Improve exception handling in S3Simulator

Centralise error response generationImprove exception handling in S3Simulator, driven by throwing and catching exceptions. Add a method to BoxException to quickly check what type of exception it is, and a macro to make this even shorter.
boxbackup · Nov 14, 2016 · b81caf3 · b81caf3
1 parent 39fc054
commit b81caf3
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Showing 2 changed files with 26 additions and 23 deletions.
diff --git a/lib/common/BoxException.h b/lib/common/BoxException.h
@@ -29,11 +29,17 @@ class BoxException : public std::exception
 
 	virtual unsigned int GetType() const throw() = 0;
 	virtual unsigned int GetSubType() const throw() = 0;
+	bool IsType(unsigned int Type, unsigned int SubType)
+	{
+		return GetType() == Type && GetSubType() == SubType;
+	}
 	virtual const std::string& GetMessage() const = 0;
 
 private:
 };
 
+#define EXCEPTION_IS_TYPE(exception_obj, type, subtype) \
+	exception_obj.IsType(type::ExceptionType, type::subtype)
 
 #endif // BOXEXCEPTION__H
 
diff --git a/lib/httpserver/S3Simulator.cpp b/lib/httpserver/S3Simulator.cpp
@@ -167,9 +167,8 @@ void S3Simulator::Handle(HTTPRequest &rRequest, HTTPResponse &rResponse)
 		if (!rRequest.GetHeader("authorization", &actualAuth) ||
 			actualAuth != expectedAuth)
 		{
-			rResponse.SetResponseCode(HTTPResponse::Code_Unauthorized);
-			SendInternalErrorResponse("Authentication Failed",
-				rResponse);
+			THROW_EXCEPTION_MESSAGE(HTTPException, AuthenticationFailed,
+				"Authentication code mismatch");
 		}
 		else if (rRequest.GetMethod() == HTTPRequest::Method_GET)
 		{
@@ -181,14 +180,27 @@ void S3Simulator::Handle(HTTPRequest &rRequest, HTTPResponse &rResponse)
 		}
 		else
 		{
-			rResponse.SetResponseCode(HTTPResponse::Code_BadRequest);
-			SendInternalErrorResponse("Unsupported Method",
-				rResponse);
+			THROW_EXCEPTION_MESSAGE(HTTPException, BadRequest,
+				"Unsupported Amazon S3 Method");
 		}
 	}
-	catch (CommonException &ce)
+	catch (BoxException &ce)
 	{
 		SendInternalErrorResponse(ce.what(), rResponse);
+
+		// Override the default status code 500 for a few specific exceptions.
+		if(EXCEPTION_IS_TYPE(ce, CommonException, OSFileOpenError))
+		{
+			rResponse.SetResponseCode(HTTPResponse::Code_NotFound);
+		}
+		else if(EXCEPTION_IS_TYPE(ce, CommonException, AccessDenied))
+		{
+			rResponse.SetResponseCode(HTTPResponse::Code_Forbidden);
+		}
+		else if(EXCEPTION_IS_TYPE(ce, HTTPException, AuthenticationFailed))
+		{
+			rResponse.SetResponseCode(HTTPResponse::Code_Unauthorized);
+		}
 	}
 	catch (std::exception &e)
 	{
@@ -231,22 +243,7 @@ void S3Simulator::HandleGet(HTTPRequest &rRequest, HTTPResponse &rResponse)
 	path += rRequest.GetRequestURI();
 	std::auto_ptr<FileStream> apFile;
 
-	try
-	{
-		apFile.reset(new FileStream(path));
-	}
-	catch (CommonException &ce)
-	{
-		if (ce.GetSubType() == CommonException::OSFileOpenError)
-		{
-			rResponse.SetResponseCode(HTTPResponse::Code_NotFound);
-		}
-		else if (ce.GetSubType() == CommonException::AccessDenied)
-		{
-			rResponse.SetResponseCode(HTTPResponse::Code_Forbidden);
-		}
-		throw;
-	}
+	apFile.reset(new FileStream(path));
 
 	// http://docs.amazonwebservices.com/AmazonS3/2006-03-01/UsingRESTOperations.html
 	apFile->CopyStreamTo(rResponse);