CustomAwsExtensionsReader.java

import static com.google.common.base.Strings.isNullOrEmpty;

import java.util.ArrayList;
import java.util.List;

import org.springframework.core.MethodParameter;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.method.HandlerMethod;

import com.google.common.base.Optional;

import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiImplicitParams;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import io.swagger.annotations.ApiResponse;
import io.swagger.annotations.ApiResponses;
import springfox.documentation.service.ObjectVendorExtension;
import springfox.documentation.service.StringVendorExtension;
import springfox.documentation.service.VendorExtension;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spi.service.OperationBuilderPlugin;
import springfox.documentation.spi.service.contexts.OperationContext;
import springfox.documentation.swagger.annotations.Annotations;
import springfox.documentation.swagger.common.SwaggerPluginSupport;

@Component
@Order(SwaggerPluginSupport.SWAGGER_PLUGIN_ORDER)
public class CustomAwsExtensionsReader implements OperationBuilderPlugin {

	private static final String AWS_X_AMAZON_APIGATEWAY_INTEGRATION = "x-amazon-apigateway-integration";
	private static final String AWS_X_AMAZON_APIGATEWAY_INTEGRATION_TYPE = "type";
	private static final String AWS_X_AMAZON_APIGATEWAY_INTEGRATION_HTTPMETHOD = "httpMethod";
	private static final String AWS_X_AMAZON_APIGATEWAY_INTEGRATION_URI = "uri";
	private static final String AWS_X_AMAZON_APIGATEWAY_INTEGRATION_REQUEST_PARAMS = "requestParameters";
	private static final String AWS_X_AMAZON_APIGATEWAY_INTEGRATION_REQUEST_RESPONSES = "responses";


	@Override
	public void apply(OperationContext context) {

		HandlerMethod handlerMethod = context.getHandlerMethod();
		Optional<ApiOperation> apiOperationOperational = Annotations
				.findApiOperationAnnotation(handlerMethod.getMethod());
		String awsApiGatewayBaseUri  = "";//Fetch it from DB/Service
		
		if (apiOperationOperational.isPresent()) {
			ApiOperation apiOperation = apiOperationOperational.get();
			ObjectVendorExtension extension = new ObjectVendorExtension(
					ensurePrefixed(AWS_X_AMAZON_APIGATEWAY_INTEGRATION));
			extension.addProperty(new StringVendorExtension(AWS_X_AMAZON_APIGATEWAY_INTEGRATION_TYPE, "http"));
			extension.addProperty(new StringVendorExtension(AWS_X_AMAZON_APIGATEWAY_INTEGRATION_HTTPMETHOD, apiOperation.httpMethod()));
			extension.addProperty(new StringVendorExtension(AWS_X_AMAZON_APIGATEWAY_INTEGRATION_URI, awsApiGatewayBaseUri + getRequestUri(handlerMethod)));

			ObjectVendorExtension requestParameters = new ObjectVendorExtension(AWS_X_AMAZON_APIGATEWAY_INTEGRATION_REQUEST_PARAMS);

			processApiParamAnnotation(requestParameters, handlerMethod);
			processApiImplicitParamsAnnotation(handlerMethod, requestParameters);

			ObjectVendorExtension awsResponses = new ObjectVendorExtension(AWS_X_AMAZON_APIGATEWAY_INTEGRATION_REQUEST_RESPONSES);
			processApiResponsesAnnotation( awsResponses,handlerMethod);

			if (requestParameters != null && requestParameters.getValue() != null
					&& requestParameters.getValue().size() > 0) {
				extension.addProperty(requestParameters);
			}
			if (awsResponses != null && awsResponses.getValue() != null
					&& awsResponses.getValue().size() > 0) {
				extension.addProperty(awsResponses);
			}
			
			List<VendorExtension> extensions = new ArrayList<VendorExtension>();
			extensions.add(extension);
			context.operationBuilder().extensions(extensions);

		}
	}

	private String getRequestUri(HandlerMethod handlerMethod){
		RequestMapping requestMapping = handlerMethod.getMethodAnnotation(RequestMapping.class);
		RequestMapping controllerRequestMapping = handlerMethod.getBeanType().getAnnotation(RequestMapping.class);
		String[] paths = requestMapping.path();
		String[] requestPaths = controllerRequestMapping.value();
		String requestUri = "";
		if (requestPaths != null && requestPaths.length > 0) {
			requestUri = requestPaths[0];
			if (paths != null && paths.length > 0) {
				requestUri = requestUri + paths[0];
			}
		}
		return requestUri;
	}
	private void processApiResponsesAnnotation(ObjectVendorExtension awsResponses,HandlerMethod handlerMethod) {
		Optional<ApiResponses> apiResponsesOptional = Annotations
				.findApiResponsesAnnotations(handlerMethod.getMethod());
		if (apiResponsesOptional.isPresent()) {
			ApiResponses apiResponses = apiResponsesOptional.get();
			ApiResponse[] apiResponseArray = apiResponses.value();
			for (ApiResponse apiResponse : apiResponseArray) {
				ObjectVendorExtension awsResponse = new ObjectVendorExtension(String.valueOf(apiResponse.code()));
				awsResponse
						.addProperty(new StringVendorExtension("statusCode", String.valueOf(apiResponse.code())));
				awsResponses.addProperty(awsResponse);
			}

		}
	}

	private void processApiImplicitParamsAnnotation(HandlerMethod handlerMethod,
			ObjectVendorExtension requestParameters) {
		ApiImplicitParams apiImplicitParams = handlerMethod.getMethodAnnotation(ApiImplicitParams.class);
		if (apiImplicitParams != null) {
			String requestParameterIntegration = "";
			String requestParameterMethod = "";
			for (ApiImplicitParam apiImplicitParam : apiImplicitParams.value()) {
				if (apiImplicitParam.paramType() != null && apiImplicitParam.paramType().equals("path")) {
					requestParameterIntegration = "integration.request.path." + apiImplicitParam.name();
					requestParameterMethod = "method.request.path." + apiImplicitParam.name();
					requestParameters.addProperty(
							new StringVendorExtension(requestParameterIntegration, requestParameterMethod));
				} else if (apiImplicitParam.paramType() != null && apiImplicitParam.paramType().equals("query")) {
					requestParameterIntegration = "integration.request.querystring." + apiImplicitParam.name();
					requestParameterMethod = "method.request.querystring." + apiImplicitParam.name();
					requestParameters.addProperty(
							new StringVendorExtension(requestParameterIntegration, requestParameterMethod));
				}
			}
		}
	}

	private void processApiParamAnnotation(ObjectVendorExtension requestParameters, HandlerMethod handlerMethod) {
		MethodParameter[] methodParameters = handlerMethod.getMethodParameters();
		for (MethodParameter methodParameter : methodParameters) {
			ApiParam apiParam = methodParameter.getParameterAnnotation(ApiParam.class);
			String requestParameterIntegration = "";
			String requestParameterMethod = "";
			if (apiParam != null) {
				PathVariable pathVariable = methodParameter.getParameterAnnotation(PathVariable.class);
				RequestParam requestParam = methodParameter.getParameterAnnotation(RequestParam.class);
				if (pathVariable != null) {
					requestParameterIntegration = "integration.request.path." + apiParam.name();
					requestParameterMethod = "method.request.path." + apiParam.name();
					requestParameters.addProperty(
							new StringVendorExtension(requestParameterIntegration, requestParameterMethod));
				} else if (requestParam != null) {
					requestParameterIntegration = "integration.request.querystring." + apiParam.name();
					requestParameterMethod = "method.request.querystring." + apiParam.name();
					requestParameters.addProperty(
							new StringVendorExtension(requestParameterIntegration, requestParameterMethod));
				}
			}
		}
	}

	private String ensurePrefixed(String name) {
		if (!isNullOrEmpty(name)) {
			if (!name.startsWith("x-")) {
				name = "x-" + name;
			}
		}
		return name;
	}

	@Override
	public boolean supports(DocumentationType delimiter) {
		return SwaggerPluginSupport.pluginDoesApply(delimiter);
	}
}