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181

Can I store a file in memory with Node.js?

rated 0 times [ 182] [ 1] / answers: 1 / hits: 31436 / 10 Years ago, fri, may 23, 2014, 12:00:00

I'm doing some file manipulation work with node.js and many of the packages that I use require a path to be sent so that they can open the file, do some work, and so on.

But I'm parsing millions of files and rather than actually store them on disk, I'd like to store them in memory. The contents of the files are all in my database and I'd hate to write them to disk, just to do my insanely awesome work on them.

So is such a thing possible?

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latrelllloydb

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4 Years ago

answered 10 Years ago alorac · Accepted Answer

If you are using a Linux system then you can merely create your own tmpfs (RAM) via the following nodejs code. This creates a tmpfs at /mnt/myramdisk as per the node code. The directory /mnt/myramdisk must be manually created beforehand obviously via mkdir /mnt/myramdisk.

var MountPoint='/mnt/myramdisk';

var TextFile='/MyTextFileInRAM.txt';

var RAM_Size='512m';



const fs = require('fs');



const { exec } = require('child_process');

exec(awk '{print $2}' /proc/mounts | grep +MountPoint, (err, stdout, stderr) => {

  if (err) {

    // node couldn't execute the command

    //console.log(err);

    console.log(MountPoint+' is Not Mounted yet. Im mounting it now:n');

    NotMountedYetSoMountIt();

    return;

  }

  // the *entire* stdout and stderr (buffered)

  if(stdout)

    {

        console.log(MountPoint+' is Already Mounted');

        TextToWriteToFileOnTMPFS();

    } 

});



function NotMountedYetSoMountIt()

{

    const { exec } = require('child_process');

    exec('df -h && echo && mount -t tmpfs -o size='+RAM_Size+' tmpfs '+MountPoint+' && echo && df -h', (err, stdout, stderr) => {

      if (err) {

        // node couldn't execute the command

        return;

      }

    // the *entire* stdout and stderr (buffered)

    console.log(`stdout: ${stdout}`);

    TextToWriteToFileOnTMPFS();

    console.log(`stderr: ${stderr}`);

    });

}



function TextToWriteToFileOnTMPFS()

{



    let TextToWrite = 'Hellon' + 

                      'world @'+CurrentTime();



    fs.writeFile(MountPoint+TextFile, TextToWrite, (err) => {

        // throws an error, you could also catch it here

        if (err) throw err;

        // success case, the file was saved

        console.log('saved!');

    });

}



function addZero(i) {

  if (i < 10) {

    i = 0 + i;

  }

  return i;

}

function CurrentTime()

{

  var d = new Date();

  var h = addZero(d.getHours());

  var m = addZero(d.getMinutes());

  var s = addZero(d.getSeconds());

  return h + : + m + : + s;

}

Output:

root@box:/daemons#node tmpfs_test.js && cat /mnt/myramdisk/MyTextFileInRAM.txt

/mnt/myramdisk is Not Mounted yet. Im mounting it now:



stdout: Filesystem      Size  Used Avail Use% Mounted on

udev            7.8G     0  7.8G   0% /dev

tmpfs           1.6G  1.4M  1.6G   1% /run

/dev/sda2       938G  436G  454G  49% /

tmpfs           7.8G  449M  7.4G   6% /dev/shm

tmpfs           5.0M     0  5.0M   0% /run/lock

tmpfs           7.8G     0  7.8G   0% /sys/fs/cgroup

/dev/loop1       90M   90M     0 100% /snap/core/8213

/dev/sda1       511M  6.1M  505M   2% /boot/efi

/dev/loop2       90M   90M     0 100% /snap/core/8268





Filesystem      Size  Used Avail Use% Mounted on

udev            7.8G     0  7.8G   0% /dev

tmpfs           1.6G  1.4M  1.6G   1% /run

/dev/sda2       938G  436G  454G  49% /

tmpfs           7.8G  449M  7.4G   6% /dev/shm

tmpfs           5.0M     0  5.0M   0% /run/lock

tmpfs           7.8G     0  7.8G   0% /sys/fs/cgroup

/dev/loop1       90M   90M     0 100% /snap/core/8213

/dev/sda1       511M  6.1M  505M   2% /boot/efi

/dev/loop2       90M   90M     0 100% /snap/core/8268

tmpfs           512M     0  512M   0% /mnt/myramdisk



stderr:

saved!

Hello

world @23:09:15







root@box:/daemons# node tmpfs_test.js && cat /mnt/myramdisk/MyTextFileInRAM.txt

/mnt/myramdisk is Already Mounted

saved!

Hello

world @23:09:19