Allow use of Schema hooks on OneOfSchema #130
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Rather than overriding the `dump()` and `load()` methods of the Schema class, override `_serialize` and `_deserialize`, which are the "concrete" steps in schema loading and dumping which handle loading or dumping on a field-by-field basis. This still uses load() and dump() methods of the type schemas being used, but it happens between the various hooks which may run on the OneOfSchema instance. Add a test that checks that a `post_dump` hook to remove the `type` field works. The most significant downside of this change is that it makes use of several private APIs within marshmallow. Not only are `_serialize` and `_deserialize` private methods, but the error_store object which is used here is also considered private (per marshmallow docs). In order to better guarantee behavior near-identical to marshmallow, several methods from marshmallow.utils have been copied in-tree here. One notable API change here is that arbitrary keyword arguments are no longer being passed from `OneOfSchema.load()` and `OneOfSchema.dump()` down into the type schemas' load and dump methods. As a result, you cannot specify a load or dump parameter here and expect it to take effect. With the switch to overriding `_serialize` and `_deserialize`, there is no practical way to pass parameters like that. closes marshmallow-code#4
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Reviewing existing issues, I believe this will also resolve #74 , since it allows |
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Something which has been bothering me about this since I opened it is that On the one hand, this implementation strikes me as much simpler and makes all of the hooks work for free. On the other hand, I don't see how to make this work for the case cited in #111 without additional upstream changes in |
NOTE: this change is very mildly backwards-incompatible, but since 3.0 is coming up for this lib, I think it's okay.
Rather than overriding the
dump()andload()methods of the Schema class, override_serializeand_deserialize, which are the "concrete" steps in schema loading and dumping which handle loading or dumping on a field-by-field basis.This still uses load() and dump() methods of the type schemas being used, but it happens between the various hooks which may run on the OneOfSchema instance.
Add a test that checks that a
post_dumphook to remove thetypefield works.The most significant downside of this change is that it makes use of several private APIs within marshmallow. Not only are
_serializeand_deserializeprivate methods, but the error_store object which is used here is also considered private (per marshmallow docs).In order to better guarantee behavior near-identical to marshmallow, several methods from marshmallow.utils have been copied in-tree here.
One notable API change here is that arbitrary keyword arguments are no longer being passed from
OneOfSchema.load()andOneOfSchema.dump()down into the type schemas' load and dump methods. As a result, you cannot specify a load or dump parameter here and expect it to take effect.With the switch to overriding
_serializeand_deserialize, there is no practical way to pass parameters like that.closes #4