Attachment download contents

lib/jira/resource/attachment.rb

@@ -1,4 +1,5 @@
 require 'net/http/post/multipart'
+require 'open-uri'
 
 module JIRA
   module Resource
@@ -19,6 +20,45 @@ def self.meta(client)
         parse_json(response.body)
       end
 
+      # Opens a file streaming the download of the attachment.
+      # @example Write file contents to a file.
+      #   File.open('some-filename', 'wb') do |output|
+      #     download_file do |file|
+      #       IO.copy_stream(file, output)
+      #     end
+      #   end
+      # @example Stream file contents for an HTTP response.
+      #   response.headers[ "Content-Type" ] = "application/octet-stream"
+      #   download_file do |file|
+      #     chunk = file.read(8000)
+      #     while chunk.present? do
+      #       response.stream.write(chunk)
+      #       chunk = file.read(8000)
+      #     end
+      #   end
+      #   response.stream.close
+      # @param [Hash] headers Any additional headers to call Jira.
+      # @yield |file|
+      # @yieldparam [IO] file The IO object streaming the download.
+      def download_file(headers = {}, &block)
+        default_headers = client.options[:default_headers]
+        URI.open(content, default_headers.merge(headers), &block)
+      end
+
+      # Downloads the file contents as a string object.
+      #
+      # Note that this reads the contents into a ruby string in memory.
+      # A file might be very large so it is recommend to avoid this unless you are certain about doing so.
+      # Use the download_file method instead and avoid calling the read method without a limit.
+      #
+      # @param [Hash] headers Any additional headers to call Jira.
+      # @return [String,NilClass] The file contents.
+      def download_contents(headers = {})
+        download_file(headers) do |file|
+          file.read
+        end
+      end
+
       def save!(attrs, path = url)
         file = attrs['file'] || attrs[:file] # Keep supporting 'file' parameter as a string for backward compatibility
         mime_type = attrs[:mimeType] || 'application/binary'

spec/jira/resource/attachment_spec.rb

@@ -59,6 +59,43 @@
     end
   end
 
+  context 'there is an attachment on an issue' do
+    let(:client) do
+      JIRA::Client.new(username: 'username', password: 'password', auth_type: :basic, use_ssl: false )
+    end
+    let(:attachment_file_contents) { 'file contents' }
+    let(:file_target) { double(read: :attachment_file_contents) }
+    let(:attachment_url) { "https:jirahost/secure/attachment/32323/myfile.txt" }
+    subject(:attachment) do
+      JIRA::Resource::Attachment.new(
+        client,
+        issue: JIRA::Resource::Issue.new(client),
+        attrs: { 'author' => { 'foo' => 'bar' }, 'content' => attachment_url }
+      )
+    end
+
+    describe '.download_file' do
+      it 'passes file object to block' do
+        expect(URI).to receive(:open).with(attachment_url, anything).and_yield(file_target)
+
+        attachment.download_file do |file|
+          expect(file).to eq(file_target)
+        end
+
+      end
+    end
+
+    describe '.download_contents' do
+      it 'downloads the file contents as a string' do
+        expect(URI).to receive(:open).with(attachment_url, anything).and_return(attachment_file_contents)
+
+        result_str = attachment.download_contents
+
+        expect(result_str).to eq(attachment_file_contents)
+      end
+    end
+  end
+
   context 'when there is a local file' do
     let(:file_name) { 'short.txt' }
     let(:file_size) { 11 }