Graphql Demo

This project is a demo project to explore GraphQL with spring boot and mongodb. REST endpoint is also exposed for available domain entities.

MongoDB Relational Mapping

The recommended relational mapping with spring boot and mongodb is also utilized in this project with the help of @DocumentReference annotation mapping and handling optimized OneToMany type mapping with the help of @ReadOnlyProperty annotation. Here is the code example:

class Comment {
    @Id
    private Long id;
    private String content;
    
    @DocumentReference
    private Post post;
}

class Post {
    @Id
    private Long id;
    private String title;
    
    // @ReadOnlyProperty | Disabling linking from post -> comment 
    // and only enabling one way link from comment -> post
    @ReadOnlyProperty
    // @DocumentReference | 'post' is the name of the java Variable 
    // inside Comment class and #self is post itself
    @DocumentReference(lazy = true, lookup = "{'post' : ?#{#self.id}}")
    private List<Comment> comments;
}

Run the project

Run with Test Container

This project uses testcontainer dependency. So the system should have docker installed and running. Go to the test container enabled main class located in test/java/com/tapusd/graphqldemo/TestGraphqldemoApplication and run the project from that file to run without preparing a local mongodb instance.

Keep in mind that the test container will restart everytime you restart the server. So
better utilize the intellij & spring devtools to restart the service by just re building the project. If you are using intellij idea then press (Ctrl + F9) to rebuild the project to get new changes or search for the rebuild option and click it from the menu.

Run as a normal spring boot project

The project expect a mongodb instance uri to start the project so you need to provide a mongodb connection url before running the application.

1. First export the following variable to the system level

# if username and password is set for the mongodb 
# then use the following connection string pattern
export SPRING_DATA_MONGODB_URI=mongodb://[username:password]@[host[:port]]/[database_name]
# else
export SPRING_DATA_MONGODB_URI=mongodb://host[:port]/[database_name]

2. Then run the project with maven

mvn clean spring-boot:run

Alternatively you can make a handly run script named run.sh like following:

export SPRING_DATA_MONGODB_URI=mongodb://host[:port]/[database_name]
mvn clean spring-boot:run

And then and run the project with it with bash run.sh command.

Test the graphql interactive query console

Go to the following url http://localhost:8080/graphiql to get the default graphiql query console to perform query against the graphql server.

Populating MongoDB with dummy data

The source directory has a bash file with rest call to fill up the test container with dummy data. Run the following bash file with the following command bash dummydata-populate.sh to do so.

Populating With Dummy Graphql

The file dummygraphql-query.graphqls contains the some mutations to add new data through graphql.
Copy the contents of the file and past it to the graphiql console and hit run to add new data with graphql
mutations.

Mongock Dataloader

By default, mongock data loader migration will populate the database with some dummy data that is written in DataLoader.java file.

Don't run the mutations endpoints unless untill you read and perform the Populating MongoDB with dummy data section

The source directory has a bash file with rest call to fill up the test container with dummy data. Run the following bash file with the following command bash dummydata-populate.sh to do so.

References

• https://spring.io/blog/2021/11/29/spring-data-mongodb-relation-modelling
• https://dev.to/tleipzig/using-documentreference-for-relations-in-spring-boot-mongodb-34c6
• https://foojay.io/today/exposing-your-data-using-spring-graphql/
• https://bootify.io/mongodb/document-reference-in-spring-boot-mongodb.html