go-eth-proxy

commit 108a711d8af91229a8a821dae197da6840a9879c
parent d2dd7addd817f1c373e2fa8c0dc197fd70500fcf
Author: lash <dev@holbrook.no>
Date:   Fri, 28 Jun 2024 21:23:14 +0100

Successful passthrough

Diffstat:
M
Makefile
 | 
3
+++
M
cmd/main.go
 | 
6
++----
M
proxy/rpc.go
 | 
86
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
proxy/service.go
 | 
4
----

4 files changed, 91 insertions(+), 8 deletions(-)
diff --git a/Makefile b/Makefile
@@ -1,2 +1,5 @@
 all:
 	go build -v -o eth-proxy ./cmd/
+
+run: all
+	./eth-proxy
diff --git a/cmd/main.go b/cmd/main.go
@@ -8,13 +8,13 @@ import (
 
 	"defalsify.org/go-eth-proxy/proxy"
 	"defalsify.org/go-eth-proxy/store/lmdb"
-	"github.com/ethereum/go-ethereum/rpc"
 
 )
 
 
 func main() {
 	dbpath := flag.String("cachepath", ".", "Path to lmdb data")
+	flag.Parse()
 	db, err := lmdb.NewStore(*dbpath)
 	if err != nil {
 		log.Printf("%s", err)
@@ -23,13 +23,11 @@ func main() {
 	defer db.Close()
 
 	svc := proxy.NewProxyService(db)
-	h := rpc.NewServer()
-	err = h.RegisterName("eth", svc)
+	h, err := proxy.NewProxyServer(svc, flag.Args()[0])
 	if err != nil {
 		log.Printf("%s", err)
 		os.Exit(1)
 	}
-
 	srv := &http.Server{
 		Handler: h,
 		Addr: "0.0.0.0:8080",
diff --git a/proxy/rpc.go b/proxy/rpc.go
@@ -1,3 +1,89 @@
 package proxy
 
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
 
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+type jsonRpcMsg struct {
+	Jsonrpc string
+	Id string
+	Method string
+	Params []any
+
+}
+type ProxyServer struct {
+	*rpc.Server
+	uri *url.URL
+}
+
+func NewProxyServer(svc *ProxyService, remoteURI string) (*ProxyServer, error) {
+	uri, err := url.Parse(remoteURI)
+	if err != nil {
+		return nil, err
+	}
+	srv := &ProxyServer{
+		Server: rpc.NewServer(),
+		uri: uri,
+	}
+	err = srv.Server.RegisterName("eth", svc)
+	if err != nil {
+		return nil, err
+	}
+	return srv, nil
+}
+
+func (s *ProxyServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var rr io.Reader
+	msg := jsonRpcMsg{}
+	b := make([]byte, r.ContentLength)
+	_, err := io.ReadFull(r.Body, b)
+	if (err != nil) {
+		log.Printf("%s", err)
+		r.Body.Close()
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	r.Body.Close()
+	err = json.Unmarshal(b, &msg)
+	if (err != nil) {
+		log.Printf("%s", err)
+		r.Body.Close()
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	rr = bytes.NewReader(b)
+	r.Body = io.NopCloser(rr)
+
+	for _, k := range([]string{
+		"eth_getTransactionFromHash",
+	}) {
+		if msg.Method == k {
+			log.Printf("match %s", msg.Method)
+			s.Server.ServeHTTP(w, r)
+			return
+		}
+	}
+	client_req := r.Clone(r.Context())
+	client_req.RequestURI = ""
+	client_req.Method = "POST"
+	client_req.URL = s.uri
+	client := &http.Client{}
+	res, err := client.Do(client_req)
+	if err != nil {
+		log.Printf("%s", err)
+		r.Body.Close()
+		w.WriteHeader(http.StatusBadGateway)
+		return
+	}
+	w.WriteHeader(res.StatusCode)
+	rr = io.TeeReader(r.Body, w)
+	io.ReadAll(rr)
+}
diff --git a/proxy/service.go b/proxy/service.go
@@ -20,10 +20,6 @@ func NewProxyService(store store.Store) (*ProxyService) {
 	}
 }
 
-func (p *ProxyService) GasPrice() (string, error) {
-	return "0x0", nil
-}
-
 func (p *ProxyService) GetTransactionByHash(ctx context.Context, hsh string) (*types.Transaction, error) {
 	log.Printf("get tx hash %s", hsh)
 	b := common.FromHex(hsh)