| Class | Rack::ShowExceptions |
| In: |
lib/rack/showexceptions.rb
|
| Parent: | Object |
Rack::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.
| CONTEXT | = | 7 |
# File lib/rack/showexceptions.rb, line 17
17: def initialize(app)
18: @app = app
19: @template = ERB.new(TEMPLATE)
20: end
# File lib/rack/showexceptions.rb, line 22
22: def call(env)
23: @app.call(env)
24: rescue StandardError, LoadError, SyntaxError => e
25: [500, {"Content-Type" => "text/html"}, pretty(env, e)]
26: end
# File lib/rack/showexceptions.rb, line 28
28: def pretty(env, exception)
29: req = Rack::Request.new(env)
30: path = (req.script_name + req.path_info).squeeze("/")
31:
32: frames = exception.backtrace.map { |line|
33: frame = OpenStruct.new
34: if line =~ /(.*?):(\d+)(:in `(.*)')?/
35: frame.filename = $1
36: frame.lineno = $2.to_i
37: frame.function = $4
38:
39: begin
40: lineno = frame.lineno-1
41: lines = ::File.readlines(frame.filename)
42: frame.pre_context_lineno = [lineno-CONTEXT, 0].max
43: frame.pre_context = lines[frame.pre_context_lineno...lineno]
44: frame.context_line = lines[lineno].chomp
45: frame.post_context_lineno = [lineno+CONTEXT, lines.size].min
46: frame.post_context = lines[lineno+1..frame.post_context_lineno]
47: rescue
48: end
49:
50: frame
51: else
52: nil
53: end
54: }.compact
55:
56: env["rack.errors"].puts "#{exception.class}: #{exception.message}"
57: env["rack.errors"].puts exception.backtrace.map { |l| "\t" + l }
58: env["rack.errors"].flush
59:
60: [@template.result(binding)]
61: end