Object serialization feature tuning

Сергей Нелюбин

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Oct 30, 2019, 1:07:32 PM10/30/19

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Hello, Andrus!

Can i customize serialization settings for agrest output?

For example, i want disable serialize nullable attributes.

Andrus Adamchik

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Oct 31, 2019, 2:49:57 AM10/31/19

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Hi Sergey,

There are a few ways to customize aspects of JSON encoding. Here is one that may be applicable in your case. Since Agrest 3.3 there is an injectable ValueEncoders service that maintains a collection of common property encoders per value type as well as a generic fallback encoder, and ValueEncodersProvider that builds an instance of that class. You can create a provider subclass, and bind it via a custiom Module:

AgBuilder.builder(runtime).module(binder -> {
binder.bind(ValueEncoders.class).toProvider(MyValueEncodersProvider.class);
})
.build();

In MyValueEncodersProvider you may override "createValueEncoders" method to decorate all the preloaded encoders to skip null values.

Andrus

Сергей Нелюбин

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Oct 31, 2019, 6:19:14 AM10/31/19

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Hi Andrus,

It worked!

But what about calculated attributes (built by AgEntityOverlay) ?

If i return null at method addAttribute, null value serialized.

четверг, 31 октября 2019 г., 9:49:57 UTC+3 пользователь Andrus Adamchik написал:

Andrus Adamchik

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Oct 31, 2019, 6:33:08 AM10/31/19

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This is odd. AgEntityOverlay attributes are handled the same way as any regular attributes. Could be a bug (?)

Are you using Agrest 3.3? Also are you attaching the overlay per request, or load it to Agrest runtime on startup?

Andrus

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Сергей Нелюбин

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Oct 31, 2019, 7:12:00 AM10/31/19

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Yes, version 3.3, load Overlay on startup.

I make wrapper for defaultEncoder only

protected ValueEncoders createValueEncoders(Map<Class<?>, Encoder> encoders, Encoder defaultEncoder) {
    return super.createValueEncoders(encoders, new GenericEncoderExt( defaultEncoder ));
}

Map<Class<?>, Encoder> encoders contains only Date/Time Encoders

четверг, 31 октября 2019 г., 13:33:08 UTC+3 пользователь Andrus Adamchik написал:

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Сергей Нелюбин

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Oct 31, 2019, 7:17:56 AM10/31/19

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And further, my overlay is Map type

This is probably the reason, because genericEncoder applies to simple attributes, not collections

четверг, 31 октября 2019 г., 14:12:00 UTC+3 пользователь Сергей Нелюбин написал:

Сергей Нелюбин

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Oct 31, 2019, 7:35:09 AM10/31/19

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Can i override ListEncoder behavior ?

четверг, 31 октября 2019 г., 14:17:56 UTC+3 пользователь Сергей Нелюбин написал:

Andrus Adamchik

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Nov 4, 2019, 1:12:03 AM11/4/19

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Yeah, Agrest makes a distinction between "values" and "entities" when creating JSON. Entities result in JSON trees, and hence require recursive descent during encoding. Can't say whether this will work with your Map structure or not, but to customize entity encoding, you'd use EntityEncoderFilter (as opposed to ValueEncoders). EntityEncoderFilters can also be registered either once for the entire Ag stack or per request.

Andrus

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