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 (
"encoding/json"
"net/http"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/node"
"github.com/graph-gophers/graphql-go"
)
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(&params); err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
response := h.Schema.Exec(r.Context(), params.Query, params.OperationName, params.Variables)
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, cors, vhosts []string) error {
if backend == nil {
panic("missing backend")
}
// check if http server with given endpoint exists and enable graphQL on it
return newHandler(stack, backend, cors, vhosts)
}
// 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, cors, vhosts []string) error {
q := Resolver{backend}
s, err := graphql.ParseSchema(schema, &q)
if err != nil {
return err
}
h := handler{Schema: s}
handler := node.NewHTTPHandlerStack(h, cors, vhosts)
stack.RegisterHandler("GraphQL UI", "/graphql/ui", GraphiQL{})
stack.RegisterHandler("GraphQL", "/graphql", handler)
stack.RegisterHandler("GraphQL", "/graphql/", handler)
return nil
}