Streams (#47)

* Streams Service (WIP)

* Complete Streams Service

streams/handler/create_message.go

@@ -0,0 +1,53 @@
+package handler
+
+import (
+	"context"
+
+	"github.com/google/uuid"
+	"github.com/micro/micro/v3/service/errors"
+	"github.com/micro/micro/v3/service/logger"
+	pb "github.com/micro/services/streams/proto"
+	"gorm.io/gorm"
+)
+
+// Create a message within a conversation
+func (s *Streams) CreateMessage(ctx context.Context, req *pb.CreateMessageRequest, rsp *pb.CreateMessageResponse) error {
+	// validate the request
+	if len(req.AuthorId) == 0 {
+		return ErrMissingAuthorID
+	}
+	if len(req.ConversationId) == 0 {
+		return ErrMissingConversationID
+	}
+	if len(req.Text) == 0 {
+		return ErrMissingText
+	}
+
+	return s.DB.Transaction(func(tx *gorm.DB) error {
+		// lookup the conversation
+		var conv Conversation
+		if err := s.DB.Where(&Conversation{ID: req.ConversationId}).First(&conv).Error; err == gorm.ErrRecordNotFound {
+			return ErrNotFound
+		} else if err != nil {
+			logger.Errorf("Error reading conversation: %v", err)
+			return errors.InternalServerError("DATABASE_ERROR", "Error connecting to database")
+		}
+
+		// create the message
+		msg := &Message{
+			ID:             uuid.New().String(),
+			SentAt:         s.Time(),
+			Text:           req.Text,
+			AuthorID:       req.AuthorId,
+			ConversationID: req.ConversationId,
+		}
+		if err := s.DB.Create(msg).Error; err != nil {
+			logger.Errorf("Error creating message: %v", err)
+			return errors.InternalServerError("DATABASE_ERROR", "Error connecting to database")
+		}
+
+		// serialize the response
+		rsp.Message = msg.Serialize()
+		return nil
+	})
+}