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https://github.com/bahamas10/node-condexec
Conditionally shell out an exec
https://github.com/bahamas10/node-condexec
Last synced: about 2 months ago
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Conditionally shell out an exec
- Host: GitHub
- URL: https://github.com/bahamas10/node-condexec
- Owner: bahamas10
- Created: 2013-01-30T04:48:25.000Z (almost 12 years ago)
- Default Branch: master
- Last Pushed: 2013-04-17T04:18:50.000Z (over 11 years ago)
- Last Synced: 2024-10-05T13:47:57.546Z (3 months ago)
- Language: JavaScript
- Size: 113 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
condexec
========
Conditionally shell out an exec
Installation
------------
npm install condexec
Usage
-----
``` js
var condexec = require('condexec');
var opts = {
cwd: '/',
onlyif: 'test -f /etc/passwd',
notif: 'test -d /this/doesnt/exist',
exec: 'echo "hello $USER you are in $PWD"'
};
condexec(opts, function(err) {
console.log('done');
});
```
yields
```
hello dave you are in /
done
```
any and all output from the commands executed will be piped directly
to the proper streams (stdout/stderr).
### shell parsing
When the `exec`, `onlyif`, or `notif` attributes are given as strings, they are parsed
by the shell before they are ran; they are executed as ['`/bin/sh`', '`-c`', '`{string}`'].
Alternatively, you can pass an array of arguments instead of a string, which will allow
you to bypass shell-parsing/word-splitting logic.
``` js
var file = '/etc/passwd';
var msg = 'this message has double"quotes and single\'quotes';
condexec({
exec: ['echo', msg],
onlyif: ['test', '-f', file]
});
```
yields
```
this message has double"quotes and single'quotes
```
Notice that you didn't need to worry about escaping the quotes before you
passed them to exec.
### error handling
When the callback is fired, it will contain what specifically produced an error.
``` js
var opts = {
onlyif: 'test -d /etc/passwd',
notif: 'test -f /aoehsutoehnaueohs/fake/fake/fake',
exec: 'echo "hello $USER you are in $PWD"'
};
condexec(opts, function(err) {
console.error(err.message);
});
```
yields
```
[onlyif] command `test -d /etc/passwd` returned with code 1
```
It tells you what command failed, in what clause, and with what code.
Notice that, because the command failed, the exec line was never called.
### debug
Pass in a debug attribute to see exactly what is happening
``` js
var opts = {
debug: true,
cwd: '/',
onlyif: 'test -f /etc/passwd',
notif: 'test -d /aoehsutoehnaueohs/fake/fake/fake',
exec: 'echo "hello $USER you are in $PWD"'
};
condexec(opts, function(err) {
console.log('success!');
});
```
yields
```
[onlyif] about to execute `test -f /etc/passwd`, expects 0
[onlyif] command `test -f /etc/passwd` returned with code 0
[notif] about to execute `test -d /aoehsutoehnaueohs/fake/fake/fake`, expects != 0
[notif] command `test -d /aoehsutoehnaueohs/fake/fake/fake` returned with code 1
[exec] about to execute `echo "hello $USER you are in $PWD"`, expects 0
hello dave you are in /
[exec] command `echo "hello $USER you are in $PWD"` returned with code 0
success!
```
Function
--------
### function condexec(options, callback(err))
#### `options`
* `exec`: a string or array of commands to execute given the 2 optional conditions are satisfied
* `notif`: an optional condition to meet before the `exec` command is run, expects this to return non-0
* `onlyif`: an optional condition to meet before the `exec` command is run, expects this to return 0
* `debug`: turn on debug output
This object is then passed into `child_process.spawn`, so pass in any options that you would like,
such as `cwd`, `env`, etc.
#### `callback`
The callback runs when the conditional exec has finished, either successfully or with an error.
The `err` object will be `null` if it was successful
License
-------
MIT