "",
"topic": "",
"input": "",
"inputType": "date",
"inTz": "Australia/Sydney",
"adjAmount": 0,
"adjType": "days",
"adjDir": "add",
"format": "YYYY/MM/DD HH:mm:ss",
"locale": "en-AU",
"output": "payload.timestamp",
"outputType": "msg",
"outTz": "Australia/Sydney",
"x": 540,
"y": 320,
"wires": [
[
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]
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{
"id": "9aca17142d600f72",
"type": "change",
"z": "1b4901acc4991304",
"g": "950ed30da8e3c242",
"name": "put",
"rules": [
{
"t": "set",
"p": "topic",
"pt": "msg",
"to": "put",
"tot": "str"
}
],
"action": "",
"property": "",
"from": "",
"to": "",
"reg": false,
"x": 710,
"y": 320,
"wires": [
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{
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"type": "inject",
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"g": "950ed30da8e3c242",
"name": "",
"props": [
{
"p": "topic",
"vt": "str"
}
],
"repeat": "",
"crontab": "",
"once": true,
"onceDelay": 0.1,
"topic": "clear",
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"y": 360,
"wires": [
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{
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"type": "inject",
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"g": "950ed30da8e3c242",
"name": "",
"props": [
{
"p": "topic",
"vt": "str"
}
],
"repeat": "",
"crontab": "",
"once": false,
"onceDelay": 0.1,
"topic": "list",
"x": 710,
"y": 400,
"wires": [
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},
{
"id": "9312d56a835a4e4f",
"type": "subflow:069fdecd535f40a9",
"z": "1b4901acc4991304",
"g": "950ed30da8e3c242",
"name": "",
"env": [
{
"name": "Buffer_Size",
"value": "20",
"type": "num"
}
],
"x": 870,
"y": 320,
"wires": [
[],
[
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"0c1175cc7e234777"
]
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},
{
"id": "0c1175cc7e234777",
"type": "ui-table",
"z": "1b4901acc4991304",
"g": "950ed30da8e3c242",
"group": "d7d93ed8bc83f115",
"name": "History",
"label": "Offline",
"order": 1,
"width": 0,
"height": 0,
"maxrows": "10",
"passthru": false,
"autocols": false,
"showSearch": true,
"selectionType": "click",
"columns": [
{
"title": "Time",
"key": "timestamp",
"keyType": "key",
"type": "text",
"width": "",
"align": "start"
},
{
"title": "Topic",
"key": "topic",
"keyType": "key",
"type": "text",
"width": "20",
"align": "center"
}
],
"mobileBreakpoint": "sm",
"mobileBreakpointType": "defaults",
"action": "replace",
"x": 1020,
"y": 320,
"wires": [
[]
]
},
{
"id": "d7d93ed8bc83f115",
"type": "ui-group",
"name": "Offline Devices",
"page": "520f6c0b2e1e3ea3",
"width": "4",
"height": "1",
"order": 5,
"showTitle": true,
"className": "",
"visible": "true",
"disabled": "false",
"groupType": "default"
},
{
"id": "520f6c0b2e1e3ea3",
"type": "ui-page",
"name": "Main !",
"ui": "a0ddd2d7af1545fc",
"path": "/Main",
"icon": "home",
"layout": "flex",
"theme": "0d7c977402df5308",
"order": 1,
"className": "",
"visible": true,
"disabled": "false"
},
{
"id": "a0ddd2d7af1545fc",
"type": "ui-base",
"name": "DB2",
"path": "/dashboard",
"includeClientData": true,
"acceptsClientConfig": [
"ui-notification",
"ui-control"
],
"showPathInSidebar": false,
"navigationStyle": "default",
"titleBarStyle": "default"
},
{
"id": "0d7c977402df5308",
"type": "ui-theme",
"name": "Default Theme",
"colors": {
"surface": "#ffffff",
"primary": "#808080",
"bgPage": "#000000",
"groupBg": "#b8b7b7",
"groupOutline": "#616161"
},
"sizes": {
"pagePadding": "12px",
"groupGap": "12px",
"groupBorderRadius": "4px",
"widgetGap": "12px",
"density": "default"
}
}
]`Preformatted text`
