Manage non expected json payloads

[ssanabriacec]

Problem description:

EventManager endpoint expects the following structure for a payload:

{
    "Name": "event_name",
    "Payload": [
        {
            "key": "value",
        }
    ],
    "Timestamp": "2020-10-27 13:12:49",
    "ExtraParams": {
        "key": "value",
    }
}

But if the payload differs like this one:

{
    "key": "value"
}

it then crashes on InvokeAsync method because the properties are expected there.

Error message:

System.ArgumentNullException: Value cannot be null. (Parameter 'value')
   at Newtonsoft.Json.Linq.JToken.EnsureValue(JToken value)
   at Newtonsoft.Json.Linq.JToken.op_Explicit(JToken value)
   at EventManager.Middleware.EventManagerMiddleware.InvokeAsync(HttpContext httpContext)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

HEADERS
=======
Accept: */*
Accept-Encoding: gzip, deflate, br
Cache-Control: no-cache
Connection: keep-alive
Content-Length: 868
Content-Type: application/json
Host: localhost:40861
User-Agent: PostmanRuntime/7.26.8
Postman-Token: a109ae8c-af76-4e17-9e83-c988a6dc32b3

Another issue:

Also, malformed json payload (missing the last curly brace) throws the following error:

Newtonsoft.Json.JsonReaderException: Unexpected end of content while loading JObject. Path 'key', line 42, position 2.
   at Newtonsoft.Json.Linq.JContainer.ReadTokenFrom(JsonReader reader, JsonLoadSettings options)
   at Newtonsoft.Json.Linq.JObject.Load(JsonReader reader, JsonLoadSettings settings)
   at Newtonsoft.Json.Linq.JObject.Parse(String json, JsonLoadSettings settings)
   at Newtonsoft.Json.Linq.JObject.Parse(String json)
   at EventManager.Middleware.EventManagerMiddleware.InvokeAsync(HttpContext httpContext)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

HEADERS
=======
Accept: */*
Accept-Encoding: gzip, deflate, br
Cache-Control: no-cache
Connection: keep-alive
Content-Length: 867
Content-Type: application/json
Host: localhost:40861
User-Agent: PostmanRuntime/7.26.8
Postman-Token: 7a9b0216-4e88-46d3-9d43-378b5b3df382

Possible Solutions:

Dispatch/ throw an exception (BadRequest or similar) that can be catched on upper calls, one for the properties, and another one for the malformed json

[tupini07]

Thanks for creating this issue! I would suggest doing as you say but creating a custom exception (eg, MalformedEventDispatch), so that it is clearer what is happening.

Another thing we can do is have the EventManagerMiddleware return a BadRequest status code whenever someone sends a request to the event reception endpoint using a malformed event.