JarCastingElide
Opinionated APIs for web & mobile applications.
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Table of Contents
Background
Elide is a Java library that lets you setup model driven GraphQL or JSON API web service with minimal effort. Elide supports two variants of APIs:
- A CRUD (Create, Read, Update, Delete) API for reading and manipulating models.
- An analytic API for aggregating measures over zero or more model attributes.
Elide supports a number of features:
Security Comes Standard
Control access to fields and entities through a declarative, intuitive permission syntax.
Mobile Friendly APIs
JSON-API & GraphQL lets developers fetch entire object graphs in a single round trip. Only requested elements of the data model are returned. Our opinionated approach for mutations addresses common application scenarios:
- Create a new object and add it to an existing collection in the same operation.
- Create a set of related, composite objects (a subgraph) and connect it to an existing, persisted graph.
- Differentiate between deleting an object vs disassociating an object from a relationship (but not deleting it).
- Change the composition of a relationship to something different.
- Reference a newly created object inside other mutation operations.
Filtering, sorting, pagination, and text search are supported out of the box.
Atomicity For Complex Writes
Elide supports multiple data model mutations in a single request in either JSON-API or GraphQL. Create objects, add them to relationships, modify or delete together in a single atomic request.
Analytic Query Support
Elide supports analytic queries against models crafted with its powerful semantic layer. Elide APIs work natively with Yavin to visualize, explore, and report on your data.
Schema Introspection
Explore, understand, and compose queries against your Elide API through generated Swagger documentation or GraphQL schema.
Customize
Customize the behavior of data model operations with computed attributes, data validation annotations, and request lifecycle hooks.
Storage Agnostic
Elide is agnostic to your particular persistence strategy. Use an ORM or provide your own implementation of a data store.
Documentation
More information about Elide can be found at elide.io.
Install
To try out an Elide example service (with a Postgres database), you can deploy via Heroku.
The code that generates this example can be found here.
Alternatively, use elide-standalone which allows you to quickly setup a local instance of Elide running inside an embedded Jetty application.
Usage
The following examples leverage elide 5 (now in pre-release). For documentation on prior/stable versions, visit here.
For CRUD APIs
The simplest way to use Elide is by leveraging JPA to map your Elide models to persistence:
The models should represent the domain model of your web service:
@Entity
public class Book {
@Id
private Integer id;
private String title;
@ManyToMany(mappedBy = "books")
private Set<Author> authors;
}
Add Elide annotations to both expose your models through the web service and define security policies for access:
@Entity
@Include(rootLevel = true)
@ReadPermission("Everyone")
@CreatePermission("Admin OR Publisher")
@DeletePermission("Noone"
@UpdatePermission("Noone")
public class Book {
@Id
private Integer id;
@UpdatePermission("Admin OR Publisher")
private String title;
@ManyToMany(mappedBy = "books")
private Set<Author> authors;
}
Add Lifecycle hooks to your models to embed custom business logic that execute inline with CRUD operations through the web service:
@Entity
@Include(rootLevel = true)
@ReadPermission("Everyone")
@CreatePermission("Admin OR Publisher")
@DeletePermission("None")
@UpdatePermission("None")
@LifeCycleHookBinding(operation = UPDATE, hook = BookCreationHook.class, phase = PRECOMMIT)
public class Book {
@Id
private Integer id;
@UpdatePermission("Admin OR Publisher")
private String title;
@ManyToMany(mappedBy = "books")
private Set<Author> authors;
}
public class BookCreationHook implements LifeCycleHook<Book> {
@Override
public void execute(LifeCycleHookBinding.Operation operation,
LifeCycleHookBinding.TransactionPhase phase,
Book book,
RequestScope requestScope,
Optional<ChangeSpec> changes) {
//Do something
}
}
Map expressions to security functions or predicates that get pushed to the persistence layer:
@SecurityCheck("Admin")
public static class IsAdminUser extends UserCheck {
@Override
public boolean ok(User user) {
return isUserInRole(user, UserRole.admin);
}
}
To expose and query these models, follow the steps documented in the getting started guide.
For example API calls, look at:
For Analytic APIs
Analytic models including tables, measures, dimensions, and joins can be created with a friendly HJSON configuration language:
{
tables: [
{
name: Orders
table: order_details
measures: [
{
name: orderTotal
type: DECIMAL
definition: 'SUM({{order_total}})'
}
]
dimensions: [
{
name: orderId
type: TEXT
definition: '{{order_id}}'
}
]
}
]
}
More information on configuring or querying analytic models can be found here.
Security
Security is documented in depth here.
Contribute
Please refer to the contributing.md file for information about how to get involved. We welcome issues, questions, and pull requests.
If you are contributing to Elide using an IDE, such as IntelliJ, make sure to install the Lombok plugin.
Discussion is on spectrum or through filing issues.
License
This project is licensed under the terms of the Apache 2.0 open source license. Please refer to LICENSE for the full terms.
Articles
Create a JSON API REST Service With Spring Boot and Elide
Custom Security With a Spring Boot/Elide Json API Server
Logging Into a Spring Boot/Elide JSON API Server
Securing a JSON API REST Service With Spring Boot and Elide
Creating Entities in a Spring Boot/Elide JSON API Server
Updating and Deleting with a Spring Boot/Elide JSON API Server
