Optional nesting (handling an embed parameter)

I’m aware of how to nest items, as described in the documentation. Per those examples (with slight modifications) I am able to nest, say, a Author in a Book:

class AuthorSchema(Schema):
    class Meta:
        fields = ('id', 'name')

class BookSchema(Schema):
    author = fields.Nested(AuthorSchema, only='id')
    class Meta:
        fields = ('id', 'title', 'author')

This is all fine and dandy. However, say I was exposing these models over a REST API and I wanted to implement an embed paremeter, as described here. From what I can see, I would need to either (a) define a huge number of alternative schemas (i.e. BookSchema_AuthorID, BookSchema_AuthorName, BookSchema_AuthorIDName etc.) or (b) perform some processing on the serialized output and strip out fields I don’t want. Neither of these are ideal. Is there any alternative?

[deckar01]

Fixed by #468.

[deckar01]

Version 2.8.0 added support for specifying nested field names to the onlyand exclude options on your schema constructors. This allows you to spin up deeply customized schema instances without declaring new schema classes or reaching into undocumented parts of the schema interface.

Check out the documentation for the dotted nesting syntax in the “Nesting Schema’s” section of the docs.

https://marshmallow.readthedocs.io/en/latest/nesting.html#specifying-which-fields-to-nest

class SiteSchema(Schema):
    blog = fields.Nested(BlogSchema2)

schema = SiteSchema(only=['blog.author.email'])
result, errors = schema.dump(site)
pprint(result)
# {
#     'blog': {
#         'author': {'email': u'[e-mail]'}
#     }
# }