The easiest way of adding live queries to your GraphQL server!
npm install @envelop/live-query@envelop/live-queryThe easiest way of adding live queries to your GraphQL server!
Push new data to your clients automatically once the data selected by a GraphQL operation becomes
stale by annotating your query operation with the @live directive.
``graphql`
query UserProfile @live {
me {
id
login
bio
}
}
The invalidation mechanism is based on GraphQL ID fields and schema coordinates. Once a query
operation has been invalidated, the query is re-executed and the result is pushed to the client.
`bash`
yarn add @envelop/live-query @n1ru4l/in-memory-live-query-store
`ts
import { execute, parse, specifiedRules, subscribe, validate } from 'graphql'
import { envelop, useEngine, useExtendContext, useSchema } from '@envelop/core'
import { useLiveQuery } from '@envelop/live-query'
import { makeExecutableSchema } from '@graphql-tools/schema'
import { InMemoryLiveQueryStore } from '@n1ru4l/in-memory-live-query-store'
const schema = makeExecutableSchema({
typeDefs: [
/ GraphQL /
type Query {
greetings: [String!]
}
,
GraphQLLiveDirectiveSDL
],
resolvers: {
Query: {
greetings: (_, __, context) => context.greetings
}
}
})
const liveQueryStore = new InMemoryLiveQueryStore()
const greetings = ['Hello', 'Hi', 'Ay', 'Sup']
// Shuffle greetings and invalidate queries selecting Query.greetings every second.
setInterval(() => {
const firstElement = greetings.pop()
greetings.unshift(firstElement)
liveQueryStore.invalidate('Query.greetings')
}, 1000)
const getEnveloped = envelop({
plugins: [
useEngine({ parse, validate, specifiedRules, execute, subscribe }),
useSchema(schema),
useLiveQuery({ liveQueryStore }),
useExtendContext(() => ({ greetings }))
/ other plugins /
]
})
`
You need to pass the GraphQLLiveDirective to the list of directives:
`tsx
import { GraphQLSchema } from 'graphql'
import { GraphQLLiveDirective } from '@envelop/live-query'
const schema = new GraphQLSchema({
directives: [...specifiedDirectives, GraphQLLiveDirective]
})
`
By using a patch middleware you can significantly reduce the size of the GraphQL execution result
payload that is sent over the wire from the server to the client. We recommend using the
@n1ru4l/graphql-live-query-patch-jsondiffpatch patch generator.
You can learn more about it here.
`bash`
yarn add @n1ru4l/graphql-live-query-patch-jsondiffpatch
`ts
import { applyLiveQueryJSONDiffPatchGenerator } from '@n1ru4l/graphql-live-query-patch-jsondiffpatch'
import { InMemoryLiveQueryStore } from '@n1ru4l/in-memory-live-query-store'
const liveQueryStore = new InMemoryLiveQueryStore()
const plugin = useLiveQuery({
liveQueryStore,
applyLiveQueryPatchGenerator: applyLiveQueryJSONDiffPatchGenerator
})
`
This plugin requires you to use a graphql transports that supports usage of the @defer and@stream directives, as it is built upon the same concepts (return an AsyncIterable fromexecute).
The following transports have been successfully tested:
| Package | Transport | Version | Downloads |
| -------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| @n1ru4l/socket-io-graphql-server | GraphQL over Socket.io (WebSocket/HTTP Long Polling) |  |  |
| graphql-helix | GraphQL over HTTP (IncrementalDelivery/SSE) |  |  |
| graphql-ws | GraphQL over WebSocket (WebSocket) |  |  |
| graphql-sse` | GraphQL over Server-Sent Events (SSE) |  |  |
For more details check out the live query repository
or the
introduction blog post.