1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
// 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 (
"context"
"encoding/json"
"net/http"
"strconv"
"sync"
"time"
"github.com/ethereum/go-ethereum/eth/filters"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/rpc"
"github.com/graph-gophers/graphql-go"
gqlErrors "github.com/graph-gophers/graphql-go/errors"
)
type handler struct {
Schema *graphql.Schema
}
func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
var params struct {
Query string `json:"query"`
OperationName string `json:"operationName"`
Variables map[string]interface{} `json:"variables"`
}
if err := json.NewDecoder(r.Body).Decode(¶ms); err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
var (
ctx = r.Context()
responded sync.Once
timer *time.Timer
cancel context.CancelFunc
)
ctx, cancel = context.WithCancel(ctx)
defer cancel()
if timeout, ok := rpc.ContextRequestTimeout(ctx); ok {
timer = time.AfterFunc(timeout, func() {
responded.Do(func() {
// Cancel request handling.
cancel()
// Create the timeout response.
response := &graphql.Response{
Errors: []*gqlErrors.QueryError{{Message: "request timed out"}},
}
responseJSON, err := json.Marshal(response)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
// Setting this disables gzip compression in package node.
w.Header().Set("transfer-encoding", "identity")
// Flush the response. Since we are writing close to the response timeout,
// chunked transfer encoding must be disabled by setting content-length.
w.Header().Set("content-type", "application/json")
w.Header().Set("content-length", strconv.Itoa(len(responseJSON)))
w.Write(responseJSON)
if flush, ok := w.(http.Flusher); ok {
flush.Flush()
}
})
})
}
response := h.Schema.Exec(ctx, params.Query, params.OperationName, params.Variables)
timer.Stop()
responded.Do(func() {
responseJSON, err := json.Marshal(response)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if len(response.Errors) > 0 {
w.WriteHeader(http.StatusBadRequest)
}
w.Header().Set("Content-Type", "application/json")
w.Write(responseJSON)
})
}
// New constructs a new GraphQL service instance.
func New(stack *node.Node, backend ethapi.Backend, filterSystem *filters.FilterSystem, cors, vhosts []string) error {
_, err := newHandler(stack, backend, filterSystem, cors, vhosts)
return err
}
// newHandler returns a new `http.Handler` that will answer GraphQL queries.
// It additionally exports an interactive query browser on the / endpoint.
func newHandler(stack *node.Node, backend ethapi.Backend, filterSystem *filters.FilterSystem, cors, vhosts []string) (*handler, error) {
q := Resolver{backend, filterSystem}
s, err := graphql.ParseSchema(schema, &q)
if err != nil {
return nil, err
}
h := handler{Schema: s}
handler := node.NewHTTPHandlerStack(h, cors, vhosts, nil)
stack.RegisterHandler("GraphQL UI", "/graphql/ui", GraphiQL{})
stack.RegisterHandler("GraphQL", "/graphql", handler)
stack.RegisterHandler("GraphQL", "/graphql/", handler)
return &h, nil
}