Can't get current ServerWebExchange object using Mono.subscriberContext in webflux.
jaggerwang opened this issue · 1 comments
jaggerwang commented
I'm using graphql in spring cloud gateway, so it is a webflux environment. I've already successfully run a graphql endpoint, the data fetchers need to get data from backend services using webclient, so I need to pass through the Authorization header. I wrote a webclient filter to do this automatically. The full source code can be found at Spring Cloud in Practice.
package net.jaggerwang.scip.common.api.filter;
import org.springframework.web.reactive.function.client.ClientRequest;
import org.springframework.web.reactive.function.client.ClientResponse;
import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
import org.springframework.web.reactive.function.client.ExchangeFunction;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
import java.util.Set;
public class HeadersRelayFilter implements ExchangeFilterFunction {
private Set<String> headers;
public HeadersRelayFilter(Set<String> headers) {
this.headers = headers;
}
@Override
public Mono<ClientResponse> filter(ClientRequest clientRequest,
ExchangeFunction exchangeFunction) {
return Mono.subscriberContext()
.flatMap(ctx -> {
var upstreamExchange = ctx.getOrEmpty(ServerWebExchange.class);
if (upstreamExchange.isPresent()) {
var upstreamHeaders = ((ServerWebExchange) upstreamExchange.get())
.getRequest().getHeaders();
for (var header: headers) {
clientRequest.headers().addAll(header, upstreamHeaders.get(header));
}
}
return exchangeFunction.exchange(clientRequest);
});
}
}But the ctx is always empty. I can get current exchange object in normal webflux handler, so it seems the problem of GraphQLController. I'm using spring boot 2.2.2.RELEASE and spring cloud Hoxton.SR1.
<?xml version="1.0" ?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>net.jaggerwang</groupId>
<artifactId>spring-cloud-in-practice</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<groupId>net.jaggerwang</groupId>
<artifactId>spring-cloud-in-practice-gateway</artifactId>
<version>1.0.0-SNAPSHOT</version>
<name>spring-cloud-in-practice-gateway</name>
<description>Spring cloud in practice gateway</description>
<dependencies>
<dependency>
<groupId>net.jaggerwang</groupId>
<artifactId>spring-cloud-in-practice-common</artifactId>
<version>${scip-common.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-oauth2-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-discovery</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-circuitbreaker-reactor-resilience4j</artifactId>
</dependency>
<dependency>
<groupId>com.graphql-java</groupId>
<artifactId>graphql-java-spring-boot-starter-webflux</artifactId>
<version>${graphql-starter.version}</version>
</dependency>
<dependency>
<groupId>com.graphql-java</groupId>
<artifactId>graphql-java-extended-scalars</artifactId>
<version>${graphql-extended-scalars.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-pool2</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>jaggerwang commented
Figured it out by myself.
First we need customize ExecutionInputCustomizer to pass current ServerWebExchange into the context of GraphQL execution input.
package net.jaggerwang.scip.gateway.adapter.graphql;
import graphql.ExecutionInput;
import graphql.spring.web.reactive.ExecutionInputCustomizer;
import org.springframework.context.annotation.Primary;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
import reactor.util.context.Context;
@Component
@Primary
public class CustomExecutionInputCustomizer implements ExecutionInputCustomizer {
@Override
public Mono<ExecutionInput> customizeExecutionInput(ExecutionInput executionInput,
ServerWebExchange serverWebExchange) {
return Mono.just(executionInput.transform(builder -> builder
.context(Context.of(ServerWebExchange.class, serverWebExchange))));
}
}And pass the context of DataFetchingEnvironment to the mono returned by DataFetcher.
package net.jaggerwang.scip.gateway.adapter.graphql;
import graphql.schema.DataFetcher;
import org.springframework.stereotype.Component;
@Component
public class QueryDataFetcher extends AbstractDataFetcher {
public DataFetcher userLogged() {
return env -> userAsyncService.logged()
.subscriberContext(ctx -> env.getContext())
.toFuture();
}
public DataFetcher userInfo() {
return env -> {
var id = Long.valueOf((Integer) env.getArgument("id"));
return userAsyncService.info(id)
.subscriberContext(ctx -> env.getContext())
.toFuture();
};
}
}Then you can get ServerWebExchange from the context of Mono using Mono.subscriberContext().