lua-libmagic

libmagic binding for lua.
see man libmagic for more details.

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NOTE: this module is tested with libmagic v5.41.

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Dependencies

• libmagic: https://github.com/file/file

you should be installed libmagic-dev or equivalent package before install this module.

Installation

luarocks install libmagic

Usage

local libmagic = require('libmagic')
local m = libmagic.open( libmagic.MIME_TYPE, libmagic.NO_CHECK_COMPRESS )
assert(m:load()) -- load the default database

print(m:file('README.md'))  -- output "text/plain"

Constants

libmagic module has the following constants.

• libmagic.VERSION
• libmagic.NONE
• libmagic.DEBUG
• libmagic.SYMLINK
• libmagic.COMPRESS
• libmagic.DEVICES
• libmagic.MIME_TYPE
• libmagic.CONTINUE
• libmagic.CHECK
• libmagic.PRESERVE_ATIME
• libmagic.RAW
• libmagic.ERROR
• libmagic.MIME_ENCODING
• libmagic.MIME
• libmagic.APPLE
• libmagic.EXTENSION
• libmagic.COMPRESS_TRANSP
• libmagic.NODESC
• libmagic.NO_CHECK_COMPRESS
• libmagic.NO_CHECK_TAR
• libmagic.NO_CHECK_SOFT
• libmagic.NO_CHECK_APPTYPE
• libmagic.NO_CHECK_ELF
• libmagic.NO_CHECK_TEXT
• libmagic.NO_CHECK_CDF
• libmagic.NO_CHECK_TOKENS
• libmagic.NO_CHECK_ENCODING
• libmagic.NO_CHECK_JSON
• libmagic.NO_CHECK_ASCII
• libmagic.NO_CHECK_FORTRAN
• libmagic.NO_CHECK_TROFF

Create an instance of libmagic

local libmagic = require('libmagic')
local m = libmagic.open(libmagic.MIME_TYPE)

str, err = m( arg )

helper function to get a textual description of the contents of the file.

Parameters

• arg:string|integer|file*: pathname or file descriptor or file handle of the file.
  • arg:string: equivalent to m:file( pathname ).
  • arg:integer: equivalent to m:descriptor( fd ).
  • arg:file*: equivalent to m:filehandle( fh ).

Returns

• str:string: a textual description.
• err:string: error string.

str, err = m:file( pathname )

returns a textual description of the contents of the file.

Parameters

• pathname:string: pathname of the file.

Returns

• str:string: a textual description.
• err:string: error string.

str, err = m:descriptor( fd )

returns a textual description of the contents of the file descriptor.

Parameters

• fd:integer: file descriptor.

Returns

• str:string: a textual description.
• err:string: error string.

str, err = m:filehandle( fh )

returns a textual description of the contents of the filehandle.

Parameters

• fh:filehandle: lua filehandle.

Returns

• str:string: a textual description.
• err:string: error string.

str, err= m:buffer( buf:string )

returns a textual description of the contents of the buffer.

Parameters

• buf:string: buffer string.

Returns

• str:string: a textual description.
• err:string: error string.

err = m:error()

returns a textual explanation of the last error.

Returns

• err:string: error string.

ok = m:setflags( [flag, ...] )

set flags.

Returns

• ok:boolean: true on success.

ok, err = m:load( [pathnames:string] )

loads the database files from the colon separated list of database files.

Parameters

• pathnames:string: the colon separated list of database files.

Returns

• ok:boolean: true on success.
• err:string: error string.

ok, err = m:compile( pathnames:string )

compile the colon separated list of database files.

Parameters

• pathnames:string: the colon separated list of database files.

Returns

• ok:boolean: true on success.
• err:string: error string.

ok, err = m:check( [pathnames:string] )

check the validity of entries in the colon separated database files.

Parameters

• pathnames:string: the colon separated list of database files.

Returns

• ok:boolean: true on success.
• err:string: error string.

ok, err = m:list( [pathnames:string] )

dumps all magic entries in a human readable format

Returns

• ok:boolean: true on success.
• err:string: error string.

errno = m:errno()

returns the last operating system error number.

Returns

• errno:integer: system error number (errno).