Cinema Booking API

API stands for Application Programming Interface, which is a set of definitions and protocols for building and integrating software. Simply put, they allow two pieces of software to communicate with each other through a pre-defined interface.

Learning Objectives

• Design and build a database-backend API

Introduction

So far, we've designed a database structure for a cinema booking system and implemented that design using an ORM. The next step is to build an API that allows the cinema and its customers to interact with the database.

Frontend applications usually won't interact with a database directly, especially if it's a web app; they'll instead send instructions to a server which will process those instructions and give back a response. We decide how the server receives instructions, processes them and responds back by creating an API.

Setting up

The full database schema and seed file for this exercise has already been implemented, your focus is on building the API itself.

Note: Although we need to create a new primary database, we can reuse a shadow database across multiple projects since Prisma resets it after using it.

1. Create a new database instance in ElephantSQL and create a schema called 'prisma' in it.
2. Rename the .env.example file to .env
3. Edit the DATABASE_URL variable in .env, swapping YOUR_DATABASE_URL for the URL of the database you just created. Leave ?schema=prisma at the end.
4. Edit the SHADOW_DATABASE_URL variable in .env, swapping YOUR_SHADOW_DATABASE_URL for the URL of the shadow database you created in the earlier exercises. Leave ?schema=shadow at the end.
5. If you have not previously done so (e.g. for a past exercise), create another separate TEST database instance. Make sure you create a schema called 'prisma' in it.
6. Edit the TEST_DATABASE_URL variable in .env, swapping YOUR_TEST_DB_URL for the URL of the separate TEST database instance you just created. Leave ?schema=prisma at the end.
7. Run npm ci to install the project dependencies.
8. Run npx prisma migrate reset to execute the existing migrations & data seed. Press y when it asks if you're sure.

Instructions

• Run the app with npm start
• Work through each route detailed in the API Spec.

Extensions

• Work through each route detailed in the extended API Spec. This will require making changes to your existing routes, creating error responses for certain situations, and introducing a new route.
• You will need to create your own tests for these endpoints. Use the existing test provided in test/api/extensions as a guide.

Extensions to the Extensions

• Change your movie list GET route to only respond with movies that have a future screening time
• Add the ability for customers to leave reviews on movies
  • This will require a new entity in your diagram, schema file and seed file. Remember the npx prisma generate, npx prisma migrate dev --create-only --skip-seed --name reviews and npx prisma migrate reset commands from an earlier exercise!
• You will need to create your own tests for these endpoints. Use the existing test provided in test/api/extensions as a guide.
  • If you create the new Review entity, then you will also need to re-run npm run test:migration so that your test database runs the migration to create this table. Do this AFTER you have created the new migration file.

Testing your work

• First, make sure you have created / setup the test database instance and env var, as described in the "Setting Up" section.
• Next, run the command npm run test:migration - this will run the schema migrations against the test database. You only need to do this the one time.

Now, whenever you want to run tests locally:

• Run the test suite with npm test for core requirements.
• Run the extension test suite with npm run test-extensions.
  • When working on extensions, create your own tests by using the one provided in test/api/extensions as a guide.

So far, you may have been using curl to manually test your API endpoints. You can continue to use this approach if you choose, or you can download a tool to make things a little easier. There are two main options:

• Insomnia (recommended)
• Postman

These tools are quite similar to your web browser but have some additional functionality to make structuring API requests easier.