What are the relevant tickets?

Closes #6

Description (What does it do?)

This PR adds a new argument to initLoginButton, redirectUrl. This string argument is simply passed through as the redirect_url query string parameter to the login endpoint. If the domain of the redirect URL is set in the SOCIAL_AUTH_ALLOWED_REDIRECT_HOSTS setting on the instance of mit-open that you are hitting, then you will be redirected back to that URL after logging in.

How can this be tested?

• You will need to make a slight alteration to the code before testing this, as at the time of writing add trailing slash to currentUserUrl #5 has not been merged and it fixes an issue with the /users/me endpoint:

Replace:
const apiUrl = `${parsedBaseUrl.origin}/api/v0/users/me?format=json`
With:
const apiUrl = `${parsedBaseUrl.origin}/api/v0/users/me/?format=json`

• In order to test this, you will need a running instance of mit-open. Follow the instructions in the mit-open readme for initial setup. You will need an account in your local instance for this to work. Your instance of mit-open should be accessible at http://od.odl.local:8063. You will need to set the following environment variables:

CORS_ALLOWED_ORIGINS=["http://ocw.odl.local:3000"]
SOCIAL_AUTH_ALLOWED_REDIRECT_HOSTS=["ocw.odl.local:3000"]

• You will also need ocw-hugo-themes (https://github.com/mitodl/ocw-hugo-themes) set up locally, running a course using yarn start course. Follow the readme there for basic setup instructions and make sure you can start up a course. After you have that working, check out the cg/add-mit-open-login-button branch. Assuming you have cloned this repo, run yarn add /path/to/mit-open-login-button to add your local copy of the code for this to your locally running ocw-hugo-themes. This is necessary because the package is not yet published to NPM. You will also need an entry in your hosts file that points the ocw.odl.local domain to 127.0.0.1.
• Once you have all this running, make sure you are logged out of your local instance of mit-open
• Back in your locally running OCW course site, you should see a Login button in the upper right. Click this button and log in to your locally running mit-open
• After you have logged in, you will be sent back to http://ocw.odl.local:3000
• Confirm that you see Logged in as: username with your username in place of username
• In another tab, log out of your locally running mit-open
• Back on the local OCW page, refresh and verify that the login button reappears