Swagger documentation issue when using proto complied Pojo used in rest controller

[dockndev]

Use Case :
We are using gRPC in our microservices setup, where gRPC is utilized for internal communication, while REST APIs are employed for external interactions. Additionally, we are using the same POJOs generated after proto file compilation.

Controller is looking like

@Slf4j
@RestController
@RequestMapping("/test")
public class TestController {
    @Autowired
    private TestService service;

    @GetMapping(produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<String> getTest(@RequestBody String payload) {
        try {
            GetTestRequest.Builder requestBuilder = GetTestRequest.newBuilder();
            JsonFormat.parser().ignoringUnknownFields().merge(payload, requestBuilder);
            GetTestRequest request = requestBuilder.build();
            GetTestResponse response = service.getTest(request);
            return ResponseEntity.ok(JsonFormat.printer().print(response));
        } catch (Exception e) {
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
        }
    }
}

With this code, we are facing an issue in Swagger documentation. As the GetTestRequest is generated from the proto file and is a public static final class type, we cannot use them directly as a request body.

Thanks is advance.

[ejona86]

I don't think we'll have expertise to help you. It sounds like "yes, that doesn't work." But even if there were something to be done about it, this sounds like either a Swagger or Protobuf issue.

[ejona86]

Since you also opened an issue, let's use the issue for follow-ups. (I'm just randomly choosing between the issue and this discussion)

#11025

[panchenko]

This question is not related to gRPC.
In order to simplify the controller code org.springframework.http.converter.protobuf.ProtobufJsonFormatHttpMessageConverter should be used, with spring-boot it's enough to register it as a bean, something like

    @Bean
    ProtobufJsonFormatHttpMessageConverter protobufHttpMessageConverter() {
        return new ProtobufJsonFormatHttpMessageConverter();
    }

[bayramtturgutt]

1. Create a DTO

Create a new DTO class that represents your GetTestRequest:

// src/main/java/com/example/dto/GetTestRequestDTO.java
package com.example.dto;

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;

@ApiModel(description = "DTO for GetTestRequest")
public class GetTestRequestDTO {
    @ApiModelProperty(value = "Description of someField")
    private String someField;
    // Add other fields here

    // Getters and setters
    public String getSomeField() {
        return someField;
    }

    public void setSomeField(String someField) {
        this.someField = someField;
    }

    // Add other getters and setters
}

2. Update Controller to Use DTO

Modify your TestController to use the DTO:

// src/main/java/com/example/controller/TestController.java
package com.example.controller;

import com.example.dto.GetTestRequestDTO;
import com.example.service.TestService;
import com.google.protobuf.util.JsonFormat;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@Slf4j
@RestController
@RequestMapping("/test")
public class TestController {
    @Autowired
    private TestService service;

    @PostMapping(produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<String> getTest(@RequestBody GetTestRequestDTO dto) {
        try {
            GetTestRequest request = GetTestRequest.newBuilder()
                    .setSomeField(dto.getSomeField())
                    // Set other fields
                    .build();
            GetTestResponse response = service.getTest(request);
            return ResponseEntity.ok(JsonFormat.printer().print(response));
        } catch (Exception e) {
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
        }
    }
}

3. Ensure Swagger Configuration

Ensure Swagger is configured correctly in your project. If using Springdoc OpenAPI, ensure your configuration is set up to scan for your controllers and DTOs:

// src/main/java/com/example/config/OpenApiConfig.java
package com.example.config;

import org.springdoc.core.GroupedOpenApi;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class OpenApiConfig {

    @Bean
    public GroupedOpenApi publicApi() {
        return GroupedOpenApi.builder()
                .group("public")
                .pathsToMatch("/**")
                .build();
    }
}