SpringCloud-Gateway获取body参数，解决只能获取一次问题，终极解决方案
SpringCloudGateway，获取body的参数，网上的解决方案能试的都试了，踩了很多坑，要么代码是很复杂，要么是参数只能获取一次，要么是get类型的请求有问题了，要么是压根获取不到参数，还有一种问题是post请求下，无参数的接口访问会出问题，会返回空串
以上问题都在这里解决：
Talk is cheap. Show me the code. --Linus Torvalds
参数模型：
/**
* 网关上下文
*/
@Data
public class GatewayContext {
public static final String CACHE_GATEWAY_CONTEXT = "cacheGatewayContext";
/**
* cache headers
*/
private HttpHeaders headers;
/**
* baseHeader
*/
private BaseHeader baseHeader;
/**
* cache json body
*/
private String cacheBody;
/**
* cache formdata
*/
private MultiValueMap<String, String> formData = new LinkedMultiValueMap<>();
/**
* ipAddress
*/
private String ipAddress;
/**
* path
*/
private String path;
}
参数可以根据自己业务需求进行定制
请求参数过滤器：
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.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
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;
/**
* 请求内容存储 处理请求内容 内容放在gatewayContext中
*/
/**
* @author kam
*
*
* 请求内容存储 处理请求内容 内容放在gatewayContext中
*
*/
@Component
@Slf4j
public class RequestCoverFilter implements GlobalFilter, Ordered {
/**
* default HttpMessageReader
*/
private static final List<HttpMessageReader<?>> messageReaders = HandlerStrategies.withDefaults().messageReaders();
/**
* ReadFormData
*
* @param exchange
* @param chain
* @return
*/
private Mono<Void> readFormData(ServerWebExchange exchange, GatewayFilterChain chain,
GatewayContext gatewayContext) {
final ServerHttpRequest request = exchange.getRequest();
HttpHeaders headers = request.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 {
/**
* 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(request) {
/**
* 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
*
* @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.info("[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, and release the buffer
* //TODO when SpringCloudGateway Version Release To G.SR2,this can be update with the new version's feature
* see PR https://github.com/spring-cloud/spring-cloud-gateway/pull/1095
*/
byte[] bytes = new byte[dataBuffer.readableByteCount()];
dataBuffer.read(bytes);
DataBufferUtils.release(dataBuffer);
Flux<DataBuffer> cachedFlux = Flux.defer(() -> {
DataBuffer buffer = exchange.getResponse().bufferFactory().wrap(bytes);
DataBufferUtils.retain(buffer);
return Mono.just(buffer);
});
/**
* 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));
});
}
@Override
public int getOrder() {
return HIGHEST_PRECEDENCE;
}
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
/**
* save request path and serviceId into gateway context
*/
ServerHttpRequest request = exchange.getRequest();
ServerHttpResponse response = exchange.getResponse();
GatewayContext gatewayContext = new GatewayContext();
String path = request.getPath().pathWithinApplication().value();
gatewayContext.setPath(path);
gatewayContext.getFormData().addAll(request.getQueryParams());
gatewayContext.setIpAddress(String.valueOf(request.getRemoteAddress()));
HttpHeaders headers = request.getHeaders();
gatewayContext.setHeaders(headers);
log.debug("HttpMethod:{},Url:{}", request.getMethod(), request.getURI().getRawPath());
/// 注意，因为webflux的响应式编程 不能再采取原先的编码方式 即应该先将gatewayContext放入exchange中，否则其他地方可能取不到
/**
* save gateway context into exchange
*/
exchange.getAttributes().put(GatewayContext.CACHE_GATEWAY_CONTEXT, gatewayContext);
// 处理参数
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);
}
}
// TODO 多版本划区域控制后期实现
log.debug("[GatewayContext]ContentType:{},Gateway context is set with {}", contentType, gatewayContext);
return chain.filter(exchange);
}
}
使用的地方：
// 获取request body
GatewayContext gatewayContext = exchange.getAttribute(GatewayContext.CACHE_GATEWAY_CONTEXT);
总结：
内容参考：
SpringCloud Gateway 记录缓存请求Body和Form表单