DEV Community: paultofman

Develop and deploy your Rest Api using Mysql and Heroku

paultofman — Mon, 01 Apr 2019 15:24:59 +0000

In part one of the Rest API using Spring Boot and Heroku, we built an imaginary bucket list of places we wish to travel to or visit in our lifetime. However, the buckets are not stored in a database. This means that whenever we restart our server our buckets information get lost.

Let’s fix that.

In part two of this tutorial, you will learn how to store our bucket lists in MySQL database and deploy it to Heroku.

To get the finished code, scroll down to the bottom of this page. If you are don’t know what Rest is or want a refresher on what we have covered so far, please read part 1 of the tutorial here.

Tools used in the tutorial

1. IDE: IntelliJ    
2. Framework: Spring Boot
3. Web Maven Dependency: It provides with tomcat server which handles request and response mapping among other things.
4. Mysql maven dependency: This provides a connector for connect to mysql database
5. Maven JPA dependency: This is the ORM, Hibernate to be precise. It provides a wrapper for mapping Java classes to tables in the database.
6. Build Tool: Maven
7. Language: Java
8. Hosting platform: Heroku
9. Mysql database
10. Database GUI (not required)

My selection has been shown here

The Spring boot starter web contains everything needed to bootstrap an app such as an embedded server. Tomcat is the default.

Section 2

We need to create two Java classes. One will serve as a controller for receiving request and responding with response. The second will serve as a data model.

Here is what our Data Model(BucketList) looks like:

package com.zerotoproduction.bucketlist;

import javax.persistence.*;

@Entity
public class BucketList {

@Id
@Column(name = "id", unique = true, nullable = false)
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;

@Column(name = "name", length = 60, nullable = false)
private String name;

@Column
private  String description;

BucketList() {

}

BucketList(String name, String description){
    this.name = name;
    this.description = description;
}

BucketList(long id, String name, String description){
    this.id = id;
    this.name = name;
    this.description = description;
}

public long getId() {
    return id;
}

public void setId(long id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getDescription() {
    return description;
}

public void setDescription(String description) {
    this.description = description;
}

@Override
public String toString() {
    return "BucketList{" +
            "id=" + id +
            ", name='" + name + '\'' +
            ", description='" + description + '\'' +
            '}';
}
}

An explanation for each of the annotation

@Entity: with this annotation, we have specified that this class represents an entity in the DB.
@id : this specifies that this attribute is a primary key
@Column(name = “id”, unique = true, nullable = false): @Column specifies that this field should be column, its name should be id, the values should be unique and it cannot be null.
@GeneratedValue(strategy = GenerationType.IDENTITY). We are specified that the values should be generated by DB using Identity generation type.

We also need Data Access Object (DAO). Luckily for us, Spring comes with lots of options from CrudRepository to JPARepository. These interfaces provide CRUD functionalities out of the box for Objects annotated with @Entity annotation. However, the caveat is that your DAO interface must extend them and specify the entity and data type of the primary key for that entity. In our example, we are extending JPARepository like so: JpaRepository. The entity is BucketList and data type of its primary key is Long. Now we have all we need to persist our buckets in the DB.

Here is what our BucketListRepository looks like

package com.zerotoproduction.bucketlist;

import org.springframework.data.jpa.repository.JpaRepository;

public interface BucketRepository extends JpaRepository<BucketList, Long> {
}

Here is what the controller looks like:

 package com.zerotoproduction.bucketlist;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 import java.util.Optional;

 @RestController
 public class BucketListController {

@Autowired
BucketRepository bucketRepository;

@GetMapping(value = "/")
public ResponseEntity index() {
    return ResponseEntity.ok(bucketRepository.findAll());
}

@GetMapping(value = "/bucket")
public ResponseEntity getBucket(@RequestParam(value="id") Long id) {
    Optional<BucketList> foundBucketList = bucketRepository.findById(id);

    if(foundBucketList.isPresent()){
        return ResponseEntity.ok(foundBucketList.get());
    }else {
        return ResponseEntity.badRequest().body("No bucket with specified id " + id + " found");
    }
}

@PostMapping(value = "/")
public ResponseEntity addToBucketList(@RequestParam(value="name") String name, @RequestParam(value="description") String desc) {
    return ResponseEntity.ok(bucketRepository.save(new BucketList(name, desc)));
}

@PutMapping(value = "/")
public ResponseEntity updateBucketList(@RequestParam(value="name") String name, @RequestParam(value="id") Long id, @RequestParam(value="description") String desc) {
    Optional<BucketList> optionalBucketList = bucketRepository.findById(id);
    if(!optionalBucketList.isPresent()){
        return ResponseEntity.badRequest().body("No bucket with specified id " + id + " found");
    }

    BucketList foundBucketList = optionalBucketList.get();
    foundBucketList.setName(name);
    foundBucketList.setDescription(desc);

    return ResponseEntity.ok(bucketRepository.save(foundBucketList));
}

@DeleteMapping(value = "/")
public ResponseEntity removeBucketList(@RequestParam(value="id") Long id) {
    bucketRepository.deleteById(id);
    return ResponseEntity.noContent().build();
}

}

Here is what my folder structure looks like

Since we are connecting to a database, we need the address of the database, username and password.

We will test this locally on our pc before deploying it to Heroku. I have specified the properties in application.properties. Let’s go over it

 spring.datasource.url=jdbc:mysql://localhost:3306/zero_to_production_bucketlist_jpa?serverTimezone=UTC
 spring.datasource.username=root
 spring.datasource.password=Toor1234

# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto=update

#MySQL DIALECT
#spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

server.port=9009

Explanation

spring.datasource.url specifies the connection string for connecting to the database
spring.datasource.username specifies the username for connecting to the Db
spring.datatsource.password specifies the password.
spring.jpa.hibernate.ddl-auto specifies how hibernate will handle entities in your database. The create option means that all entities will be dropped and created at every restart while the update option adds changes to the entities without dropping it. In production, you need to use update else your data will be flushed.
server.port specifies the port number our application will run on.

It’s time to test and we will do it this time locally. We will use Postman

Test 1: Add a bucket list

http://localhost:9009?name=Visit Big Ben&description=My first list

Test 2: Get all bucket lists

http://localhost:9009

You should see a response similar to the one below

Test 3: get single bucket list

http://localhost:9009/bucket?id=1

Test 4: Update Bucket
http://localhost:9009?name=Visit Big Ben Updated&description=My first list&id=1

Test 5: Delete bucket

http://localhost:9009?id=2

Section 2: Time to deploy to Heroku

You need to create an account on Heroku
Install Heroku Cli. Heroku CLI is a command line application that lets you     create, deploy and manage Heroku apps from the command line. 
You can download Heroku CLI from Heroku Dev Center.
Login using your email and password

Set up Git and create a Heroku app
git init
git add .
git commit -m "initial commit"
heroku login

Now, create an app using heroku create like so

heroku create

Next, you need to add mysql DB like so:

heroku addons:create cleardb:ignite

Now that you have add clearDB, you need the connection url. To get this, type like so:

heroku config

It should return your connection string.

You need to replace the spring.datasource.url value with the value return from heroku config.

One last thing though, to make it work, add a database config file like so:

package com.zerotoproduction.bucketlist;

import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
public class DatabaseConfig {

@Value("${spring.datasource.url}")
private String dbUrl;

@Bean
public DataSource dataSource() {
    HikariConfig config = new HikariConfig();
    config.setJdbcUrl(dbUrl);
    return new HikariDataSource(config);
}
}

Deploy app to Heroku

git push heroku master

Our app has been deployed to Heroku now

https://tranquil-mountain-81706.herokuapp.com/

Let’s test again but you must remove the localhost and port with the url given by heroku.

For example, to get all items in our bucket list, we use

https://tranquil-mountain-81706.herokuapp.com/

and to get an item we use

https://tranquil-mountain-81706.herokuapp.com//bucket?id=1

That wraps up our tutorial today.

To follow the full series on building, securing and deploying Spring Boot Rest Api, visit our blog:

https://medium.com/zero-to-production

Contact us via email on: zerotoproduction@gmail.com

The complete code can be found here:

https://github.com/zero-to-production/bucketlist

Deploying your Spring boot to Heroku

paultofman — Sat, 30 Mar 2019 10:28:07 +0000

In this tutorial, you will learn how to use Spring Boot to develop RESTful API and publish your API to Heroku. First, we will build the api; upon completion, we will deploy to Heroku.

Introduction to REST

RESTful API or web service is an application programming interface using HTTP request types: GET, POST, DELETE and PUT to perform actions on data. It is generally preferred to its closest alternative Simple Object Access Protocol (SOAP) because it requires less resources. By writing APIs that adhere to RESTful practices, you are agreeing to adopt an architectural style of representing, requesting, storing data and deleting data.

GET: It is used for requesting data. You can request for a single item or list of items

PUT: It is used for updating an item.

POST: It is used for creating an item

DELETE: It is used for deleting an item.

Tools used in the tutorial

IDE: IntelliJ
Framework: Spring Boot
Dependency: Spring boot starter web
Build Tool: Maven
Language: Java
Hosting platform: Heroku

The Spring boot starter web contains everything needed to bootstrap an app such as an embedded server. Tomcat is the default.

If you don’t have a Heroku account, you may sign up using this link

What are we building?

Imagine we have a bucket list of places we wish to travel to or visit in our lifetime. I hope you do. We would create an app for adding, editing, viewing and deleting items in our bucket list. In this tutorial, we will be using a non-persistent DB (ArrayList); if you want a persistent store, comment below as we have another tutorial for that.

Section 1

Head over to start.spring.io and provide the group and artifact name for your app.It is a Maven project written in Java and the dependency is Web.
The only dependency needed is the Web dependency.
Click on generate project
Extract to your computer and import the downloaded maven project to your favourite Editor
Open extracted folder in your editor.

Time to write some code

We need to create two Java classes. One will serve as a controller for receiving request and responding with response. The second will serve as a data model.

Data Model(BucketList)

package com.zerotoproduction.firstrest;

public class BucketList {

private long id;
private String name;

BucketList(long id, String name){
    this.id = id;
    this.name = name;
}

public long getId() {
    return id;
}

public void setId(long id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}
}

Controller(BucketListController)

package com.zerotoproduction.firstrest;

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;

@RestController
public class BucketListController {

private List<BucketList> myBucketList = new ArrayList();
private final AtomicLong counter = new AtomicLong();

public BucketListController(){
    myBucketList.add(new BucketList(counter.incrementAndGet(), "Visit Colosseum in Rome"));
}

@GetMapping(value = "/")
public ResponseEntity index() {
    return ResponseEntity.ok(myBucketList);
}

@GetMapping(value = "/bucket")
public ResponseEntity getBucket(@RequestParam(value="id") Long id) {
    BucketList itemToReturn = null;
    for(BucketList bucket : myBucketList){
        if(bucket.getId() == id)
            itemToReturn = bucket;
    }

    return ResponseEntity.ok(itemToReturn);
}

@PostMapping(value = "/")
public ResponseEntity addToBucketList(@RequestParam(value="name") String name) {
    myBucketList.add(new BucketList(counter.incrementAndGet(), name));
    return ResponseEntity.ok(myBucketList);
}

@PutMapping(value = "/")
public ResponseEntity updateBucketList(@RequestParam(value="name") String name, @RequestParam(value="id") Long id) {
    myBucketList.forEach(bucketList ->  {
        if(bucketList.getId() == id){
            bucketList.setName(name);
        }
    });
    return ResponseEntity.ok(myBucketList);
}

@DeleteMapping(value = "/")
public ResponseEntity removeBucketList(@RequestParam(value="id") Long id) {
    BucketList itemToRemove = null;
    for(BucketList bucket : myBucketList){
        if(bucket.getId() == id)
            itemToRemove = bucket;
    }

    myBucketList.remove(itemToRemove);
    return ResponseEntity.ok(myBucketList);
}
}

As an addendum, although it is not required, you can specify a port for running your apps. If you do not specify a port, it uses port 8080 by default. I have specified my port to be 9009 in the application properties file like so:

server.port=9009

Let us test our apis locally using Postman

To get all items in bucketlist, I am using this url like so:

localhost:9009

You ought to change the port number to what you have specified locally.

You should see a response similar to the one below

To add an item, we specify the name in the url like so:
localhost:9009?name=Visit Big Ben

We have added “Visit Big Ben”

To view a single item in bucket list
localhost:9009?name=Visit Big Ben

localhost:9009/bucket?id=2

To edit an item, we specify the id and new name in the url like so:

localhost:9009?id=2&name=Visit Kensington Palace

We just changed name of the second item in our bucket list from visit big ben to Visit Kensington Palace.

To remove an item, we specify the id

localhost:9009?id=2