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Tarsana Command

A library to build command line applications using PHP. This is part of the Tarsana Project.

Table of Contents

• Installation

• Your First Command

• Initializing The Command

• Showing The Help And Version Of A Command

• Reading & Writing to The Console

• Defining Arguments and Options

• Reading Arguments and Options Interactively Since version 1.1.0

• Handeling The Filesystem

• Loading Configuration New on version 1.2.0

• Rendering Templates

• Adding SubCommands

• Testing Commands

• What's Next

• Development Notes

Installation

Install it using Composer

Your First Command

Let's write a "Hello World" command. Create a file hello.php with the following content:

Then run it from the terminal:

Congratulations, you have just written your first command :D

As you see, Tarsana\Command\Command is a class providing the basic features of a command. Every command should extend it and implement the execute() method.

Initializing The Command

In addition, Command gives the init() method which is used the initialize the command general attributes. Let's rewrite our HelloWorld command:

Here we are overriding the init() method to define the command name, version and description.

Note that the setter of an attribute foo is named foo() instead of setFoo(). I know that this is not a common convention but it makes sense for me. :P

Showing the Help and Version of a Command

To show the version of a command, we use the --version flag (we will learn after that this is actually a sub command). We also have the --help to show the help message:

Reading & Writing to the Console

The attribute console is used to handle the reading and writing operations to the console.

Let's update our command to read the user name:

• The readLine() method reads a line from the stdin and returns it as string.
• The out() method writes some text to stdout (without a line break).
• The line() method writes some text to stdout and adds a line break.
• The error() method writes some text to stderr and adds a line break.

The Console class provides some tags to control the output:

The <background:$number> and <color:$number> tags allows to set the background and foreground colors of the text to be written; the <reset> tag resets the default values. The colors are given as numbers from the 256-color mode.

List of supported tags

• <color:$n>: Sets the foreground text to the color $n in 256-color mode.
• <background:$n>: Sets the foreground text to the color $n in 256-color mode.
• <reset>: Resets the formatting default values.
• <bold>: Makes the text bold.
• <underline>: Underlines the text.

Console allows you also to define styles using aliases:

Predefined aliases are:

Note: tags and aliases can be used in all strings printed to the console, including the command and arguments descriptions.

Defining Arguments and Options

The command syntax is defined using the Syntax library. Let's start with a command that repeats a word a number of times:

We are using the method syntax() to define the syntax of arguments. The string given to this method follows the rules described here

The describe() method is used to describe an argument.

When you define the syntax of the command; arguments are parsed automatically and available in the execute() method via the args attribute.

The help subcommand shows full description of the arguments and options:

And the result is:

In the second example, the count argument takes automatically its default value.

Warning: Giving wrong arguments generates an error

Reading Arguments and Options Interactively

Some commands can have long and complicated list of arguments. Defining the syntax of such command is easy thanks to Syntax but typing the arguments in the command line becomes challenging.

Let's take the following command for example:

if you run the command using the -i flag, it will let you enter the arguments interactively:

After reading all args, the command will show the command line version of the entered args:

which means that running

would produce the same result.

Handling The Filesystem

The fs attribute is an instance of Tarsana\IO\Filesystem that you can use to handle files and directories. Read the documentation for the full API.

By default, the Filesystem instance points to the directory from which the command is run. You can also initialize it to any directory you want:

Loading Configuration

In addition to the command line arguments, the user can provide data to your command via configuration files. This is useful because it lets you define a default configuration file and lets the user change some values with a custom configuration file.

Let's write an example command which have a global configuration file at /home/user/.config.json. It lets the user customize value via the file config.json in the current directory:

• The method configPaths take a list of paths, loads them and merges them into one configuration (it use array_replace_recursive internally).

• The method config is used to retreive configuration values.

Note that:

• Only json files are supported as configuration files for the moment. Please open an issue or make a Pull Request to add other formats.

• configPaths will silently ignore paths which does not exist in the filesystem.

• A subcommand will always have the same configuration data as its parent command, unless configPaths is used to override it.

Rendering Templates

The Command class gives also possibility to render templates. The default template engine is Twig but you can use your favorite one by implementing the interfaces TemplateLoaderInterface and TemplateInterface.

Let's make a command which renders a simple template. For this we will create two files:

hello.twig

This is a simple template that print a hello message.

render-hello.php

Result

Adding SubCommands

You can add subcommands while initializing your command.

Now when you run

The FooCommand will be run with other arguments here as arguments.

Note: subcommands will always have the attributes console, fs and templatesLoader pointing to the same objects as their parent, as long as you don't change them explicitly in the subcommand's code.

Testing Commands

The class Tarsana\Tester\CommandTestCase extends PHPUnit\Framework\TestCase and adds useful methods to test Tarsana Commands.

Testing the Input and Output

Let's write a test for our HelloWorld command above which reads the user name than shows the hello message.

Sets the content of the standard input of the command.

Runs the command $c with the standard input and $args then stores its outputs for further assertions.

• printsExactly asserts that the standard output of the command equals $text. Note that tags are not applied to allow testing them easily.

• prints asserts that the standard output of the command contains $text.

• printsError asserts that error output of the command contains $text.

Testing the Arguments and Options

Let's now test the RepeatCommand above.

Assert that the parsed arguments and options of the command are equal to the given values.

Testing the Filesystem

Let's take the following command:

The test can be written as follows:

The CommandTestCase run the command with a virtual filesystem. The methods havingFile and havingDir can be used to create files and directories on that filesystem before running the command.

What's Next

Please take a look at the examples in the examples directory, and try using the library to build some awesome commands. Any feedback is welcome!

Development Notes

• Version 2.0.0 Tarsana Command now uses PHPUnit 9 and thus requires PHP 7.3 or PHP 7.4.

• Version 1.2.1 The CommandTestCase is now an abstract class to avoid PHPUnit warnings.

• Version 1.2.0 Commands can now load configuration from multiple JSON files.

• Version 1.1.1 Fixed a bug with subcommands not having the default --help, --version and -i subcommands.

• Version 1.1.0 The flag -i added to commands to enable interactive reading of arguments and options.

• Version 1.0.1 Fixed a bug of subcommands having different instances of fs and templatesLoader from their parent.

• Version 1.0.0 The first version is finally out; have fun!