multiple text fields (wildcard text) index using $** does not work

[maskiran]

mongodb supports creating a text index of all string fields using $**. mongoengine complains that there is no such field. please suport this feature.

https://docs.mongodb.com/manual/core/index-text/#create-text-index

[rrei]

Upon inspecting the source code (BaseDocument._build_index_spec()) the '$' character gets removed from field names, and since '$**' is treated like any other field therefore mongoengine ends up creating a text index on a field called '**' instead of a wildcard text index.

[esteininger]

Any update here?

[rrei]

For what it's worth, this is the solution I came up with:

import mongoengine


class WildcardTextIndexMixin:
    """A mixin to fix mongoengine's bug preventing the creation of wildcard text indices (it
    strips the leading $ character and ends up creating a text index on a field called '**').
    Note that this does not support any additional options that can be passed to text indices,
    but it can be easily extended to do so.
    """

    @classmethod
    def _build_index_spec(cls, spec):
        if spec == "$**":
            return {"fields": [("$**", "text")]}
        return super()._build_index_spec(spec)


class PrettyDocumentMixin:
    """A mixin for document classes providing a nicer more informative `repr()` as well as a
    `get_fields()` method that builds a dictionary . """

    def __repr__(self):
        return f"<{type(self).__name__} {self.get_fields()} @{id(self):x}>"

    def get_fields(self):
        return {f: getattr(self, f) for f in self._fields_ordered}


class Document(WildcardTextIndexMixin, PrettyDocumentMixin, mongoengine.Document):
    meta = {"abstract": True}


class DynamicDocument(WildcardTextIndexMixin, PrettyDocumentMixin, mongoengine.DynamicDocument):
    meta = {"abstract": True}

This is really tailored just to handle the creation of wildcard text indices. Since it relies on the internals of mongoengine, any changes to those internals will probably break this mixin, so it's a stopgap solution. Let's hope that this gets officially fixed soon. I hope it helps :)

EDIT: here's an example usage of this document subclass

import mongoengine

import utils.mongo


class Payment(utils.mongo.DynamicDocument):

    amount = mongoengine.DecimalField(required=True)
    method = mongoengine.StringField(required=True)

    # Create a wildcard text index for text queries across all fields.
    meta = {"indexes": ["$**"]}

[hiimdoublej-swag]

Any updates on this ? Would really like wildcard indexes.