Added exception handling and test for key/secret not present

include/jwt/exceptions.hpp

@@ -58,17 +58,31 @@ public:
 
 /**
  */
-class SignatureFormatError final : public std::runtime_error
+class SignatureFormatError final : public DecodeError
 {
 public:
   /**
    */
   SignatureFormatError(std::string msg)
-    : std::runtime_error(std::move(msg))
+    : DecodeError(std::move(msg))
   {
   }
 };
 
+/**
+ */
+class KeyNotPresentError final : public DecodeError
+{
+public:
+  /**
+   */
+  KeyNotPresentError(std::string msg)
+    : DecodeError(std::move(msg))
+  {
+  }
+};
+
+
 /**
  */
 class VerificationError : public std::runtime_error

include/jwt/impl/jwt.ipp

@@ -581,15 +581,6 @@ jwt_object decode(const string_view enc_str,
       ec = DecodeErrc::SignatureFormatError;
       return obj;
     }
-
-    if (!dparams.has_secret) {
-      ec = DecodeErrc::KeyNotPresent;
-      return obj;
-    }
-  } else {
-    if (dparams.has_secret) {
-      ec = DecodeErrc::KeyNotRequiredForNoneAlg;
-    }
   }
 
   //throws decode error
@@ -607,7 +598,12 @@ jwt_object decode(const string_view enc_str,
   }
 
   //Verify the signature only if some algorithm was used
-  if (obj.header().algo() != algorithm::NONE) {
+  if (obj.header().algo() != algorithm::NONE)
+  {
+    if (!dparams.has_secret) {
+      ec = DecodeErrc::KeyNotPresent;
+      return obj;
+    }
     jwt_signature jsign{dparams.secret};
  
     // Length of the encoded header and payload only.
@@ -698,6 +694,10 @@ void jwt_throw_exception(const std::error_code& ec)
       {
         throw SignatureFormatError(ec.message());
       }
+      case DecodeErrc::KeyNotPresent:
+      {
+        throw KeyNotPresentError(ec.message());
+      }
       case DecodeErrc::KeyNotRequiredForNoneAlg:
       {
         // Not an error. Just to be ignored.

tests/test_jwt_decode.cc

@@ -99,6 +99,22 @@ TEST (DecodeTest, DecodeHS256)
   EXPECT_FALSE (obj.payload().has_claim_with_value(jwt::registered_claims::issued_at, 1513862372));
 }
 
+TEST (DecodeTest, SecretKeyNotPassed)
+{
+  using namespace jwt::params;
+
+  const char* enc_str = 
+    "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9."
+    "eyJpYXQiOjE1MTM4NjIzNzEsImlkIjoiYS1iLWMtZC1lLWYtMS0yLTMiLCJpc3MiOiJhcnVuLm11cmFsaWRoYXJhbiIsInN1YiI6ImFkbWluIn0."
+    "jk7bRQKTLvs1RcuvMc2B_rt6WBYPoVPirYi_QRBPiuk";
+
+  std::error_code ec;
+  auto obj = jwt::decode(enc_str, algorithms({"none", "hs256"}), ec, verify(false));
+
+  ASSERT_TRUE (ec);
+  EXPECT_EQ (ec.value(), static_cast<int>(jwt::DecodeErrc::KeyNotPresent));
+}
+
 TEST (DecodeTest, DecodeHS384)
 {
   using namespace jwt::params;