404 with encodings_provided sets encoding Header but doesn't encode response body #144

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2. Asmod4n commented on Jan 4, 2014

   

   Asmod4n

   on Jan 4, 2014

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   A dirty trick to resolve it would be to unset the Content-Encoding header in https://github.com/seancribbs/webmachine-ruby/blob/master/lib/webmachine/errors.rb#L14 because the length is also for the unencoded response.
4. bethesque commented on Jan 15, 2015

   

   bethesque

   on Jan 15, 2015

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   Close and mark as wont-fix for now until someone else wants it?
5. Asmod4n commented on Jan 15, 2015

   

   Asmod4n

   on Jan 15, 2015

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   Dunno if I would close it, since it is a bug
6. bethesque commented on Jan 15, 2015

   

   bethesque

   on Jan 15, 2015

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   Tis. But you don't have to fix every bug ;) That's why the 'wont-fix' tag exists!

   It seems like a low impact bug which nobody is enthusiastic about fixing, so I'm not sure if there's much point in leaving it open. But we can leave it if nobody else shares my particular obsession with checking items off lists!
7. jimvm commented on Oct 11, 2015

   

   jimvm

   on Oct 11, 2015

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   I wanted to understand this issue better so I first created a resource with a to_html method containing the current 404 not found response body.

   class Resource < Webmachine::Resource
     def resource_exists?
       true
     end
   
     def to_html
       "<!DOCTYPE html><html>\n <head><title>404 Not Found</title></head>\n <body><h1>404 Not Found</h1>\n <p>The requested document was not found on this server.</p>\n <address>Webmachine-Ruby/1.4.0 server</address></body></html>\n"
     end
   end
   

   The response:
   Content-Length: 219

   Then I added the encodings_provided method.

   class Resource < Webmachine::Resource
     def resource_exists?
       false
     end
   
     def encodings_provided
       { 'gzip' => :encode_gzip,
         'deflate' => :encode_deflate,
         'identity' => :encode_identity }
     end
   
     def to_html
       "<!DOCTYPE html><html>\n <head><title>404 Not Found</title></head>\n <body><h1>404 Not Found</h1>\n <p>The requested document was not found on this server.</p>\n <address>Webmachine-Ruby/1.4.0 server</address></body></html>\n"
     end
   end
   

   The response:
   Content-Length: 175
   Content-Encoding: gzip

   Here it works because it was a 200 response, not a 404 response. The path it took through the FSM was different.

   Now I set the resource_exists? to false with no encodings_provided method present.

   class Resource < Webmachine::Resource
     def resource_exists?
       false
     end
   
     def to_html
       "hello"
     end
   end
   

   The response:
   Content-Length: 219

   And lastly I added the encodings_provided method.

   class Resource < Webmachine::Resource
     def resource_exists?
       false
     end
   
     def encodings_provided
       { 'gzip' => :encode_gzip,
         'deflate' => :encode_deflate,
         'identity' => :encode_identity }
     end
   
     def to_html
       "hello"
     end
   end
   

   The response:
   Content-Length: 219
   Content-Encoding: gzip

   The problem is that Content-Length should have been 175.

   render_error creates a response body when no body is given. A response body can be encoded when you know which encodings are provided by the resource. So I think this can't happen inside render_error because the resource isn't available there.

   A 404 response can be given because:

   1. The Dispatcher can't find a resource for a request. In this case there is no custom response body possible but also encodings_provided isn't available at all because the resource doesn't exist.
   2. resource_exists? has been set to false. Here a custom response body should be possible and encodings_provided can be used.

   I think to fix the issue for 2. the l7 state in the FSM should set up the response body and encode it before the response is passed to the render_error method. (The state diagram for reference.)

   (I tried to fix it by unsetting the Content-Encoding header in render_error but this didn't had an effect.)
8. jimvm

   added a commit that references this issue on Oct 11, 2015

   Create an error response body outside render_error. Related to issue w…

   ...

   a2019b6