Choose your RMP action via the X-Rack-Mini-Profiler header (#578)

Co-authored-by: Nate Berkopec <nate.berkopec@gmail.coml>

README.md

@@ -178,7 +178,7 @@ export RACK_MINI_PROFILER_PATCH_NET_HTTP="false"
 
 To generate [flamegraphs](http://samsaffron.com/archive/2013/03/19/flame-graphs-in-ruby-miniprofiler), add the [**stackprof**](https://rubygems.org/gems/stackprof) gem to your Gemfile.
 
-Then, to view the flamegraph as a direct HTML response from your request, just visit any page in your app with `?pp=flamegraph` appended to the URL.
+Then, to view the flamegraph as a direct HTML response from your request, just visit any page in your app with `?pp=flamegraph` appended to the URL, or add the header `X-Rack-Mini-Profiler` to the request with the value `flamegraph`.
 
 Conversely, if you want your regular response instead (which is specially useful for JSON and/or XHR requests), just append the `?pp=async-flamegraph` parameter to your request/fetch URL; the request will then return as normal, and the flamegraph data will be stored for later *async* viewing, both for this request and for all subsequent requests made by this page (based on the `REFERER` header). For viewing these async flamegraphs, use the 'flamegraph' link that will appear inside the MiniProfiler UI for these requests.
 

lib/mini_profiler.rb

@@ -160,13 +160,12 @@ def call(env)
       MiniProfiler.deauthorize_request if @config.authorization_mode == :allow_authorized
 
       status = headers = body = nil
-      query_string = env['QUERY_STRING']
       path         = env['PATH_INFO'].sub('//', '/')
 
       # Someone (e.g. Rails engine) could change the SCRIPT_NAME so we save it
       env['RACK_MINI_PROFILER_ORIGINAL_SCRIPT_NAME'] = ENV['PASSENGER_BASE_URI'] || env['SCRIPT_NAME']
 
-      skip_it = /#{@config.profile_parameter}=skip/.match?(query_string) || (
+      skip_it = matches_action?('skip', env) || (
         @config.skip_paths &&
         @config.skip_paths.any? do |p|
           if p.instance_of?(String)
@@ -212,11 +211,11 @@ def call(env)
 
       has_disable_cookie = client_settings.disable_profiling?
       # manual session disable / enable
-      if query_string =~ /#{@config.profile_parameter}=disable/ || has_disable_cookie
+      if matches_action?('disable', env) || has_disable_cookie
         skip_it = true
       end
 
-      if query_string =~ /#{@config.profile_parameter}=enable/
+      if matches_action?('enable', env)
         skip_it = false
         config.enabled = true
       end
@@ -231,26 +230,26 @@ def call(env)
       client_settings.disable_profiling = false
 
       # profile gc
-      if query_string =~ /#{@config.profile_parameter}=profile-gc/
+      if matches_action?('profile-gc', env)
         current.measure = false if current
         return serve_profile_gc(env, client_settings)
       end
 
       # profile memory
-      if query_string =~ /#{@config.profile_parameter}=profile-memory/
+      if matches_action?('profile-memory', env)
         return serve_profile_memory(env, client_settings)
       end
 
       # any other requests past this point are going to the app to be profiled
 
       MiniProfiler.create_current(env, @config)
 
-      if query_string =~ /#{@config.profile_parameter}=normal-backtrace/
+      if matches_action?('normal-backtrace', env)
         client_settings.backtrace_level = ClientSettings::BACKTRACE_DEFAULT
-      elsif query_string =~ /#{@config.profile_parameter}=no-backtrace/
+      elsif matches_action?('no-backtrace', env)
         current.skip_backtrace = true
         client_settings.backtrace_level = ClientSettings::BACKTRACE_NONE
-      elsif query_string =~ /#{@config.profile_parameter}=full-backtrace/ || client_settings.backtrace_full?
+      elsif matches_action?('full-backtrace', env) || client_settings.backtrace_full?
         current.full_backtrace = true
         client_settings.backtrace_level = ClientSettings::BACKTRACE_FULL
       elsif client_settings.backtrace_none?
@@ -259,7 +258,7 @@ def call(env)
 
       flamegraph = nil
 
-      trace_exceptions = query_string =~ /#{@config.profile_parameter}=trace-exceptions/ && defined? TracePoint
+      trace_exceptions = matches_action?('trace-exceptions', env) && defined? TracePoint
       status, headers, body, exceptions, trace = nil
 
       if trace_exceptions
@@ -283,19 +282,19 @@ def call(env)
         # Prevent response body from being compressed
         env['HTTP_ACCEPT_ENCODING'] = 'identity' if config.suppress_encoding
 
-        if query_string =~ /pp=(async-)?flamegraph/ || env['HTTP_REFERER'] =~ /pp=async-flamegraph/
+        if matches_action?('flamegraph', env) || matches_action?('async-flamegraph', env) || env['HTTP_REFERER'] =~ /pp=async-flamegraph/
           if defined?(StackProf) && StackProf.respond_to?(:run)
             # do not sully our profile with mini profiler timings
             current.measure = false
-            match_data      = query_string.match(/flamegraph_sample_rate=([\d\.]+)/)
+            match_data      = action_parameters(env)['flamegraph_sample_rate']
 
             if match_data && !match_data[1].to_f.zero?
               sample_rate = match_data[1].to_f
             else
               sample_rate = config.flamegraph_sample_rate
             end
 
-            mode_match_data = query_string.match(/flamegraph_mode=([a-zA-Z]+)/)
+            mode_match_data = action_parameters(env)['flamegraph_mode']
 
             if mode_match_data && [:cpu, :wall, :object, :custom].include?(mode_match_data[1].to_sym)
               mode = mode_match_data[1].to_sym
@@ -342,7 +341,7 @@ def call(env)
       if trace_exceptions
         body.close if body.respond_to? :close
 
-        query_params = Rack::Utils.parse_nested_query(query_string)
+        query_params = action_parameters(env)
         trace_exceptions_filter = query_params['trace_exceptions_filter']
         if trace_exceptions_filter
           trace_exceptions_regex = Regexp.new(trace_exceptions_filter)
@@ -352,19 +351,19 @@ def call(env)
         return client_settings.handle_cookie(dump_exceptions exceptions)
       end
 
-      if query_string =~ /#{@config.profile_parameter}=env/
+      if matches_action?("env", env)
         return tool_disabled_message(client_settings) if !advanced_debugging_enabled?
         body.close if body.respond_to? :close
         return client_settings.handle_cookie(dump_env env)
       end
 
-      if query_string =~ /#{@config.profile_parameter}=analyze-memory/
+      if matches_action?("analyze-memory", env)
         return tool_disabled_message(client_settings) if !advanced_debugging_enabled?
         body.close if body.respond_to? :close
         return client_settings.handle_cookie(analyze_memory)
       end
 
-      if query_string =~ /#{@config.profile_parameter}=help/
+      if matches_action?("help", env)
         body.close if body.respond_to? :close
         return client_settings.handle_cookie(help(client_settings, env))
       end
@@ -373,7 +372,7 @@ def call(env)
       page_struct[:user] = user(env)
       page_struct[:root].record_time((Process.clock_gettime(Process::CLOCK_MONOTONIC) - start) * 1000)
 
-      if flamegraph && query_string =~ /#{@config.profile_parameter}=flamegraph/
+      if flamegraph && matches_action?("flamegraph", env)
         body.close if body.respond_to? :close
         return client_settings.handle_cookie(self.flamegraph(flamegraph, path, env))
       elsif flamegraph # async-flamegraph
@@ -403,6 +402,15 @@ def call(env)
       self.current = nil
     end
 
+    def matches_action?(action, env)
+      env['QUERY_STRING'] =~ /#{@config.profile_parameter}=#{action}/ ||
+        env['HTTP_X_RACK_MINI_PROFILER'] == action
+    end
+
+    def action_parameters(env)
+      query_params = Rack::Utils.parse_nested_query(env['QUERY_STRING'])
+    end 
+
     def inject_profiler(env, status, headers, body)
       # mini profiler is meddling with stuff, we can not cache cause we will get incorrect data
       # Rack::ETag has already inserted some nonesense in the chain

lib/mini_profiler/views.rb

@@ -164,6 +164,8 @@ def help(client_settings, env)
                 #{make_link "flamegraph_embed", env} : a graph representing sampled activity (requires the stackprof gem), embedded resources for use on an intranet.
                 #{make_link "trace-exceptions", env} : will return all the spots where your application raises exceptions
                 #{make_link "analyze-memory", env} : will perform basic memory analysis of heap
+
+                All features can also be accessed by adding the X-Rack-Mini-Profiler header to the request, with any of the values above (e.g. 'X-Rack-Mini-Profiler: flamegraph')
               </pre>
             </body>
           </html>

spec/integration/mini_profiler_spec.rb

@@ -376,6 +376,14 @@ def load_prof(response)
         expect(last_response.body).to include('QUERY_STRING')
         expect(last_response.body).to include('CONTENT_LENGTH')
       end
+
+      it 'works via HTTP header' do 
+        Rack::MiniProfiler.config.enable_advanced_debugging_tools = true
+        get '/html', nil, { 'HTTP_X_RACK_MINI_PROFILER' => 'env' }
+
+        expect(last_response.body).to include('QUERY_STRING')
+        expect(last_response.body).to include('CONTENT_LENGTH')
+      end 
     end
   end
 
@@ -413,6 +421,11 @@ def load_prof(response)
       get '/html?pp=profile-gc'
       expect(last_response.header['Content-Type']).to include('text/plain')
     end
+
+    it "should return a report when an HTTP header is used" do 
+      get '/html', nil, { 'HTTP_X_RACK_MINI_PROFILER' => 'profile-gc' }
+      expect(last_response.header['Content-Type']).to include('text/plain')
+    end 
   end
 
   describe 'error handling when storage_instance fails to save' do
@@ -654,4 +667,11 @@ def load_prof(response)
       expect(last_response.body).to eq("Snapshot with id '"><qss>' not found"), "id should be escaped to prevent XSS"
     end
   end
+
+  describe 'when triggering via HTTP header' do
+    it 'can trigger the help option via an HTTP header' do
+      get '/html', nil, { 'HTTP_X_RACK_MINI_PROFILER' => 'help' }
+      expect(last_response.body).to include('This is the help menu')
+    end
+  end
 end