In this tutorial I will illustrate how you can build your own RESTful API in Go and MongoDB. All the code used in this demo can be found on my Github.
1 — API Specification
The REST API service will expose endpoints to manage a store of movies. The operations that our endpoints will allow are:
2 — Fetching Dependencies
Before we begin, we need to get the packages we need to setup the API:
go get github.com/BurntSushi/toml gopkg.in/mgo.v2 github.com/gorilla/mux
- toml : Parse the configuration file (MongoDB server & credentials)
- mux : Request router and dispatcher for matching incoming requests to their respective handler
- mgo : MongoDB driver
3 — API structure
Once the dependencies are installed, we create a file called “app.go“, with the following content:
The code above creates a controller for each endpoint, then expose an HTTP server on port 3000.
Note: We are using GET, POST, PUT, and DELETE where appropriate. We are also defining parameters that can be passed in
To run the server in local, type the following command:
go run app.go
If you point your browser to http://localhost:3000/movies, you should see:
4 — Model
Now that we have a minimal application, it’s time to create a basic Movie model. In Go, we use struct keyword to create a model:
Next, we will create the Data Access Object to manage database operations.
5 — Data Access Object
5.1 — Establish Connection
The connect() method as its name implies, establish a connection to MongoDB database.
5.2 — Database Queries
The implementation is relatively straighforward and just includes issuing right method using db.C(COLLECTION) object and returning the results. These methods can be implemented as follows:
6 — Setup API Endpoints
6.1 — Create a Movie
Update the CreateMovieEndpoint method as follows:
It decodes the request body into a movie object, assign it an ID, and uses the DAO Insert method to create a movie in database.
Let’s test it out:
With Postman:
With cURL
curl -sSX POST -d ‘{“name”:”dunkirk”,”cover_image”:”https://image.tmdb.org/t/p/w640/cUqEgoP6kj8ykfNjJx3Tl5zHCcN.jpg", “description”:”world war 2 movie”}’ http://localhost:3000/movies | jq ‘.’
6.2 — List of Movies
The code below is self explanatory:
It uses FindAll method of DAO to fetch list of movies from database.
Let’s test it out:
With Postman:
With cURL:
curl -sSX GET http://localhost:3000/movies | jq ‘.’
6.3 — Find a Movie
We will use the mux library to get the parameters that the users passed in with the request:
Let’s test it out:
With Postman:
With cURL:
curl -sSX GET http://localhost:3000/movies/599570faf0429b4494cfa5d4 | jq ‘.’
6.4 — Update an existing Movie
Update the UpdateMovieEndPoint method as follows:
Let’s test it out:
With Postman:
With cURL:
curl -sSX PUT -d ‘{“name”:”dunkirk”,”cover_image”:”https://image.tmdb.org/t/p/w640/cUqEgoP6kj8ykfNjJx3Tl5zHCcN.jpg", “description”:”world war 2 movie”}’ http://localhost:3000/movies | jq ‘.’
6.5 — Delete an existing Movie
Update the DeleteMovieEndPoint method as follows:
Let’s test it out:
With Postman:
With cURL:
curl -sSX DELETE -d ‘{“name”:”dunkirk”,”cover_image”:”https://image.tmdb.org/t/p/w640/cUqEgoP6kj8ykfNjJx3Tl5zHCcN.jpg", “description”:”world war 2 movie”}’ http://localhost:3000/movies | jq ‘.’
Taking this further ? On my upcoming posts, I will show you how :
- Write Unit Tests in Go for each Endpoint
- Build a UI in Angular 4
- Setup a CI/CD with CircleCI
- Deploy the stack on AWS and much more …
So stay tuned !