Multipart breaks requests without ParamPart/FilePart

[mkroman]

Basic Info

• Faraday Version: HEAD (1.0.1 @ 5acab36)
• Ruby Version: 2.7.1p83

Issue description

When creating a Faraday instance with the multipart middleware, requests that don't contain a Faraday::ParamPart or Faraday::FilePart fails

I'd expect it to simply send a regular POST request.

This is the backtrace:

Traceback (most recent call last):
	18: from test.rb:15:in `<main>'
	17: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/connection.rb:279:in `post'
	16: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/connection.rb:492:in `run_request'
	15: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/rack_builder.rb:154:in `build_response'
	14: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/request/multipart.rb:30:in `call'
	13: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/adapter/net_http.rb:68:in `call'
	12: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/adapter.rb:61:in `connection'
	11: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/adapter/net_http.rb:70:in `block in call'
	10: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/adapter/net_http.rb:128:in `perform_request'
	 9: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/adapter/net_http.rb:137:in `request_with_wrapped_block'
	 8: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/adapter/net_http.rb:152:in `request_via_request_method'
	 7: from /home/…/.rbenv/versions/2.7.1/lib/ruby/2.7.0/net/http.rb:933:in `start'
	 6: from /home/…/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/bundler/gems/faraday-5acab3623994/lib/faraday/adapter/net_http.rb:158:in `block in request_via_request_method'
	 5: from /home/…/.rbenv/versions/2.7.1/lib/ruby/2.7.0/net/http.rb:1492:in `request'
	 4: from /home/…/.rbenv/versions/2.7.1/lib/ruby/2.7.0/net/http.rb:1519:in `transport_request'
	 3: from /home/…/.rbenv/versions/2.7.1/lib/ruby/2.7.0/net/http.rb:1519:in `catch'
	 2: from /home/…/.rbenv/versions/2.7.1/lib/ruby/2.7.0/net/http.rb:1521:in `block in transport_request'
	 1: from /home/…/.rbenv/versions/2.7.1/lib/ruby/2.7.0/net/http/generic_request.rb:123:in `exec'
/home/…/.rbenv/versions/2.7.1/lib/ruby/2.7.0/net/http/generic_request.rb:184:in `send_request_with_body': undefined method `bytesize' for {:username=>"admin", :password=>"password"}:Hash (NoMethodError)

Steps to reproduce

#!/usr/bin/env ruby
# frozen_string_literal: true

require 'faraday'

http = Faraday.new('http://localhost:8080') do |conn|
  conn.request :multipart
end

body = {
  username: 'admin',
  password: 'password'
}

http.post '/auth/login', body

If you add body[:something] = Faraday::ParamPart.new('abc', 'text/plain'), the issue is gone.

[iMacTia]

Hi @mkroman, you can't send a Hash as a request body, you need to either manually make it a string or have a middleware do that for you.

If the server you're trying to contact expects a x-www-form-urlencoded body, then add the url_encoded middleware, if it expects json, you can add the json middleware instead. These middleware can be added together with the multipart one and they will play nicely as per your expectation:

http = Faraday.new('http://localhost:8080') do |conn|
  conn.request :multipart
  conn.request :url_encoded # or :json
  conn.adapter :net_http # don't forget to put the adapter when you customise the connection
end

This should work as expected, please give it a try and let us know