A full-featured framework for building command line applications (cli) with node.js, including help generation, colored output, verbosity control, custom logger, coercion and casting, typos suggestions, and auto-complete for bash/zsh/fish.
Simply add Caporal as a dependency:
npm install caporal --save
// Or if you are using yarn (https://yarnpkg.com/lang/en/)
yarn add caporal --save
- Program: a cli app that you can build using Caporal
- Command: a command within your program. A program may have multiple commands.
- Argument: a command may have one or more arguments passed after the command.
- Options: a command may have one or more options passed after (or before) arguments.
Angled brackets (e.g. <item>
) indicate required input. Square brackets (e.g. [env]
) indicate optional input.
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
// you specify arguments using .argument()
// 'app' is required, 'env' is optional
.command('deploy', 'Deploy an application')
.argument('<app>', 'App to deploy', /^myapp|their-app$/)
.argument('[env]', 'Environment to deploy on', /^dev|staging|production$/, 'local')
// you specify options using .option()
// if --tail is passed, its value is required
.option('--tail <lines>', 'Tail <lines> lines of logs after deploy', prog.INT)
.action(function(args, options, logger) {
// args and options are objects
// args = {"app": "myapp", "env": "production"}
// options = {"tail" : 100}
});
prog.parse(process.argv);
// ./myprog deploy myapp production --tail 100
You can use ...
to indicate variadic arguments. In that case, the resulted value will be an array.
Note: Only the last argument of a command can be variadic !
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.command('deploy', 'Our deploy command')
// 'app' and 'env' are required
// and you can pass additional environments
.argument('<app>', 'App to deploy')
.argument('<env>', 'Environment')
.argument('[other-env...]', 'Other environments')
.action(function(args, options, logger) {
console.log(args);
// {
// "app": "myapp",
// "env": "production",
// "otherEnv": ["google", "azure"]
// }
});
prog.parse(process.argv);
// ./myprog deploy myapp production aws google azure
For a very simple program with just one command, you can omit the .command() call:
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.description('A simple program that says "biiiip"')
.action(function(args, options, logger) {
logger.info("biiiip")
});
prog.parse(process.argv);
Inside your action(), use the logger argument (third one) to log informations.
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.command('deploy', 'The deploy command')
.action((args, options, logger) => {
// Available methods:
// - logger.debug()
// - logger.info() or logger.log()
// - logger.warn()
// - logger.error()
logger.info("Application deployed !");
});
prog.parse(process.argv);
The default logging level is 'info'. The predifined options can be used to change the logging level:
-v, --verbose
: Set the logging level to 'debug' so debug() logs will be output.--quiet, --silent
: Set the logging level to 'warn' so only warn() and error() logs will be output.
Caporal uses winston
for logging. You can provide your own winston-compatible logger using .logger()
the following way:
#!/usr/bin/env node
const prog = require('caporal');
const myLogger = require('/path/to/my/logger.js');
prog
.version('1.0.0')
.logger(myLogger)
.command('foo', 'Foo command description')
.action((args, options, logger) => {
logger.info("Foo !!");
});
prog.parse(process.argv);
-v, --verbose
: Set the logging level to 'debug' so debug() logs will be output.--quiet, --silent
: Set the logging level to 'warn' so only warn() and error() logs will be output.
You can apply coercion and casting using various validators:
INT
(orINTEGER
): Check option looks like an int and cast it withparseInt()
FLOAT
: Will Check option looks like a float and cast it withparseFloat()
BOOL
(orBOOLEAN
): Check for string like0
,1
,true
,false
,on
,off
and cast itLIST
(orARRAY
): Transform input to array by spliting it on commaREPEATABLE
: Make the option repeatable, eg./mycli -f foo -f bar -f joe
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.command('order pizza')
.option('--number <num>', 'Number of pizza', prog.INT, 1)
.option('--kind <kind>', 'Kind of pizza', /^margherita|hawaiian$/)
.option('--discount <amount>', 'Discount offer', prog.FLOAT)
.option('--add-ingredients <ingredients>', prog.LIST)
.action(function(args, options) {
// options.kind = 'margherita'
// options.number = 1
// options.addIngredients = ['pepperoni', 'onion']
// options.discount = 1.25
});
prog.parse(process.argv);
// ./myprog order pizza --kind margherita --discount=1.25 --add-ingredients=pepperoni,onion
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.command('concat') // concat files
.option('-f <file>', 'File to concat', prog.REPEATABLE)
.action(function(args, options) {
});
prog.parse(process.argv);
// Usage:
// ./myprog concat -f file1.txt -f file2.txt -f file3.txt
Using this method, you can check and cast user input. Make the check fail by throwing an Error
,
and cast input by returning a new value from your function.
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.command('order pizza')
.option('--kind <kind>', 'Kind of pizza', function(opt) {
if (['margherita', 'hawaiian'].includes(opt) === false) {
throw new Error("You can only order margherita or hawaiian pizza!");
}
return opt.toUpperCase();
})
.action(function(args, options) {
// options = { "kind" : "MARGHERITA" }
});
prog.parse(process.argv);
// ./myprog order pizza --kind margherita
Using an Array
, Caporal will check that it contains the argument/option passed.
Note: It is not possible to cast user input with this method, only checking it, so it's basically only interesting for strings, but a major advantage is that this method will allow autocompletion of arguments and option values.
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.command('order pizza')
.option('--kind <kind>', 'Kind of pizza', ["margherita", "hawaiian"])
.action(function(args, options) {
});
prog.parse(process.argv);
// ./myprog order pizza --kind margherita
Simply pass a RegExp object to test against it. Note: It is not possible to cast user input with this method, only checking it, so it's basically only interesting for strings.
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
.command('order pizza')
.option('--kind <kind>', 'Kind of pizza', /^margherita|hawaiian$/)
.action(function(args, options) {
});
prog.parse(process.argv);
// ./myprog order pizza --kind margherita
By default, Caporal will output colors for help and errors.
This behaviour can be disabled by passing --no-colors
.
Caporal automaticaly generates help/usage instructions for you.
Help can be displayed using -h
or --help
options, or with the default help
command.
Caporal will automaticaly make suggestions for option typos.
Caporal comes with an auto-completion feature out of the box for bash
, zsh
, and fish
,
thanks to tabtab.
For this feature to work, you will have to:
- Put your cli app in your
$PATH
(this is the case if your app is installed globally usingnpm install -g <myapp>
) - Setup auto-completion for your shell, like bellow.
# For bash
source <(myapp completion bash)
# or add it to your .bashrc to make it persist
echo "source <(myapp completion bash)" >> ~/.bashrc
# For zsh
source <(myapp completion zsh)
# or add it to your .bashrc to make it persist
echo "source <(myapp completion zsh)" >> ~/.zshrc
# For fish
source <(myapp completion fish)
# or add it to your .bashrc to make it persist
echo "source <(myapp completion fish)" >> ~/.fishrc
By default, it will autocomplete commands and option names. Also, options having an Array validator will be autocompleted.
#!/usr/bin/env node
const prog = require('caporal');
prog
.version('1.0.0')
// the "order" command
.command('order', 'Order a pizza')
.alias('give-it-to-me')
// <kind> will be auto-magicaly autocompleted by providing the user with 3 choices
.argument('<kind>', 'Kind of pizza', ["margherita", "hawaiian", "fredo"])
.argument('<from-store>', 'Which store to order from')
// enable auto-completion for <from-store> argument using a sync function returning an array
.complete(function() {
return ['store-1', 'store-2', 'store-3', 'store-4', 'store-5'];
})
.argument('<account>', 'Which account id to use')
// enable auto-completion for <account> argument using a Promise
.complete(function() {
return Promise.resolve(['account-1', 'account-2']);
})
.option('-n, --number <num>', 'Number of pizza', prog.INT, 1)
.option('-d, --discount <amount>', 'Discount offer', prog.FLOAT)
.option('-p, --pay-by <mean>', 'Pay by option')
// enable auto-completion for -p | --pay-by argument using a Promise
.complete(function() {
return Promise.resolve(['cash', 'credit-card']);
})
// --extra will be auto-magicaly autocompleted by providing the user with 3 choices
.option('-e <ingredients>', 'Add extra ingredients', ['pepperoni', 'onion', 'cheese'])
.action(function(args, options, logger) {
logger.info("Command 'order' called with:");
logger.info("arguments: %j", args);
logger.info("options: %j", options);
})
// the "return" command
.command('return', 'Return an order')
// <kind> will be auto-magicaly autocompleted by providing the user with 3 choices
.argument('<order-id>', 'Order id')
// enable auto-completion for <from-store> argument using a Promise
.complete(function() {
return Promise.resolve(['#82792', '#71727', '#526Z52']);
})
.argument('<to-store>', 'Store id')
.option('--ask-change <other-kind-pizza>', 'Ask for other kind of pizza')
.complete(function() {
return Promise.resolve(["margherita", "hawaiian", "fredo"]);
})
.option('--say-something <something>', 'Say something to the manager')
.action(function(args, options, logger) {
logger.info("Command 'return' called with:");
logger.info("arguments: %j", args);
logger.info("options: %j", options);
});
prog.parse(process.argv);
Returns a Program
instance.
Set the version of your program. You may want to use your package.json
version to fill it:
const myProgVersion = require('./package.json').version;
const prog = require('caporal');
prog
.version(myProgVersion)
// [...]
prog.parse(process.argv);
Your program will then automaticaly handle -V
and --version
options:
matt@mb:~$ ./my-program --version
1.0.0
Set up a new command with name and description. Multiple commands can be added to one program. Returns a {Command}.
const prog = require('caporal');
prog
.version('1.0.0')
// one command
.command('walk', 'Make the player walk')
.action((args, options, logger) => { logger.log("I'm walking !")}) // you must attach an action for your command
// a second command
.command('run', 'Make the player run')
.action((args, options, logger) => { logger.log("I'm running !")})
// a command may have multiple words
.command('cook pizza', 'Make the player cook a pizza')
.argument('<kind>', 'Kind of pizza')
.action((args, options, logger) => { logger.log("I'm cooking a pizza !")})
// [...]
prog.parse(process.argv);
Get or set the logger instance. Without argument, it returns the logger instance (winston by default). With the logger argument, it sets a new logger.
Add an argument to the command. Can be called multiple times to add several arguments.
- synopsis (String): something like
<my-required-arg>
or<my-optional-arg>
- description (String): argument description
- validator (Caporal Flag | Function | Array | RegExp): optional validator, see Coercion and casting
- defaultValue (*): optional default value
Add an option to the command. Can be called multiple times to add several options.
- synopsis (String): You can pass short or long notation here, or both. See examples.
- description (String): option description
- validator (Caporal Flag | Function | Array | RegExp): optional validator, see Coercion and casting
- defaultValue (*): optional default value
- required (Bool): Is the option itself required ? Default to
false
Define the action, e.g a Function, for the current command. The action callback will be called with 3 arguments: args, options, and logger.
Define an alias for the current command. A command can only have one alias.
const prog = require('caporal');
prog
.version('1.0.0')
// one command
.command('walk', 'Make the player walk')
.alias('w')
.action((args, options, logger) => { logger.log("I'm walking !")}) // you must attach an action for your command
prog.parse(process.argv);
// ./myapp w
// same as
// ./myapp walk
Define an auto-completion handler for the latest argument or option added to the command.
- completer (Function): The completer function has to return either an
Array
or aPromise
which resolves to anArray
.
Caporal is strongly inspired by commander.js and Symfony Console. Caporal make use of the following npm packages:
- chalk for colors
- cli-table2 for cli tables
- fast-levenshtein for suggestions
- tabtab for auto-completion
- minimist for argument parsing
- prettyjson to output json
- winston for logging
Copyright © Matthias ETIENNE
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
The Software is provided “as is”, without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and noninfringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the software or the use or other dealings in the Software.