require file:// prefix in body if loading a file

.github/workflows/test.yml

@@ -8,6 +8,11 @@ on:
 jobs:
   main:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        body:
+          - file://README.md
+          - Test of action completed successfully!
     steps:
       - name: Checkout
         uses: actions/checkout@v1
@@ -19,6 +24,6 @@ jobs:
           username: ${{secrets.USERNAME}}
           password: ${{secrets.PASSWORD}}
           subject: ${{github.repository}}
-          body: Test of action completed successfully!
+          body: ${{matrix.body}}
           to: ${{secrets.USERNAME}}
           from: github-actions

Dockerfile

@@ -1,5 +1,5 @@
 FROM ruby:2.6-alpine
 
-COPY entrypoint.rb /
+COPY *.rb /
 
-ENTRYPOINT ["/entrypoint.rb"]
+ENTRYPOINT ["/main.rb"]

README.md

@@ -13,7 +13,10 @@ An action that simply sends a mail to multiple recipients.
     username: ${{secrets.MAIL_USERNAME}}
     password: ${{secrets.MAIL_PASSWORD}}
     subject: Github Actions job result
+    # Literal body:
     body: Build job of ${{github.repository}} completed successfully!
+    # Read file contents as body:
+    body: file://README.md
     to: obiwan@tatooine.com,yoda@dagobah.com
     from: Luke Skywalker
 ```

action.yml

@@ -21,7 +21,7 @@ inputs:
     description: Subject of mail message
     required: true
   body:
-    description: Body of mail message
+    description: Body of mail message (might be a filename to read from)
     required: true
   to:
     description: Recipients mail addresses (separated with comma)

entrypoint.rb

@@ -1,33 +0,0 @@
-#!/usr/bin/env ruby
-# frozen_string_literal: true
-
-require 'net/smtp'
-
-# Inputs
-address = ENV["INPUT_SERVER_ADDRESS"]
-port = ENV["INPUT_SERVER_PORT"]
-username = ENV["INPUT_USERNAME"]
-password = ENV["INPUT_PASSWORD"]
-subject = ENV["INPUT_SUBJECT"]
-body = ENV["INPUT_BODY"]
-to = ENV["INPUT_TO"]
-from = ENV["INPUT_FROM"]
-
-# Message
-message = <<EOM
-Subject: #{subject}
-From: #{from} <#{username}>
-
-#{body}
-EOM
-
-# Send
-begin
-  smtp = Net::SMTP.new(address, port.to_i)
-  smtp.enable_tls
-  smtp.start(address, username, password, :login)
-  smtp.send_message(message, username, to.split(","))
-rescue StandardError => e
-  puts "Error: #{e.message}"
-  exit 1
-end

main.rb

@@ -0,0 +1,42 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'net/smtp'
+
+# Inputs
+address = ENV['INPUT_SERVER_ADDRESS']
+port = ENV['INPUT_SERVER_PORT']
+username = ENV['INPUT_USERNAME']
+password = ENV['INPUT_PASSWORD']
+subject = ENV['INPUT_SUBJECT']
+body = ENV['INPUT_BODY']
+to = ENV['INPUT_TO']
+from = ENV['INPUT_FROM']
+
+# Body
+prefix = 'file://'
+body = if body.start_with?(prefix)
+         path = body.delete_prefix(prefix)
+         File.read(path)
+       else
+         body
+       end
+
+# Message
+message = <<~END_OF_MESSAGE
+  Subject: #{subject}
+  From: #{from} <#{username}>
+
+  #{body}
+END_OF_MESSAGE
+
+# Send
+begin
+  smtp = Net::SMTP.new(address, port.to_i)
+  smtp.enable_tls
+  smtp.start(address, username, password, :login)
+  smtp.send_message(message, username, to.split(','))
+rescue StandardError => e
+  puts "Error: #{e.message}"
+  exit 1
+end