func (c *Client) write(request *protobuf.Request) chan protobuf.Response {
data, err := proto.Marshal(request)
if err != nil {
log.Printf("Marshaling error: %v\n", err)
return nil
}
length := len(data)
lengthBytes := make([]byte, 4)
binary.BigEndian.PutUint32(lengthBytes, uint32(length))
// Guarantee squential write of length then protobuf on stream
c.connLock.Lock()
defer c.connLock.Unlock()
_, err = c.conn.Write(lengthBytes)
if err != nil {
log.Printf("Error writing data: %v\n", err)
return nil
}
_, err = c.conn.Write(data)
if err != nil {
log.Printf("Error writing data: %v\n", err)
return nil
}
callback := make(chan protobuf.Response)
c.pending[request.GetId()] = callback
return callback
}
func (c *Client) Get(key string) (int, string) {
request := new(protobuf.Request)
request.Id = proto.String(randomId())
request.Type = proto.String("get")
request.Key = proto.String(key)
callback := c.write(request)
if callback == nil {
return -1, ""
}
// Block on callback
response := <-callback
return int(response.GetResult()), response.GetValue()
}
func (s *Server) run() {
for {
if conn, err := s.listener.Accept(); err == nil {
go func(s *Server, conn net.Conn) {
defer conn.Close()
log.Println("Connection established with client")
for {
data := make([]byte, 4)
_, err := conn.Read(data)
if err != nil {
log.Printf("Error reading length: %v", err)
return
}
length := int(binary.BigEndian.Uint32(data))
data = make([]byte, length)
for i := 0; i < length; {
//Read the data waiting on the connection and put it in the data buffer
n, err := conn.Read(data[i : length-i])
i += n
if err != nil {
log.Printf("Error reading request: %v", err)
return
}
}
//Create an struct pointer of type protobuf.Request and protobuf.Response struct
request := new(protobuf.Request)
//Convert all the data retrieved into the ProtobufTest.TestMessage struct type
err = proto.Unmarshal(data[:length], request)
if err != nil {
log.Printf("Error in Unmarshalling: %v\n", err)
return
}
response := new(protobuf.Response)
response.Id = request.Id
if request.GetType() == "get" {
result, value := s.Get(request.GetKey())
response.Result = proto.Int32(int32(result))
response.Value = proto.String(value)
} else {
result, value := s.Set(request.GetKey(), request.GetValue())
response.Result = proto.Int32(int32(result))
response.Value = proto.String(value)
}
data, err = proto.Marshal(response)
if err != nil {
log.Printf("Marshaling error: %v\n", err)
continue
}
length = len(data)
lengthBytes := make([]byte, 4)
binary.BigEndian.PutUint32(lengthBytes, uint32(length))
_, err = conn.Write(lengthBytes)
if err != nil {
log.Printf("Error writing data: %v\n", err)
return
}
_, err = conn.Write(data)
if err != nil {
log.Printf("Error writing data: %v\n", err)
return
}
}
}(s, conn)
} else {
continue
}
}
}
