# Rack::Lint::LintError: No Content-Type header found **URL:** \ **Category:** uncategorized\ **Created:** [August 1, 2012, 6:50am UTC](https://community.miniprofiler.com/t/rack-lint-linterror-no-content-type-header-found/83 "2012-08-01T06:50:42Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![terenced](https://sea2.discourse-cdn.com/flex016/user_avatar/community.miniprofiler.com/terenced/32/1021_2.png) [@terenced](https://community.miniprofiler.com/u/terenced)\ **Post date:** [August 1, 2012, 6:50am UTC](https://community.miniprofiler.com/t/rack-lint-linterror-no-content-type-header-found/83/1 "2012-08-01T06:50:42Z")
I can’t get MiniProfiler to run with Sinatra. I get the following error: Rack::Lint::LintError: No Content-Type header found /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/lint.rb:19:in `assert' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/lint.rb:476:in`check\_content\_type’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/lint.rb:54:in `_call' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/lint.rb:36:in`call’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/lint.rb:48:in `_call' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/lint.rb:36:in`call’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/showexceptions.rb:24:in `call' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/commonlogger.rb:20:in`call’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/shotgun-0.9/lib/shotgun/loader.rb:86:in `proceed_as_child' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/shotgun-0.9/lib/shotgun/loader.rb:31:in`call!’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/shotgun-0.9/lib/shotgun/loader.rb:18:in `call' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/shotgun-0.9/lib/shotgun/favicon.rb:12:in`call’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/shotgun-0.9/lib/shotgun/static.rb:14:in `call' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/builder.rb:134:in`call’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/thin-1.3.1/lib/thin/connection.rb:80:in `block in pre_process' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/thin-1.3.1/lib/thin/connection.rb:78:in`catch’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/thin-1.3.1/lib/thin/connection.rb:78:in `pre_process' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/thin-1.3.1/lib/thin/connection.rb:53:in`process’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/thin-1.3.1/lib/thin/connection.rb:38:in `receive_data' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in`run\_machine’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/thin-1.3.1/lib/thin/backends/base.rb:61:in`start’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/thin-1.3.1/lib/thin/server.rb:159:in `start' /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/rack-1.4.1/lib/rack/handler/thin.rb:13:in`run’ /Users/terry/.rvm/gems/ruby-1.9.2-p290@seevibes/gems/shotgun-0.9/bin/shotgun:156:in `' bin/shotgun:16:in`load’ bin/shotgun:16:in `’ ---
**Author:** ![sam](https://sea2.discourse-cdn.com/flex016/user_avatar/community.miniprofiler.com/sam/32/377_2.png) [@sam](https://community.miniprofiler.com/u/sam)\ **Post date:** [August 1, 2012, 11:43am UTC](https://community.miniprofiler.com/t/rack-lint-linterror-no-content-type-header-found/83/2 "2012-08-01T11:43:23Z")
Ouch no good … what particular resource was it? ---
**Author:** ![terenced](https://sea2.discourse-cdn.com/flex016/user_avatar/community.miniprofiler.com/terenced/32/1021_2.png) [@terenced](https://community.miniprofiler.com/u/terenced)\ **Post date:** [August 2, 2012, 3:16am UTC](https://community.miniprofiler.com/t/rack-lint-linterror-no-content-type-header-found/83/3 "2012-08-02T03:16:02Z")
I just figured out the problem was. I was using the shotgun gem and that was what was causing the problem. When I switched to using unicorn, mini-profiler started working.