Module: Roda::RodaPlugins::ExceptionPage::InstanceMethods

Defined in:

lib/roda/plugins/exception_page.rb

Instance Method Summary

• #exception_page(exception, opts = OPTS) ⇒ Object

  Return a HTML page showing the exception, allowing a developer more information for debugging.

• #exception_page_css ⇒ Object

  The CSS to use on the exception page.

• #exception_page_js ⇒ Object

  The JavaScript to use on the exception page.

Instance Method Details

#exception_page(exception, opts = OPTS) ⇒ Object

Return a HTML page showing the exception, allowing a developer more information for debugging. Designed to be called inside an exception handler, passing in the received exception. Sets the Content-Type header in the response, and returns the string used for the body. If the Accept request header is present and text/html is accepted, return an HTML page with the backtrace with the ability to see the context for each backtrace line, as well as the GET, POST, cookie, and rack environment data. If text/html is not accepted, then just show a plain text page with the exception class, message, and backtrace.

Options:

:assets

If true, sets :css_file to /exception_page.css and :js_file to /exception_page.js, assuming that r.exception_page_assets is called in the route block to serve the exception page assets. If a String, uses the string as a prefix, assuming that r.exception_page_assets is called in a nested block inside the route block. If false, doesn’t use any CSS or JS.

:context

The number of context lines before and after each line in the backtrace (default: 7).

:css_file

A path to the external CSS file for the HTML exception page. If false, doesn’t use any CSS.

:js_file

A path to the external javascript file for the HTML exception page. If false, doesn’t use any JS.

:json

Return a hash of exception information. The hash will have a single key, “exception”, with a value being a hash with three keys, “class”, “message”, and “backtrace”, which contain information derived from the given exception. Designed to be used with the json exception, which will automatically convert the hash to JSON format.

# File 'lib/roda/plugins/exception_page.rb', line 198

def exception_page(exception, opts=OPTS)
  message = exception_page_exception_message(exception)
  if opts[:json]
    @_response[RodaResponseHeaders::CONTENT_TYPE] = "application/json"
    {
      "exception"=>{
        "class"=>exception.class.to_s,
        "message"=>message,
        "backtrace"=>exception.backtrace.map(&:to_s)
      }
    }
  elsif env['HTTP_ACCEPT'] =~ /text\/html/
    @_response[RodaResponseHeaders::CONTENT_TYPE] = "text/html"

    context = opts[:context] || 7
    css_file = opts[:css_file]
    js_file = opts[:js_file]

    case prefix = opts[:assets]
    when false
      css_file = false if css_file.nil?
      js_file = false if js_file.nil?
    when nil
      # nothing
    else
      prefix = '' if prefix == true
      css_file ||= "#{prefix}/exception_page.css"
      js_file ||= "#{prefix}/exception_page.js"
    end

    css = case css_file
    when nil
      "<style type=\"text/css\">#{exception_page_css}</style>"
    when false
      # :nothing
    else
      "<link rel=\"stylesheet\" href=\"#{h css_file}\" />"
    end

    js = case js_file
    when nil
      "<script type=\"text/javascript\">\n//<!--\n#{exception_page_js}\n//-->\n</script>"
    when false
      # :nothing
    else
      "<script type=\"text/javascript\" src=\"#{h js_file}\"></script>"
    end

    frames = exception.backtrace.map.with_index do |line, i|
      frame = {:id=>i}
      if line =~ /\A(.*?):(\d+)(?::in `(.*)')?\Z/
        filename = frame[:filename] = $1
        lineno = frame[:lineno] = $2.to_i
        frame[:function] = $3

        begin
          lineno -= 1
          lines = ::File.readlines(filename)
          if line = lines[lineno]
            pre_lineno = [lineno-context, 0].max
            if (pre_context = lines[pre_lineno...lineno]) && !pre_context.empty?
              frame[:pre_context_lineno] = pre_lineno
              frame[:pre_context] = pre_context
            end

            post_lineno = [lineno+context, lines.size].min
            if (post_context = lines[lineno+1..post_lineno]) && !post_context.empty?
              frame[:post_context_lineno] = post_lineno
              frame[:post_context] = post_context
            end

            frame[:context_line] = line.chomp
          end
        rescue
        end

        frame
      end
    end.compact

    r = @_request
    begin 
      post_data = r.POST
      missing_post = "No POST data"
    rescue
      missing_post = "Invalid POST data"
    end
    info = lambda do |title, id, var, none|
      <<END
  <h3 id="#{id}">#{title}</h3>
  #{(var && !var.empty?) ? (<<END1) : "<p>#{none}</p>"
    <table class="req">
      <thead>
<tr>
  <th>Variable</th>
  <th>Value</th>
</tr>
      </thead>
      <tbody>
  #{var.sort_by{|k, _| k.to_s}.map{|key, val| (<<END2)}.join
  <tr>
    <td>#{h key}</td>
    <td class="code"><div>#{h val.inspect}</div></td>
  </tr>
END2
}
      </tbody>
    </table>
END1
}
END
    end

    <<END
<!DOCTYPE html>
<html lang="en">
<head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8" />
  <title>#{h exception.class} at #{h r.path}</title>
  #{css}
</head>
<body>

<div id="summary">
  <h1>#{h exception.class} at #{h r.path}</h1>
  <h2>#{h message}</h2>
  <table><tr>
    <th>Ruby</th>
    <td>
#{(first = frames.first) ? "<code>#{h first[:filename]}</code>: in <code>#{h first[:function]}</code>, line #{first[:lineno]}" : "unknown location"}
    </td>
  </tr><tr>
    <th>Web</th>
    <td><code>#{r.request_method} #{h r.host}#{h r.path}</code></td>
  </tr></table>

  <h3>Jump to:</h3>
  <ul id="quicklinks">
    <li><a href="#get-info">GET</a></li>
    <li><a href="#post-info">POST</a></li>
    <li><a href="#cookie-info">Cookies</a></li>
    <li><a href="#env-info">ENV</a></li>
  </ul>
</div>

<div id="traceback">
  <h2>Traceback <span>(innermost first)</span></h2>
  <ul class="traceback">
#{frames.map{|frame| id = frame[:id]; (<<END1)}.join
      <li class="frame">
<code>#{h frame[:filename]}:#{frame[:lineno]}</code> in <code>#{h frame[:function]}</code>

  #{frame[:context_line] ? (<<END2) : '</li>'
  <div class="context" id="c#{id}">
    #{frame[:pre_context] ? (<<END3) : ''
    <ol start="#{frame[:pre_context_lineno]+1}" id="bc#{id}">
      #{frame[:pre_context].map{|line| "<li>#{h line}</li>"}.join}
    </ol>
END3
}

    <ol start="#{frame[:lineno]}" class="context-line">
      <li>#{h frame[:context_line]}<span>...</span></li>
    </ol>

    #{frame[:post_context] ? (<<END4) : ''
    <ol start='#{frame[:lineno]+1}' id="ac#{id}">
      #{frame[:post_context].map{|line| "<li>#{h line}</li>"}.join}
    </ol>
END4
}
  </div>
END2
}
END1
}
  </ul>
</div>

<div id="requestinfo">
  <h2>Request information</h2>

  #{info.call('GET', 'get-info', r.GET, 'No GET data')}
  #{info.call('POST', 'post-info', post_data, missing_post)}
  #{info.call('Cookies', 'cookie-info', r.cookies, 'No cookie data')}
  #{info.call('Rack ENV', 'env-info', r.env, 'No Rack env?')}
</div>

<div id="explanation">
  <p>
    You're seeing this error because you use the Roda exception_page plugin.
  </p>
</div>

#{js}
</body>
</html>
END
  else
    @_response[RodaResponseHeaders::CONTENT_TYPE] = "text/plain"
    "#{exception.class}: #{message}\n#{exception.backtrace.map{|l| "\t#{l}"}.join("\n")}"
  end
end

#exception_page_css ⇒ Object

The CSS to use on the exception page

# File 'lib/roda/plugins/exception_page.rb', line 403

def exception_page_css
  ExceptionPage.css
end

#exception_page_js ⇒ Object

The JavaScript to use on the exception page

# File 'lib/roda/plugins/exception_page.rb', line 408

def exception_page_js
  ExceptionPage.js
end