spring cloud gateway, Is Request size limit filter is available

Question

I am working in a project with spring-cloud-gateway. I see that the Request Size limitation filter is yet not available. But I need to develop it. Any idea , is it coming ? or should I start my own development.

I Know that it is difficult to get any answer, as except the developers there are a few persons who are working on it.

Answer 1

I have created a filter named RequestSizeGatewayFilterFactory, It is working fine for our application as of now. But not sure this can be a part of the spring-cloud-gateway project.

package com.api.gateway.somename.filter;

import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * This filter blocks the request, if the request size is more than
 * the permissible size.The default request size is 5 MB
 *
 * @author Arpan
 */
public class RequestSizeGatewayFilterFactory
        extends AbstractGatewayFilterFactory<RequestSizeGatewayFilterFactory.RequestSizeConfig> {

    private static String PREFIX = "kMGTPE";
    private static String ERROR = "Request size is larger than permissible limit." +
            "Request size is %s where permissible limit is %s";

    public RequestSizeGatewayFilterFactory() {
        super(RequestSizeGatewayFilterFactory.RequestSizeConfig.class);
    }

    @Override
    public GatewayFilter apply(RequestSizeGatewayFilterFactory.RequestSizeConfig requestSizeConfig) {
        requestSizeConfig.validate();
        return (exchange, chain) -> {
            ServerHttpRequest request = exchange.getRequest();
            String contentLength = request.getHeaders().getFirst("content-length");
            if (!StringUtils.isEmpty(contentLength)) {
                Long currentRequestSize = Long.valueOf(contentLength);
                if (currentRequestSize > requestSizeConfig.getMaxSize()) {
                    exchange.getResponse().setStatusCode(HttpStatus.PAYLOAD_TOO_LARGE);
                    exchange.getResponse().getHeaders().add("errorMessage",
                            getErrorMessage(currentRequestSize, requestSizeConfig.getMaxSize()));
                    return exchange.getResponse().setComplete();
                }
            }
            return chain.filter(exchange);
        };
    }

    public static class RequestSizeConfig {

        // 5 MB is the default request size
        private Long maxSize = 5000000L;

        public RequestSizeGatewayFilterFactory.RequestSizeConfig setMaxSize(Long maxSize) {
            this.maxSize = maxSize;
            return this;
        }

        public Long getMaxSize() {
            return maxSize;
        }

        public void validate() {
            Assert.isTrue(this.maxSize != null && this.maxSize > 0,
                    "maxSize must be greater than 0");
            Assert.isInstanceOf(Long.class, maxSize, "maxSize must be a number");
        }
    }

    private static String getErrorMessage(Long currentRequestSize, Long maxSize) {
        return String.format(ERROR,
                getHumanReadableByteCount(currentRequestSize),
                getHumanReadableByteCount(maxSize));
    }

    private static String getHumanReadableByteCount(long bytes) {
        int unit = 1000;
        if (bytes < unit) return bytes + " B";
        int exp = (int) (Math.log(bytes) / Math.log(unit));
        String pre = Character.toString(PREFIX.charAt(exp - 1));
        return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
    }
}

And the configuration for the filter is: When it works as a default filter:

spring:
  application:
    name: somename
  cloud:
    gateway:
      default-filters:
      - Hystrix=default
      - RequestSize=7000000

When needs to be applied in some API

# ===========================================
  - id: request_size_route
    uri: ${test.uri}/upload
    predicates:
    - Path=/upload
    filters:
    - name: RequestSize
      args:
        maxSize: 5000000

Also you need to configure the bean in some component scanable class in your project, which is GatewayAutoConfiguration for the spring-cloud-gateway-core project.

@Bean
public RequestSizeGatewayFilterFactory requestSizeGatewayFilterFactory() {
   return new RequestSizeGatewayFilterFactory();
}