Call a child process with the ease of exec and safety of spawn
npm install flex-execflex-exec
=========
Call a child process with the ease of exec and safety of spawn
INFORMAION We don't like a DEPRECATED text printed in console. So, I clone
project and changed it.
DEPRECATED: If your version of node supports child_process.execFile, consider
using that instead, as that does everything this module does and more... the usage
is slightly different.
[http://nodejs.org/api/child_process.html#child_process_child_process_execfile_file_args_options_callback]
(http://nodejs.org/api/child_process.html#child_process_child_process_execfile_file_args_options_callback)
Why?
----
This module provides the best of both worlds of spawn and exec
It will callback with 2 strings containing stdout and stderr
(like child_process.exec), but will take an array of process arguments
(like child_process.spawn) to avoid any potentially harmful shell expansion.
Usage
-----
`` js`
var exec = require('exec');
Example
-------
` js
var exec = require('exec');
exec(['ls', '-lha'], function(err, out, code) {
if (err instanceof Error)
throw err;
process.stderr.write(err);
process.stdout.write(out);
process.exit(code);
});
`
The example above will call ls -lha safely, by passing the arguments directlyexec(2)
to without using an shell expansion/word splitting.
It returns a child_process.spawn object, and callbacks with any stdout,ls
stderr, and the exit status of the command. The above example will throw an
error if anything went wrong during the spawn, otherwise it will print the stdout,
stderr, and exit with the exit code of .
NOTE: If err is an instanceof Error, it means that child_process.spawn emittederror
and event, and err is set to that error object.
err and out are encoded asutf-8 strings by default
For backwards compatibility with child_process.exec, it is also possibleexec
to pass a string to . The string will automatically be converted to['/bin/sh', '-c', '{string}'], which will cause the string to be parsed on the
shell. Note that if you use this method, you are at risk of shell expansion,
word splitting, and other shell features that could be potentially unsafe.
` js`
exec('cat foo | grep bar', function(err, out, code) {
if (err instanceof Error)
throw err;
process.stderr.write(err);
process.stdout.write(out);
process.exit(code);
});
Functions
---------
- args: an array of arguments to executeopts
- : is additional options to pass to child_process.spawn
In addition to the child_process.spawn options, more options have been added to mimic the behaviorchild_process.exec
of
- opts.timeout: number of milliseconds to wait for the program to complete before sending itSIGTERM. Note that by default, your program will wait indefinitely for theexec
spawned program to terminate. Upon sending the fatal signal, will returnopts.killSignal
with whatever stdout and stderr was produced.
- : the signal to use when opts.timeout is used, defaults to SIGTERMopts.encoding
- : the encoding to use for stdout and stderr. NOTE: unlike child_process.exec, this defaults'utf-8'
to if unset. Set to 'buffer'` to handle binary data.
Installation
------------
npm install exec
License
-------
MIT