feat(inspectdb): hack inspectdb
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drupal2spip_lal/base/management/commands/inspectdb.py
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303
drupal2spip_lal/base/management/commands/inspectdb.py
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import keyword
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import re
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from django.core.management.base import BaseCommand, CommandError
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from django.db import DEFAULT_DB_ALIAS, connections
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from django.db.models.constants import LOOKUP_SEP
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class Command(BaseCommand):
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help = "Introspects the database tables in the given database and outputs a Django model module."
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requires_system_checks = False
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stealth_options = ('table_name_filter',)
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db_module = 'django.db'
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def add_arguments(self, parser):
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parser.add_argument(
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'table', nargs='*', type=str,
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help='Selects what tables or views should be introspected.',
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)
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parser.add_argument(
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'--database', default=DEFAULT_DB_ALIAS,
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help='Nominates a database to introspect. Defaults to using the "default" database.',
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)
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parser.add_argument(
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'--include-partitions', action='store_true', help='Also output models for partition tables.',
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)
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parser.add_argument(
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'--include-views', action='store_true', help='Also output models for database views.',
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)
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def handle(self, **options):
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try:
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for line in self.handle_inspection(options):
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self.stdout.write("%s\n" % line)
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except NotImplementedError:
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raise CommandError("Database inspection isn't supported for the currently selected database backend.")
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def handle_inspection(self, options):
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connection = connections[options['database']]
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# 'table_name_filter' is a stealth option
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table_name_filter = options.get('table_name_filter')
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def table2model(table_name):
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return re.sub(r'[^a-zA-Z0-9]', '', table_name.title())
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with connection.cursor() as cursor:
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yield "# This is an auto-generated Django model module."
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yield "# You'll have to do the following manually to clean this up:"
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yield "# * Rearrange models' order"
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yield "# * Make sure each model has one field with primary_key=True"
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yield "# * Make sure each ForeignKey and OneToOneField has `on_delete` set to the desired behavior"
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yield (
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"# * Remove `managed = False` lines if you wish to allow "
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"Django to create, modify, and delete the table"
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)
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yield "# Feel free to rename the models, but don't rename db_table values or field names."
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yield 'from %s import models' % self.db_module
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known_models = []
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table_info = connection.introspection.get_table_list(cursor)
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# Determine types of tables and/or views to be introspected.
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types = {'t'}
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if options['include_partitions']:
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types.add('p')
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if options['include_views']:
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types.add('v')
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for table_name in (options['table'] or sorted(info.name for info in table_info if info.type in types)):
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if table_name_filter is not None and callable(table_name_filter):
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if not table_name_filter(table_name):
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continue
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try:
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try:
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relations = connection.introspection.get_relations(cursor, table_name)
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except NotImplementedError:
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relations = {}
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try:
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constraints = connection.introspection.get_constraints(cursor, table_name)
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except NotImplementedError:
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constraints = {}
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primary_key_column = connection.introspection.get_primary_key_column(cursor, table_name)
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unique_columns = [
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c['columns'][0] for c in constraints.values()
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if c['unique'] and len(c['columns']) == 1
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]
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table_description = connection.introspection.get_table_description(cursor, table_name)
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except Exception as e:
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yield "# Unable to inspect table '%s'" % table_name
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yield "# The error was: %s" % e
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continue
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yield ''
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yield ''
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yield 'class %s(models.Model):' % table2model(table_name)
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known_models.append(table2model(table_name))
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used_column_names = [] # Holds column names used in the table so far
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column_to_field_name = {} # Maps column names to names of model fields
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for row in table_description:
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comment_notes = [] # Holds Field notes, to be displayed in a Python comment.
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extra_params = {} # Holds Field parameters such as 'db_column'.
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column_name = row.name
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is_relation = column_name in relations
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is_pk = column_name == primary_key_column
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has_pk = primary_key_column
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att_name, params, notes = self.normalize_col_name(
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column_name, used_column_names, is_relation, is_pk, has_pk)
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extra_params.update(params)
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comment_notes.extend(notes)
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used_column_names.append(att_name)
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column_to_field_name[column_name] = att_name
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# Add primary_key and unique, if necessary.
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if is_pk or (column_name == 'id' and not has_pk):
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extra_params['primary_key'] = True
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elif column_name in unique_columns:
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extra_params['unique'] = True
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if is_relation:
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if extra_params.pop('unique', False) or extra_params.get('primary_key'):
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rel_type = 'OneToOneField'
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else:
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rel_type = 'ForeignKey'
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rel_to = (
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"self" if relations[column_name][1] == table_name
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else table2model(relations[column_name][1])
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)
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if rel_to in known_models:
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field_type = '%s(%s' % (rel_type, rel_to)
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else:
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field_type = "%s('%s'" % (rel_type, rel_to)
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else:
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# Calling `get_field_type` to get the field type string and any
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# additional parameters and notes.
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field_type, field_params, field_notes = self.get_field_type(connection, table_name, row)
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extra_params.update(field_params)
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comment_notes.extend(field_notes)
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field_type += '('
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# Don't output 'id = meta.AutoField(primary_key=True)', because
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# that's assumed if it doesn't exist.
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if att_name == 'id' and extra_params == {'primary_key': True}:
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if field_type == 'AutoField(':
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continue
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elif field_type == 'IntegerField(' and not connection.features.can_introspect_autofield:
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comment_notes.append('AutoField?')
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# Add 'null' and 'blank', if the 'null_ok' flag was present in the
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# table description.
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if row.null_ok: # If it's NULL...
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extra_params['blank'] = True
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extra_params['null'] = True
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field_desc = '%s = %s%s' % (
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att_name,
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# Custom fields will have a dotted path
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'' if '.' in field_type else 'models.',
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field_type,
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)
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if field_type.startswith(('ForeignKey(', 'OneToOneField(')):
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field_desc += ', models.DO_NOTHING'
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if extra_params:
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if not field_desc.endswith('('):
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field_desc += ', '
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field_desc += ', '.join('%s=%r' % (k, v) for k, v in extra_params.items())
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field_desc += ')'
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if comment_notes:
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field_desc += ' # ' + ' '.join(comment_notes)
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yield ' %s' % field_desc
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is_view = any(info.name == table_name and info.type == 'v' for info in table_info)
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is_partition = any(info.name == table_name and info.type == 'p' for info in table_info)
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for meta_line in self.get_meta(table_name, constraints, column_to_field_name, is_view, is_partition):
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yield meta_line
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def normalize_col_name(self, col_name, used_column_names, is_relation, is_pk, has_pk):
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"""
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Modify the column name to make it Python-compatible as a field name
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"""
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field_params = {}
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field_notes = []
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new_name = col_name.lower()
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if new_name != col_name:
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field_notes.append('Field name made lowercase.')
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if is_relation:
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if new_name.endswith('_id'):
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new_name = new_name[:-3]
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else:
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field_params['db_column'] = col_name
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new_name, num_repl = re.subn(r'\W', '_', new_name)
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if num_repl > 0:
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field_notes.append('Field renamed to remove unsuitable characters.')
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if new_name.find(LOOKUP_SEP) >= 0:
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while new_name.find(LOOKUP_SEP) >= 0:
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new_name = new_name.replace(LOOKUP_SEP, '_')
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if col_name.lower().find(LOOKUP_SEP) >= 0:
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# Only add the comment if the double underscore was in the original name
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field_notes.append("Field renamed because it contained more than one '_' in a row.")
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if new_name.startswith('_'):
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new_name = 'field%s' % new_name
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field_notes.append("Field renamed because it started with '_'.")
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if new_name.endswith('_'):
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new_name = '%sfield' % new_name
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field_notes.append("Field renamed because it ended with '_'.")
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if keyword.iskeyword(new_name):
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new_name += '_field'
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field_notes.append('Field renamed because it was a Python reserved word.')
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if new_name == 'id' and not is_pk and has_pk:
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new_name += '_field'
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field_notes.append("Field renamed because 'id' can only be used as a field name if the field also sets 'primary_key=True'")
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if new_name[0].isdigit():
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new_name = 'number_%s' % new_name
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field_notes.append("Field renamed because it wasn't a valid Python identifier.")
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if new_name in used_column_names:
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num = 0
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while '%s_%d' % (new_name, num) in used_column_names:
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num += 1
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new_name = '%s_%d' % (new_name, num)
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field_notes.append('Field renamed because of name conflict.')
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if col_name != new_name and field_notes:
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field_params['db_column'] = col_name
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return new_name, field_params, field_notes
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def get_field_type(self, connection, table_name, row):
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"""
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Given the database connection, the table name, and the cursor row
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description, this routine will return the given field type name, as
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well as any additional keyword parameters and notes for the field.
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"""
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field_params = {}
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field_notes = []
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try:
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field_type = connection.introspection.get_field_type(row.type_code, row)
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except KeyError:
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field_type = 'TextField'
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field_notes.append('This field type is a guess.')
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# Add max_length for all CharFields.
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if field_type == 'CharField' and row.internal_size:
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field_params['max_length'] = int(row.internal_size)
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if field_type == 'DecimalField':
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if row.precision is None or row.scale is None:
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field_notes.append(
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'max_digits and decimal_places have been guessed, as this '
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'database handles decimal fields as float')
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field_params['max_digits'] = row.precision if row.precision is not None else 10
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field_params['decimal_places'] = row.scale if row.scale is not None else 5
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else:
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field_params['max_digits'] = row.precision
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field_params['decimal_places'] = row.scale
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return field_type, field_params, field_notes
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def get_meta(self, table_name, constraints, column_to_field_name, is_view, is_partition):
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"""
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Return a sequence comprising the lines of code necessary
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to construct the inner Meta class for the model corresponding
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to the given database table name.
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"""
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unique_together = []
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has_unsupported_constraint = False
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for params in constraints.values():
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if params['unique']:
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columns = params['columns']
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if None in columns:
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has_unsupported_constraint = True
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columns = [x for x in columns if x is not None]
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if len(columns) > 1:
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unique_together.append(str(tuple(column_to_field_name[c] for c in columns)))
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if is_view:
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managed_comment = " # Created from a view. Don't remove."
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elif is_partition:
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managed_comment = " # Created from a partition. Don't remove."
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else:
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managed_comment = ''
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meta = ['']
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if has_unsupported_constraint:
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meta.append(' # A unique constraint could not be introspected.')
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meta += [
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' class Meta:',
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' managed = False%s' % managed_comment,
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' db_table = %r' % table_name
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]
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if unique_together:
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tup = '(' + ', '.join(unique_together) + ',)'
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meta += [" unique_together = %s" % tup]
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return meta
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