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monolyth/cliff

Command line interface for Monolyth unframework

Installation

Using Composer:

Usage

cliff is Monolyth's command line tool. It allows you to create and run commands from your CLI, supporting arguments.

cliff normalises the command given by capitalising the namespace and replacing forward with backward slashes. Thus, the command my/command will resolve to a classname of My\Command which Composer's autoloader must be able to load.

If the command's classname is itself Command, cliff will prepend that automagically. Thus, if no class My\Command is found, it will look for My\Command\Command before giving up.

All cliff command classes must extend Monolyth\Cliff\Command for convenience reasons (see below).

Writing commands

Write a class extending Monolyth\Cliff\Command. It is easiest to call the class itself Command too so you may omit it on the CLI, but this is not required in any way:

Whenever a cliff command is called, its magic __invoke method is called. Any arguments passed to the invocation will be passed verbatim, in order. So, say your command expects path and filename as arguments, your definition would be as follows:

If the command gets called with any required argument missing, cliff will automatically show a helpful error message (see below).

If the command class does not extend Monolyth\Cliff\Command, everything will run as normal - but obviously you won't be able to make use of Cliff's argument parsing, help features (see below) etc. Cliff will show a warning about it; if you're not using Cliff you shouldn't, ehm, be using Cliff ;)

Options

A "option" is an invocation component prefixed by - or --. Traditionally on Unix-like systems, a single dash implies "followed by a single letter, and optionally a value", whilst the double dash implies "followed by multiple letters, an equals sign and a more complex value". cliff follows this tradition.

All options are set as properties on the command. The options are "normalised", i.e. an option my-user-name will end up as $this->myUserName.

The implementor should define all options as public properties. Any non-public property is not considered a option but e.g. a dependency injection.

Defining short-hand options

The default for any option is to also define a short-hand version with its first letter in lowercase, e.g. a option --password will also be available as -p. For complicated commands with many arguments, this may give conflicts. cliff will first use the uppercased version of the duplicate argument. If that too is already taken, it will ignore the duplicate shorthand option.

So e.g. if your command class specifies the file, format and foo properties, only -f for ---file and -F for format will be available as a shorthand.

To explicitly specify the short-hand version you want, you may use an attribute:

Note that only the longhand variant is set as a property, unless the option is defined as shorthand-only (i.e., a property with a single-letter name). In other words, only the properties defined on the class are used.

Long option names

$snakeCased option properties are translated hyphen-separated options on the CLI (--snake-cased) and vice versa. For Pete's sake don't use an upper case character as the first one on your public properties; for one, it's butt-ugly; but more importantly, Cliff won't account for this, so $Foo would become ---foo which makes no sense (and most probably will cause an error).

Option types

Options come in three variants: required, optional and empty (an empty option is optional by default). Defining these in your command class is simple:

Note that the marking the option "required" simply means one has to pass a value when using the option; the option itself can never be "required". If you always require values to be passed to the command when run, use arguments to your __invoke method.

In other words, an optional option can act as either having a value or a boolean.

If an optional argument has a default value of an empty string, it is set to NULL instead so various PHP coalesce operators will work as expected. Hence, optional string options with no default must be nullable (?string).

Only the string, bool and array types are allowed for option properties. This is the nature of a CLI interface.

Negating empty options

If an empty option is set, the default boolean value is negated. So if the default is true, setting the option makes it false and vice versa. Typically a default of false will make the most sense, but this might come in handy if your code's logic is... peculiar.

Array options

If an option is type hinted as an array (of strings), it automatically allows multiple values to be paased, e.g.:

Like with string options, empty strings will be forced to null.

Manually passing options

Sometimes you'll want to run a command from another script, e.g. when using the Monolyth\Croney scheduler. To override the options passed to the command, pass an array containing the desired commands to the constructor:

This is identical to invoking with vendor/bin/cliff foo --bar baz.

Chaining commands

Commands may be chained or output redirected using the standard features of your operating system of choice. E.g., on Unix-like systems this would be done using the pipe (|) and angular bracket (<) operator. Prior to Cliff 0.7, a more convoluted mechanism was used, but why reinvent the wheel, right?

Input may be read using PHP's standard STDIN stream. To output something another script or command can use as input, simply echo it.

A previous version of this readme had the following example: a command that generated a list of users, and another command that filtered it by female users only. This could now be achieved with something like this:

Documentation, help and error reporting

Via reflection, the doccomments of the class, the __invoke method and the options properties are utilised.

Use the doccomment of the class to describe general usage. This is akin to calling common Unix commands with the -h[elp] option.

Use the doccomment of your __invoke method to described which arguments the command expects. This message is shown when any required argument is missing.

Use the doccomment of any option property for detailed help when it is passed as a value to the -h or --help options. This option is defined on the Command baseclass. You can override it in your own command, but it is handled in the base constructor (which you probably don't want to override...).

If the __invoke method throws any uncaught exception, its message is shown and a non-zero exit status is returned. Note that exit status 1 is reserved for when required arguments are missing.

Preloading files

Like vendor/autoload.php, your command might require some bootstrapping, e.g. if you're using a framework. You can use the Monolyth\Cliff\Preload("filename") attribute to automate this (instead of using require_once calls which are slightly ugly). This attribute should be placed on the class.

Multiple Preload attributes are included in order. Note that all paths should be relative to getcwd(). If you prefer require_once though, be our guest. :-)