> For the complete documentation index, see [llms.txt](https://docs.digit.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.digit.org/platform/guides/developer-guide/backend-developer-guide/section-1-create-project/build-the-web-layer.md).

# Build The Web Layer

Implementing the controller layer in Spring

## **Overview**

The web/controller layer handles all the incoming REST requests to a service.

## **Steps**

Follow the steps below to set up the request handler in the controller layer.

1. Make a call to the method in the Service Layer and get the response back from it.
2. Build the responseInfo.
3. Build the final response to be returned to the client.

![Sample request handler in controller layer](https://3868804918-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FegsIWleSdyH9rMLJ8ShI%2Fuploads%2Fgit-blob-975f64015ae73f4ac24375fdc9866ed8ee0aebff%2Fimage.png?alt=media)

The controller class reflects the following content -

{% code lineNumbers="true" %}

```java
package digit.web.controllers;


import digit.service.BirthRegistrationService;
import digit.util.ResponseInfoFactory;
import digit.web.models.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import io.swagger.annotations.ApiParam;
import io.swagger.v3.oas.annotations.Parameter;
import io.swagger.v3.oas.annotations.enums.ParameterIn;
import io.swagger.v3.oas.annotations.media.Schema;
import org.egov.common.contract.response.ResponseInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestMapping;
import java.io.IOException;
import java.util.Collections;
import java.util.List;

import jakarta.validation.Valid;
import jakarta.servlet.http.HttpServletRequest;


@jakarta.annotation.Generated(value = "org.egov.codegen.SpringBootCodegen", date = "2024-03-07T11:10:12.732364039+05:30[Asia/Kolkata]")
@Controller
    @RequestMapping("")
    public class BirthApiController{

    private final ObjectMapper objectMapper;

    private final HttpServletRequest request;

    private BirthRegistrationService birthRegistrationService;

    @Autowired
    private ResponseInfoFactory responseInfoFactory;

    @Autowired
    public BirthApiController(ObjectMapper objectMapper, HttpServletRequest request, BirthRegistrationService birthRegistrationService) {
        this.objectMapper = objectMapper;
        this.request = request;
        this.birthRegistrationService = birthRegistrationService;
    }

    @RequestMapping(value="/registration/v1/_create", method = RequestMethod.POST)
    public ResponseEntity<BirthRegistrationResponse> v1RegistrationCreatePost(@ApiParam(value = "Details for the new Birth Registration Application(s) + RequestInfo meta data." ,required=true )  @Valid @RequestBody BirthRegistrationRequest birthRegistrationRequest) {
        List<BirthRegistrationApplication> applications = birthRegistrationService.registerBtRequest(birthRegistrationRequest);
        ResponseInfo responseInfo = responseInfoFactory.createResponseInfoFromRequestInfo(birthRegistrationRequest.getRequestInfo(), true);
        BirthRegistrationResponse response = BirthRegistrationResponse.builder().birthRegistrationApplications(applications).responseInfo(responseInfo).build();
        return new ResponseEntity<>(response, HttpStatus.OK);
    }

    @RequestMapping(value="/v1/registration/_search", method = RequestMethod.POST)
    public ResponseEntity<BirthRegistrationResponse> v1RegistrationSearchPost(@ApiParam(value = "Details for the new Birth Registration Application(s) + RequestInfo meta data." ,required=true )  @Valid @RequestBody BirthApplicationSearchRequest birthApplicationSearchRequest) {
        List<BirthRegistrationApplication> applications = birthRegistrationService.searchBtApplications(birthApplicationSearchRequest.getRequestInfo(), birthApplicationSearchRequest.getBirthApplicationSearchCriteria());
        ResponseInfo responseInfo = responseInfoFactory.createResponseInfoFromRequestInfo(birthApplicationSearchRequest.getRequestInfo(), true);
        BirthRegistrationResponse response = BirthRegistrationResponse.builder().birthRegistrationApplications(applications).responseInfo(responseInfo).build();
        return new ResponseEntity<>(response,HttpStatus.OK);
    }

    @RequestMapping(value="/registration/v1/_update", method = RequestMethod.POST)
    public ResponseEntity<BirthRegistrationResponse> v1RegistrationUpdatePost(@ApiParam(value = "Details for the new (s) + RequestInfo meta data." ,required=true )  @Valid @RequestBody BirthRegistrationRequest birthRegistrationRequest) {
        BirthRegistrationApplication application = birthRegistrationService.updateBtApplication(birthRegistrationRequest);

        ResponseInfo responseInfo = responseInfoFactory.createResponseInfoFromRequestInfo(birthRegistrationRequest.getRequestInfo(), true);
        BirthRegistrationResponse response = BirthRegistrationResponse.builder().birthRegistrationApplications(Collections.singletonList(application)).responseInfo(responseInfo).build();
        return new ResponseEntity<>(response, HttpStatus.OK);
    }


        }

```

{% endcode %}

{% hint style="info" %}
**NOTE:** At this point, your IDE must be showing a lot of errors, but do not worry, we will add all dependent layers as we progress through this guide, and the errors will go away.
{% endhint %}

The web layer is now set up.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.digit.org/platform/guides/developer-guide/backend-developer-guide/section-1-create-project/build-the-web-layer.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.