I'm using the Shopify GraphQL to apply a mutation as shown at the bottom.
I want to declare a union type for ShopifyReturnUrl in that mutation for which I have declared this:
import gql from 'graphql-tag';
const shopifyReturnUrl = gql`
union ShopifyReturnUrl = String | URL
`;
However how do I actually get this into my ApolloClient instance which is currently defined like so:
const client = new ApolloClient({
fetchOptions: {
credentials: 'include'
},
});
And for context, I'm using this in my React app like so:
<ApolloProvider client={client}>
<Component {...pageProps} />
</ApolloProvider>
Finally, the mutation where I actually want to use ShopifyReturnUrl
export const SUBSCRIPTION_MODIFY = gql`
mutation($subName: String!, $subPrice: String!, $returnUrl: ShopifyReturnUrl) {
appSubscriptionCreate(
name: $subName
returnUrl: $returnUrl
)
}
`
Any help appreciated.
Thanks.
There's a couple of issues here:
Unions can only be created for object types, not scalars like String.
Type definitions are written on the server, not on the client. As a client, you can't add additional types to the schema that's exposed by the server since the server wouldn't know how to handle those types.
If appSubscriptionCreate takes a returnUrl argument, then the variable you pass to that argument (in this case named $returnUrl) should be of the same type as the argument. If you don't know the type of the argument, check your server's documentation or its GraphiQL interface (if it exposes one). In this specific case, the argument's type is URL!, so that's what your variable should be.
Related
the enum define in OrderTypesEnum.gql
enum OrderTypes {
full_buy
pink_buy
}
import OrderTypesEnum.gql file
import OrderTypes from '#/graphql/OrderTypesEnum.gql'`
but, How to get enum in code ?
I use OrderTypes.full_buy get some error:
self.$apollo.mutate({
mutation: createOrder,
variables: {
subjectId: self.subject.id,
types: OrderTypes.full_buy
}
})
Mutation createOrderMutation error: Invariant Violation: Schema type definitions not allowed in queries. Found: "EnumTypeDefinition"
the inspect of OrderTypes type enum
Prerequisites:
< SomeEnumType > is defined in GraphQL schema (server side, no client configuration needed)
Let's assume we have:
enum SomeEnumType {
OPTION1,
OPTION2,
OPTION3
}
Apollo Client should be configured appropriate way and connected with the GraphQL API.
Then on the client side:
export const OUR_MUTATION = gql`
mutation ourMutation($foo: SomeEnumType){
ourMutation(foo: $foo){
bar
}
}
`
Only by doing this, we can pass an enum as a variable in our query or mutation. For example, with useMutation hook we can now mutate as follows:
const [ourMutation] = useMutation(OUR_MUTATION, {
variables: {
foo: "OPTION2"
},
Since the type definition in gql tag equals the definition in Schema, GraphQL recognizes a variable as an enum type despite giving it as a string.
If we want to pass an enum to variables using typescript enums we can do it as follows:
enum SomeEnumType {
OPTION1 = 0,
OPTION2 = 1,
OPTION3 = 2
}
const [ourMutation] = useMutation(OUR_MUTATION, {
variables: {
foo: SomeEnumType[SomeEnumType.OPTION1]
},
UPDATE: String enums and type generation
Personally, I recommend using string enums if possible. The usage of string enums is more straightforward.
enum SomeEnumType {
OPTION1 = "OPTION1",
OPTION2 = "OPTION2",
OPTION3 = "OPTION3"
}
...
...
variables: {
foo: SomeEnumType.OPTION1
}
For next-level coding, enum types, and all other type definitions can be automatically generated to the frontend with graphql-codegen. I really recommend using this approach, since backend schema updates and additions directly can be directly reflected in your frontend code revealing bugs and helping you code faster and more reliable.
As the error message is suggesting, Schema type definitions not allowed in queries., you can't add an enum definition in an operation document (ExecutableDefinition). You can only have operations (query, mutation, or subscription), or fragments definitions. That is, this is invalid:
enum OrderTypes {
FULL_BUY
PINK_BUY
}
mutation createOrderMutation {
...
}
If you want to define a local enum on your client, you can use the typeDefs property during ApolloClient initialization:
const client = new ApolloClient({
cache,
typeDefs: gql`
enum OrderTypes {
FULL_BUY,
PINK_BUY
}
`,
});
And then you'll be able to see the OrderTypes enum on client-side introspection (i.e Apollo extension).
Pay attention to the client-side highlight: if you try to send a request with this enum for a non-client field (i.e without the #client directive) and it makes through your server, you'll get a schema error saying that the enum type does not exist, unless you define it on your backend.
I am using apollo-cache-inmemory, apollo-client, react-apollo.
My local state contains a users array like so: -
users: [{
__typename: "User",
userId: "hashid1",
...
},
{
__typename: "User",
userId: "hashid2",
...
}]
Now I can obviously run a simple query to retrieve all the users from the local state: -
import gql from "graphql-tag"
export default gql`{users #client {userId}}`
However, what I would like to do is to be able to query the users array directly, passing variables like so: -
const userDetails = await client.query({ query: USER_DETAILS, variables: {id: "hashId1"}})
Is it possible to run this query without using a resolver? I have attempted the following but { data } returns as null: -
export default gql`query user($id: String!) {users(userId: $id) #client {userId}}`
I already use resolvers and can easily write one to take care of this issue but I am wondering if there it is possible to perform this task without one?
It looks like you're looking for some magic ;)
You must write customization code (overwrite default resolver - return all records) to have a customized behavior (return data filtered by your criteria). That should be obviuos.
There is no default/ready/built in searching/filtering syntax in graphql - therefore, there is no default behaviours for them in apollo-client (no matter local/remote server/data). It is up to you to implement what you need.
I've been reading through the graphQL docs and found that they've explained the implementation of the graphql server in 2 ways: one using graphql-yoga which is a fully featured graphql server and another one is using graphql, express-graphql and express. In both cases, we pass the schema and resolver functions while creating the server instance.
But the implementation of resolver function differs. While using graphql-yoga, the resolver function is provided with 4 arguments which contains information about the parent object, arguments received, context, info. whereas in the other case (using graphql), the resolver function only gets the arguments object.
Why is that so ? If I want the info, context objects, how do I get it ?
Using graphql-yoga example: https://graphql.org/learn/execution/
Using graphql example: https://graphql.github.io/graphql-js/mutations-and-input-types/
// Code example using graphql
var express = require('express');
var graphqlHTTP = require('express-graphql');
var { buildSchema } = require('graphql');
var schema = buildSchema(`
type Query {
rollDice(numDice: Int!, numSides: Int): [Int]
}
type Mutation {
addDice(numDice: Int): String
}
`);
var root = {
rollDice({numDice, numSides}) {
return [1, 2];
},
addDice({numDice}) {
console.log("Adding something");
return "Added";
}
};
var app = express();
app.use('/graphql', graphqlHTTP({
schema: schema,
rootValue: root,
graphiql: true,
}));
app.listen(4000);
console.log('Running a GraphQL API server at localhost:4000/graphql');
// Code example using graphql-yoga
let graphqlServer = require("graphql-yoga");
const typeDefs = `
type Query {
rollDice(numDice: Int!, numSides: Int): [Int]
}
type Mutation {
addDice(numDice: Int): String
}
`;
const resolvers = {
Query: {
rollDice(parent, args, context, info) {
console.log(args.numDice);
console.log(args.numSides);
return [1, 2];
}
},
Mutation: {
addDice(parent, args, context, info) {
console.log(args.numDice);
return "Added";
}
}
};
const server = new graphqlServer.GraphQLServer({
typeDefs,
resolvers
});
server.start(() => {
console.log("server started on localhost:4000");
});
Difference between these 2 code snippets:
The resolver functions are present inside appropriate types (i.e. Query, Mutation) in one case. In the other case, they are present inside one root object. This means that I can have methods with same name in Query and Mutation in the first case, whereas in the second case that's not possible since they are keys of a single object and keys should be unique.
Why is this so ? Am I basically missing something ? How can the implementation details differ from one package to another ?
REAL TALK: the GraphQL.js docs are not that great. In my opinion, they never should have used examples with buildSchema in the first place because it understandably leads to this kind of confusion.
GraphQL.js (i.e. the graphql package) is the JavaScript implementation of GraphQL. Building a schema in GraphQL.js is done programmatically, by constructing an instance of the GraphQLSchema class:
const userType = new GraphQLObjectType({
name: 'User',
fields: {
id: {
type: GraphQLID,
},
email: {
type: GraphQLString,
},
},
});
const queryType = new GraphQLObjectType({
name: 'Query',
fields: {
user: {
type: userType,
resolve: () => ({ id: 1, email: 'john.doe#example.com' }),
},
},
});
const schema = new GraphQLSchema({
query: queryType,
})
If we print this schema in Schema Definition Language (SDL), it looks like this:
type Query {
user: User
}
type User {
id: ID
email: String
}
Working with SDL is much easier than having to write out all that code. However, GraphQL.js does not provide a way to build a fully-featured schema from SDL. It does provide a buildSchema function, but this utility constructs a schema without any resolvers (and a number of other features like union/interface type resolution).
The graphql-tools package provides a makeExecutableSchema function that lets you build a schema from SDL and a resolver map object. This is what's used under the hood by apollo-server and graphql-yoga. makeExecutableSchema constructs a schema from SDL using buildSchema and then mutates the resulting object, adding the resolvers in after the fact.
In GraphQL.js, the resolve function (or resolver) for a field takes four parameters -- the parent value, the field's arguments, the context and a GraphQLResolveInfo object. If we're creating a GraphQLObjectType like userType in the above example, this is the optional function we can provide for each of the fields in our object. This is the same function you define when you construct a resolver map to use with graphql-yoga. This is the only implementation of a field resolver.
So what's the deal with buildSchema??
The examples in the docs take advantage of GraphQL's default field resolver:
export const defaultFieldResolver: GraphQLFieldResolver<any, *> = function(
source,
args,
contextValue,
info,
) {
if (typeof source === 'object' || typeof source === 'function') {
const property = source[info.fieldName];
if (typeof property === 'function') {
return source[info.fieldName](args, contextValue, info);
}
return property;
}
};
As you can see, the default resolution logic looks for a property with the same name as the field on the source (parent) value. In our example above, the user resolver returns {id: 1, email: 'john.doe#example.com'} -- this is the value the field resolves to. The field is of the type User. We do not have a resolver defined for our id field, so the default resolver does its thing. The id field resolves to 1 because that's the value of the property named id on the parent object the resolver receives.
However, the parent value can also be a function instead of an object. If it's a function, it gets called first and then the return value is used. What does the function get called with? Well, it can't pass it a parent value (because of infinite recursion), but it can pass it the remaining three parameters (args, context and info). So that's what it does.
Now for the magic trick 🎩🐇
In our example, I can omit the resolver for the user field and pass a function to the root value instead.
const root = {
user: () => ({id: 1, email: 'john.doe#example.com'})
}
The root object is just an optional object that's passed down as the parent value to resolvers at the root level (like your Query or Mutation types). Otherwise, those resolvers would not have a parent value.
Query is an operational root type -- it serves as an "entry point" to the rest of your schema. Any fields on the Query type will be passed the root object as the parent value. If I omit a resolver for the user field, the default resolver will 1) examine the parent object for a property with the same name, 2) find a property and determine that it's a function, 3) call the function, 4) resolve the field to the return value of the function.
TADA!
However, because the function is called by the default resolver, and is not used as a resolver itself, it will only receive the three aforementioned parameters, instead of 4.
This is a neat way to work around not being able to actually provide custom resolvers for a schema, but it's very limited. It only works for root types, so we can't similarly provide fake resolvers for User fields or other types. We can't use interfaces or unions in our schema because we can't provide resolveType functions. And so on...
Hopefully that provides some clarity. And hopefully we can get the docs updated in the near future to avoid all this confusion in the first place.
I want to add introspection from a variable to my app.
I have this kind of introspection:
{"data":{"__schema":{"queryType":{"name":"PageContentQuery"}....
(that im getting from rest request)
I want this variable to be the schema provider, is it possible?
The full variable is here: https://stackblitz.com/edit/ts-graphql-demo-ypgi18?file=index.tsx
const fetcher = (params: any) => {
console.log(params);
return graphql(schema, params.query, params.variables);
}
const defaultQuery = `{
page{id,contents}
}`;
render(
<GraphiQL fetcher={fetcher} schema={schema} defaultQuery={defaultQuery}/>,
document.getElementById('root'),
);
thanks
Given the results of an introspection query, you can build a schema using buildClientSchema:
import { buildClientSchema } from 'graphql'
const schema = buildClientSchema(introspectionResult)
You can then pass that schema as prop to the GraphiQL component:
<GraphiQL fetcher={fetcher} schema={schema} />
Of course, that's generally not necessary -- if the schema is not passed in, then GraphiQL will just make an introspection query for you using the fetcher you provide.
I'm working with GraphQL and having some trouble finding the best way to pipe variables from the query to the result.
I have a schema like so:
type Fragment {
# The id of the fragment
id: String!
# The key of the fragment
key: String!
# The type of component
component_type: String!
# The params used to build the fragment
params: JSON
# Component data
data: JSON
children: [JSON]
items: [JSON]
}
The fragment is meant as a "cms" fragment. I want to pass some query data through to another backend after this resolves.
My query looks like this:
query getFragmentsWithItems($keys: [String!]!
$platform: PlatformType
$version: String
$userInfo: UserInput
$userId: Int
) {
fragmentsWithItems(keys: $keys, platform: $platform, version: $version, userInfo: $userInfo, userId: $userId) {
key
data
children
params
items
}
}
Here's the problem: I have some query data in the data field from the Fragment. That data is not available until that Fragment has resolved. I want to take that data and send it to a different backend. I want to do this with GraphQL, and I was hoping to do something like:
Fragment: () => {
async query(obj, args, context, info, {modles}) => {
const items = await models.getItems(obj.query_string);
}
}
But I need the user_info and user_id that I passed to the original query. Apparently that is only accessible from the info argument which is not meant to be used.
The other path I've taken is to have a manual resolver that does something like so:
const resolveFI = ({ keys, platform, version, userInfo, userId, models }) => {
if (!keys || !keys.length) {
return Promise.resolve(null);
}
return models.release.get({ platform, version }).then(release =>
Promise.all(
keys.map(key =>
models.fragments.get({
key,
platform,
version,
release: release.id
})
)
).then(data => {
const promises = [];
data.rows.forEach(r => {
if (r.data.query_data) {
const d = {
// Can just ignore
filters: r.data.query_data.filters || {},
user_info: userInfo,
user_id: userId
};
promises.push(
new Promise(resolve => {
resolve(
models.itemSearch.get(d).then(i => ({ items: i.items, ...r }))
);
})
);
}
...etc other backends
This works, however a manual promise chain seems to defeat the purpose of using GraphQL.
The last thing I tried was making items a non-scalar type, something like:
type Fragment {
items: ItemSearchResult(user_info: UserInput) etc
But since I can't pipe the actual result from Fragment to the ItemSearchResult that doesn't work.
I realize this is pretty long-winded so I'm open to edits or clarifying.
I'm looking to see if I've missed a better approach or if I should just bag it and have the client apps do the item query after they get the Fragment data back.
It's not that you're not supposed to use info -- it's just a tremendous pain in the butt to use ;) In all seriousness, it's meant to be used for optimization and more advanced use cases, so you shouldn't hesitate to use it if a better solution doesn't present itself. There are libraries out there (like this one) that you can use to parse the object more easily.
That said, there's a couple of ways I imagine you could handle this:
1.) Inside your query resolver(s)
getFragmentsWithItems: async (obj, args, ctx, info) => {
const fragments = await howeverYouDoThat()
const backendCalls = fragments.map(fragment => {
// extract whatever data you need from the fragment
return asyncCallToBackEnd()
})
await backendCalls
return fragments
}
Unfortunately, if you have a lot of different queries returning fragments, you'll end up with redundancy.
2.) Inside the resolver for an existing field (or an additional one) on the Fragment type.
If you go this route, and you need args passed to the query field, you can extract them using the info. Alternatively, you can also mutate the context object inside your query resolver and attach those arguments to it. Then, all resolvers "below" the query resolver (like the resolvers for your Fragment fields) can access those arguments through the context.
3.) Apollo Server lets you define a formatResponse function when configuring its middleware. This essentially provides a hook to do whatever you want with the response before it's returned to the client. You could parse the response inside that function and make the calls to the other backend from there.