userinput

A simple user input library

Usage

User interaction is handled by the UserInput::Prompt object. As a convenience, this can be created using the UserInput.new method:

> require 'userinput'
=> true
> prompt = UserInput.new(message: 'Username')
=> #<UserInput::Prompt:0x007fdfba1681f8 @attempts=nil, @message="Username", @default=nil, @secret=false, @validation=nil>
> prompt.ask
Username? leet_dude
=> "leet_dude"

You can optionally provide a default:

> require 'userinput'
=> true
> prompt = UserInput.new(default: '_other')
=> #<UserInput::Prompt:0x007fb7eb163f00 @attempts=nil, @message="", @default="_other", @secret=false, @validation=nil>
> prompt.ask
? [_other] answer
=> "answer"
> prompt.ask
? [_other]
=> "_other"

If you provide a validation Regexp, Enumerable, or a code block, the input will be validated using that:

> require 'userinput'
=> true
> prompt = UserInput.new(validation: /[0-9]+/)
=> #<UserInput::Prompt:0x007f99909637b0 @attempts=nil, @message="", @default=nil, @secret=false, @validation=/[0-9]+/>
> prompt.ask
? _str
? 23
=> "23"
> other_prompt = UserInput.new { |x| x == '_correct' }
=> #<UserInput::Prompt:0x007f9990920eb0 @attempts=nil, @message="", @default=nil, @secret=false, @validation=#<Proc:0x007f99909211d0@(irb):4>>
> other_prompt.ask
? _wrong
? 23
? _correct
=> "_correct"

Providing a number of attempts will cause an ArgumentError to be raised after that many failed inputs:

> require 'userinput'
=> true
> prompt = UserInput.new(attempts: 3, validation: /[0-9]+/)
=> #<UserInput::Prompt:0x007f9f6a950270 @attempts=3, @message="", @default=nil, @secret=false, @validation=/[0-9]+/>
> prompt.ask
? _str
? _other
? _attempt
ArgumentError: No valid input provided

For sensitive input, pass the secret parameter, which will try to disable terminal printing of the user's input:

> require 'userinput'
=> true
> prompt = UserInput.new(message: 'Password', secret: true)
=> #<UserInput::Prompt:0x007fb8ab9220a0 @attempts=nil, @message="Password", @default=nil, @secret=true, @validation=nil>
> prompt.ask
Password?
=> "_password"

Setting the file descriptor lets you control where output is sent (for instance, use this to print messages on STDERR or to a custom IO object):

> require 'userinput'
=> true
> prompt = UserInput.new(message: 'Password', secret: true, fd: STDERR)
=> #<UserInput::Prompt:0x007f888110a138 @attempts=nil, @message="Password", @default=nil, @secret=true, @fd=#<IO:<STDERR>>, @validation=nil>
> prompt.ask
Password?
=> "_password"

Boolean helper

UserInput::Boolean is a subclass of Prompt that is designed for asking yes/no questions.

It valiates that answers match /(y|yes|n|no)/i, and returns the response as a boolean true/false rather than a string.

To use it:

a = UserInput::Boolean.new(message: 'Do you like cats')
response = a.ask

Installation

gem install userinput

License

userinput is released under the MIT License. See the bundled LICENSE file for details.