# Generating Jakarta REST resources with Panache

A lot of web applications are monotonous CRUD applications with REST APIs that are tedious to write. To streamline this task, REST Data with Panache extension can generate the basic CRUD endpoints for your entities and repositories.

Currently, this extension supports Hibernate ORM and MongoDB with Panache and can generate CRUD resources that work with `application/json` and `application/hal+json` content and generates REST Resources backed by Quarkus REST.

## Setting up REST Data with Panache

Quarkus provides the following extensions to set up REST Data with Panache. Please, check out the next compatibility table to use the right one according to the technology you are using:

Table 1. Compatibility Table
Extension | Status | Hibernate
--- | --- | ---
quarkus-hibernate-orm-rest-data-panache | `Stable` | `ORM`
quarkus-hibernate-reactive-rest-data-panache | `Experimental` | `Reactive`
quarkus-mongodb-rest-data-panache | `Experimental` | `ORM`

### Hibernate ORM

- Add the required dependencies to your build file

  - Hibernate ORM REST Data with Panache extension (`quarkus-hibernate-orm-rest-data-panache`)

  - A JDBC driver extension (`quarkus-jdbc-postgresql`, `quarkus-jdbc-h2`, `quarkus-jdbc-mariadb`, …​)

  - One of the REST JSON serialization extensions (such as `quarkus-rest-jackson`)

pom.xml

    <dependency>
        <groupId>io.quarkus</groupId>
        <artifactId>quarkus-hibernate-orm-rest-data-panache</artifactId>
    </dependency>
    <dependency>
        <groupId>io.quarkus</groupId>
        <artifactId>quarkus-jdbc-postgresql</artifactId>
    </dependency>

    <dependency>
        <groupId>io.quarkus</groupId>
        <artifactId>quarkus-rest-jackson</artifactId>
    </dependency>
    -->

build.gradle

    implementation("io.quarkus:quarkus-hibernate-orm-rest-data-panache")
    implementation("io.quarkus:quarkus-jdbc-postgresql")

    implementation("io.quarkus:quarkus-rest-jackson")

- Implement the Panache entities and/or repositories as explained in the Hibernate ORM with Panache guide.

- Define the interfaces for generation as explained in the Generating resources section.

To see the Hibernate ORM REST Data with Panache in action, you can check out the hibernate-orm-rest-data-panache-quickstart quickstart.

### Hibernate Reactive

- Add the required dependencies to your `pom.xml`

  - Hibernate Reactive REST Data with Panache extension (`quarkus-hibernate-reactive-rest-data-panache`)

  - A Vert.x reactive database driver extension (`quarkus-reactive-pg-client`, `quarkus-reactive-mysql-client`, …​)

  - One of the Quarkus REST serialization extensions (`quarkus-rest-jackson`, `quarkus-rest-jsonb`, …​)

    <dependencies>
        <dependency>
            <groupId>io.quarkus</groupId>
            <artifactId>quarkus-hibernate-reactive-rest-data-panache</artifactId>
        </dependency>
        <dependency>
            <groupId>io.quarkus</groupId>
            <artifactId>quarkus-reactive-pg-client</artifactId>
        </dependency>
       <!-- Use this if you are using REST Jackson for serialization -->
        <dependency>
            <groupId>io.quarkus</groupId>
            <artifactId>quarkus-rest-jackson</artifactId>
        </dependency>
    </dependencies>

- Implement the Panache entities and/or repositories as explained in the Hibernate Reactive with Panache guide.

- Define the interfaces for generation as explained in the resource generation section.

### MongoDB

- Add the required dependencies to your build file

  - MongoDB REST Data with Panache extension (`quarkus-mongodb-rest-data-panache`)

  - One of the RESTEasy JSON serialization extensions (`quarkus-rest-jackson` or `quarkus-rest-jsonb`)

pom.xml

    <dependency>
        <groupId>io.quarkus</groupId>
        <artifactId>quarkus-mongodb-rest-data-panache</artifactId>
    </dependency>

    <!-- Use this if you are using Quarkus REST -->
    <dependency>
        <groupId>io.quarkus</groupId>
        <artifactId>quarkus-rest-jackson</artifactId>
    </dependency>

build.gradle

    implementation("io.quarkus:quarkus-mongodb-rest-data-panache")

    // Use this if you are using Quarkus REST
    implementation("io.quarkus:quarkus-rest-jackson")

- Implement the Panache entities and/or repositories as explained in the MongoDB with Panache guide.

- Define the interfaces for generation as explained in the resource generation section.

## Generating resources

REST Data with Panache generates Jakarta REST resources based on the interfaces available in your application. For each entity and repository that you want to generate, provide a resource interface. Do not implement these interfaces and don’t provide custom methods because they will be ignored. You can, however, override the methods from the extended interface in order to customize them (see the section at the end).

### PanacheEntityResource

If your application has an entity (e.g. `Person`) that extends either `PanacheEntity` or `PanacheEntityBase` class, you could instruct REST Data with Panache to generate its Jakarta REST resource with the following interface:

    public interface PeopleResource extends PanacheEntityResource<Person, Long> {
    }

### PanacheRepositoryResource

If your application has a simple entity (e.g. `Person`) and a repository (e.g. `PersonRepository`) that implements either `PanacheRepository` or `PanacheRepositoryBase` interface, you could instruct REST Data with Panache to generate its Jakarta REST resource with the following interface:

    public interface PeopleResource extends PanacheRepositoryResource<PersonRepository, Person, Long> {
    }

### PanacheMongoEntityResource

If your application has an entity (e.g. `Person`) that extends either `PanacheMongoEntity` or `PanacheMongoEntityBase` class, you could instruct REST Data with Panache to generate its Jakarta REST resource with the following interface:

    public interface PeopleResource extends PanacheMongoEntityResource<Person, Long> {
    }

### PanacheMongoRepositoryResource

If your application has a simple entity (e.g. `Person`) and a repository (e.g. `PersonRepository`) that implements either `PanacheMongoRepository` or `PanacheMongoRepositoryBase` interface, you could instruct REST Data with Panache to generate its Jakarta REST resource with the following interface:

    public interface PeopleResource extends PanacheMongoRepositoryResource<PersonRepository, Person, Long> {
    }

### The generated resource

The generated resources will be functionally equivalent for both entities and repositories. The only difference being the particular data access pattern and data storage in use.

If you have defined one of the `PeopleResource` interfaces mentioned above, this extension will generate its implementation using a particular data access strategy. The implemented class then will be used by a generated Jakarta REST resource, which will look like this:

    public class PeopleResourceJaxRs { // The actual class name is going to be unique
        @Inject
        PeopleResource resource;

        @GET
        @Path("{id}")
        @Produces("application/json")
        public RestResponse<Person> get(@PathParam("id") Long id){
            Person person = resource.get(id);
            if (person == null) {
                return ResponseBuilder.create(404).build();
            } else {
                return ResponseBuilder.ok(person).build();
            }
        }

        @GET
        @Produces("application/json")
        public RestResponse<Person> list(@QueryParam("sort") List<String> sortQuery,
                @QueryParam("page") @DefaultValue("0") int pageIndex,
                @QueryParam("size") @DefaultValue("20") int pageSize) {
            Page page = Page.of(pageIndex, pageSize);
            Sort sort = getSortFromQuery(sortQuery);
            List<Person> people = resource.list(page, sort);
            // ... build a response with page links and return a 200 response with a list
        }

        @GET
        @Path("/count")
        public RestResponse<Long> count() {
            return ResponseBuilder.ok(resource.count()).build();
        }

        @Transactional
        @POST
        @Consumes("application/json")
        @Produces("application/json")
        public RestResponse<Person> add(Person personToSave) {
            Person person = resource.add(personToSave);
            // ... build a new location URL and return 201 response with an entity
        }

        @Transactional
        @PUT
        @Path("{id}")
        @Consumes("application/json")
        @Produces("application/json")
        public RestResponse<Person> update(@PathParam("id") Long id, Person personToSave) {
            if (resource.get(id) == null) {
                Person person = resource.update(id, personToSave);
                return ResponseBuilder.create(204).build();
            }
            Person person = resource.update(id, personToSave);
            // ... build a new location URL and return 201 response with an entity
        }

        @Transactional
        @DELETE
        @Path("{id}")
        public RestResponse<Person> delete(@PathParam("id") Long id) {
            return !resource.delete(id) ? ResponseBuilder.create(404).build() : ResponseBuilder.create(204).build();
        }
    }

## Resource customisation

REST Data with Panache provides a `@ResourceProperties` and `@MethodProperties` annotations that can be used to customize certain features of the resource.

It can be used in your resource interface:

    @ResourceProperties(hal = true, path = "my-people")
    public interface PeopleResource extends PanacheEntityResource<Person, Long> {
        @MethodProperties(path = "all")
        List<Person> list(Page page, Sort sort);

        @MethodProperties(exposed = false)
        boolean delete(Long id);
    }

### Available options

`@ResourceProperties`

- `exposed` - whether resource could be exposed. A global resource property that can be overridden for each method. Default is `true`.

- `path` - resource base path. Default path is a hyphenated lowercase resource name without a suffix of `resource` or `controller`.

- `rolesAllowed` - List of the security roles permitted to access the resources. It needs a Quarkus Security extension to be present, otherwise it will be ignored. Default is empty.

- `paged` - whether collection responses should be paged or not. First, last, previous and next page URIs are included in the response headers if they exist. Request page index and size are taken from the `page` and `size` query parameters that default to `0` and `20` respectively. Default is `true`.

- `hal` - in addition to the standard `application/json` responses, generates additional methods that can return `application/hal+json` responses if requested via an `Accept` header. Default is `false`.

- `halCollectionName` - name that should be used when generating a hal collection response. Default name is a hyphenated lowercase resource name without a suffix of `resource` or `controller`.

`@MethodProperties`

- `exposed` - does not expose a particular HTTP verb when set to `false`. Default is `true`.

- `path` - operation path (this is appended to the resource base path). Default is an empty string.

- `rolesAllowed` - List of the security roles permitted to access this operation. It needs a Quarkus Security extension to be present, otherwise it will be ignored. Default is empty.

## Adding additional methods to the generated resource

You can add additional methods to the generated resources by the REST Data with Panache extension by adding these methods to the resource interface, for example:

    @ResourceProperties
    public interface PeopleResource extends PanacheEntityResource<Person, Long> {
        @GET
        @Path("/name/{name}")
        @Produces("application/json")
        default List<Person> findByName(@PathParam("name") String name) {
            return Person.find("name = :name", Collections.singletonMap("name", name)).list();
        }
    }

And this method will be exposed along with the generated methods using `http://localhost:8080/people/name/Johan`.

## Securing endpoints

REST Data with Panache will use the Security annotations within the package `jakarta.annotation.security` that are defined on your resource interfaces:

    import jakarta.annotation.security.DenyAll;
    import jakarta.annotation.security.RolesAllowed;

    @DenyAll
    @ResourceProperties
    public interface PeopleResource extends PanacheEntityResource<Person, Long> {
        @RolesAllowed("superuser")
        boolean delete(Long id);
    }

Additionally, if you are only interested in specifying the roles that are allowed to use the resources, the `@ResourceProperties` and `@MethodProperties` annotations have the field `rolesAllowed` to list the security roles permitted to access the resource or operation.

### Using @Authenticated

Additionally, REST Data with Panache can be used in conjunction with `io.quarkus.security.Authenticated`, by either:

- Setting `@ResourceProperties(authenticated=true)` which results in all methods of the resource requiring authentication

- The same result can also be achieved by adding the `@Authenticated` annotation on the interface instead of using the `authenticated` property

- Finally, the `@Authenticated` annotation can be used on specific methods, meaning that only those will require an authenticated user. An example might look like so:

    @ResourceProperties
    public interface PeopleResource extends PanacheEntityResource<Person, Long> {
        @Authenticated
        boolean delete(Long id);
    }

## Query parameters to list entities

REST Data with Panache supports the following query parameters to get the list of entities:

- `page` - a page number which should be returned by a list operation. It applies to the paged resources only and is a number starting with 0. Default is 0.

- `size` - a page size which should be returned by a list operation. It applies to the paged resources only and is a number starting with 1. Default is 20.

- `sort` - a comma separated list of fields which should be used for sorting a result of a list operation. Fields are sorted in the ascending order unless they’re prefixed with a `-`. E.g. `?sort=name,-age` will sort the result by the name ascending by the age descending.

- `namedQuery` - a named query that should be configured at entity level using the annotation `@NamedQuery`.

For example, if you want to get two `People` entities in the first page, you should call `http://localhost:8080/people?page=0&size=2`, and the response should look like:

    [
      {
        "id": 1,
        "name": "John Johnson",
        "birth": "1988-01-10"
      },
      {
        "id": 2,
        "name": "Peter Peterson",
        "birth": "1986-11-20"
      }
    ]

Additionally, you can also filter by the entity fields by adding a query param with the name of the field and the value, for example, calling `http://localhost:8080/people?name=Peter Peterson` would return:

    [
      {
        "id": 2,
        "name": "Peter Peterson",
        "birth": "1986-11-20"
      }
    ]

| Filtering by fields is only supported for String, Boolean, Character, Double, Float, Integer, Long, Short, Byte and the primitive types.

## Complex filtering to list entities using @NamedQuery

You can specify a named query to filter when listing the entities. For example, having the following named query in your entity:

    @Entity
    @NamedQuery(name = "Person.containsInName", query = "from Person where name like CONCAT('%', CONCAT(:name, '%'))")
    public class Person extends PanacheEntity {
      String name;
    }

In this example, we have added a named query to list all the persons that contains some text in the `name` field.

Next, we can set a query param `namedQuery` when listing the entities using the generated resource with the name of the named query that we want to use, for example, calling `http://localhost:8080/people?namedQuery=Person.containsInName&name=ter` would return all the persons which name contains the text "ter".

For more information about how named queries work, go to the Hibernate ORM guide or to the Hibernate Reactive guide.

## Resource Method Before/After Listeners

REST Data with Panache supports the subscription to the following resource method hooks:

- Before/After add resource

- Before/After update resource

- Before/After delete resource

To register your resource method listener, you need to provide a bean that implements the interface `RestDataResourceMethodListener`, for example:

    @ApplicationScoped
    public class PeopleRestDataResourceMethodListener implements RestDataResourceMethodListener<Person> {
        @Override
        public void onBeforeAdd(Person person) {
            System.out.println("Before Save Person: " + person.name);
        }
    }

## Response body examples

As mentioned above REST Data with Panache supports the `application/json` and `application/hal+json` response content types. Here are a couple of examples of how a response body would look like for the `get` and `list` operations assuming there are five `Person` records in a database.

### GET /people/1

`Accept: application/json`

    {
      "id": 1,
      "name": "John Johnson",
      "birth": "1988-01-10"
    }

`Accept: application/hal+json`

    {
      "id": 1,
      "name": "John Johnson",
      "birth": "1988-01-10",
      "_links": {
        "self": {
          "href": "http://example.com/people/1"
        },
        "remove": {
          "href": "http://example.com/people/1"
        },
        "update": {
          "href": "http://example.com/people/1"
        },
        "add": {
          "href": "http://example.com/people"
        },
        "list": {
          "href": "http://example.com/people"
        }
      }
    }

### GET /people?page=0&size=2

`Accept: application/json`

    [
      {
        "id": 1,
        "name": "John Johnson",
        "birth": "1988-01-10"
      },
      {
        "id": 2,
        "name": "Peter Peterson",
        "birth": "1986-11-20"
      }
    ]

`Accept: application/hal+json`

    {
      "_embedded": [
        {
          "id": 1,
          "name": "John Johnson",
          "birth": "1988-01-10",
          "_links": {
            "self": {
              "href": "http://example.com/people/1"
            },
            "remove": {
              "href": "http://example.com/people/1"
            },
            "update": {
              "href": "http://example.com/people/1"
            },
            "add": {
              "href": "http://example.com/people"
            },
            "list": {
              "href": "http://example.com/people"
            }
          }
        },
        {
          "id": 2,
          "name": "Peter Peterson",
          "birth": "1986-11-20",
          "_links": {
            "self": {
              "href": "http://example.com/people/2"
            },
            "remove": {
              "href": "http://example.com/people/2"
            },
            "update": {
              "href": "http://example.com/people/2"
            },
            "add": {
              "href": "http://example.com/people"
            },
            "list": {
              "href": "http://example.com/people"
            }
          }
        }
      ],
      "_links": {
        "add": {
          "href": "http://example.com/people"
        },
        "list": {
          "href": "http://example.com/people"
        },
        "first": {
          "href": "http://example.com/people?page=0&size=2"
        },
        "last": {
          "href": "http://example.com/people?page=2&size=2"
        },
        "next": {
          "href": "http://example.com/people?page=1&size=2"
        }
      }
    }

Both responses would also contain these headers:

- Link: < http://example.com/people?page=0&size=2 >; rel="first"

- Link: < http://example.com/people?page=2&size=2 >; rel="last"

- Link: < http://example.com/people?page=1&size=2 >; rel="next"

A `previous` link header (and hal link) would not be included, because the previous page does not exist.

## Include/Exclude Jakarta REST classes

### Using Build time conditions

Quarkus enables the inclusion or exclusion of Jakarta REST Resources, Providers and Features directly thanks to build time conditions in the same that it does for CDI beans. Thus, the REST Data with Panache interfaces can be annotated with profile conditions (`@io.quarkus.arc.profile.IfBuildProfile` or `@io.quarkus.arc.profile.UnlessBuildProfile`) and/or with property conditions (`io.quarkus.arc.properties.IfBuildProperty` or `io.quarkus.arc.properties.UnlessBuildProperty`) to indicate to Quarkus at build time under which conditions the generated Jakarta REST classes should be included.

In the following example, Quarkus will include the generated resource from the `PeopleResource` interface if and only if the build profile `app1` has been enabled.

    @IfBuildProfile("app1")
    public interface PeopleResource extends PanacheEntityResource<Person, Long> {
    }

### Using a runtime property

| This option is only available when using the Quarkus REST Quarkus extension.

Quarkus can also conditionally disable the generated Jakarta REST Resources based on the value of runtime properties using the `@io.quarkus.resteasy.reactive.server.EndpointDisabled` annotation.

In the following example, Quarkus will exclude the generated resource from the `PeopleResource` interface at runtime if the application has `some.property` configured to `"disable"`.

    @EndpointDisabled(name = "some.property", stringValue = "disable")
    public interface PeopleResource extends PanacheEntityResource<Person, Long> {
    }