Class: Sinatra::ShowExceptions

Inherits:
Rack::ShowExceptions
  • Object
show all
Defined in:
lib/sinatra/show_exceptions.rb

Overview

Sinatra::ShowExceptions catches all exceptions raised from the app it wraps. It shows a useful backtrace with the sourcefile and clickable context, the whole Rack environment and the request data.

Be careful when you use this on public-facing sites as it could reveal information helpful to attackers.

Constant Summary collapse

@@eats_errors = 
Object.new

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ ShowExceptions

Returns a new instance of ShowExceptions.



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# File 'lib/sinatra/show_exceptions.rb', line 17

def initialize(app)
  @app = app
end

Class Method Details

.flush ⇒ Object 



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# File 'lib/sinatra/show_exceptions.rb', line 14

def @@eats_errors.flush(*) end

.puts ⇒ Object 



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# File 'lib/sinatra/show_exceptions.rb', line 15

def @@eats_errors.puts(*) end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/sinatra/show_exceptions.rb', line 21

def call(env)
  @app.call(env)
rescue Exception => e
  errors, env["rack.errors"] = env["rack.errors"], @@eats_errors

  if prefers_plain_text?(env)
    content_type = "text/plain"
    body = dump_exception(e)
  else
    content_type = "text/html"
    body = pretty(env, e)
  end

  env["rack.errors"] = errors

  [
    500,
    {
      "Content-Type" => content_type,
      "Content-Length" => body.bytesize.to_s
    },
    [body]
  ]
end

#pretty(env, exception) ⇒ Object

Pulled from Rack::ShowExceptions in order to override TEMPLATE. If Rack provides another way to override, this could be removed in the future.



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# File 'lib/sinatra/show_exceptions.rb', line 49

def pretty(env, exception)
  req = Rack::Request.new(env)

  # This double assignment is to prevent an "unused variable" warning on
  # Ruby 1.9.3.  Yes, it is dumb, but I don't like Ruby yelling at me.
  path = path = (req.script_name + req.path_info).squeeze("/")

  # This double assignment is to prevent an "unused variable" warning on
  # Ruby 1.9.3.  Yes, it is dumb, but I don't like Ruby yelling at me.
  frames = frames = exception.backtrace.map { |line|
    frame = OpenStruct.new
    if line =~ /(.*?):(\d+)(:in `(.*)')?/
      frame.filename = $1
      frame.lineno = $2.to_i
      frame.function = $4

      begin
        lineno = frame.lineno-1
        lines = ::File.readlines(frame.filename)
        frame.pre_context_lineno = [lineno-CONTEXT, 0].max
        frame.pre_context = lines[frame.pre_context_lineno...lineno]
        frame.context_line = lines[lineno].chomp
        frame.post_context_lineno = [lineno+CONTEXT, lines.size].min
        frame.post_context = lines[lineno+1..frame.post_context_lineno]
      rescue
      end

      frame
    else
      nil
    end
  }.compact

  TEMPLATE.result(binding)
end