How to modify value of a property in a json text in C#?-CodePudding

I have a service that receives some data with random structure in JSON format and persists these data in a document-based database. I have no control over sending services and there are some sensitive data that should not be persisted in my database. I just want to filter those fields and replace their values with some masking characters. Is there any built-in solution in dotnet5 without adding third-party libraries like json.net or Json Newtonsoft?

I cannot deserialize incoming JSON to a static typed class because I have no idea about how many different types are sent from other services. An also working with reflection and dynamic typing has its own performance penalties.

CodePudding user response：

if you don't have any way to change in code, you can handle it in sql at the time of json insert. like:

CREATE PROCEDURE dbo.InsertJson(@doc  NVARCHAR(MAX))
AS BEGIN
  INSERT INTO Person (id, name, surname, age)
  SELECT id, firstNAme, lastName, age
  FROM OPENJSON(@json)
       WITH (id int, firstName nvarchar(50), lastName nvarchar(50),age int)
END

CodePudding user response：

I finally used regex to find and make masked using this code snipped.

 private string GetMaskedJson(string json, string[] fieldNames)
        {
            if (string.IsNullOrEmpty(json)) return string.Empty;
            foreach (var field in fieldNames)
            {
                var pattern = "\"" field "\"\\s*:\\s*(\"?)(. ?)((\")|\\,|\\})";
                var maskedValue = "===MASKED VALUE===";
                var r = new Regex(pattern);
                var k = r.GetGroupNames(); 
                var t = Regex.Matches(json, pattern);
                //R
                foreach (var ma in t.Reverse().ToList())
                {
                    var masked = maskedValue; 
                    if (string.IsNullOrWhiteSpace(ma.Groups[1].Value)) masked = $"\"{maskedValue}\""; 
                    json = json.Remove(ma.Groups[2].Index, ma.Groups[2].Length)
                        .Insert(ma.Groups[2].Index, masked);
                }
            }

            return json;
        }