I have a graphql implementation, below is my .graphqls file
schema {
query: Query
}
type Product {
id: Int!
name: String!
description: String!
productTypes: [ProductType]!
}
type City {
id: Int!
name: String!
}
type ProductType {
id: Int!
type: String!
product: Int
}
type Query {
products: [Product]!
cities: [City]!
productTypes: [ProductType]!
}
This is my query resolver code
public class Query implements GraphQLQueryResolver {
#Autowired
ProductRespository productRespository;
#Autowired
EntityManager em;
#Autowired
CityRepository cityRepository;
#Autowired
ProductTypeRepository productTypeRepository;
public List<Map<String, Object>> products() {
javax.persistence.Query q = em.createQuery("select new
map(p.name as productName, p.id as productId) from Product p");
List<Map<String, Object>> list = q.getResultList();
return list;
}
public Iterable<City> cities() {
return cityRepository.findAll();
}
}
when I am running the application I am getting below error
Type java.util.Map cannot be
mapped to a GraphQL type! Since GraphQL-Java deals with erased types at
runtime, only non-parameterized classes can represent a GraphQL type.
This allows for reverse-lookup by java class in interfaces and union
types
So how I can handle this kind of return type in Query Section of .graphqls
Thanks in Advance
Related
Using org.springframework.boot:spring-boot-starter-graphql and WebMvc, I would like to handle, in the #Controller, nested fields.
Schema:
type Movie {
name: String
actor: Actor
}
type Actor {
name: String
homeAddress: Address
officeAddress: Address
}
type Address {
street: String
city: String
}
query:
query {
movie(name: "xyz") {
name
actor {
name
homeAddress {
street
city
}
}
}
}
The #Controller handles the first field with:
#QueryMapping
public Movie movie(#Argument name) {...}
2nd with schemaMapping:
#SchemaMapping(type=“Movie”, field=“actor”)
public Actor actor(Movie movie) {...}
But how to handle the third level field (address)?
#SchemaMapping(typeName=“Actor”, field=“homeAddress”)
public Address homeAddress(Actor actor) {...}
this doesn't work
How to implement query filters and sorting using Graphql SPQR?
I'm looking for a solution with Graphql SPQR for schema which looks something like this.
schema {
query: Query
mutation: Mutation
}
enumSortOrder {
ASC
DESC
}
type Article {
id: String
name: String
createdByUserId: String
createdOn: String
lastUpdatedOn: String
}
type Feedback {
id: String
feedbackText: String
articleId: String
createdByUserId: String
createdOn: String
lastUpdatedOn: String
}
type Query {
getAllArticles(pageNumber: Int!, pageSize : Int!, sortOrder: SortOrder!, sortBy: String!): [Article]
getFeedBacksForArticle(articleId: String!): [Feedback]
}
type Mutation {
createArticle(name: String!, createdByUserId: String!): Article
createNewFeedback(feedbackText: String!, articleId: String!, createdByUserId: String!): Feedback
}
GraphQL SPQR relies on a code-first approach. You need to create your java classes and resolver and annotate them properly:
public enum SortOrder {
#GraphQLEnumValue(name = "ASC") ASC,
#GraphQLEnumValue(name = "DESC") DESC
}
public class Article {
//Article implementation here
}
public class Feedback {
//Feedback implementation here
}
public class GraphQLResolver {
#GraphQLQuery(name = "getAllArticles", description = "Search articles")
public List<Article> getAllArticles(
#NotNull #GraphQLArgument(name = "pageNumber") int pageNumber,
#NotNull #GraphQLArgument(name = "pageSize") int pageSize,
#NotNull #GraphQLArgument(name = "sortOrder") SortOrder sortOrder,
#NotNull #GraphQLArgument(name = "sortBy") String sortBy) {
//Query implementation here
}
//implement other queries and mutation
}
Follow the readme at https://github.com/leangen/graphql-spqr to expose your graphql resolver.
I'm making an api for querying nested entity with Spring Data JPA Projection.
My Code
The Entity:
#Entity
class User {
#Id
var userId: String
var name: String
var age: Int
#OneToOne
#JoinColumn(name = "userId")
var address: Address
}
#Entity
class Address {
var userId: String
var street: String
var city: String
var country: String
}
The Repository:
interface UserView {
val name: String
val address: AddressView
interface AddressView {
val city: String
val country: String
}
}
#Repository
interface UserRepository : JPARepository<User, String> {
fun findAll(): List<UserView>
}
Expected Response
{
"name": "example",
"city": "example-city",
"country": "example-country"
}
My code produces
{
"name": "example",
"address": {
"city": "example-city",
"country": "example-country"
}
}
I Tried
I tried another view to flatten object:
interface UserView {
val name: String
val addressCity: String
val addressCountry: String
}
But this case, the variable naming is too complicate.
I want to solve this problem with projection. How can I solve this problem?
In JPA, you can do this using #NamedNativeQuery only:
#NamedNativeQuery(
name = "getUser",
query = "SELECT u.name, a.city, a.country FROM User u and Address a where a.userId = u.id ", resultClass=UserView .class)
#Entity
class User {
...
}
For Reference hibernate-named-query
Try this:
data class UserView(name: String, city: String, country: String)
#Repository
interface UserRepository : JPARepository<User, String> {
#Query(value = "select new your.pkg.UserView(u.name, u.address.city, u.address.country) from User u")
fun findAllFlat(): List<UserView>
}
You can use #Value and combine more fields or even access the fields of objects.
From the spring-data-rest documentation:
You can create a projection that combines the two data fields in the preceding example together, as follows:
#Projection(name = "virtual", types = { Person.class })
public interface VirtualProjection {
#Value("#{target.firstName} #{target.lastName}")
String getFullName();
}
Spring’s #Value annotation lets you plug in a SpEL expression that takes the target object and splices together its firstName and lastName attributes to render a read-only fullName.
Flattening also works for me:
#Value("#{target.document.title}")
String getDocumentTitle();
I want to create a service in order to populate dropdown from database. I tried this:
Merchant Class:
export class Merchant {
constructor(
public id: string,
public name: string,
public state_raw: string,
public users: string,
) {}
}
Merchant Service:
getList(): Observable<Merchant> {
return this.http.get<Merchant>(environment.api.urls.merchants.base, {});
}
Rest Api impl:
#GetMapping
public ResponseEntity<?> get() {
return merchantRepository
.findAll()
.map(mapper::toDTO)
.map(ResponseEntity::ok)
.orElseGet(() -> notFound().build());
}
SQL query:
#Override
public Iterable<Merchants> findAll() {
String hql = "select e from " + Merchants.class.getName() + " e";
TypedQuery<Merchants> query = entityManager.createQuery(hql, Merchants.class);
List<Merchants> merchants = query.getResultList();
return merchants;
}
But I get this error:
The method map(mapper::toDTO) is undefined for the type Iterable<Merchants>
How should I implement properly this mapping for the response?
Seems like you meant to stream the entities.
#GetMapping
public ResponseEntity<?> get() {
return StreamSupport.stream(merchantRepository.findAll().spliterator(), false)
.map(mapper::toDTO)
.map(ResponseEntity::ok)
.findFirst()
.orElseGet(() -> notFound().build());
}
I am new to graphql. I am trying to implement custom scalar type "Email". but am getting below error. Could you please help me?
by: com.coxautodev.graphql.tools.SchemaClassScannerError: Expected a
user-defined GraphQL scalar type with name 'Email' but found none! at
com.coxautodev.graphql.tools.SchemaClassScanner.validateAndCreateResult(SchemaClassScanner.kt:144)
~[graphql-java-tools-4.3.0.jar:na] at
com.coxautodev.graphql.tools.SchemaClassScanner.scanForClasses(SchemaClassScanner.kt:94)
~[graphql-java-tools-4.3.0.jar:na]
Configurations :
scalar Email
type Greeting {
id: ID!
message: String!
email:Email
}
type Query {
getGreeting(id: ID!): Greeting
}
type Mutation {
newGreeting(message: String!): Greeting!
}
Version info:
springBootVersion = '1.5.8.RELEASE'
com.graphql-java:graphql-java:6.0')
com.graphql-java:graphql-java-tools:4.3.0')
com.graphql-java:graphql-java-servlet:4.7.0')
org.springframework.boot:spring-boot-starter-web')
com.graphql-java:graphql-spring-boot-starter:3.10.0')
com.graphql-java:graphiql-spring-boot-starter:3.10.0')
Please help...
Try this:
#Component
public class ScalarEMail extends GraphQLScalarType {
public ScalarEMail() {
super("Email", "Scalar Email", new Coercing() {
#Override
public Object serialize(Object o) throws CoercingSerializeException {
return ((Email) o).getEmail();
}
#Override
public Object parseValue(Object o) throws CoercingParseValueException {
return serialize(o);
}
#Override
public Object parseLiteral(Object o) throws CoercingParseLiteralException {
return Email.valueOf(((StringValue) o).getValue());
}
});
}
}