Implement RPC

rpc/call.go

@@ -0,0 +1,82 @@
+package rpc
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/google/uuid"
+	"nhooyr.io/websocket"
+)
+
+func (s *server) Call(ctx context.Context, c *websocket.Conn, method string, params, result any) (*Response, error) {
+	id := uuid.New().String()
+	resp := make(chan *Response, 1)
+
+	var dataParams []byte
+	var err error
+	if params != nil {
+		dataParams, err = json.Marshal(params)
+		if err != nil {
+			return nil, fmt.Errorf("Error Marshalling Params: %w", err)
+		}
+	}
+
+	rawParams := json.RawMessage(dataParams)
+
+	req := Request{
+		ID:     id,
+		Method: method,
+		Params: &rawParams,
+	}
+
+	reqData, err := json.Marshal(req)
+	if err != nil {
+		return nil, fmt.Errorf("Error Marshalling Request: %w", err)
+	}
+
+	// Add Call to Request Map
+	func() {
+		s.requestMutex.Lock()
+		defer s.requestMutex.Unlock()
+
+		s.requests[id] = resp
+	}()
+
+	// Remove Call from Request map
+	defer func() {
+		s.requestMutex.Lock()
+		defer s.requestMutex.Unlock()
+
+		delete(s.requests, id)
+	}()
+
+	// Write Request
+	err = c.Write(ctx, websocket.MessageText, reqData)
+	if err != nil {
+		return nil, fmt.Errorf("Error Writing Request: %w", err)
+	}
+
+	// Wait for Response, TODO add Select Timeout
+	response := <-resp
+
+	if response.Error != nil {
+		return response, fmt.Errorf("Call Error: %w", err)
+	}
+
+	if result == nil {
+		return response, nil
+	}
+
+	if response.Result == nil {
+		return response, fmt.Errorf("Got Empty Result")
+	}
+
+	err = json.Unmarshal(*response.Result, &result)
+	if err != nil {
+		return response, fmt.Errorf("Error Parsing Result: %w", err)
+	}
+	return response, nil
+}
+
+// TODO Call with Multiple Response (Chunked file upload)