node: refactor package node (#21105)

This PR significantly changes the APIs for instantiating Ethereum nodes in
a Go program. The new APIs are not backwards-compatible, but we feel that
this is made up for by the much simpler way of registering services on
node.Node. You can find more information and rationale in the design
document: https://gist.github.com/renaynay/5bec2de19fde66f4d04c535fd24f0775.

There is also a new feature in Node's Go API: it is now possible to
register arbitrary handlers on the user-facing HTTP server. In geth, this
facility is used to enable GraphQL.

There is a single minor change relevant for geth users in this PR: The
GraphQL API is no longer available separately from the JSON-RPC HTTP
server. If you want GraphQL, you need to enable it using the
./geth --http --graphql flag combination.

The --graphql.port and --graphql.addr flags are no longer available.

graphql/graphql_test.go

@@ -17,12 +17,118 @@
 package graphql
 
 import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strings"
 	"testing"
+
+	"github.com/ethereum/go-ethereum/eth"
+	"github.com/ethereum/go-ethereum/node"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestBuildSchema(t *testing.T) {
+	stack, err := node.New(&node.DefaultConfig)
+	if err != nil {
+		t.Fatalf("could not create new node: %v", err)
+	}
 	// Make sure the schema can be parsed and matched up to the object model.
-	if _, err := newHandler(nil); err != nil {
+	if err := newHandler(stack, nil, []string{}, []string{}); err != nil {
 		t.Errorf("Could not construct GraphQL handler: %v", err)
 	}
 }
+
+// Tests that a graphQL request is successfully handled when graphql is enabled on the specified endpoint
+func TestGraphQLHTTPOnSamePort_GQLRequest_Successful(t *testing.T) {
+	stack := createNode(t, true)
+	defer stack.Close()
+	// start node
+	if err := stack.Start(); err != nil {
+		t.Fatalf("could not start node: %v", err)
+	}
+	// create http request
+	body := strings.NewReader("{\"query\": \"{block{number}}\",\"variables\": null}")
+	gqlReq, err := http.NewRequest(http.MethodGet, fmt.Sprintf("http://%s/graphql", "127.0.0.1:9393"), body)
+	if err != nil {
+		t.Error("could not issue new http request ", err)
+	}
+	gqlReq.Header.Set("Content-Type", "application/json")
+	// read from response
+	resp := doHTTPRequest(t, gqlReq)
+	bodyBytes, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatalf("could not read from response body: %v", err)
+	}
+	expected := "{\"data\":{\"block\":{\"number\":\"0x0\"}}}"
+	assert.Equal(t, expected, string(bodyBytes))
+}
+
+// Tests that a graphQL request is not handled successfully when graphql is not enabled on the specified endpoint
+func TestGraphQLHTTPOnSamePort_GQLRequest_Unsuccessful(t *testing.T) {
+	stack := createNode(t, false)
+	defer stack.Close()
+	if err := stack.Start(); err != nil {
+		t.Fatalf("could not start node: %v", err)
+	}
+
+	// create http request
+	body := strings.NewReader("{\"query\": \"{block{number}}\",\"variables\": null}")
+	gqlReq, err := http.NewRequest(http.MethodPost, fmt.Sprintf("http://%s/graphql", "127.0.0.1:9393"), body)
+	if err != nil {
+		t.Error("could not issue new http request ", err)
+	}
+	gqlReq.Header.Set("Content-Type", "application/json")
+	// read from response
+	resp := doHTTPRequest(t, gqlReq)
+	bodyBytes, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		t.Fatalf("could not read from response body: %v", err)
+	}
+	// make sure the request is not handled successfully
+	assert.Equal(t, 404, resp.StatusCode)
+	assert.Equal(t, "404 page not found\n", string(bodyBytes))
+}
+
+func createNode(t *testing.T, gqlEnabled bool) *node.Node {
+	stack, err := node.New(&node.Config{
+		HTTPHost: "127.0.0.1",
+		HTTPPort: 9393,
+		WSHost:   "127.0.0.1",
+		WSPort:   9393,
+	})
+	if err != nil {
+		t.Fatalf("could not create node: %v", err)
+	}
+	if !gqlEnabled {
+		return stack
+	}
+
+	createGQLService(t, stack, "127.0.0.1:9393")
+
+	return stack
+}
+
+func createGQLService(t *testing.T, stack *node.Node, endpoint string) {
+	// create backend
+	ethBackend, err := eth.New(stack, &eth.DefaultConfig)
+	if err != nil {
+		t.Fatalf("could not create eth backend: %v", err)
+	}
+
+	// create gql service
+	err = New(stack, ethBackend.APIBackend, []string{}, []string{})
+	if err != nil {
+		t.Fatalf("could not create graphql service: %v", err)
+	}
+}
+
+func doHTTPRequest(t *testing.T, req *http.Request) *http.Response {
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		t.Fatal("could not issue a GET request to the given endpoint", err)
+
+	}
+	return resp
+}