#1 2020-10-16 11:14:22

mdbs99
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From: Rio de Janeiro, Brazil
Registered: 2018-01-20
Posts: 47
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RecordLoadJSON(): how to know what has changed in JSON?

I'm consuming a third API using RecordLoadJSON() a lot with proper TTextWriter.RegisterCustomJSONSerializerFromText() to register and fill records/objects "automagically".

My issue is that they, eventually, change the API without notify us before, and it breaks the system. What I do is search API responses—using the log—to find out which has changes, which new fields they introduced, etc.

Is there a way for mORMot tells me which is different between the JSON response and my record(s) structure?

best regards.

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#2 2020-10-16 17:24:42

ab
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From: France
Registered: 2010-06-21
Posts: 11,597
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Re: RecordLoadJSON(): how to know what has changed in JSON?

There is an option to let the parser ignore unknown fields IIRC, so it will work even if there some new fields in the returned JSON.

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#3 2020-10-16 17:43:28

mdbs99
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From: Rio de Janeiro, Brazil
Registered: 2018-01-20
Posts: 47
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Re: RecordLoadJSON(): how to know what has changed in JSON?

I may set this option to make it safer, however I've already got change even in field types on the API.

I think this API is new and still under construction...

IIRC, TTextWriter.RegisterCustomJSONSerializerFromText() shows a nice error, if record/object do not match with its "data string configuration". It would be nice, if RecordLoadJSON() could do the same.

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#4 2020-10-16 17:48:33

ab
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From: France
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Re: RecordLoadJSON(): how to know what has changed in JSON?

If your API is not backward compatible, then you need to use a versioned API.
But even a new API can be backward compatible. You can add fields.
I don't think that something magic may happen in RecordLoadJSON.

Perhaps a record is not the best structure for you, something more versatile like a TDocVariant or a class with custom serialization (not published properties, but manual reader/writer methods) may be used.
Then, once it is stabilized, use records.

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#5 2020-10-16 22:05:14

mdbs99
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From: Rio de Janeiro, Brazil
Registered: 2018-01-20
Posts: 47
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Re: RecordLoadJSON(): how to know what has changed in JSON?

If your API is not backward compatible, then you need to use a versioned API.

It's not my API, otherwise it wouldn't have this issue smile

I don't think that something magic may happen in RecordLoadJSON

"Roger that."

Perhaps a record is not the best structure for you, something more versatile like a TDocVariant or a class with custom serialization (not published properties, but manual reader/writer methods) may be used.
Then, once it is stabilized, use records.

I've coded the client that consume the API and it's written using records/objects all over the place—I can't change this now.

Thanks for try to help. If the API continues changing, I will continue investigating what has changed.

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#6 2020-10-19 16:19:05

macfly
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Registered: 2016-08-20
Posts: 237

Re: RecordLoadJSON(): how to know what has changed in JSON?

If you use a DocVariant you can do the validation.
There are methods that allow you to check if a property exists, extract the properties and check if there is a new one, etc.

You do not need to stop using the Records you already have. After validating you load in to Record.

You could also do this validation once a hour/day so as not to overload the system.

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#7 2020-10-19 22:42:32

mdbs99
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From: Rio de Janeiro, Brazil
Registered: 2018-01-20
Posts: 47
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Re: RecordLoadJSON(): how to know what has changed in JSON?

macfly,
I'm thinking to do some like that. The issue is how do it in an automatically way. I don't want to test every field manually, using Exists(), at first.

However, if it isn't possible, I will code this in regression tests.

Thanks.

Last edited by mdbs99 (2020-10-19 22:43:05)

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