Exception Page

A library for displaying exceptional exception pages for easier debugging.

Installation

Add this to your application's shard.yml:

dependencies:
  exception_page:
    github: crystal-loot/exception_page

Usage

Require the shard:

require "exception_page"

Create an exception page:

class MyApp::ExceptionPage < ExceptionPage
  def styles
    ExceptionPage::Styles.new(
      accent: "purple", # Choose the HTML color value. Can be hex
    )
  end
end

Render the HTML when an exception occurs:

class MyErrorHandler
  include HTTP::Handler

  def call_next(context)
    begin
      # Normally you'd call some code to handle the request
      # We're hard-coding an error here to show you how to use the lib.
      raise SomeError.new("Something went wrong")
    rescue e
      context.response.status_code = 500
      context.response.print MyApp::ExceptionPage.for_runtime_exception(context, e).to_s
    end
  end

Customizing the page

class MyApp::ExceptionPage < ExceptionPage
  def styles
    ExceptionPage::Styles.new(
      accent: "purple", # Required
      highlight: "gray", # Optional
      flash_highlight: "red", # Optional
      logo_uri: "base64_encoded_data_uri" # Optional. Defaults to Crystal logo. Generate a logo here: https://dopiaza.org/tools/datauri/index.php
    )
  end

  # Optional. If provided, clicking the logo will open this page
  def project_url
    "https://myproject.com"
  end

  # Optional
  def stack_trace_heading_html
    <<-HTML
    <a href="#" onclick="sayHi()">Say hi</a>
    HTML
  end

  # Optional
  def extra_javascript
    <<-JAVASCRIPT
    window.sayHi = function() {
      alert("Say Hi!");
    }
    JAVASCRIPT
  end
end

Development

TODO: Write development instructions here

Contributing

1. Fork it (https://github.com/crystal-loot/exception_page/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• @paulcsmith Paul Smith
• @faustinoaq Faustino Aigular - Wrote the initial Amber PR adding exception pages

Special Thanks

This exception page is heavily based on the Phoenix error page by @rstacruz. Thanks to the Phoenix team and @rstacruz!