Custom JSON marshal/unmarshal

[mitar]

Is your feature request related to a problem? Please describe.

I have two use cases where I think custom function to do JSON marshal/unmarshal would help (instead of default json.Marshal/json.Unmarshal:

• I want to marshal with SetEscapeHTML(false) set, because there is no point in escaping HTML when storing into a database. Similarly, I want to set KnownFields(true) when unmarshal, to detect errors early.
• I want to store a polymorphic JSON into a database (one where depending on its type field it gets unmarshal into different structs), the type being an interface. So I would use a custom unmarshal function which first checks the type and then does the rest.

Describe the solution you'd like

Some easy way to specify the default json.Marshal and json.Unmarshal function to be used.

Describe alternatives you've considered

It seems I could remove the json codec and create my own copy of it, with only difference being that it does not call json.Marshal. I would like to avoid having to maintain such a copy where the only difference is in the function which gets called.

[jackc]

You could implement json.Marshaler' and json.Unmarshaler` on your types that need this special behavior.

I think you could also insert your own logic in Map.TryWrapEncodePlanFuncs and Map.TryWrapScanPlanFuncs.

JSONCodec could be changed in a similar manner to 33360ab to allow for adding configuration. I'm not sure exactly what the interface would be though. If such a change is to be made it should allow for using entirely different json encoders (such as the rumored json/v2 or entirely third party json libraries).

[mitar]

You could implement json.Marshaler and json.Unmarshaler on your types that need this special behavior.

Sure, but then I have to do it on all types. It is a bit cumbersome.

I'm not sure exactly what the interface would be though. If such a change is to be made it should allow for using entirely different json encoders (such as the rumored json/v2 or entirely third party json libraries).

Oh, that is easy: func (input any) ([]byte, error) For both json/v2 and third party JSON libraries then you can provide a closure or a wrapper function which does any extra initialization or anything you want. See example in zerolog.

If you are open, I can make a PR adding such configuration option?

[jackc]

If you are open, I can make a PR adding such configuration option?

Sure.