Class: Webmachine::Trace::TraceResource

Inherits:
Resource
  • Object
show all
Defined in:
lib/webmachine/trace/trace_resource.rb

Overview

Implements the user-interface of the visual debugger. This includes serving the static files (the PNG flow diagram, CSS and JS for the UI) and the HTML for the individual traces.

Constant Summary collapse

MAP_EXTERNAL = 
%w[static map.png]
MAP_FILE = 
File.expand_path('../static/http-headers-status-v3.png', __FILE__)
SCRIPT_EXTERNAL = 
%w[static wmtrace.js]
SCRIPT_FILE = 
File.expand_path("../#{SCRIPT_EXTERNAL.join "/"}", __FILE__)
STYLE_EXTERNAL = 
%w[static wmtrace.css]
STYLE_FILE = 
File.expand_path("../#{STYLE_EXTERNAL.join "/"}", __FILE__)
TRACELIST_ERB = 
File.expand_path('../static/tracelist.erb', __FILE__)
TRACE_ERB = 
File.expand_path('../static/trace.erb', __FILE__)

Instance Attribute Summary

Attributes inherited from Resource

#request, #response

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Resource

new, run

Methods included from Resource::Tracing

#trace?

Methods included from Resource::EntityTags

#weak_etag

Methods included from Resource::Encodings

#encode_deflate, #encode_gzip, #encode_identity

Methods included from Resource::Callbacks

#allow_missing_post?, #allowed_methods, #base_uri, #charsets_provided, #content_types_accepted, #create_path, #delete_completed?, #delete_resource, #encodings_provided, #finish_request, #forbidden?, #generate_etag, #handle_exception, #is_authorized?, #is_conflict?, #known_content_type?, #known_methods, #language_chosen, #languages_provided, #malformed_request?, #moved_permanently?, #moved_temporarily?, #multiple_choices?, #options, #post_is_create?, #previously_existed?, #process_post, #service_available?, #uri_too_long?, #valid_content_headers?, #valid_entity_length?, #validate_content_checksum, #variances

Class Method Details

.trace ⇒ Object

The ERB template for a single trace



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# File 'lib/webmachine/trace/trace_resource.rb', line 25

def self.trace
  @@trace ||= ERB.new(File.read(TRACE_ERB))
end

.tracelist ⇒ Object

The ERB template for the trace list



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# File 'lib/webmachine/trace/trace_resource.rb', line 20

def self.tracelist
  @@tracelist ||= ERB.new(File.read(TRACELIST_ERB))
end

Instance Method Details

#content_types_provided ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 29

def content_types_provided
  case request.path_tokens
  when []
    [['text/html', :produce_list]]
  when MAP_EXTERNAL
    [['image/png', :produce_file]]
  when SCRIPT_EXTERNAL
    [['text/javascript', :produce_file]]
  when STYLE_EXTERNAL
    [['text/css', :produce_file]]
  else
    [['text/html', :produce_trace]]
  end
end

#encode_decisions(decisions) ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 101

def encode_decisions(decisions)
  decisions.each_with_object([]) do |event, list|
    case event[:type]
    when :decision
      # Don't produce new decisions for sub-steps in the graph
      unless /[a-z]$/.match?(event[:decision].to_s)
        list << {'d' => event[:decision], 'calls' => []}
      end
    when :attempt
      list.last['calls'] << {
        'call' => event[:name],
        'source' => event[:source],
        'input' => event[:args] && event[:args].inspect
      }
    when :result
      list.last['calls'].last['output'] = event[:value].inspect
    when :exception
      list.last['calls'].last['exception'] = {
        'class' => event[:class],
        'backtrace' => event[:backtrace].join("\n"),
        'message' => event[:message]
      }
    end
  end
end

#encode_trace(data) ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 91

def encode_trace(data)
  data = data.dup
  # Request is first, response is last
  treq = data.shift.dup
  tres = data.pop.dup
  treq.delete :type
  tres.delete :type
  [MultiJson.dump(treq), MultiJson.dump(tres), MultiJson.dump(encode_decisions(data))]
end

#expires ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 67

def expires
  (Time.now + 30 * 86400).utc if @file
end

#last_modified ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 63

def last_modified
  File.mtime(@file) if @file
end

#produce_file ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 71

def produce_file
  # TODO: Add support for IO objects as response bodies,
  # allowing server optimizations like sendfile or chunked
  # downloads
  File.binread(@file)
end

#produce_list ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 78

def produce_list
  base = request.uri.path.chomp('/')
  traces = Trace.traces.map { |t| [t, "#{base}/#{t}"] }
  self.class.tracelist.result(binding)
end

#produce_trace ⇒ Object 



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# File 'lib/webmachine/trace/trace_resource.rb', line 84

def produce_trace
  data = Trace.fetch(@trace)
  treq, tres, trace = encode_trace(data)
  name = @trace
  self.class.trace.result(binding)
end

#resource_exists? ⇒ Boolean 



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# File 'lib/webmachine/trace/trace_resource.rb', line 44

def resource_exists?
  case request.path_tokens
  when []
    true
  when MAP_EXTERNAL
    @file = MAP_FILE
    File.exist?(MAP_FILE)
  when SCRIPT_EXTERNAL
    @file = SCRIPT_FILE
    File.exist?(SCRIPT_FILE)
  when STYLE_EXTERNAL
    @file = STYLE_FILE
    File.exist?(STYLE_FILE)
  else
    @trace = request.path_tokens.first
    Trace.traces.include? @trace
  end
end