Error handling on generate handler

examples/net-http.go

@@ -45,7 +45,7 @@ func main() {
 		panic(err)
 	}
 	protect := http.HandlerFunc(protectMe)
-	http.HandleFunc("/authenticate", j.GenerateToken)
+	http.Handle("/authenticate", j.GenerateToken())
 	http.Handle("/secure", j.Secure(protect, verifyClaimsFunc))
 	http.ListenAndServe(":8080", nil)
 }

jwt.go

@@ -162,64 +162,83 @@ func (m *JWTMiddleware) Secure(h http.Handler, v VerifyClaimsFunc) http.Handler
 	return errorHandler(secureHandler)
 }
 
-func (m *JWTMiddleware) GenerateToken(w http.ResponseWriter, r *http.Request) {
-	var b map[string]string
-	err := json.NewDecoder(r.Body).Decode(&b)
-	if err != nil {
-		log.Printf("error (%v) while parsing authorization", err)
-		http.Error(w, ErrParsingCredentials.Error(), http.StatusInternalServerError)
-		return
-	}
-	err = m.auth(b["email"], b["password"])
-	if err != nil {
-		log.Printf("error (%v) while performing authorization", err)
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
+func (m *JWTMiddleware) GenerateToken() http.Handler {
+	generateHandler := func(w http.ResponseWriter, r *http.Request) *jwtError {
+		var b map[string]string
+		err := json.NewDecoder(r.Body).Decode(&b)
+		if err != nil {
+			return &jwtError{
+				status:  http.StatusInternalServerError,
+				err:     ErrParsingCredentials,
+				message: "parsing authorization",
+			}
+		}
+		err = m.auth(b["email"], b["password"])
+		if err != nil {
+			return &jwtError{
+				status:  http.StatusInternalServerError,
+				err:     err,
+				message: "performing authorization",
+			}
+		}
+
+		// For now, the header will be static
+		header, err := encode(fmt.Sprintf(`{"typ":%q,"alg":%q}`, typ, alg))
+		if err != nil {
+			return &jwtError{
+				status:  http.StatusInternalServerError,
+				err:     ErrEncoding,
+				message: "encoding header",
+			}
+		}
+
+		// Generate claims for user
+		claims, err := m.claims(b["email"])
+		if err != nil {
+			return &jwtError{
+				status:  http.StatusInternalServerError,
+				err:     err,
+				message: "generating claims",
+			}
+		}
+
+		claimsJson, err := json.Marshal(claims)
+		if err != nil {
+			return &jwtError{
+				status:  http.StatusInternalServerError,
+				err:     ErrEncoding,
+				message: "marshalling claims",
+			}
+		}
+
+		claimsSet, err := encode(claimsJson)
+		if err != nil {
+			return &jwtError{
+				status:  http.StatusInternalServerError,
+				err:     ErrEncoding,
+				message: "encoding claims",
+			}
+		}
+
+		toSig := strings.Join([]string{header, claimsSet}, ".")
+
+		h := hmac.New(sha256.New, []byte(m.secret))
+		h.Write([]byte(toSig))
+		sig, err := encode(h.Sum(nil))
+		if err != nil {
+			return &jwtError{
+				status:  http.StatusInternalServerError,
+				err:     ErrEncoding,
+				message: "encoding signature",
+			}
+		}
+
+		response := strings.Join([]string{toSig, sig}, ".")
+		w.Write([]byte(response))
+		return nil
 	}
 
-	// For now, the header will be static
-	header, err := encode(fmt.Sprintf(`{"typ":%q,"alg":%q}`, typ, alg))
-	if err != nil {
-		log.Printf("error (%v) while encoding header", err)
-		http.Error(w, ErrEncoding.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	// Generate claims for user
-	claims, err := m.claims(b["email"])
-	if err != nil {
-		log.Printf("error (%v) while generating claims", err)
-		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	claimsJson, err := json.Marshal(claims)
-	if err != nil {
-		log.Printf("error (%v) while marshalling claims")
-		http.Error(w, ErrEncoding.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	claimsSet, err := encode(claimsJson)
-	if err != nil {
-		log.Printf("error (%v) while encoding claims")
-		http.Error(w, ErrEncoding.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	toSig := strings.Join([]string{header, claimsSet}, ".")
-
-	h := hmac.New(sha256.New, []byte(m.secret))
-	h.Write([]byte(toSig))
-	sig, err := encode(h.Sum(nil))
-	if err != nil {
-		log.Printf("error (%v) while encoding signature")
-		http.Error(w, ErrEncoding.Error(), http.StatusInternalServerError)
-		return
-	}
-
-	response := strings.Join([]string{toSig, sig}, ".")
-	w.Write([]byte(response))
+	return errorHandler(generateHandler)
 }
 
 func encode(s interface{}) (string, error) {

jwt_test.go

@@ -72,7 +72,7 @@ func newToken(t *testing.T) (string, *JWTMiddleware) {
 		t.Error(err)
 	}
 
-	ts := httptest.NewServer(http.HandlerFunc(middleware.GenerateToken))
+	ts := httptest.NewServer(middleware.GenerateToken())
 	defer ts.Close()
 
 	resp, err := http.Post(ts.URL, "application/json", bytes.NewReader(body))