Go-Swagger: User Registration with MySql & Go

Go has really gained a lot of momentum in the market. Combining Go with swagger using go-swagger, makes it a very powerful yet simple web framework to work with.

If you are new to go-swagger then I’ll strongly recommend to read my introductory article. In the intro, I have explained the steps to install go-swagger on your local machine. Later you can refer the implementation part in another article of mine. If you have this knowledge, then you can skip and go ahead in this article.

Prerequisite:

• Install MySql into your machine and create a schema named ecommerce . Have username and password as root (you can change it as well, but make sure you make necessary change in client_builder.go as shown below )
• Run below SQL query in ecommerce schema to create TABLE:

CREATE TABLE `ecommerce`.`customer`
(
    `customerId` INT          NOT NULL AUTO_INCREMENT,
    `firstName`  VARCHAR(45)  NOT NULL,
    `lastName`   VARCHAR(45)  NULL,
    `phoneNo`    INT          NULL,
    `password`   VARCHAR(10) NULL,
    `email`      VARCHAR(60)  NOT NULL,
    PRIMARY KEY (`email`),
    UNIQUE INDEX `phoneNo_UNIQUE` (`phoneNo` ASC) VISIBLE,
    UNIQUE INDEX `id_UNIQUE` (`customerId` ASC) VISIBLE
);

Step 1: Create swagger file

To start with the development of this new endpoint, you need to recognize the model of request & response and define them inswagger.yaml file as below :

1. /register endpoint which is of type POST .
2. Created request payload model named RegisterUser which containes email, fname , lname , password & phoneNo .
3. Created response payload model named SuccessResponse .

You can copy-paste & use online swagger editor to visualize this swagger file

Step 2: Generate boilerplate code using swagger file

Once we have the swagger.yaml file ready, we can use below command to generate the swagger generated code:

swagger generate server -f swagger.yaml --default-scheme http --exclude-main

For better visualization, you can refer to the final code which I have created using these steps, in my GitHub e-commerce server code . In the GitHub code, I have kept the swagger.yaml under /api folder. You need to go into /api folder and run swagger generate command as mentioned above.

Step 3: Install MySql package and shareable DB connection

• Install Mysql go package using

go get -u github.com/go-sql-driver/mysql

• Create a client_builder.go under clients folder & import mysql connection driver and to use it across all endpoints.

• Navigate to api/restapi/configure_e_food.go and go to func configureAPI() to create a connection client object as below:

func configureAPI(api *operations.EFoodAPI) http.Handler {
  clientBuilder := clients.NewClientBuilder()
  dbClient := clientBuilder.BuildSqlClient() // dbClient can be injected to APIs
  // .... remaining code here
}

Step 4: Create DAO struct to manage Customer details

• Create ./pkg/dao/customer.go file with a function to insert new user details
• Since we want to save password in Database without exposing to other users as well as system admins, we’ll be encrypting it using bcrypt package. To install bcrypt , we can run below command:

go get -u golang.org/x/crypto/bcrypt

• Below is the final code which uses bcrypt to encrypt the user password.

Note : The *models.RegisterUser type in the args has been created by swagger.yaml when we ran swagger generator command.

Step 5: Attach DAO function with Endpoint

Now, that we have all the code in place, we can simply wireup the RegisterNewUser function with /register endpoint. To do that:

• Create ./handlers/post_register_user.go file and write code as below. The final code with Dependency Injected can be found here.

Are you wondering what just happened in this code ? Check out this article of mine to understand the project structuring.

• Go to configure_e_food.go file and write api.UserRegisterHandler:

Step 6: Make HTTP call to get response

Run the code using :

go run cmd\e-food-server\main.go — scheme http — port=8080

Go to postman and try hitting POST endpoint http://127.0.0.1:8080/v1/register

And that’s it !

In my next tutorial (coming soon …) , I’ll show you how to login using JWT for the registered user

To explore authentication of the registered user, you can read below article

Go-Swagger : User Authentication & securing API using JWT — Part 1

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