From fa0b0efc14f84ff87789cabe0010f3240245407c Mon Sep 17 00:00:00 2001 From: hozan23 Date: Fri, 31 May 2024 02:17:56 +0200 Subject: init commit --- client/client.go | 289 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 289 insertions(+) create mode 100644 client/client.go (limited to 'client/client.go') diff --git a/client/client.go b/client/client.go new file mode 100644 index 0000000..7ad64fd --- /dev/null +++ b/client/client.go @@ -0,0 +1,289 @@ +package client + +import ( + "bytes" + "encoding/json" + "fmt" + "math/rand" + "strconv" + "time" + + "github.com/gorilla/websocket" + log "github.com/sirupsen/logrus" + + "github.com/karyontech/karyon-go/message" +) + +const ( + // JsonRPCVersion defines the version of the JSON-RPC protocol being used. + JsonRPCVersion = "2.0" + + // Default timeout for receiving requests from the server, in milliseconds. + DefaultTimeout = 3000 +) + +// RPCClientConfig holds the configuration settings for the RPC client. +type RPCClientConfig struct { + Timeout int // Timeout for receiving requests from the server, in milliseconds. + Addr string // Address of the RPC server. +} + +// RPCClient +type RPCClient struct { + config RPCClientConfig + conn *websocket.Conn + request_chans channels[message.RequestID, message.Response] + subscriptions channels[message.SubscriptionID, json.RawMessage] + stop_signal chan struct{} +} + +// NewRPCClient creates a new instance of RPCClient with the provided configuration. +// It establishes a WebSocket connection to the RPC server. +func NewRPCClient(config RPCClientConfig) (*RPCClient, error) { + conn, _, err := websocket.DefaultDialer.Dial(config.Addr, nil) + if err != nil { + return nil, err + } + log.Infof("Successfully connected to the server: %s", config.Addr) + + if config.Timeout == 0 { + config.Timeout = DefaultTimeout + } + + stop_signal := make(chan struct{}, 2) + + client := &RPCClient{ + conn: conn, + config: config, + request_chans: newChannels[message.RequestID, message.Response](1), + subscriptions: newChannels[message.SubscriptionID, json.RawMessage](10), + stop_signal: stop_signal, + } + + go func() { + if err := client.backgroundReceivingLoop(stop_signal); err != nil { + client.Close() + } + }() + + return client, nil +} + +// Close closes the underlying websocket connection and stop the receiving loop. +func (client *RPCClient) Close() error { + log.Warn("Close the rpc client...") + client.stop_signal <- struct{}{} + + err := client.conn.Close() + if err != nil { + log.WithError(err).Error("Close websocket connection") + } + + client.request_chans.clear() + client.subscriptions.clear() + return nil +} + +// Call sends an RPC call to the server with the specified method and parameters. +// It returns the response from the server. +func (client *RPCClient) Call(method string, params any) (*json.RawMessage, error) { + log.Tracef("Call -> method: %s, params: %v", method, params) + param_raw, err := json.Marshal(params) + if err != nil { + return nil, err + } + + response, err := client.sendRequest(method, param_raw) + if err != nil { + return nil, err + } + + return response.Result, nil +} + +// Subscribe sends a subscription request to the server with the specified method and parameters. +// It returns the subscription ID and a channel to receive notifications. +func (client *RPCClient) Subscribe(method string, params any) (message.SubscriptionID, <-chan json.RawMessage, error) { + log.Tracef("Sbuscribe -> method: %s, params: %v", method, params) + param_raw, err := json.Marshal(params) + if err != nil { + return 0, nil, err + } + + response, err := client.sendRequest(method, param_raw) + if err != nil { + return 0, nil, err + } + + if response.Result == nil { + return 0, nil, fmt.Errorf("Invalid response result") + } + + var subID message.SubscriptionID + err = json.Unmarshal(*response.Result, &subID) + if err != nil { + return 0, nil, err + } + + ch := client.subscriptions.add(subID) + + return subID, ch, nil +} + +// Unsubscribe sends an unsubscription request to the server to cancel the given subscription. +func (client *RPCClient) Unsubscribe(method string, subID message.SubscriptionID) error { + log.Tracef("Unsubscribe -> method: %s, subID: %d", method, subID) + subIDJSON, err := json.Marshal(subID) + if err != nil { + return err + } + + _, err = client.sendRequest(method, subIDJSON) + if err != nil { + return err + } + + // on success remove the subscription from the map + client.subscriptions.remove(subID) + + return nil +} + +// backgroundReceivingLoop starts reading new messages from the underlying connection. +func (client *RPCClient) backgroundReceivingLoop(stop_signal <-chan struct{}) error { + log.Debug("Background loop started") + for { + select { + case <-stop_signal: + log.Warn("Stopping background receiving loop: received stop signal") + return nil + default: + _, msg, err := client.conn.ReadMessage() + if err != nil { + log.WithError(err).Error("Receive a new msg") + return err + } + + err = client.handleNewMsg(msg) + if err != nil { + log.WithError(err).Error("Handle a new received msg") + } + } + } +} + +// handleNewMsg attempts to decode the received message into either a Response +// or Notification struct. +func (client *RPCClient) handleNewMsg(msg []byte) error { + // try to decode the msg into message.Response + response := message.Response{} + decoder := json.NewDecoder(bytes.NewReader(msg)) + decoder.DisallowUnknownFields() + if err := decoder.Decode(&response); err == nil { + if response.ID == nil { + return fmt.Errorf("Response doesn't have an id") + } + + if v := client.request_chans.remove(*response.ID); v != nil { + v <- response + } + + return nil + } + + // try to decode the msg into message.Notification + notification := message.Notification{} + if err := json.Unmarshal(msg, ¬ification); err == nil { + + notificationResult := message.NotificationResult{} + if err := json.Unmarshal(*notification.Params, ¬ificationResult); err != nil { + return fmt.Errorf("Failed to unmarshal notification params: %w", err) + } + + err := client.subscriptions.notify( + notificationResult.Subscription, + *notificationResult.Result, + ) + if err != nil { + return fmt.Errorf("Notify a subscriber: %w", err) + } + + log.Debugf("<-- %s", notification.String()) + + return nil + } + + return fmt.Errorf("Receive unexpected msg: %s", msg) +} + +// sendRequest sends a request and wait the response +func (client *RPCClient) sendRequest(method string, params []byte) (message.Response, error) { + id := strconv.Itoa(rand.Int()) + params_raw := json.RawMessage(params) + + req := message.Request{ + JSONRPC: JsonRPCVersion, + ID: id, + Method: method, + Params: ¶ms_raw, + } + + response := message.Response{} + + reqJSON, err := json.Marshal(req) + if err != nil { + return response, err + } + + err = client.conn.WriteMessage(websocket.TextMessage, []byte(string(reqJSON))) + if err != nil { + return response, err + } + + log.Debugf("--> %s", req.String()) + + req_chan := client.request_chans.add(id) + + response, err = client.waitResponse(req_chan) + if err != nil { + log.WithError(err).Errorf("Receive a response from the server") + client.request_chans.remove(id) + return response, err + } + + err = validateResponse(&response, id) + if err != nil { + return response, err + } + + log.Debugf("<-- %s", response.String()) + + return response, nil +} + +// waitResponse waits the response, it fails and return error if it exceed the timeout +func (client *RPCClient) waitResponse(ch <-chan message.Response) (message.Response, error) { + response := message.Response{} + select { + case response = <-ch: + return response, nil + case <-time.After(time.Duration(client.config.Timeout) * time.Millisecond): + return response, fmt.Errorf("Timeout error") + } +} + +// validateResponse Checks the error field and whether the request id is the +// same as the response id +func validateResponse(res *message.Response, reqID message.RequestID) error { + if res.Error != nil { + return fmt.Errorf("Receive An Error: %s", res.Error.String()) + } + + if res.ID != nil { + if *res.ID != reqID { + return fmt.Errorf("Invalid response id") + } + } + + return nil +} -- cgit v1.2.3