theandrewdavis/rest-to-gmail-example

An example web app that sends emails from a GMail account

An example web app to demonstrate sending emails from a GMail account. This Sinatra app accepts a POST request and uses the gmail gem to send an email with the provided subject and body.

This little app provided me an opportunity to explore unit testing and code coverage in Ruby using minitest, rack-test, and SimpleCov.

Installation

Here's how you can install and run this app on Ubuntu 14.04. First, clone the repo.

git clone https://github.com/theandrewdavis/rest-to-gmail-example.git

To be able to programmatically send emails from a single GMail account, we'll need to create OAuth credentials for that account. Google provides quick runthrough docs, which I'll follow below.

Log into Google Developers Console and create a project. Choose "Enable and Manage APIs" and find the GMail API. Enable it, then go to the Credentials tab. In the Credentials wizard, choose GMail as the API, "Other UI" as the API type, and "User data" as the data to access. The wizard will direct you to create a OAuth 2.0 Client ID and set up the user consent screen. Then you can download a credentials file, client_id.json. Save this file in the secret subdirectory of the cloned repo.

Next, we'll need to authorize a GMail account to send emails programmatically. Find the client id and client secret in the downloaded client_id.json file and run the following.

git clone https://github.com/google/gmail-oauth2-tools.git
python gmail-oauth2-tools/python/oauth2.py --generate_oauth2_token --client_id=???.apps.googleusercontent.com --client_secret=???

This will direct you to a consent website and will provide a code to paste back into the CLI when done. This will give you a refresh token, which our web app can use to authenticate.

Now we'll configure the web app by giving it the refresh token and telling it where to send its emails. Copy secret/config.json.example to secret/config.json and fill out secret/config.json with the new refresh token, the 'from' email address that you just authenticated, and the 'to' email address where new emails will be sent.

Next, we need to build ruby 2.2 since Ubuntu 14.04 comes with 1.9 by default.

First install some dependencies:

sudo apt-get install -y libssl-dev libreadline-dev zlib1g-dev    

Then follow the instructions from gorails.com:

cd
git clone git://github.com/sstephenson/rbenv.git .rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL

git clone git://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
exec $SHELL

git clone https://github.com/sstephenson/rbenv-gem-rehash.git ~/.rbenv/plugins/rbenv-gem-rehash

rbenv install 2.2.3
rbenv global 2.2.3
ruby -v

You can run the app's tests with:

gem install bundler
bundle install
bundle exec ruby test.rb

And finally, run the app on port 8000 with:

sudo bundle exec ruby server.rb -p 8000

To see it in action, try sending a POST request to the running app:

curl --data "subject=subj1&body=body1" http://localhost:8000/