strapi/docs/3.0.0-beta.x/guides/controllers.md

Controllers

See the controllers' concepts for a simple overview.

Core controllers

When you create a new Content type or a new model. You will see a new empty controller has been created. It is because Strapi builds a generic controller for your models by default and allows you to override and extend it in the generated files.

Extending a Model Controller

Here are the core methods (and their current implementation). You can simply copy and paste this code in your own controller file to customize the methods.

::: warning In the following example we will consider your controller, service and model is named product :::

find

module.exports = {
  /**
   * Retrieve records.
   *
   * @return {Array}
   */

  find(ctx) {
    if (ctx.query._q) {
      return strapi.services.product.search(ctx.query);
    }
    return strapi.services.product.find(ctx.query);
  },
};

findOne

module.exports = {
  /**
   * Retrieve a record.
   *
   * @return {Object}
   */

  findOne(ctx) {
    return strapi.services.product.findOne(ctx.params);
  },
};

count

module.exports = {
  /**
   * Count records.
   *
   * @return {Number}
   */

  count(ctx) {
    if (ctx.query._q) {
      return strapi.services.product.countSearch(ctx.query);
    }
    return strapi.services.product.count(ctx.query);
  },
};

create

module.exports = {
  /**
   * Create a record.
   *
   * @return {Object}
   */

  create(ctx) {
    return strapi.services.product.create(ctx.request.body);
  },
};

update

module.exports = {
  /**
   * Update a record.
   *
   * @return {Object}
   */

  update(ctx) {
    return strapi.services.product.update(ctx.params, ctx.request.body);
  },
};

delete

module.exports = {
  /**
   * delete a record.
   *
   * @return {Object}
   */

  delete(ctx) {
    return strapi.services.product.delete(ctx.params);
  },
};

Custom controllers

You can also create custom controllers to build your own business logic and API endpoints.

How to create a custom controller

There are two ways to create a controller:

• Using the CLI strapi generate:controller product. Read the CLI documentation for more information.
• Manually create a JavaScript file in ./api/**/controllers.

Adding Endpoints

Each controller’s action must be an async function. Every action receives a context (ctx) object as first parameter containing the request context and the response context.

::: note Every action must be referenced by a route. :::

Example

In this example, we are defining a specific route in ./api/hello/config/routes.json that takes Hello.index as handler.

It means that every time a request GET /hello is sent to the server, Strapi will call the index action in the Hello.js controller. Our index action will return Hello World!. You can also return a JSON object.

Path — ./api/hello/config/routes.json.

{
  "routes": [
    {
      "method": "GET",
      "path": "/hello",
      "handler": "Hello.index"
    }
  ]
}

Path — ./api/hello/controllers/Hello.js.

module.exports = {
  // GET /hello
  index: async ctx => {
    ctx.send('Hello World!');
  },
};

::: note A route handler can only access the controllers defined in the ./api/**/controllers folders. :::