temp

What is temp?

The 'temp' npm package is designed to handle temporary files and directories in a Node.js environment. It provides utilities to create, manage, and clean up temporary files and directories, ensuring that they are properly removed when no longer needed.

What are temp's main functionalities?

Creating a Temporary File

This feature allows you to create a temporary file with a specified prefix. The callback provides information about the file, including its path and file descriptor.

const temp = require('temp');
temp.open('myprefix', function(err, info) {
  if (!err) {
    console.log('File: ', info.path);
    console.log('File descriptor: ', info.fd);
  }
});

Creating a Temporary Directory

This feature allows you to create a temporary directory with a specified prefix. The callback provides the path to the created directory.

const temp = require('temp');
temp.mkdir('myprefix', function(err, dirPath) {
  if (!err) {
    console.log('Directory: ', dirPath);
  }
});

Automatic Cleanup

This feature enables automatic cleanup of temporary files and directories when the process exits. By calling `temp.track()`, you ensure that all temporary files and directories are removed when they are no longer needed.

const temp = require('temp');
temp.track();
temp.open('myprefix', function(err, info) {
  if (!err) {
    console.log('File: ', info.path);
    console.log('File descriptor: ', info.fd);
  }
});

Other packages similar to temp

tmp

The 'tmp' package provides similar functionality for creating temporary files and directories. It also supports automatic cleanup and offers a more modern API with promises and async/await support. Compared to 'temp', 'tmp' is more actively maintained and has a larger user base.

fs-extra

The 'fs-extra' package extends the native 'fs' module with additional methods, including utilities for handling temporary files and directories. While it is not solely focused on temporary file management, it provides a comprehensive set of file system utilities that can be useful in various scenarios.

README

Temporary files, directories, and streams for Node.js.

Handles generating a unique file/directory name under the appropriate system temporary directory, changing the file to an appropriate mode, and supports automatic removal (if asked)

temp has a similar API to the fs module.

Node.js Compatibility

Supports v6.0.0+.

Please let me know if you have problems running it on a later version of Node.js or have platform-specific problems.

Installation

Install it using npm:

$ npm install temp

Or get it directly from: http://github.com/bruce/node-temp

Synopsis

You can create temporary files with open and openSync, temporary directories with mkdir and mkdirSync, or you can get a unique name in the system temporary directory with path.

Working copies of the following examples can be found under the examples directory.

Temporary Files

To create a temporary file use open or openSync, passing them an optional prefix, suffix, or both (see below for details on affixes). The object passed to the callback (or returned) has path and fd keys:

{ path: "/path/to/file",
, fd: theFileDescriptor
}

In this example we write to a temporary file and call out to grep and wc -l to determine the number of time foo occurs in the text. The temporary file is chmod'd 0600 and cleaned up automatically when the process at exit (because temp.track() is called):

var temp = require('temp'),
    fs   = require('fs'),
    util  = require('util'),
    exec = require('child_process').exec;

// Automatically track and cleanup files at exit
temp.track();

// Fake data
var myData = "foo\nbar\nfoo\nbaz";

// Process the data (note: error handling omitted)
temp.open('myprefix', function(err, info) {
  if (!err) {
    fs.write(info.fd, myData, (err) => {
		console.log(err);
	});
    fs.close(info.fd, function(err) {
      exec("grep foo '" + info.path + "' | wc -l", function(err, stdout) {
        util.puts(stdout.trim());
      });
    });
  }
});

Want Cleanup? Make sure you ask for it.

As noted in the example above, if you want temp to track the files and directories it creates and handle removing those files and directories on exit, you must call track(). The track() function is chainable, and it's recommended that you call it when requiring the module.

var temp = require("temp").track();

Why is this necessary? In pre-0.6 versions of temp, tracking was automatic. While this works great for scripts and Grunt tasks, it's not so great for long-running server processes. Since that's arguably what Node.js is for, you have to opt-in to tracking.

But it's easy.

Cleanup anytime

When tracking, you can run cleanup() and cleanupSync() anytime (cleanupSync() will be run for you on process exit). An object will be returned (or passed to the callback) with cleanup counts and the file/directory tracking lists will be reset.

> temp.cleanupSync();
{ files: 1,
  dirs:  0 }

> temp.cleanup(function(err, stats) {
    console.log(stats);
  });
{ files: 1,
  dirs:  0 }

Note: If you're not tracking, an error ("not tracking") will be passed to the callback.

Temporary Directories

To create a temporary directory, use mkdir or mkdirSync, passing it an optional prefix, suffix, or both (see below for details on affixes).

In this example we create a temporary directory, write to a file within it, call out to an external program to create a PDF, and read the result. While the external process creates a lot of additional files, the temporary directory is removed automatically at exit (because temp.track() is called):

var temp = require('temp'),
    fs   = require('fs'),
    util = require('util'),
    path = require('path'),
    exec = require('child_process').exec;

// Automatically track and cleanup files at exit
temp.track();

// For use with ConTeXt, http://wiki.contextgarden.net
var myData = "\\starttext\nHello World\n\\stoptext";

temp.mkdir('pdfcreator', function(err, dirPath) {
  var inputPath = path.join(dirPath, 'input.tex')
  fs.writeFile(inputPath, myData, function(err) {
    if (err) throw err;
    process.chdir(dirPath);
    exec("texexec '" + inputPath + "'", function(err) {
      if (err) throw err;
      fs.readFile(path.join(dirPath, 'input.pdf'), function(err, data) {
        if (err) throw err;
        sys.print(data);
      });
    });
  });
});

Temporary Streams

To create a temporary WriteStream, use 'createWriteStream', which sits on top of fs.createWriteStream. The return value is a fs.WriteStream with a path property containing the temporary file path for the stream. The path is registered for removal when temp.cleanup is called (because temp.track() is called).

var temp = require('temp');

// Automatically track and cleanup files at exit
temp.track();

var stream = temp.createWriteStream();
// stream.path contains the temporary file path for the stream
stream.write("Some data");
// Maybe do some other things
stream.end();

Affixes

You can provide custom prefixes and suffixes when creating temporary files and directories. If you provide a string, it is used as the prefix for the temporary name. If you provide an object with prefix, suffix and dir keys, they are used for the temporary name.

Here are some examples:

• "aprefix": A simple prefix, prepended to the filename; this is shorthand for:
• {prefix: "aprefix"}: A simple prefix, prepended to the filename
• {suffix: ".asuffix"}: A suffix, appended to the filename (especially useful when the file needs to be named with specific extension for use with an external program).
• {prefix: "myprefix", suffix: "mysuffix"}: Customize both affixes
• {dir: path.join(os.tmpdir(), "myapp")}: default prefix and suffix within a new temporary directory.
• null: Use the defaults for files and directories (prefixes "f-" and "d-", respectively, no suffixes).

In this simple example we read a pdf, write it to a temporary file with a .pdf extension, and close it.

var fs   = require('fs'),
    temp = require('temp');

fs.readFile('/path/to/source.pdf', function(err, data) {
  temp.open({suffix: '.pdf'}, function(err, info) {
    if (err) throw err;
    fs.write(info.fd, data, (err) => {
			console.log(err)
		});
    fs.close(info.fd, function(err) {
      if (err) throw err;
      // Do something with the file
    });
  });
});

Just a path, please

If you just want a unique name in your temporary directory, use path:

var fs = require('fs');
var tempName = temp.path({suffix: '.pdf'});
// Do something with tempName

Note: The file isn't created for you, and the mode is not changed -- and it will not be removed automatically at exit. If you use path, it's all up to you.

Using it with Grunt

If you want to use the module with Grunt, make sure you use async() in your Gruntfile:

module.exports = function (grunt) {
  var temp = require("temp");
  temp.track(); // Cleanup files, please
  grunt.registerTask("temptest", "Testing temp", function() {

    var done = this.async(); // Don't forget this!

    grunt.log.writeln("About to write a file...");
    temp.open('tempfile', function(err, info) {
      // File writing shenanigans here
      grunt.log.writeln("Wrote a file!")

      done(); // REALLY don't forget this!

    });
  });
};

For more information, see the Grunt FAQ.

Testing

$ npm test

Contributing

You can find the repository at: http://github.com/bruce/node-temp

Issues/Feature Requests can be submitted at: http://github.com/bruce/node-temp/issues

I'd really like to hear your feedback, and I'd love to receive your pull-requests!

Copyright

Copyright (c) 2010-2014 Bruce Williams. This software is licensed under the MIT License, see LICENSE for details.