add otp service (#88)

otp/handler/otp.go

@@ -0,0 +1,92 @@
+package handler
+
+import (
+	"context"
+	"time"
+
+	"github.com/micro/micro/v3/service/errors"
+	"github.com/micro/micro/v3/service/logger"
+	pb "github.com/micro/services/otp/proto"
+	"github.com/micro/services/pkg/cache"
+
+	"github.com/pquerna/otp"
+	"github.com/pquerna/otp/totp"
+)
+
+type Otp struct{}
+
+func (e *Otp) Generate(ctx context.Context, req *pb.GenerateRequest, rsp *pb.GenerateResponse) error {
+	if len(req.Id) == 0 {
+		return errors.BadRequest("otp.generate", "missing id")
+	}
+
+	// check if a key exists for the user
+	var secret string
+
+	if err := cache.Get(req.Id, &secret); err != nil {
+		// generate a key
+		key, err := totp.Generate(totp.GenerateOpts{
+			Issuer:      "Micro",
+			AccountName: req.Id,
+		})
+		if err != nil {
+			logger.Error("Failed to generate secret: %v", err)
+			return errors.InternalServerError("otp.generate", "failed to generate code")
+		}
+
+		secret = key.Secret()
+
+		if err := cache.Put(req.Id, secret, time.Now().Add(time.Minute*5)); err != nil {
+			logger.Error("Failed to store secret: %v", err)
+			return errors.InternalServerError("otp.generate", "failed to generate code")
+		}
+	}
+
+	// generate a new code
+	code, err := totp.GenerateCodeCustom(secret, time.Now(), totp.ValidateOpts{
+		Period:    60,
+		Skew:      1,
+		Digits:    otp.DigitsSix,
+		Algorithm: otp.AlgorithmSHA512,
+	})
+
+	if err != nil {
+		return errors.InternalServerError("otp.generate", "failed to generate code: %v", err)
+	}
+
+	// return the code
+	rsp.Code = code
+
+	return nil
+}
+
+func (e *Otp) Validate(ctx context.Context, req *pb.ValidateRequest, rsp *pb.ValidateResponse) error {
+	if len(req.Id) == 0 {
+		return errors.BadRequest("otp.generate", "missing id")
+	}
+	if len(req.Code) == 0 {
+		return errors.BadRequest("otp.generate", "missing code")
+	}
+
+	var secret string
+
+	if err := cache.Get(req.Id, &secret); err != nil {
+		logger.Error("Failed to get secret from store: %v", err)
+		return errors.InternalServerError("otp.generate", "failed to validate code")
+	}
+
+	ok, err := totp.ValidateCustom(req.Code, secret, time.Now(), totp.ValidateOpts{
+		Period:    60,
+		Skew:      1,
+		Digits:    otp.DigitsSix,
+		Algorithm: otp.AlgorithmSHA1,
+	})
+	if err != nil {
+		return errors.InternalServerError("otp.generate", "failed to validate code")
+	}
+
+	// set the response
+	rsp.Success = ok
+
+	return nil
+}