move messages to mail (#56)

mail/handler/handler.go

@@ -0,0 +1,116 @@
+package handler
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/micro/micro/v3/service/errors"
+	"github.com/micro/micro/v3/service/store"
+	pb "github.com/micro/services/mail/proto"
+)
+
+const (
+	messagePrefix = "message"
+	joinKey       = "/"
+)
+
+type Mail struct{}
+
+// Send a message
+func (m *Mail) Send(ctx context.Context, req *pb.SendRequest, rsp *pb.SendResponse) error {
+	// validate the request
+	if len(req.To) == 0 {
+		return errors.BadRequest("mail.Send.MissingTo", "Missing to")
+	}
+	if len(req.From) == 0 {
+		return errors.BadRequest("mail.Send.MissingFrom", "Missing from")
+	}
+	if len(req.Text) == 0 {
+		return errors.BadRequest("mail.Send.MissingText", "Missing text")
+	}
+
+	// construct the message and marshal it to json
+	msg := &pb.Message{
+		Id:      uuid.New().String(),
+		To:      req.To,
+		From:    req.From,
+		Subject: req.Subject,
+		Text:    req.Text,
+		SentAt:  time.Now().Unix(),
+	}
+	bytes, err := json.Marshal(msg)
+	if err != nil {
+		return errors.BadRequest("mail.Send.Unknown", "Error encoding message")
+	}
+
+	// write the message to the store under the recipients key
+	key := strings.Join([]string{messagePrefix, req.To, msg.Id}, joinKey)
+	if err := store.Write(&store.Record{Key: key, Value: bytes}); err != nil {
+		return errors.BadRequest("mail.Send.Unknown", "Error writing to the store")
+	}
+
+	// write the message to the store under the id (so it can be looked up without needing to know
+	// the users id)
+	key = strings.Join([]string{messagePrefix, msg.Id}, joinKey)
+	if err := store.Write(&store.Record{Key: key, Value: bytes}); err != nil {
+		return errors.BadRequest("mail.Send.Unknown", "Error writing to the store")
+	}
+
+	return nil
+}
+
+// List mail for a user
+func (m *Mail) List(ctx context.Context, req *pb.ListRequest, rsp *pb.ListResponse) error {
+	// validate the request
+	if len(req.User) == 0 {
+		return errors.BadRequest("mail.List.MissingUser", "Missing user")
+	}
+
+	// query the store for any mail sent to the user
+	prefix := strings.Join([]string{messagePrefix, req.User}, joinKey)
+	recs, err := store.Read(prefix, store.ReadPrefix())
+	if err != nil {
+		return errors.BadRequest("mail.List.Unknown", "Error reading from the store")
+	}
+
+	// serialize the result
+	rsp.Mail = make([]*pb.Message, len(recs))
+	for i, r := range recs {
+		var msg pb.Message
+		if err := json.Unmarshal(r.Value, &msg); err != nil {
+			return errors.BadRequest("mail.List.Unknown", "Error decoding message")
+		}
+		rsp.Mail[i] = &msg
+	}
+
+	return nil
+}
+
+// Read a message
+func (m *Mail) Read(ctx context.Context, req *pb.ReadRequest, rsp *pb.ReadResponse) error {
+	// validate the request
+	if len(req.Id) == 0 {
+		return errors.BadRequest("mail.Read.MissingUser", "Missing user")
+	}
+
+	// query the store
+	key := strings.Join([]string{messagePrefix, req.Id}, joinKey)
+	recs, err := store.Read(key)
+	if err == store.ErrNotFound {
+		return errors.NotFound("message.Read.InvalidID", "Message not found with ID")
+	} else if err != nil {
+		return errors.BadRequest("mail.Read.Unknown", "Error reading from the store")
+	}
+
+	// serialize the response
+	var msg pb.Message
+	if err := json.Unmarshal(recs[0].Value, &msg); err != nil {
+		return errors.BadRequest("mail.Read.Unknown", "Error decoding message")
+	}
+	rsp.Message = &msg
+
+	return nil
+}