plugeth/graphql/service.go

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// Copyright 2019 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package graphql
import (
"fmt"
"net"
"net/http"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rpc"
"github.com/graph-gophers/graphql-go"
"github.com/graph-gophers/graphql-go/relay"
)
// Service encapsulates a GraphQL service.
type Service struct {
endpoint string // The host:port endpoint for this service.
cors []string // Allowed CORS domains
vhosts []string // Recognised vhosts
timeouts rpc.HTTPTimeouts // Timeout settings for HTTP requests.
backend ethapi.Backend // The backend that queries will operate on.
handler http.Handler // The `http.Handler` used to answer queries.
listener net.Listener // The listening socket.
}
// New constructs a new GraphQL service instance.
func New(backend ethapi.Backend, endpoint string, cors, vhosts []string, timeouts rpc.HTTPTimeouts) (*Service, error) {
return &Service{
endpoint: endpoint,
cors: cors,
vhosts: vhosts,
timeouts: timeouts,
backend: backend,
}, nil
}
// Protocols returns the list of protocols exported by this service.
func (s *Service) Protocols() []p2p.Protocol { return nil }
// APIs returns the list of APIs exported by this service.
func (s *Service) APIs() []rpc.API { return nil }
// Start is called after all services have been constructed and the networking
// layer was also initialized to spawn any goroutines required by the service.
func (s *Service) Start(server *p2p.Server) error {
var err error
s.handler, err = newHandler(s.backend)
if err != nil {
return err
}
if s.listener, err = net.Listen("tcp", s.endpoint); err != nil {
return err
}
// create handler stack and wrap the graphql handler
handler := node.NewHTTPHandlerStack(s.handler, s.cors, s.vhosts)
// make sure timeout values are meaningful
node.CheckTimeouts(&s.timeouts)
// create http server
httpSrv := &http.Server{
Handler: handler,
ReadTimeout: s.timeouts.ReadTimeout,
WriteTimeout: s.timeouts.WriteTimeout,
IdleTimeout: s.timeouts.IdleTimeout,
}
go httpSrv.Serve(s.listener)
log.Info("GraphQL endpoint opened", "url", fmt.Sprintf("http://%s", s.endpoint))
return nil
}
// newHandler returns a new `http.Handler` that will answer GraphQL queries.
// It additionally exports an interactive query browser on the / endpoint.
func newHandler(backend ethapi.Backend) (http.Handler, error) {
q := Resolver{backend}
s, err := graphql.ParseSchema(schema, &q)
if err != nil {
return nil, err
}
h := &relay.Handler{Schema: s}
mux := http.NewServeMux()
mux.Handle("/", GraphiQL{})
mux.Handle("/graphql", h)
mux.Handle("/graphql/", h)
return mux, nil
}
// Stop terminates all goroutines belonging to the service, blocking until they
// are all terminated.
func (s *Service) Stop() error {
if s.listener != nil {
s.listener.Close()
s.listener = nil
log.Info("GraphQL endpoint closed", "url", fmt.Sprintf("http://%s", s.endpoint))
}
return nil
}