github.com/mprishchepo/go-ethereum@v1.9.7-0.20191031044858-21506be82b68/graphql/service.go (about)

     1  // Copyright 2019 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package graphql
    18  
    19  import (
    20  	"fmt"
    21  	"net"
    22  	"net/http"
    23  
    24  	"github.com/Fantom-foundation/go-ethereum/internal/ethapi"
    25  	"github.com/Fantom-foundation/go-ethereum/log"
    26  	"github.com/Fantom-foundation/go-ethereum/p2p"
    27  	"github.com/Fantom-foundation/go-ethereum/rpc"
    28  	"github.com/graph-gophers/graphql-go"
    29  	"github.com/graph-gophers/graphql-go/relay"
    30  )
    31  
    32  // Service encapsulates a GraphQL service.
    33  type Service struct {
    34  	endpoint string           // The host:port endpoint for this service.
    35  	cors     []string         // Allowed CORS domains
    36  	vhosts   []string         // Recognised vhosts
    37  	timeouts rpc.HTTPTimeouts // Timeout settings for HTTP requests.
    38  	backend  ethapi.Backend   // The backend that queries will operate onn.
    39  	handler  http.Handler     // The `http.Handler` used to answer queries.
    40  	listener net.Listener     // The listening socket.
    41  }
    42  
    43  // New constructs a new GraphQL service instance.
    44  func New(backend ethapi.Backend, endpoint string, cors, vhosts []string, timeouts rpc.HTTPTimeouts) (*Service, error) {
    45  	return &Service{
    46  		endpoint: endpoint,
    47  		cors:     cors,
    48  		vhosts:   vhosts,
    49  		timeouts: timeouts,
    50  		backend:  backend,
    51  	}, nil
    52  }
    53  
    54  // Protocols returns the list of protocols exported by this service.
    55  func (s *Service) Protocols() []p2p.Protocol { return nil }
    56  
    57  // APIs returns the list of APIs exported by this service.
    58  func (s *Service) APIs() []rpc.API { return nil }
    59  
    60  // Start is called after all services have been constructed and the networking
    61  // layer was also initialized to spawn any goroutines required by the service.
    62  func (s *Service) Start(server *p2p.Server) error {
    63  	var err error
    64  	s.handler, err = newHandler(s.backend)
    65  	if err != nil {
    66  		return err
    67  	}
    68  	if s.listener, err = net.Listen("tcp", s.endpoint); err != nil {
    69  		return err
    70  	}
    71  	go rpc.NewHTTPServer(s.cors, s.vhosts, s.timeouts, s.handler).Serve(s.listener)
    72  	log.Info("GraphQL endpoint opened", "url", fmt.Sprintf("http://%s", s.endpoint))
    73  	return nil
    74  }
    75  
    76  // newHandler returns a new `http.Handler` that will answer GraphQL queries.
    77  // It additionally exports an interactive query browser on the / endpoint.
    78  func newHandler(backend ethapi.Backend) (http.Handler, error) {
    79  	q := Resolver{backend}
    80  
    81  	s, err := graphql.ParseSchema(schema, &q)
    82  	if err != nil {
    83  		return nil, err
    84  	}
    85  	h := &relay.Handler{Schema: s}
    86  
    87  	mux := http.NewServeMux()
    88  	mux.Handle("/", GraphiQL{})
    89  	mux.Handle("/graphql", h)
    90  	mux.Handle("/graphql/", h)
    91  	return mux, nil
    92  }
    93  
    94  // Stop terminates all goroutines belonging to the service, blocking until they
    95  // are all terminated.
    96  func (s *Service) Stop() error {
    97  	if s.listener != nil {
    98  		s.listener.Close()
    99  		s.listener = nil
   100  		log.Info("GraphQL endpoint closed", "url", fmt.Sprintf("http://%s", s.endpoint))
   101  	}
   102  	return nil
   103  }