133 lines
4.1 KiB
Go
133 lines
4.1 KiB
Go
// Copyright 2019 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package graphql
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import (
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"context"
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"encoding/json"
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"net/http"
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"strconv"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/eth/filters"
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"github.com/ethereum/go-ethereum/internal/ethapi"
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"github.com/ethereum/go-ethereum/node"
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"github.com/ethereum/go-ethereum/rpc"
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"github.com/graph-gophers/graphql-go"
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gqlErrors "github.com/graph-gophers/graphql-go/errors"
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)
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type handler struct {
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Schema *graphql.Schema
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}
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func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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var params struct {
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Query string `json:"query"`
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OperationName string `json:"operationName"`
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Variables map[string]interface{} `json:"variables"`
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}
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if err := json.NewDecoder(r.Body).Decode(¶ms); err != nil {
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http.Error(w, err.Error(), http.StatusBadRequest)
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return
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}
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var (
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ctx = r.Context()
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responded sync.Once
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timer *time.Timer
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cancel context.CancelFunc
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)
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ctx, cancel = context.WithCancel(ctx)
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defer cancel()
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if timeout, ok := rpc.ContextRequestTimeout(ctx); ok {
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timer = time.AfterFunc(timeout, func() {
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responded.Do(func() {
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// Cancel request handling.
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cancel()
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// Create the timeout response.
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response := &graphql.Response{
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Errors: []*gqlErrors.QueryError{{Message: "request timed out"}},
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}
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responseJSON, err := json.Marshal(response)
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if err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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// Setting this disables gzip compression in package node.
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w.Header().Set("transfer-encoding", "identity")
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// Flush the response. Since we are writing close to the response timeout,
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// chunked transfer encoding must be disabled by setting content-length.
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w.Header().Set("content-type", "application/json")
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w.Header().Set("content-length", strconv.Itoa(len(responseJSON)))
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w.Write(responseJSON)
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if flush, ok := w.(http.Flusher); ok {
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flush.Flush()
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}
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})
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})
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}
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response := h.Schema.Exec(ctx, params.Query, params.OperationName, params.Variables)
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if timer != nil {
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timer.Stop()
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}
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responded.Do(func() {
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responseJSON, err := json.Marshal(response)
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if err != nil {
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http.Error(w, err.Error(), http.StatusInternalServerError)
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return
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}
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if len(response.Errors) > 0 {
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w.WriteHeader(http.StatusBadRequest)
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}
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w.Header().Set("Content-Type", "application/json")
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w.Write(responseJSON)
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})
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}
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// New constructs a new GraphQL service instance.
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func New(stack *node.Node, backend ethapi.Backend, filterSystem *filters.FilterSystem, cors, vhosts []string) error {
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_, err := newHandler(stack, backend, filterSystem, cors, vhosts)
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return err
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}
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// newHandler returns a new `http.Handler` that will answer GraphQL queries.
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// It additionally exports an interactive query browser on the / endpoint.
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func newHandler(stack *node.Node, backend ethapi.Backend, filterSystem *filters.FilterSystem, cors, vhosts []string) (*handler, error) {
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q := Resolver{backend, filterSystem}
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s, err := graphql.ParseSchema(schema, &q)
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if err != nil {
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return nil, err
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}
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h := handler{Schema: s}
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handler := node.NewHTTPHandlerStack(h, cors, vhosts, nil)
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stack.RegisterHandler("GraphQL UI", "/graphql/ui", GraphiQL{})
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stack.RegisterHandler("GraphQL UI", "/graphql/ui/", GraphiQL{})
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stack.RegisterHandler("GraphQL", "/graphql", handler)
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stack.RegisterHandler("GraphQL", "/graphql/", handler)
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return &h, nil
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}
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