# Storing a value in text format\_ using local pc as database
**URL:** https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777
**Category:** General
**Tags:** function-node
**Created:** [29 May 2023 09:58 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777 "2023-05-29T09:58:59Z")
**Posts on this page:** 19
**Page:** 1
### Author:  [@colin0031](https://discourse.nodered.org/u/colin0031)
#### Post date: [29 May 2023 09:58 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/1 "2023-05-29T09:58:59Z")
Hello,
I am creating a graph and want to store value for long period of time and for that I want to store the value in a database- doesn't want to loose it even if the PC got turned off which will most likely happen.
Since its only one number, I would like to store it in text formal using write node.
Everything goes well\_ it stores a number and reads the same number from file until node -red is restarted. When it restarted it initializes with one.
Any suggestion how to overcome this??
```auto
[
{
"id": "d3e1163e876f1c6f",
"type": "inject",
"z": "146ab432f501375f",
"name": "",
"props": [
{
"p": "payload"
},
{
"p": "topic",
"vt": "str"
}
],
"repeat": "",
"crontab": "",
"once": true,
"onceDelay": 0.1,
"topic": "",
"payload": "true",
"payloadType": "bool",
"x": 90,
"y": 620,
"wires": [
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"efcea3e48f367448"
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]
},
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"id": "efcea3e48f367448",
"type": "function",
"z": "146ab432f501375f",
"name": "",
"func": "\n\nif(msg.payload== true)\n{\n var count=global.get('assembly')||0;\n count = count+1;\n msg.payload= count;\n \nreturn msg;\n}\nelse\n{\n return null;\n}",
"outputs": 1,
"noerr": 0,
"initialize": "",
"finalize": "",
"libs": [],
"x": 300,
"y": 620,
"wires": [
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"type": "file",
"z": "146ab432f501375f",
"name": "",
"filename": "D:\\Node_red_write\\hello.txt",
"appendNewline": true,
"createDir": false,
"overwriteFile": "true",
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"statusType": "auto",
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"id": "db04ca1b12942cb4",
"type": "file in",
"z": "146ab432f501375f",
"name": "",
"filename": "D:\\Node_red_write\\hello.txt",
"format": "utf8",
"chunk": false,
"sendError": false,
"encoding": "none",
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"y": 760,
"wires": [
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{
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"name": "",
"props": [
{
"p": "payload"
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{
"p": "topic",
"vt": "str"
}
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"repeat": "1",
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"once": true,
"onceDelay": 0.1,
"topic": "",
"payload": "",
"payloadType": "date",
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},
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"func": "\nglobal.set('assembly',msg.payload);\nreturn msg;",
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"noerr": 0,
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"y": 760,
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{
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"name": "Extracting value from a pc and setting into global variable",
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}
]
```
---
### Author:  [@mudwalker](https://discourse.nodered.org/u/mudwalker)
#### Post date: [29 May 2023 10:08 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/2 "2023-05-29T10:08:12Z")
Are the values timestamped?
If so, you could use InfluxDB and then recall the values between `timeX` and `timeY`, or even `now`. You can also use a `Retention Policy` for InfluxDB to store the values for certain period of time
If this is a route you could use, there are plenty of topics available on the Forum covering this.
---
### Author:  [@colin0031](https://discourse.nodered.org/u/colin0031)
#### Post date: [29 May 2023 10:29 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/3 "2023-05-29T10:29:02Z")
The pc will be a standalone and will not be communicating with external network. Do you know if its possible without influxdb, just with the local machine only?
---
### Author:  [@jbudd](https://discourse.nodered.org/u/jbudd)
#### Post date: [29 May 2023 10:36 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/4 "2023-05-29T10:36:52Z")
Have you read up on persistent context?
[https://nodered.org/docs/user-guide/context#context-stores](https://nodered.org/docs/user-guide/context#context-stores)
---
### Author:  [@colin0031](https://discourse.nodered.org/u/colin0031)
#### Post date: [29 May 2023 10:41 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/5 "2023-05-29T10:41:38Z")
Yes, its storing value into variables isnt it. I want to store restored even if the pc got restarted.
I believe context value will be erased when node red stopped.
---
### Author:  [@smanjunath211](https://discourse.nodered.org/u/smanjunath211)
#### Post date: [29 May 2023 10:42 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/6 "2023-05-29T10:42:02Z")
may be write to a CSV file ?
```auto
[{"id":"e73ad588de171439","type":"inject","z":"7a196fc9029e392d","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":240,"y":360,"wires":[["dbf01a4280a355a6"]]},{"id":"a006353a01d13b7a","type":"file","z":"7a196fc9029e392d","name":"","filename":"c:\\temp\\test1.csv","filenameType":"str","appendNewline":true,"createDir":true,"overwriteFile":"false","encoding":"none","x":780,"y":360,"wires":[[]]},{"id":"5d9b99b9a9a195ec","type":"change","z":"7a196fc9029e392d","name":"","rules":[{"t":"set","p":"payload","pt":"msg","to":"$string(payload, true)\t","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":560,"y":360,"wires":[["a006353a01d13b7a"]]},{"id":"dbf01a4280a355a6","type":"function","z":"7a196fc9029e392d","name":"function 1","func":"var one = Math.floor(Math.random() * 100);\nmsg.payload=one;\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":390,"y":360,"wires":[["5d9b99b9a9a195ec"]]}]
```
---
### Author:  [@mudwalker](https://discourse.nodered.org/u/mudwalker)
#### Post date: [29 May 2023 10:46 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/7 "2023-05-29T10:46:08Z")
I would use the InfluxDB route if the dataset is over a period of time, InfluxDB should be able to be loaded onto the local PC.
Other than that, you could build an array and then when you have enough values, delete the first value, move the locations of the rest of the values up one, and add the new value at the end (FIFO - First In First Out). As to how to do this, I did use a flow at one time, and the relevant part for a FIFO is this:
```auto
[{"id":"a823c9cf.2a6178","type":"function","z":"b4973237.46ab6","name":"2 msg transport delay","func":"// stores messages in a fifo until the specified number have been received, \n// then releases them as new messages are received.\n// during the filling phase the earliest message is passed on each time \n// a message is received, but it is also left in the fifo\nvar fifoMaxLength = 2;\nvar fifo = context.get('fifo') || [];\n// push the new message onto the top of the array, messages are shifted down and\n// drop off the front\nvar length = fifo.push(msg); // returns new length\nif (length > fifoMaxLength) {\n newMsg = fifo.shift();\n} else {\n // not full yet, make a copy of the msg and pass it on\n var newMsg = JSON.parse(JSON.stringify(fifo[0]));\n}\ncontext.set('fifo', fifo);\nreturn newMsg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":258,"y":208,"wires":[["999a52c2.f465f"]]}]
```
BTW, I can't claim credit for this Node - iirc it was @Colin and it was built, in this case, for 2 values, but that could be increased.
---
### Author:  [@jbudd](https://discourse.nodered.org/u/jbudd)
#### Post date: [29 May 2023 10:53 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/8 "2023-05-29T10:53:45Z")
> [@colin0031](#):
>
> Since its only one number, I would like to store it in text formal using write node.
I am a fan of using databases for data storage. However, it would be ridiculous to install a database to store just one number.
> [@jbudd](#):
>
> Have you read up on persistent context?
> [@colin0031](#):
>
> Yes, its storing value into variables isnt it. I want to store restored even if the pc got restarted.
>
> I believe context value will be erased when node red stopped.
No, you believe wrong.
[This forum post](https://discourse.nodered.org/t/a-guide-to-understanding-persistent-context/4115) might better explain persistent context, though it is 4 years old.
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [29 May 2023 13:23 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/9 "2023-05-29T13:23:11Z")
Persistent context should certainly do what you want.
Alternatively, if you are using MQTT then put it in a Retained Topic in MQTT and when you restart the latest value will automatically be made available.
---
### Author:  [@dceejay](https://discourse.nodered.org/u/dceejay)
#### Post date: [29 May 2023 13:58 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/10 "2023-05-29T13:58:31Z")
> [@Colin](#):
>
> Retained Topic in MQTT
again if you do this - you need to configure MQTT to save retained topics to disk, or it will also get lost if the PC reboots.
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [29 May 2023 14:12 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/11 "2023-05-29T14:12:04Z")
Indeed. Though that is the default for mosquitto (on pi and ubuntu at least).
---
### Author:  [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)
#### Post date: [29 May 2023 16:12 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/12 "2023-05-29T16:12:32Z")
> [@colin0031](#):
>
> I believe context value will be erased when node red stopped.
You simply need to configure a persistent store and use that for your value. No external services needed.
In settings.js:
```auto
/** Context Storage
* The following property can be used to enable context storage. The configuration
* provided here will enable file-based context that flushes to disk every 30 seconds.
* Refer to the documentation for further options: https://nodered.org/docs/api/context/
*
* Default is to use 'memory' only.
* 'memory' and 'localfilesystem' are both synchronous.
*/
contextStorage: {
default: {
module: 'memory',
},
file: {
module: 'localfilesystem',
// config: {
// flushInterval: '10', // default is 30s
// dir: '/home/user/.node-red/context',
// },
},
},
```
You can define multiple file stores if you wish to have different flush intervals for different things. There are also alternative plug-in store types such as the REDIS one.
---
### Author:  [@colin0031](https://discourse.nodered.org/u/colin0031)
#### Post date: [31 May 2023 12:54 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/13 "2023-05-31T12:54:48Z")
Hello,
Even though there are many solution, I found persistent context as the easiest solution for my issue.
Is there any space limitation for this feature?? for another usecase I would like to store 10 values in the same flow by using persistent context variable.
---
### Author:  [@colin0031](https://discourse.nodered.org/u/colin0031)
#### Post date: [31 May 2023 12:55 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/14 "2023-05-31T12:55:31Z")
Thanks Colin. This is also a good solution.
---
### Author:  [@colin0031](https://discourse.nodered.org/u/colin0031)
#### Post date: [31 May 2023 12:56 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/15 "2023-05-31T12:56:15Z")
Thanks a lot. I am not using influx DB yet, however thats my next topic to learn.
---
### Author:  [@colin0031](https://discourse.nodered.org/u/colin0031)
#### Post date: [31 May 2023 12:56 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/16 "2023-05-31T12:56:46Z")
Thanks for the solution.
---
### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [31 May 2023 12:56 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/17 "2023-05-31T12:56:52Z")
You should have no problem.
---
### Author:  [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)
#### Post date: [31 May 2023 16:14 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/18 "2023-05-31T16:14:37Z")
> [@colin0031](#):
>
> Is there any space limitation for this feature?? for another usecase I would like to store 10 values in the same flow by using persistent context variable.
I have context variables with thousands of entries. you should remember, however, that it will not only be stored on-disk but also in memory. For reference, my current live server has 2.4Mb of content.
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [14 June 2023 16:14 UTC](https://discourse.nodered.org/t/storing-a-value-in-text-format-using-local-pc-as-database/78777/19 "2023-06-14T16:14:48Z")
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