Initial commit with a working version
It can already collect all the registered models and make a query on different fields. It displays the first 10 records matching the query. There are currently no means to filter the data.
This commit is contained in:
212
flask_sqlalchemy_webquery/__init__.py
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212
flask_sqlalchemy_webquery/__init__.py
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from flask import current_app, Blueprint, render_template, request, jsonify
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class FlaskSQLAlchemyWebquery(object):
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def __init__(self, app=None):
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self.models = {}
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self.blueprint = None
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self.db = None
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if app:
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self.init_app(app)
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def list_models(self):
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return render_template('flask_sqlalchemy_webquery/list-models.html')
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def get_joins(self, from_model, to_model):
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if from_model == to_model:
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return []
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from math import inf
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Q = set()
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dist = {}
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prev = {}
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for model, model_data in self.models.items():
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# v: model
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dist[model] = inf
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prev[model] = None
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Q.add(model)
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dist[from_model] = 0
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while Q:
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dests = sorted(Q, key=lambda x: dist[x])
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u = dests[0]
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if u == to_model:
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break
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Q.remove(u)
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for v in self.models[u]['related_tables'].keys():
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if v not in Q:
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continue
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alt = dist[u] + 1
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if alt < dist[v]:
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dist[v] = alt
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prev[v] = u
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S = []
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u = to_model
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while u in prev:
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S.append(u)
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u = prev[u]
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S.reverse()
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return S
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def update_view(self):
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if 'model' not in request.json or \
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'columns' not in request.json:
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return jsonify((400, {'error': 'Missing input'}))
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(model_class,) = [cls for cls, data in self.models.items() if data['table'].name == request.json['model']]
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available_models = {}
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to_add = [model_class]
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while to_add:
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model = to_add.pop()
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if model in available_models:
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continue
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available_models[model] = self.models[model]
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to_add += self.models[model]['related_tables'].keys()
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columns = {}
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# Collect all columns reachable from the selected model
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for cls, model_data in available_models.items():
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table_name = model_data['table'].name
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columns[table_name] = []
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for column_name, column in model_data['columns'].items():
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columns[table_name].append(column_name)
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joins = []
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# Fetch the results
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if request.json['columns']:
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requested_columns = request.json['columns']
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query = self.db.session.query(model_class)
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for data in requested_columns:
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model_name, column_name = data['model'], data['column']
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target_model = self.get_model_by_table_name(model_name)
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for cls in self.get_joins(model_class, target_model):
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if cls not in joins and cls != model_class:
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query = query.join(cls)
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joins.append(cls)
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result_count = query.count()
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results = []
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# TODO: Make this configurable
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for row in query.limit(10):
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res_row = {}
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for data in requested_columns:
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model_name, column_name = data['model'], data['column']
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target_model = self.get_model_by_table_name(model_name)
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res_key = ':'.join((model_name, column_name))
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print(row)
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if target_model == model_class:
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current_value = getattr(row, column_name)
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else:
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current = model_class
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current_value = row
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for cls in self.get_joins(model_class, target_model):
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if cls == model_class:
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continue
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next_column_name = self.models[current]['related_tables'][cls]
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current_value = getattr(current_value, next_column_name)
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current = cls
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if cls == target_model:
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current_value = getattr(current_value, column_name)
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res_row[res_key] = current_value
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results.append(res_row)
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else:
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results = None
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result_count = 0
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return jsonify({
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'results': results,
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'columns': columns,
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'count': result_count
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})
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def get_model_by_table_name(self, table_name):
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for model, model_data in self.models.items():
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if model_data['table'].name == table_name:
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return model
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def init_app(self, app):
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self.db = app.extensions['sqlalchemy'].db
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self.models = {}
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for cls in self.db.Model._decl_class_registry.values():
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if isinstance(cls, type) and issubclass(cls, self.db.Model):
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self.models[cls] = {
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'table': cls.__table__,
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'related_tables': {},
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'columns': cls.__mapper__.columns
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}
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for model in self.models:
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from sqlalchemy.orm.base import MANYTOONE
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from sqlalchemy.orm.attributes import InstrumentedAttribute
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from sqlalchemy.orm.relationships import RelationshipProperty
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relationships = {}
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for attr_name in model.__dict__:
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attr = getattr(model, attr_name)
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if isinstance(attr, InstrumentedAttribute):
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if isinstance(attr.property, RelationshipProperty):
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relationships[attr.property] = attr_name
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for r in model.__mapper__.relationships:
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# Only support many to one relationships (e.g. foreign keys)
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if r.direction != MANYTOONE:
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continue
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for local, remote in r.local_remote_pairs:
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(remote_model,) = [remote_model for remote_model, model_data in self.models.items() if model_data['table'] == remote.table]
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self.models[model]['related_tables'][remote_model] = relationships[r]
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self.blueprint = Blueprint('flask_sqlalchemy_webquery',
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__name__,
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template_folder='templates',
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static_folder='static',
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static_url_path=app.static_url_path + 'flask_sqlalchemy_webquery')
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self.blueprint.add_url_rule('/list-models', 'list_models', self.list_models)
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self.blueprint.add_url_rule('/get-columns', 'update_view', self.update_view, methods=['POST'])
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@self.blueprint.context_processor
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def inject_variables():
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return {
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'models': self.models
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}
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app.register_blueprint(self.blueprint)
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