graphqlws

README

Note: We're looking for a new maintainer for graphqlws. Please reach out via jannis@thegraph.com if you're interested.

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graphqlws

Implementation of the GraphQL over WebSocket protocol in Go. Brought to you by Functional Foundry.

API Documentation

Getting started

1. Install dependencies:

   go get github.com/sirupsen/logrus
   go get github.com/x-cray/logrus-prefixed-formatter
   go get github.com/google/uuid
   go get github.com/gorilla/websocket
   go get github.com/graphql-go/graphql
   

2. Clone the repository:

   mkdir -p "$GOPATH/src/github.com/functionalfoundry"
   cd "$GOPATH/src/github.com/functionalfoundry"
   git clone https://github.com/functionalfoundry/graphqlws
   

3. Run the tests:

   cd graphqlws
   go test
   

4. Run the example server:

   go run graphqlws/examples/server
   

Usage

Setup

package main

import (
	"net/http"

	"github.com/functionalfoundry/graphqlws"
	"github.com/graphql-go/graphql"
)

func main() {
	// Create a GraphQL schema
	schema, err := graphql.NewSchema(...)

	// Create a subscription manager
	subscriptionManager := graphqlws.NewSubscriptionManager(&schema)

	// Create a WebSocket/HTTP handler
	graphqlwsHandler := graphqlws.NewHandler(graphqlws.HandlerConfig{
		// Wire up the GraphqL WebSocket handler with the subscription manager
		SubscriptionManager: subscriptionManager,

		// Optional: Add a hook to resolve auth tokens into users that are
		// then stored on the GraphQL WS connections
		Authenticate: func(authToken string) (interface{}, error) {
			// This is just a dumb example
			return "Joe", nil
		},
	})

	// The handler integrates seamlessly with existing HTTP servers
	http.Handle("/subscriptions", graphqlwsHandler)
	http.ListenAndServe(":8080", nil)
}

Working with subscriptions

// This assumes you have access to the above subscription manager
subscriptions := subscriptionManager.Subscriptions()

for conn, _ := range subscriptions {
	// Things you have access to here:
	conn.ID()   // The connection ID
	conn.User() // The user returned from the Authenticate function

	for _, subscription := range subscriptions[conn] {
		// Things you have access to here:
		subscription.ID            // The subscription ID (unique per conn)
		subscription.OperationName // The name of the operation
		subscription.Query         // The subscription query/queries string
		subscription.Variables     // The subscription variables
		subscription.Document      // The GraphQL AST for the subscription
		subscription.Fields        // The names of top-level queries
		subscription.Connection    // The GraphQL WS connection

		// Prepare an execution context for running the query
		ctx := context.Context()

		// Re-execute the subscription query
		params := graphql.Params{
			Schema:         schema, // The GraphQL schema
			RequestString:  subscription.Query,
			VariableValues: subscription.Variables,
			OperationName:  subscription.OperationName,
			Context:        ctx,
		}
		result := graphql.Do(params)

		// Send query results back to the subscriber at any point
		data := graphqlws.DataMessagePayload{
			// Data can be anything (interface{})
			Data:   result.Data,
			// Errors is optional ([]error)
			Errors: graphqlws.ErrorsFromGraphQLErrors(result.Errors),
		}
		subscription.SendData(&data)
	}
}

Logging

graphqlws uses logrus for logging. In the future we might remove those logs entirely to leave logging entirely to developers using graphqlws. Given the current solution, you can control the logging level of graphqlws by setting it through logrus:

import (
  log "github.com/sirupsen/logrus"
)

...

log.SetLevel(log.WarnLevel)

License

Copyright © 2017-2019 Functional Foundry, LLC.

Licensed under the MIT License.

Documentation

Index

• func ErrorsFromGraphQLErrors(errors []gqlerrors.FormattedError) []error
• func NewHandler(config HandlerConfig) http.Handler
• func NewLogger(prefix string) *log.Entry
• type AuthenticateFunc
• type Connection
  • func NewConnection(ws *websocket.Conn, config ConnectionConfig) Connection
• type ConnectionConfig
• type ConnectionEventHandlers
• type DataMessagePayload
• type HandlerConfig
• type InitMessagePayload
• type OperationMessage
  • func (msg OperationMessage) String() string
• type StartMessagePayload
• type Subscription
  • func (s *Subscription) MatchesField(field string) bool
• type SubscriptionManager
  • func NewSubscriptionManager(schema *graphql.Schema) SubscriptionManager
  • func NewSubscriptionManagerWithLogger(schema *graphql.Schema, logger *log.Entry) SubscriptionManager
• type SubscriptionSendDataFunc

Functions

func ErrorsFromGraphQLErrors

func ErrorsFromGraphQLErrors(errors []gqlerrors.FormattedError) []error

ErrorsFromGraphQLErrors convert from GraphQL errors to regular errors.

func NewHandler

func NewHandler(config HandlerConfig) http.Handler

NewHandler creates a WebSocket handler for GraphQL WebSocket connections. This handler takes a SubscriptionManager and adds/removes subscriptions as they are started/stopped by the client.

func NewLogger

func NewLogger(prefix string) *log.Entry

NewLogger returns a beautiful logger that logs messages with a given prefix (typically the name of a system component / subsystem).

Types

type AuthenticateFunc

type AuthenticateFunc func(token string) (interface{}, error)

AuthenticateFunc is a function that resolves an auth token into a user (or returns an error if that isn't possible).

type Connection

type Connection interface {
	// ID returns the unique ID of the connection.
	ID() string

	// User returns the user associated with the connection (or nil).
	User() interface{}

	// SendData sends results of executing an operation (typically a
	// subscription) to the client.
	SendData(string, *DataMessagePayload)

	// SendError sends an error to the client.
	SendError(error)
}

Connection is an interface to represent GraphQL WebSocket connections. Each connection is associated with an ID that is unique to the server.

func NewConnection

func NewConnection(ws *websocket.Conn, config ConnectionConfig) Connection

NewConnection establishes a GraphQL WebSocket connection. It implements the GraphQL WebSocket protocol by managing its internal state and handling the client-server communication.

type ConnectionConfig

type ConnectionConfig struct {
	Authenticate  AuthenticateFunc
	EventHandlers ConnectionEventHandlers
}

ConnectionConfig defines the configuration parameters of a GraphQL WebSocket connection.

type ConnectionEventHandlers

type ConnectionEventHandlers struct {
	// Close is called whenever the connection is closed, regardless of
	// whether this happens because of an error or a deliberate termination
	// by the client.
	Close func(Connection)

	// StartOperation is called whenever the client demands that a GraphQL
	// operation be started (typically a subscription). Event handlers
	// are expected to take the necessary steps to register the operation
	// and send data back to the client with the results eventually.
	StartOperation func(Connection, string, *StartMessagePayload) []error

	// StopOperation is called whenever the client stops a previously
	// started GraphQL operation (typically a subscription). Event handlers
	// are expected to unregister the operation and stop sending result
	// data to the client.
	StopOperation func(Connection, string)
}

ConnectionEventHandlers define the event handlers for a connection. Event handlers allow other system components to react to events such as the connection closing or an operation being started or stopped.

type DataMessagePayload

type DataMessagePayload struct {
	Data   interface{} `json:"data"`
	Errors []error     `json:"errors"`
}

DataMessagePayload defines the result data of an operation.

type HandlerConfig

type HandlerConfig struct {
	SubscriptionManager SubscriptionManager
	Authenticate        AuthenticateFunc
}

HandlerConfig stores the configuration of a GraphQL WebSocket handler.

type InitMessagePayload

type InitMessagePayload struct {
	AuthToken string `json:"authToken"`
}

InitMessagePayload defines the parameters of a connection init message.

type OperationMessage

type OperationMessage struct {
	ID      string      `json:"id"`
	Type    string      `json:"type"`
	Payload interface{} `json:"payload"`
}

OperationMessage represents a GraphQL WebSocket message.

func (OperationMessage) String

func (msg OperationMessage) String() string

type StartMessagePayload

type StartMessagePayload struct {
	Query         string                 `json:"query"`
	Variables     map[string]interface{} `json:"variables"`
	OperationName string                 `json:"operationName"`
}

StartMessagePayload defines the parameters of an operation that a client requests to be started.

type Subscription

type Subscription struct {
	ID            string
	Query         string
	Variables     map[string]interface{}
	OperationName string
	Document      *ast.Document
	Fields        []string
	Connection    Connection
	SendData      SubscriptionSendDataFunc
}

Subscription holds all information about a GraphQL subscription made by a client, including a function to send data back to the client when there are updates to the subscription query result.

func (*Subscription) MatchesField

func (s *Subscription) MatchesField(field string) bool

MatchesField returns true if the subscription is for data that belongs to the given field.

type SubscriptionManager

type SubscriptionManager interface {
	// Subscriptions returns all registered subscriptions, grouped
	// by connection.
	Subscriptions() *sync.Map

	// AddSubscription adds a new subscription to the manager.
	AddSubscription(Connection, *Subscription) []error

	// RemoveSubscription removes a subscription from the manager.
	RemoveSubscription(Connection, *Subscription)

	// RemoveSubscriptions removes all subscriptions of a client connection.
	RemoveSubscriptions(Connection)
}

SubscriptionManager provides a high-level interface to managing and accessing the subscriptions made by GraphQL WS clients.

func NewSubscriptionManager

func NewSubscriptionManager(schema *graphql.Schema) SubscriptionManager

NewSubscriptionManager creates a new subscription manager.

func NewSubscriptionManagerWithLogger

func NewSubscriptionManagerWithLogger(schema *graphql.Schema, logger *log.Entry) SubscriptionManager

type SubscriptionSendDataFunc

type SubscriptionSendDataFunc func(*DataMessagePayload)

SubscriptionSendDataFunc is a function that sends updated data for a specific subscription to the corresponding subscriber.