Drogon + invalid json = segfault

[ranmasao]

Describe the bug When I send http request using curl with invalid json where I put value without double quotes, even if json processing is inside try-catch block, my application fails.

To Reproduce

1. Filter starting with next code:

   try {
   auto json = *req->getJsonObject();
   // here could be next code processing json data
   } catch (...) {
   std::cerr << "Invalid JSON" << std::endl;
   }

2. HttpController using this filter for some endpoint,

3. Curl request to the corresponding endpoint: curl -s -H "Content-Type: application/json" -X POST --data '{"name": value}' http://localhost:5432/someApi --trace-ascii - (--trace-ascii is to see request body in curl)

4. Result:

   20240604 13:24:57.709201 UTC 37773 DEBUG [parseJson] * Line 1, Column 10
   Syntax error: value, object or array expected.
   - HttpRequestImpl.cc:57
   Segmentation fault (core dumped)

Expected behavior I really expected the execution to continue inside catch without segfaulting the whole application.

Desktop (please complete the following information):

• OS: Arch Linux
• Browser: curl
• Version: 8.8.0

Additional context I found it accidentally when wrote some API test using curl, and started playing with environment variables substitution.

[fantasy-peak]

https://github.com/drogonframework/drogon/blob/0a889e921d23b65fb4694a9e916c4485b0437507/lib/tests/integration_test/client/main.cc#L332

[zh7314]

Just need to judge in advance，like：

 if (req->getJsonObject() == nullptr)
        {
            throw std::invalid_argument("request json is null");
        }

        auto jsonPtr = req->getJsonObject();