Multipart::Post

Adds a streamy multipart form post capability to Net::HTTP. Also supports other methods besides POST.

Features/Problems

• Appears to actually work. A good feature to have.
• Encapsulates posting of file/binary parts and name/value parameter parts, similar to most browsers' file upload forms.
• Provides an UploadIO helper class to prepare IO objects for inclusion in the params hash of the multipart post object.

Installation

bundle add multipart-post

Usage

require 'net/http/post/multipart'

url = URI.parse('http://www.example.com/upload')
File.open("./image.jpg") do |jpg|
  req = Net::HTTP::Post::Multipart.new url.path,
    "file" => UploadIO.new(jpg, "image/jpeg", "image.jpg")
  res = Net::HTTP.start(url.host, url.port) do |http|
    http.request(req)
  end
end

To post multiple files or attachments, simply include multiple parameters with UploadIO values:

require 'net/http/post/multipart'

url = URI.parse('http://www.example.com/upload')
req = Net::HTTP::Post::Multipart.new url.path,
  "file1" => UploadIO.new(File.new("./image.jpg"), "image/jpeg", "image.jpg"),
  "file2" => UploadIO.new(File.new("./image2.jpg"), "image/jpeg", "image2.jpg")
res = Net::HTTP.start(url.host, url.port) do |http|
  http.request(req)
end

To post files with other normal, non-file params such as input values, you need to pass hashes to the Multipart.new method.

In Rails 4 for example:

def model_params
  require_params = params.require(:model).permit(:param_one, :param_two, :param_three, :avatar)
  require_params[:avatar] = model_params[:avatar].present? ? UploadIO.new(model_params[:avatar].tempfile, model_params[:avatar].content_type, model_params[:avatar].original_filename) : nil
  require_params
end

require 'net/http/post/multipart'

url = URI.parse('http://www.example.com/upload')
Net::HTTP.start(url.host, url.port) do |http|
  req = Net::HTTP::Post::Multipart.new(url, model_params)
  key = "authorization_key"
  req.add_field("Authorization", key) #add to Headers
  http.use_ssl = (url.scheme == "https")
  http.request(req)
end

Or in plain ruby:

def params(file)
  params = { "description" => "A nice picture!" }
  params[:datei] = UploadIO.new(file, "image/jpeg", "image.jpg")
  params
end

url = URI.parse('http://www.example.com/upload')
File.open("./image.jpg") do |file|
  req = Net::HTTP::Post::Multipart.new(url.path, params(file))
  res = Net::HTTP.start(url.host, url.port) do |http|
    return http.request(req).body
  end
end

Parts Headers

By default, all individual parts will include the header Content-Disposition as well as Content-Length, Content-Transfer-Encoding and Content-Type for the File Parts.

You may optionally configure the headers Content-Type and Content-ID for both ParamPart and FilePart by passing in a parts header.

For example:

url = URI.parse('http://www.example.com/upload')

params = {
  "file_metadata_01" => { "description" => "A nice picture!" },
  "file_content_01"  => UploadIO.new(file, "image/jpeg", "image.jpg")
}

headers = {
  'parts': {
    'file_metadata_01': {
      'Content-Type' => "application/json"
      }
    }
  }

req = Net::HTTP::Post::Multipart.new(uri, params, headers)

This would configure the file_metadata_01 part to include Content-Type

Content-Disposition: form-data; name="file_metadata_01"
Content-Type: application/json
  {
    "description" => "A nice picture!" 
  }

Custom Parts Headers

For FileParts only.

You can include any number of custom parts headers in addition to Content-Type and Content-ID.

headers = {
  'parts': {
    'file_metadata_01': {
      'Content-Type' => "application/json",
      'My-Custom-Header' => "Yo Yo!"
    }
  }
}

Debugging

You can debug requests and responses (e.g. status codes) for all requests by adding the following code:

http = Net::HTTP.new(uri.host, uri.port)
http.set_debug_output($stdout)

Versioning

This library aims to adhere to Semantic Versioning 2.0.0. Violations of this scheme should be reported as bugs. Specifically, if a minor or patch version is released that breaks backward compatibility, a new version should be immediately released that restores compatibility. Breaking changes to the public API will only be introduced with new major versions.

As a result of this policy, you can (and should) specify a dependency on this gem using the Pessimistic Version Constraint with two digits of precision.

For example:

spec.add_dependency 'multipart-post', '~> 2.1'