From d0eb73e20c50fd7cf0d8ecaffb4eedd8a76c919b Mon Sep 17 00:00:00 2001
From: Pawan Rawal <pawan0201@gmail.com>
Date: Wed, 13 Apr 2016 10:58:30 +0530
Subject: [PATCH] Adding support for client.
Client establishes a TCP connection with server. Sends a sample query and parses response.
Server listens to client, handles the query and sends back response.
---
client/go/main.go | 66 +++++++++++++++++++++++++++++++++++++++++++++
server/main.go | 69 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 135 insertions(+)
create mode 100644 client/go/main.go
diff --git a/client/go/main.go b/client/go/main.go
new file mode 100644
index 00000000..f2d5d870
--- /dev/null
+++ b/client/go/main.go
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2015 DGraph Labs, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+ "flag"
+ "fmt"
+ "net"
+
+ "github.com/dgraph-io/dgraph/x"
+)
+
+var glog = x.Log("client")
+
+var port = flag.String("port", "3000", "Port to communicate with server")
+
+func main() {
+
+ var q0 = `
+ {
+ user(_xid_:alice) {
+ follows {
+ _xid_
+ status
+ }
+ _xid_
+ status
+ }
+ }
+`
+
+ conn, err := net.Dial("tcp", "127.0.0.1:"+*port)
+ if err != nil {
+ glog.Fatalf("While running server: %v", err)
+ }
+
+ fmt.Println("sending data", []byte(q0))
+ _, err = conn.Write([]byte(q0))
+ if err != nil {
+ x.Err(glog, err).Fatal("Error in writing to server")
+ }
+
+ reply := []byte{}
+ _, err = conn.Read(reply)
+ if err != nil {
+ x.Err(glog, err).Fatal("Error in reading response from server")
+ }
+ fmt.Println(string(reply))
+
+ conn.Close()
+
+}
diff --git a/server/main.go b/server/main.go
index 8a7c90dd..720a1785 100644
--- a/server/main.go
+++ b/server/main.go
@@ -21,6 +21,7 @@ import (
"flag"
"fmt"
"io/ioutil"
+ "net"
"net/http"
"runtime"
"strings"
@@ -195,6 +196,72 @@ func queryHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, string(js))
}
+func pbQueryHandler(q []byte) (pb []byte, rerr error) {
+ fmt.Println("in pbQueryHandler")
+ glog.WithField("q", string(q)).Debug("Query received.")
+ gq, _, err := gql.Parse(string(q))
+ if err != nil {
+ x.Err(glog, err).Error("While parsing query")
+ return pb, err
+ }
+
+ sg, err := query.ToSubGraph(gq)
+ if err != nil {
+ x.Err(glog, err).Error("While conversion to internal format")
+ return pb, err
+ }
+ glog.WithField("q", string(q)).Debug("Query parsed.")
+
+ rch := make(chan error)
+ go query.ProcessGraph(sg, rch)
+ err = <-rch
+ if err != nil {
+ x.Err(glog, err).Error("While executing query")
+ return pb, err
+ }
+
+ glog.WithField("q", string(q)).Debug("Graph processed.")
+ pb, err = sg.ToProtocolBuffer()
+ if err != nil {
+ x.Err(glog, err).Error("While converting to Json.")
+ return pb, err
+ }
+
+ return pb, err
+}
+
+func runServerForClient(address string) error {
+ ln, err := net.Listen("tcp", address)
+ if err != nil {
+ glog.Fatalf("While running server for client: %v", err)
+ return err
+ }
+ glog.WithField("address", ln.Addr()).Info("Client Worker listening")
+
+ go func() {
+ for {
+ cxn, err := ln.Accept()
+ if err != nil {
+ glog.Fatalf("listen(%q): %s\n", address, err)
+ return
+ }
+ glog.WithField("local", cxn.LocalAddr()).
+ WithField("remote", cxn.RemoteAddr()).
+ Debug("Client Worker accepted connection")
+
+ q := make([]byte, 1024000)
+ // Move to separate function
+ go func(c net.Conn) {
+ _, _ = c.Read(q)
+ fmt.Println("query received: ", string(q))
+ r, _ := pbQueryHandler(q)
+ c.Write(r)
+ }(cxn)
+ }
+ }()
+ return nil
+}
+
func main() {
flag.Parse()
if !flag.Parsed() {
@@ -239,6 +306,8 @@ func main() {
worker.Connect(addrs)
+ runServerForClient(":3000")
+
http.HandleFunc("/query", queryHandler)
glog.WithField("port", *port).Info("Listening for requests...")
if err := http.ListenAndServe(":"+*port, nil); err != nil {
--
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