Allow DEL character in request variables

Product

Hot Chocolate

Is your feature request related to a problem?

When a DEL character (0x7F) is included in a string passed in as a variable in a hot chocolate mutation call, HC throws an error parsing the request. The actual response returned to the client is something like this:

{
    "errors": [
        {
            "message": "Invalid character within String: 127.",
            "locations": [
                {
                    "line": 1,
                    "column": 3555533
                }
            ],
            "extensions": {
                "code": "HC0011"
            }
        }
    ]
}

The solution you'd like

It appears that characters like DEL are valid per the JSON spec (see discussion in https://github.com/salsify/jsonstreamingparser/issues/53). Could HC allow this character in input data?

Start by tracing Hot Chocolate's request-variable parsing path and compare its DEL-character handling with the JSON specification discussion linked in the issue. Done means a mutation variable containing character 0x7F is accepted without the HC0011 parsing error, with a regression test covering the request.