Serializable filter on any object

Question

I need a way to define a filter for an unknown type. The filter should be able to check an incoming JSON object against that filter. The filter should be JSON-serializable as well.

For example a filter that defines:

The object should have a property Prop1 with value Val1
It should have a property Prop2 that has an object as value, with SubProp1 equal to Val2
It should have a Prop3 that contains one of these values: [1, 2, 3]

Does something like this already exist, or will I need to implement this from scratch?

Just realized I may get far with JSON schema. Maybe not 100% what I need, but it's a start. — Coder14
Can you show an example how the filter string would look like? — tymtam
Well, the exact syntax is yet to be defined. I'm looking for some library that does something like this. An example in words: An object with a property Links which contains objects which have a property ID. The value of this ID property should be an item of this list: [1, 2, 42, 89, 16]. This is of course only a very small example. In reality, the filter will contain many properties, which hold on its own complex types, with many properties. — Coder14
You may want to use a JSON Schema. See the tag jsonschema. Newtonsoft has schema support as a paid extra. — dbc

tymtam tymtam · Accepted Answer · 2021-04-09T12:52:06

If your json serialiser is Json.NET then a validate method that uses JObject should do the job (official examples here).

For example:

bool Validate(string json) 
{
    JObject rss = JObject.Parse(json);
    if(((string)rss["Prop1"]) != "Val1" ) return false;
    ...

For the new .NET Core/5 System.Text.Json serialiser, a similar solution could be build with JsonDocument.Parse. An example is shown in Try the new System.Text.Json APIs.

Serializable filter on any object

1 Answers