SpringCloud Finchley Gateway 缓存请求Body和Form表单的实现

import lombok.Getter;import lombok.Setter;import lombok.ToString;import org.springframework.util.LinkedMultiValueMap;import org.springframework.util.MultiValueMap;@Getter@Setter@ToStringpublic class GatewayContext {  public static final String CACHE_GATEWAY_CONTEXT = "cacheGatewayContext";  /**   * cache json body   */  private String cacheBody;  /**   * cache formdata   */  private MultiValueMap<String, String> formData;  /**   * cache reqeust path   */  private String path;}

import com.choice.cloud.architect.usergate.option.FilterOrderEnum;import com.choice.cloud.architect.usergate.support.GatewayContext;import io.netty.buffer.ByteBufAllocator;import lombok.extern.slf4j.Slf4j;import org.springframework.cloud.gateway.filter.GatewayFilterChain;import org.springframework.cloud.gateway.filter.GlobalFilter;import org.springframework.core.Ordered;import org.springframework.core.io.ByteArrayResource;import org.springframework.core.io.buffer.DataBuffer;import org.springframework.core.io.buffer.DataBufferUtils;import org.springframework.core.io.buffer.NettyDataBufferFactory;import org.springframework.http.HttpHeaders;import org.springframework.http.MediaType;import org.springframework.http.codec.HttpMessageReader;import org.springframework.http.server.reactive.ServerHttpRequest;import org.springframework.http.server.reactive.ServerHttpRequestDecorator;import org.springframework.util.MultiValueMap;import org.springframework.web.reactive.function.server.HandlerStrategies;import org.springframework.web.reactive.function.server.ServerRequest;import org.springframework.web.server.ServerWebExchange;import reactor.core.publisher.Flux;import reactor.core.publisher.Mono;import java.io.UnsupportedEncodingException;import java.net.URLEncoder;import java.nio.charset.Charset;import java.nio.charset.StandardCharsets;import java.util.List;import java.util.Map;@Slf4jpublic class GatewayContextFilter implements GlobalFilter, Ordered {  /**   * default HttpMessageReader   */  private static final List<HttpMessageReader<?>> messageReaders = HandlerStrategies.withDefaults().messageReaders();  @Override  public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {    /**     * save request path and serviceId into gateway context     */    ServerHttpRequest request = exchange.getRequest();    String path = request.getPath().pathWithinApplication().value();    GatewayContext gatewayContext = new GatewayContext();    gatewayContext.getAllRequestData().addAll(request.getQueryParams());    gatewayContext.setPath(path);    /**     * save gateway context into exchange     */    exchange.getAttributes().put(GatewayContext.CACHE_GATEWAY_CONTEXT,gatewayContext);    HttpHeaders headers = request.getHeaders();    MediaType contentType = headers.getContentType();    long contentLength = headers.getContentLength();    if(contentLength>0){      if(MediaType.APPLICATION_JSON.equals(contentType) || MediaType.APPLICATION_JSON_UTF8.equals(contentType)){        return readBody(exchange, chain,gatewayContext);      }      if(MediaType.APPLICATION_FORM_URLENCODED.equals(contentType)){        return readFormData(exchange, chain,gatewayContext);      }    }    log.debug("[GatewayContext]ContentType:{},Gateway context is set with {}",contentType, gatewayContext);    return chain.filter(exchange);  }  @Override  public int getOrder() {    return Integer.MIN_VALUE;  }  /**   * ReadFormData   * @param exchange   * @param chain   * @return   */  private Mono<Void> readFormData(ServerWebExchange exchange,GatewayFilterChain chain,GatewayContext gatewayContext){    HttpHeaders headers = exchange.getRequest().getHeaders();    return exchange.getFormData()        .doOnNext(multiValueMap -> {          gatewayContext.setFormData(multiValueMap);          log.debug("[GatewayContext]Read FormData:{}",multiValueMap);        })        .then(Mono.defer(() -> {          Charset charset = headers.getContentType().getCharset();          charset = charset == null? StandardCharsets.UTF_8:charset;          String charsetName = charset.name();          MultiValueMap<String, String> formData = gatewayContext.getFormData();          /**           * formData is empty just return           */          if(null == formData || formData.isEmpty()){            return chain.filter(exchange);          }          StringBuilder formDataBodyBuilder = new StringBuilder();          String entryKey;          List<String> entryValue;          try {            /**             * remove system param ,repackage form data             */            for (Map.Entry<String, List<String>> entry : formData.entrySet()) {              entryKey = entry.getKey();              entryValue = entry.getValue();              if (entryValue.size() > 1) {                for(String value : entryValue){                  formDataBodyBuilder.append(entryKey).append("=").append(URLEncoder.encode(value, charsetName)).append("&");                }              } else {                formDataBodyBuilder.append(entryKey).append("=").append(URLEncoder.encode(entryValue.get(0), charsetName)).append("&");              }            }          }catch (UnsupportedEncodingException e){            //ignore URLEncode Exception          }          /**           * substring with the last char '&'           */          String formDataBodyString = "";          if(formDataBodyBuilder.length()>0){            formDataBodyString = formDataBodyBuilder.substring(0, formDataBodyBuilder.length() - 1);          }          /**           * get data bytes           */          byte[] bodyBytes = formDataBodyString.getBytes(charset);          int contentLength = bodyBytes.length;          ServerHttpRequestDecorator decorator = new ServerHttpRequestDecorator(              exchange.getRequest()) {            /**             * change content-length             * @return             */            @Override            public HttpHeaders getHeaders() {              HttpHeaders httpHeaders = new HttpHeaders();              httpHeaders.putAll(super.getHeaders());              if (contentLength > 0) {                httpHeaders.setContentLength(contentLength);              } else {                httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");              }              return httpHeaders;            }            /**             * read bytes to Flux<Databuffer>             * @return             */            @Override            public Flux<DataBuffer> getBody() {              return DataBufferUtils.read(new ByteArrayResource(bodyBytes),new NettyDataBufferFactory(ByteBufAllocator.DEFAULT),contentLength);            }          };          ServerWebExchange mutateExchange = exchange.mutate().request(decorator).build();          log.debug("[GatewayContext]Rewrite Form Data :{}",formDataBodyString);          return chain.filter(mutateExchange);        }));  }  /**   * ReadJsonBody   * @param exchange   * @param chain   * @return   */  private Mono<Void> readBody(ServerWebExchange exchange,GatewayFilterChain chain,GatewayContext gatewayContext){    /**     * join the body     */    return DataBufferUtils.join(exchange.getRequest().getBody())        .flatMap(dataBuffer -> {          /**           * read the body Flux<Databuffer>           */          DataBufferUtils.retain(dataBuffer);          Flux<DataBuffer> cachedFlux = Flux.defer(() -> Flux.just(dataBuffer.slice(0, dataBuffer.readableByteCount())));          /**           * repackage ServerHttpRequest           */          ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator(exchange.getRequest()) {            @Override            public Flux<DataBuffer> getBody() {              return cachedFlux;            }          };          /**           * mutate exchage with new ServerHttpRequest           */          ServerWebExchange mutatedExchange = exchange.mutate().request(mutatedRequest).build();          /**           * read body string with default messageReaders           */          return ServerRequest.create(mutatedExchange, messageReaders)              .bodyToMono(String.class)              .doOnNext(objectValue -> {                gatewayContext.setCacheBody(objectValue);                log.debug("[GatewayContext]Read JsonBody:{}",objectValue);              }).then(chain.filter(mutatedExchange));        });  }}