Implement Connection in terms of Net::HTTP Request

[seanpdoyle]

Proposal

This commit changes the private Connection#request method to invoke Net::HTTP#request, rather than the individual verb methods (like get, post, etc.).

Since the Net::HTTP#request method expects an instance (rather than its constituent parts), this commit also changes the Connection#request method to construct an instance of the HTTP method-appropriate class:

• GET builds Net::HTTP::Get
• PUT builds Net::HTTP::Put
• POST builds Net::HTTP::Post
• PATCH builds Net::HTTP::Patch
• DELETE builds Net::HTTP::Delete
• HEAD builds Net::HTTP::Head

While the behavior changes aim to be minimal, the availability of a Net::HTTP request instance enables more future pre-request modifications (for example, to support for Files through multipart/form-data requests like outlined in #394).

Additional information

Net::HTTP Request instances downcase all HTTP header names, but supports reading from values regardless of the key's casing:

request["Accept"] = "application/json"  # => "application/json"
request.each.to_h                       # => {"accept"=>"application/json"}
request["Accept"]                       # => "application/json"
request["accept"]                       # => "application/json"

Additionally, new Net::HTTP Request instances come with default headers:

accept-encoding: gzip;q=1.0,deflate;q=0.6,identity;q=0.3
user-agent: Ruby
host: 37s.sunrise.i:3000

The host: key is inferred from the request instance's URI.

For the sake of backwards compatibility, this commit clears all default headers prior to merging any provided or inferred headers (like content-type or accept).

[rafaelfranca]

Suggested change

	payload[:headers] = request.each.to_h
	payload[:headers] = request.to_hash

?

[seanpdoyle]

Unfortunately, there is a different between the value returned by Net::HTTPHeader#to_hash and Net::HTTPHeader#each_capitalized`:

request.to_hash                # => {"accept"=>["application/json"]}
request. each_capitalized.to_h # => {"accept"=>"application/json"}

Calling to_hash results in a Hash where all the values are wrapped in Arrays, whereas each_capitalized.to_h does not.

In my opinion, calling to_hash is more correct, in that Net HTTP knows how to transform multi-value headers to the underlying HTTP request.

Having said that, it probably represents a backwards incompatibile breaking change from the current behavior. We could merge this and include it in a release, and then replace each_capitalized.to_h with to_hash in a future major release. What do you think @rafaelfranca ?

[rafaelfranca]

I'm ok with current implementation. Let's keep as is