[英]Graphql federation returning null on extended relation
I'm trying to setup a prototype for using graphql across multiple java microservices, which requires me to join multiple graphql schema's into one.我正在尝试设置一个原型,以便在多个 java 微服务中使用 graphql,这需要我将多个 graphql 模式合并为一个。
I'm using 2 java-services and the ApolloServer with ApolloGateway;我正在使用 2 个 java 服务和带有 ApolloGateway 的 ApolloServer; which shows the following schema in the playground:
它在操场上显示了以下架构:
type Client {
id: ID!
name: String
linkeduser: User
}
type Query {
user(id: ID!): User
users: [User]
client(id: ID!): Client
clients: [Client]
}
type User {
id: ID!
name: String
}
When running the simple query:运行简单查询时:
query client {
client(id: 1) {
id
name
linkeduser {
id
name
}
}
}
What I expect this to return is a client with a linkeduser;我希望这会返回一个带有链接用户的客户端; When debugging the client service gets queried, the user service gets queried, yet the response is:
调试时查询客户端服务,查询用户服务,但响应为:
{
"data": {
"client": {
"id": "1",
"name": "Bob",
"linkeduser": null
}
}
}
How do I get a linked user response in my client?如何在我的客户端中获得链接的用户响应?
I've tried returning lists of users, a new client object with a list of linkedusers, a single user.我试过返回用户列表,一个新客户端 object 和一个链接用户列表,一个用户。 The example of https://github.com/apollographql/federation-jvm is the base of this code, though I've yet to see this working.
https://github.com/apollographql/federation-jvm的示例是此代码的基础,尽管我还没有看到它有效。
Code:代码:
Service 1: Client服务一:客户端
@WebServlet(loadOnStartup = 1, urlPatterns = "/graphql")
public class GraphQLService extends GraphQLHttpServlet {
@Override
protected GraphQLConfiguration getConfiguration() {
return GraphQLConfiguration.with(getGraphQLSchema()).build();
}
private static GraphQLSchema getGraphQLSchema() {
InputStream inputStream = client.GraphQLService.class
.getClassLoader().getResourceAsStream("schema.graphqls");
TypeDefinitionRegistry parse = new SchemaParser().parse(inputStream);
RuntimeWiring runtimeWiring = RuntimeWiring.newRuntimeWiring()
.type("Query", builder -> builder.defaultDataFetcher(GraphQLService::getClient))
.build();
return com.apollographql.federation.graphqljava.Federation.transform(parse, runtimeWiring)
.fetchEntities(env -> env.<List<Map<String, Object>>>getArgument(_Entity.argumentName)
.stream()
.map(values -> {
if ("Client".equals(values.get("__typename"))) {
final Object id = values.get("id");
if (id instanceof String) {
return getSingleClient((String) id);
}
}
return null;
})
.collect(Collectors.toList()))
.resolveEntityType(env -> {
final Object src = env.getObject();
if (src instanceof Client) {
return env.getSchema().getObjectType("Client");
}
return null;
}).build();
}
private static Object getClient(DataFetchingEnvironment environment) {
switch (environment.getFieldDefinition().getName()) {
case "client":
return getSingleClient(environment.getArgument("id"));
case "clients":
return getAllClients();
default:
return null;
}
}
//... extra code with simple getters
}
With this schema:使用此架构:
extend type Query {
client(id: ID!): Client
clients: [Client]
}
type Client @key(fields: "id"){
id: ID!
name: String
}
Service 2: User服务 2:用户
@WebServlet(loadOnStartup = 1, urlPatterns = "/graphql")
public class GraphQLService extends GraphQLHttpServlet {
@Override
protected GraphQLConfiguration getConfiguration() {
return GraphQLConfiguration.with(getGraphQLSchema()).build();
}
private static GraphQLSchema getGraphQLSchema() {
InputStream inputStream = user.GraphQLService.class
.getClassLoader().getResourceAsStream("schema.graphqls");
TypeDefinitionRegistry parse = new SchemaParser().parse(inputStream);
RuntimeWiring runtimeWiring = RuntimeWiring.newRuntimeWiring()
.type("Query", builder -> builder.defaultDataFetcher(GraphQLService::getUser))
.build();
return com.apollographql.federation.graphqljava.Federation.transform(parse, runtimeWiring)
.fetchEntities(env -> env.<List<Map<String, Object>>>getArgument(_Entity.argumentName)
.stream()
.map(values -> {
if ("Client".equals(values.get("__typename"))) {
final Object id = values.get("id");
if (id instanceof String) {
return getSingleUser((String) id);
}
}
return null;
})
.collect(Collectors.toList()))
.resolveEntityType(env -> {
final Object src = env.getObject();
if (src instanceof User) {
return env.getSchema().getObjectType("User");
}
return null;
})
.build();
}
private static Object getUser(DataFetchingEnvironment environment) {
switch (environment.getFieldDefinition().getName()) {
case "user":
return getSingleUser(environment.getArgument("id"));
case "users":
return getAllUsers();
default:
return null;
}
}
//... extra code with simple getters
}
With this schema:使用此架构:
type Query @extends{
user (id: ID!): User
users: [User]
}
type User @key(fields: "id") {
id: ID!
name: String
}
type Client @key(fields: "id") @extends{
id: ID! @external
linkeduser : User
}
Version in POM.xml POM.xml 中的版本
<graphql.version>14.0</graphql.version>
<graphql-tools.version>5.2.4</graphql-tools.version>
<graphql-servlet.version>9.0.1</graphql-servlet.version>
<graphql-federation-support.version>0.4.0</graphql-federation-support.version>
In user service, you need to return a pojo of the type client, with a getter for a linkeduser (only the extends fields need to be present) :在用户服务中,您需要返回一个客户端类型的 pojo,以及一个用于链接用户的 getter (只需要存在扩展字段) :
if ("Client".equals(values.get("__typename"))) {
final Object id = values.get("id");
if (id instanceof String) {
return new Client((String) id, getSingleUser((String) id));
}
}
Also the resolveTypeEntity needs to resolve to said client resolveTypeEntity 也需要解析到所述客户端
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