xsd_to_django_model

Generate Django models from an XSD schema description (and a bunch of hints)

TODO

• More examples.
• More heuristics.
• Better xs:complexType/(xs:simpleContent|xs:complexContent)/xs:restriction support.
• xs:simpleType/xs:union support.
• ...?

Getting started

Usage:
    xsd_to_django_model.py [-m <models_filename>] [-f <fields_filename>] [-j <mapping_filename>] <xsd_filename> <xsd_type>...
    xsd_to_django_model.py -h | --help

Options:
    -h --help              Show this screen.
    -m <models_filename>   Output models filename [default: models.py].
    -f <fields_filename>   Output fields filename to build custom Django field classes.
    -j <mapping_filename>  Output JSON mapping filename [default: mapping.json].
    <xsd_filename>         Input XSD schema filename.
    <xsd_type>             XSD type (or, if starting with `/`, the name of the toplevel element of the type) for which a Django model should be generated.

If you have xsd_to_django_model_settings.py in your PYTHONPATH or in the current directory, it will be imported.

Examples

See the examples subdirectory.

Settings

If you have xsd_to_django_model_settings.py in your PYTHONPATH or in the current directory, it will be imported. It may define the following module-level variables:

• MAX_LINE_LENGTH is maximum line length in generated Python code. Wrapping works for most of the cases; probably one should use black if that matters anyways.

• TYPE_MOODEL_MAP is a collections.OrderedDict (you can use dict but then processing order is not guaranteed) which maps XSD xs:complexType names (including ones autogenerated for anonymous xs:complexTypes) to Django model class names, using regular expressions, e.g., if the XSD types are all called like tMyStrangeTasteType, this will generate model names like MyStrangeTaste:

  from collections import OrderedDict
  
  TYPE_MODEL_MAP = OrderedDict([
      (r't([A-Z].*)Type', r'\1'),
  ])

  If you are mapping different XSD types to a single Django model, prefix the Django model's name with + to make sure model merging logic works well.

• MODEL_OPTIONS is a dict mapping model names to dicts of options applied when processing this model:

  MODEL_OPTIONS = {
      'MyStrangeTaste': {
          'abstract': True,
      },
  }

  Supported model options:

  • abstract - when True, enforce abstract = True in Django models Meta`.
  • add_fields - a list of extra fields which should be included in the final Django model class. Most of the options should be set in these definitions, overrides won't work. Example:

    'add_fields': [
        {
            'name': 'content_md5',                # Django model field name
            'dotted_name': 'a.any',               # path to the field in XML
            'django_field': 'models.UUIDField',   # Django field class
            'doc': 'A hash to speed up lookups',  # Django field's verbose_name
            'options': ['db_index=True'],         # Django field's options
        },
    ],

  • add_json_attrs - a mapping of extra JSON attributes to their documentation.
  • array_fields - a list of XSD fields for which django.contrip.postgres.fields.ArrayFields should be generated. The corresponding xs:element should either have maxOccurs="unbounded" or contain an xs:complexType whose only member has maxOccurs="unbounded".
  • coalesce_fields - a dict mapping generated field names to actual field names in Django models, using regular expressions, e.g.:

    'coalesce_fields': {
        r'a_very_long_autogenerated_prefix_(.+)': r'myprefix_\1',
    },

  • custom - when True, treat the model as a custom model which does not have a corresponding xs:complexType in XSD schema. Makes sense to use at least add_fields as well in such case.
  • drop_fields - a list of field names to be ignored when encountered, e.g.:

    'drop_fields': ['digitalSignature2KBInSize'],

  • field_docs - a dict which allows to override verbose_name Django model field option for given fields:

    'field_docs': {
        'objectName': 'Fully qualified object name',
    }

  • field_options - a dict mapping final Django model field names to a list of their overridden options, e.g.:

    'field_options': {
        'schemeVersion': ['max_length=7'],
    }

  • flatten_fields - a list of fields where the contained xs:complexType should not be treated as a separate Django model, but is to be merged in the current model, with member field names prefixed with this field's name and a _:

    'flatten_fields': ['section1', 'section2'],

  • flatten_prefixes - a list of field name prefixes which trigger the same flattening logic as flatten_fields. I do not recommend to use this option as things get too much automatic with it.
  • foreign_key_overrides - a dict mapping field names to XSD type names when this field is to be treated as a ForeignKey reference to that type`s corresponding model.
  • gin_index_fields - a list of Django model fields for which indexes are defined in Meta using Django 1.11+ indexes and django.contrib.postgres.indexes.GinIndex.
  • if_type - a dict mapping XSD type names to dicts of options which are used only when source XSD type name matches that type name; used by model merging logic to ensure merged fields do not differ in models being merged:

    'if_type': {
        'tMyStrangeTasteType': {
            'abstract': True,
        },
    },

  • ignore_merge_mismatch_fields: a list of fields for which generated code differences are to be ignored when model merging takes place. I do not recommend to use this option as it gets harder to track changes over time.
  • include_parent_fields: when True, the parent (xs:complexType/xs:complexContent/xs:extension[@base] type's fields are simply included in the current model instead of making Django model inheritance structures.
  • index_fields - a list of Django model fields for which db_index=True option should be generated.
  • json_fields - a list of XSD fields which do not get their own Django model fields but are all mapped to a single attrs = django.contrib.postgres.fields.JSONField().
  • many_to_many_field_overrides - a dict mapping field names to XSD type names when this field is to be treated as a ManyToManyField reference to that type`s corresponding model.
  • many_to_many_fields - a list of field names that get mapped to Django ManyToManyFields.
  • meta - a list of Django model Meta options' string templates added to the generated model's Meta:

    'meta': [
        'db_table = "my_%(model_lower)s"',
    ]

    Template variables:
    • model_lower resolves to lowercased model name.
  • methods - a list of strings that are included as methods in the generated model class, e.g.:

    'methods': [
        '    def __unicode__(self): return "%s: %s" % (self.code, self.amount)',
    ],

  • null_fields - a list of field names for which null=True Django model field option should be enforced.
  • one_to_many_field_overrides - a dict mapping one-to-many relationship field names to related Django model names when automated logic does not work well.
  • one_to_many_fields - a list of field names that get mapped to one-to-many relationships in Django, that is, a ForeignKey to this model is added to the related model's fields.
  • one_to_one_fields - a list of field names that get mapped to one-to-one (shared primary key) relationships in Django, that is, a OneToOneField(primary_key=True) to this model is added to the related models's fields.
  • override_field_class - a dict mapping field names to corresponding Django field class names when automated logic does not work well, e.g.:

    'override_field_class': {
        'formattedNumber': 'models.TextField',  # The actual data does not meet maximum length restriction
    }

  • parent_type - an XSD xs:complexType name which is to be used as this model's parent type when automated logic does not work, e.g., when custom is True.
  • plain_index_fields - a list of Django model fields for which indexes are defined in Meta using Django 1.11+ indexes and models.Index. This is useful when you don't need extra index for LIKE queries autogenerated with db_index=True option.
  • primary_key specifies a single field name for which primary_key=True Django model field option is to be generated.
  • reference_extension_fields - a list of field names which use xs:complexType/xs:complexContent/xs:extension' inheritance schema but extend the base type with extra members; these fields will be mapped to a ForeignKeyto their base type's model, and the extension members will be flattened (as inflatten_fields`).
  • reverse_fields - Sort fields in reflected lexicographic order to simplify merging fields from different flattened branches at mapping development time.
  • skip_code - if True, the generated model code is to be skipped when saving the models module.
  • strategy - if 1, the strategy is to flatten all nested structures by default unless they refer to a toplevel model, or to a N:many relationship.
  • strict_index_fields - a list of Django model fields to generate a composite index including the primary key.
  • unique_fields - a list of Django model fields for which unique=True option should be generated.

• GLOBAL_MODEL_OPTIONS is a dict of model options applied to each model (but may be overridden by the respective options in that very model):

  GLOBAL_MODEL_OPTIONS = {
      'json_fields': ['attachments', 'abracatabra'],
  }

  Additional global options:

  • charfield_max_length_factor (defaults to 1) - a factor to multiply every CharFields max_length by, e.g. when actual XML data is bigger than XSD dictates.

• TYPE_OVERRIDES is a dict mapping XSD type names to Django model fields when automatic heuristics don't work, e.g.:

  TYPE_OVERRIDES = {
      'xs:IDREF': ('A reference to xs:ID', 'CharField', {'max_length': 64}),
  }

• BASETYPE_OVERRIDES is a dict mapping XSD base type names to Django field to override default ones, e.g.:

  BASETYPE_OVERRIDES = {
      'xs:hexBinary': 'CharField',
  }

• IMPORTS is a string inserted after the automatically generated imports in the output models file, e.g.:

  IMPORTS = "from mycooldjangofields import StarTopologyField"

• DOC_PREPROCESSOR is a function to preprocess documentation strings, e.g.:

  def doc_preprocessor(s):
      return s.replace('\n', ' ')
  
  DOC_PREPROCESSOR = doc_preprocessor

• JSON_DOC_HEADING is documentation heading template for JsonFields.

• JSON_GROUP_HEADING is documentation attribute group heading template for JsonFields.

• JSON_DOC_INDENT is indent prefix in documentation sublists. The default is 4 spaces, which is compatible between Markdown and reStructuredText.