Rewind IO-alike request body after it was consumed.

[ixti]

Webmock triggers body.each twice upon inital request recording:

1. to perform request
2. to record request data into webmock request registry

But even without WebMock, generally Body#each must be replayable IMO.

Simple reproduction

This is a simple snippet that is doing something similar to what I was doing when I clashed this issue.

require "http"
require "webmock"
require "vcr"

VCR.configure do |config|
  config.hook_into :webmock
  config.cassette_library_dir = File.realpath("#{__dir__}/vcr")
end

VCR.use_cassette("httpbin", :match_requests_on => %i[method uri body]) do
  res = HTTP.post("https://httpbin.org/post", :form => { "a" => "z" })
  puts res.parse(:json)
end

[ixti]

I'm gonna merge this down and release as v 3.2.1
And then will prepare this patch with extra idea for master branch

[tycooon]

Would be cool to have specs for that.

[ixti]

@tycooon good catch! Thank you! done.

[ixti]

I'm gonna "harden" readable body source validation in master - so that if given io-alike object does not respond to size and rewind - it will fail. Not gonna add it as part of 3.x branch as it's quiet breaking change for people using non-rewindable objects and not using webmock.

UPDATE: Actually not. I just realized that one may want to pass IO.pipe which is readable and good suit (probably) for chunked requests.

[mikker]

We're using IO.pipe for chunked POST requests in @elastic's APM Agent and I'm stubbing away rewind on my reader objects because of this.

# HTTP.rb calls #rewind the body stream which IO.pipes don't support
class ModdedIO < IO
  def self.pipe(ext_enc = nil)
    super(ext_enc).tap do |rw|
      rw[0].define_singleton_method(:rewind) { nil }
    end
  end
end

Just wanted to provide an actual use of IO.pipe.

[ixti]

@mikker I have opened an issue with your comment. Let's continue discussion there. We ended up with not requiring IO to respond to rewind:

http/lib/http/request/body.rb

Lines 46 to 53 in f5ddbae

	def validate_source_type!
	return if @source.is_a?(String)
	return if @source.respond_to?(:read)
	return if @source.is_a?(Enumerable)
	return if @source.nil?
	raise RequestError, "body of wrong type: #{@source.class}"
	end

But, I have a feeling that the problem might come from the form data:

https://github.com/httprb/form_data/blob/02800358e4a794e33dfc9cd5308e21ff5efccd2a/lib/http/form_data/composite_io.rb#L56-L60