Request headers name normalization

Rails
1

I believe, there’s inconsistency between how Rails and curl normalize
header names.

If I do a curl -H "some_header: value" it will send the header as
HTTP_SOME_HEADER. Then in Rails controller I would expect that header
to
be accessible as request.headers[:some_header], but it’s not. The
culprit
is in the ActionDispatch::Http::Headers#env_name <https://github.com/rails/rails/blob/e994fa11cfdb3fc6d96068dbb40c309783563b04/actionpack/lib/action_dispatch/http/headers.rb#L89-L96>,
which doesn’t adjust the header name if it contains an underscore.

Which of the two is correct? Do you think the issue could addressed in
Rails?

2

I am not sure I understand your question, but how does the headers hash
look like? maybe if you show me the result will be easier to understand
the
mistake!

Also gives a concrete example of which headers you trying to set.

I have always done curl requests like this:

curl -i --header “Accept: application/json” --header “Content-Type:
application/json”

the -i option from the manual:

-i, --include
(HTTP) Include the HTTP-header in the output. The
HTTP-header
includes things like server-
name, date of the document, HTTP-version and more…

so you can see the answer to your curl call.

3

I figured, it’s not related to curl but to Rails and Rack only.
Here’s what I do:

curl -v -H “hello_world: true” localhost:3000/empty

Now in the controller I dump the request headers and see
“HTTP_HELLO_WORLD”=>“true”. Rack converted “hello_world” to
“HTTP_HELLO_WORLD”.
But if I try to access the header like request.headers[:hello_world]
or
request.headers["hello_world"], it will return nil.

If I used ‘hello-world’ instead of ‘hello_world’ (underscore instead of
dash), everything would have worked as expected.

4

Thanks, Anuj. I didn’t know that nginx also makes its contribution to
confusion with headers.

5

Hello Roman,

I wrote a blog post about it a while ago:

http://www.andhapp.com/blog/2013/03/03/rack-nginx-custom-http-header-http_-and-_/

I hope it helps.

Anuj

On 23 October 2014 09:39, Roman [email protected] wrote:

          name, date of the document, HTTP-version and more...

https://groups.google.com/d/msgid/rubyonrails-talk/22f6a897-2cda-45f5-bbad-32b55e74a5d1%40googlegroups.com

https://groups.google.com/d/msgid/rubyonrails-talk/22f6a897-2cda-45f5-bbad-32b55e74a5d1%40googlegroups.com?utm_medium=email&utm_source=footer

.
For more options, visit https://groups.google.com/d/optout.

–
Anuj DUTTA