Remove references to deprecated ::Parts and ::UploadIO (#6)

* remove references to deprecated ::Parts and ::UploadIO
* add backwards compatibility by detecting version of multipart-post gem
* find a way to work with multipart_post 2.1 and 2.2
* add notes to CHANGELOG.md
* move version.rb around so it loads first, to allow others to pick this up
* simplify multipart-port dependency in faraday-multipart.gemspec

Author: jsvd

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
 ## Unreleased
+  * Drop support for 'multipart-post' < 2.0.0. This is not a breaking change as the code didn't work with 1.x.
+  * Change references to UploadIO and Parts according to class reorganization in 'multipart-post' 2.2.0 (PR [#89](https://github.com/socketry/multipart-post/pull/89))
+  * Introduce a backwards compatible safeguard so the gem still works with previous 'multipart-post' 2.x releases.
+
 
 *   Initial release.

faraday-multipart.gemspec

@@ -31,5 +31,5 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = '>= 2.4', '< 4'
 
-  spec.add_dependency 'multipart-post', '>= 1.2', '< 3'
+  spec.add_dependency 'multipart-post', '~> 2'
 end

lib/faraday/multipart.rb

@@ -1,9 +1,9 @@
 # frozen_string_literal: true
 
+require_relative 'multipart/version'
 require_relative 'multipart/file_part'
 require_relative 'multipart/param_part'
 require_relative 'multipart/middleware'
-require_relative 'multipart/version'
 
 module Faraday
   # Main Faraday::Multipart module.
@@ -16,5 +16,11 @@ module Multipart
   ParamPart = Multipart::ParamPart
   Parts = Multipart::Parts
   CompositeReadIO = Multipart::CompositeReadIO
-  UploadIO = ::UploadIO
+  # multipart-post v2.2.0 introduces a new class hierarchy for classes like Parts and UploadIO
+  # For backwards compatibility, detect the gem version and use the right class
+  UploadIO = if ::Gem::Requirement.new('>= 2.2.0').satisfied_by?(Multipart.multipart_post_version)
+               ::Multipart::Post::UploadIO
+             else
+               ::UploadIO
+             end
 end

lib/faraday/multipart/file_part.rb

@@ -2,11 +2,10 @@
 
 require 'stringio'
 
-# multipart-post gem
-require 'composite_io'
-require 'parts'
-
 module Faraday
+  # Rubocop doesn't seem to understand that this is an extension to the
+  # Multipart module, so let's add a nodoc
+  # #:nodoc:
   module Multipart
     # Multipart value used to POST a binary data from a file or
     #
@@ -51,9 +50,16 @@ module Multipart
     # The open IO object for the uploaded file.
     #
     # @return [IO]
-    FilePart = ::UploadIO
-
-    Parts = ::Parts
+    if ::Gem::Requirement.new('>= 2.2.0').satisfied_by?(multipart_post_version)
+      require 'multipart/post'
+      FilePart = ::Multipart::Post::UploadIO
+      Parts = ::Multipart::Post::Parts
+    else
+      require 'composite_io'
+      require 'parts'
+      FilePart = ::UploadIO
+      Parts = ::Parts
+    end
 
     # Similar to, but not compatible with CompositeReadIO provided by the
     # multipart-post gem.

lib/faraday/multipart/version.rb

@@ -1,7 +1,16 @@
 # frozen_string_literal: true
 
 module Faraday
+  # #:nodoc:
   module Multipart
     VERSION = '1.0.3'
+
+    def self.multipart_post_version
+      require 'multipart/post/version'
+      ::Gem::Version.new(::Multipart::Post::VERSION)
+    rescue LoadError
+      require 'multipart_post'
+      ::Gem::Version.new(::MultipartPost::VERSION)
+    end
   end
 end