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63 lines
2.0 KiB
Markdown
63 lines
2.0 KiB
Markdown
# Add Color To The IRB Console Prompt
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IRB has a little-known [`Color`
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module](https://docs.ruby-lang.org/en/3.2/IRB/Color.html) with some helpers for
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adding a splash of color to the IRB prompt. I like to clearly differentiate the
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environment I'm in when connecting to the `rails console`, so I have a
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customize the prompt to display and colorize the current environment.
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I can wrap any string in ANSI escape codes that instruct the terminal to style
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the text with color. For instance, here is how I can style the word `DEV` to be
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inverted against a blue background.
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```ruby
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IRB::Color.colorize("DEV", [:BLUE, :BOLD, :REVERSE])
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```
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which will clearly stand out from `PROD` against a red background:
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```ruby
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IRB::Color.colorize("PROD", [:RED, :BOLD, :REVERSE])
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```
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Here is a full example of customizing the prompt from the
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`config/application.rb` file.
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```ruby
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module MyApp
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class Application < Rails::Application
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# ...
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console do
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# Get the application module name and convert to kebab-case
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app_name = Rails.application.class.module_parent.name
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kebab_name = app_name.underscore.dasherize
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# Environment color coding
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env_colors = {
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"development" => IRB::Color.colorize("DEV", [:BLUE, :BOLD, :REVERSE]),
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"production" => IRB::Color.colorize("PROD", [:RED, :BOLD, :REVERSE]),
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"test" => IRB::Color.colorize("TEST", [:YELLOW, :BOLD, :REVERSE]),
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}
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colored_env = "(#{env_colors[Rails.env]})"
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# Docs: https://docs.ruby-lang.org/en/3.2/IRB.html#module-IRB-label-Customizing+the+IRB+Prompt
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IRB.conf[:PROMPT][:RAILS_APP] = {
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PROMPT_I: "#{kebab_name}#{colored_env}> ",
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PROMPT_N: "#{kebab_name}#{colored_env}* ",
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PROMPT_S: "#{kebab_name}#{colored_env}% ",
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PROMPT_C: "#{kebab_name}#{colored_env}? ",
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RETURN: "=> %s\n"
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}
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# Set it as the current prompt
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IRB.conf[:PROMPT_MODE] = :RAILS_APP
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end
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end
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end
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```
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The Ruby docs have more about [IRB Prompt
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Customization](https://docs.ruby-lang.org/en/3.2/IRB.html#module-IRB-label-Customizing+the+IRB+Prompt).
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