An async libmagic binding for node.js for detecting content types by data inspection.

• node.js -- v4.0.0 or newer

npm install mmmagic

• Get general description of a file:

  var Magic = require('mmmagic').Magic;

  var magic = new Magic();
  magic.detectFile('node_modules/mmmagic/build/Release/magic.node', function(err, result) {
      if (err) throw err;
      console.log(result);
      // output on Windows with 32-bit node:
      //    PE32 executable (DLL) (GUI) Intel 80386, for MS Windows
  });

• Get mime type for a file:

  var mmm = require('mmmagic'),
      Magic = mmm.Magic;

  var magic = new Magic(mmm.MAGIC_MIME_TYPE);
  magic.detectFile('node_modules/mmmagic/build/Release/magic.node', function(err, result) {
      if (err) throw err;
      console.log(result);
      // output on Windows with 32-bit node:
      //    application/x-dosexec
  });

• Get mime type and mime encoding for a file:

  var mmm = require('mmmagic'),
      Magic = mmm.Magic;

  var magic = new Magic(mmm.MAGIC_MIME_TYPE | mmm.MAGIC_MIME_ENCODING);
  // the above flags can also be shortened down to just: mmm.MAGIC_MIME
  magic.detectFile('node_modules/mmmagic/build/Release/magic.node', function(err, result) {
      if (err) throw err;
      console.log(result);
      // output on Windows with 32-bit node:
      //    application/x-dosexec; charset=binary
  });

• Get general description of the contents of a Buffer:

  var Magic = require('mmmagic').Magic;

  var magic = new Magic(),
        buf = new Buffer('import Options\nfrom os import unlink, symlink');
  
  magic.detect(buf, function(err, result) {
      if (err) throw err;
      console.log(result);
      // output: Python script, ASCII text executable
  });

• (constructor)([< mixed >magicSource][, < Integer >flags]) - Creates and returns a new Magic instance. magicSource (if specified) can either be a path string that points to a (compatible) magic file to use or it can be a Buffer containing the contents of a (compatible) magic file. If magicSource is not a string and not false, the bundled magic file will be used. If magicSource is false, mmmagic will default to searching for a magic file to use (order of magic file searching: MAGIC env var -> various file system paths (see man file)). flags is a bitmask with the following valid values (available as constants on require('mmmagic')):

  • MAGIC_NONE - No flags set
  • MAGIC_DEBUG - Turn on debugging
  • MAGIC_SYMLINK - Follow symlinks (default for non-Windows)
  • MAGIC_DEVICES - Look at the contents of devices
  • MAGIC_MIME_TYPE - Return the MIME type
  • MAGIC_CONTINUE - Return all matches (returned as an array of strings)
  • MAGIC_CHECK - Print warnings to stderr
  • MAGIC_PRESERVE_ATIME - Restore access time on exit
  • MAGIC_RAW - Don't translate unprintable chars
  • MAGIC_MIME_ENCODING - Return the MIME encoding
  • MAGIC_MIME - (MAGIC_MIME_TYPE | MAGIC_MIME_ENCODING)
  • MAGIC_APPLE - Return the Apple creator and type
  • MAGIC_NO_CHECK_TAR - Don't check for tar files
  • MAGIC_NO_CHECK_SOFT - Don't check magic entries
  • MAGIC_NO_CHECK_APPTYPE - Don't check application type
  • MAGIC_NO_CHECK_ELF - Don't check for elf details
  • MAGIC_NO_CHECK_TEXT - Don't check for text files
  • MAGIC_NO_CHECK_CDF - Don't check for cdf files
  • MAGIC_NO_CHECK_TOKENS - Don't check tokens
  • MAGIC_NO_CHECK_ENCODING - Don't check text encodings

• detectFile(< String >path, < Function >callback) - (void) - Inspects the file pointed at by path. The callback receives two arguments: an < Error > object in case of error (null otherwise), and a < String > containing the result of the inspection.

• detect(< Buffer >data, < Function >callback) - (void) - Inspects the contents of data. The callback receives two arguments: an < Error > object in case of error (null otherwise), and a < String > containing the result of the inspection.