flask-sqlalchemy-qs
flask-sqlalchemy-qs is a Python library that enables processing of query strings and its usage in conjunction with Flask and SQLAlchemy. The library provides tools for generating and manipulating SQLAlchemy filters and sorts from query strings in the URL, making it easier to build robust and flexible RESTful APIs.
A User model has a username column attribute to filter:
/users?filters[username][eq]=awesomeuser@example.com
A User model has a person relationship attribute, and a list of users has to be filtered and sorted by an attribute of that relationship:
/users?filters[person][age][gte]=22&sorts[0][person][age]=DESC&limit=10&offset=0
Installation
Install flask-sqlalchemy-qs with pip:
pip install flask-sqlalchemy-qs
Usage
To get the filters, sorts, limit, and offset from the query string is necesarry to follow the next syntaxis:
For the "filters" parameter
Filter your list result by column and relationship model properties.
GET /api/endpoint?filters[field][operator]=value
The following operators are available:
eq | Equal |
ne | Not equal |
is | Is |
is_not | Is not |
lt | Less than |
lte | Less than or equal to |
gt | Greater than |
gte | Greater than or equal to |
in | Included in an array |
nin | Not included in an array |
contains | Contains |
ncontains | Does not contain |
icontains | Contains (case-insensitive) |
like | Like |
ilike | Like (case-insensitive) |
not_like | Not Like |
not_ilike | Not Like (case-insensitive) |
nicontains | Does not contain (case-insensitive) |
startswith | Starts with |
istartswith | Starts with (case-insensitive) |
endswith | Ends with |
iendswith | Ends with (case-insensitive) |
or | Joins the filters in an "or" expression |
and | Joins the filters in an "and" expression |
not | Joins the filters in an "not" expression |
Examples:
/users?filters[username][eq]=username@example.com
- Relationship usage (User has a person)
/users?filters[person][name][eq]=Marco
/users?filters[username][contains]=awesome.com&filters[person][age][gte]=25
/users?filters[person][age][in][0]=20&filters[person][age][in][1]=25&filters[person][age][in][2]=30
/users?filters[or][0][username][eq]=username1&filters[or][1][username][eq]=username2
/users?filters[or][0][username][contains]=awesome.com&filters[or][1][not][0][and][0][person][age][gte]=20&filters[or][1][not][0][and][1][person][age][lte]=30
- JSON support followed by dot notation
/users?filters[json_column.foo][eq]=bar
For the "sorts" parameter
Sort your list result by column and relationship model properties.
GET /api/endpoint?sorts[priority_index][field]=order
Examples:
/users?sorts[0][username]=DESC
- Multiple order priority and relationship usage
/users?sorts[0][username]=DESC&sorts[1][person][age]=ASC
For the "limit" and "offset" parameter
Limt (amount of elements) and offset (amount of skipped elements) for your list result.
GET /api/endpoint?limit=10&offset=2
Examples:
/users?limit=100&offset=5
Implementation
In order to use it in the sqlalchemy query object. The BaseQuery needs to be imported and set as the query_class in the model
from typing import Dict, List, Tuple, Union
from flask_sqlalchemy_qs import get_url_query_ctx, BaseQuery
...
db = SQLAlchemy(app)
class Base(db.Model):
__abstract__ = True
query_class = BaseQuery
class User(Base):
id = db.Column(db.Integer, primary_key=True)
...
...
FilterType = Dict[str, Union[bool, str, Dict]]
SortType = Dict[str, Union[str, Dict]]
...
@myblueprint.route('/users', methods=['GET'])
def get_all_users():
ctx: Dict[str, Union[FilterType, List[SortType], int]] = get_url_query_ctx()
filters:FilterType = ctx["filters"]
sorts:List[SortType] = ctx["sorts"]
limit:int = ctx["limit"]
offset:int = ctx["offset"]
query = User.query.filter_by_ctx(filters=filters) \
.sort_by_ctx(sorts=sorts) \
.offset(offset) \
.limit(limit)
...
results = query.all()
...
Version
1.1.5
Requirements
SQLALCHEMYSQLAlchemy~=2.0
flask~=2.2
flask-sqlalchemy~=3.0
Contribution
Contributions to this project are welcome. Please open an issue or make a pull request.
License
This project is licensed under the terms of the MIT license.
Support
If you have any issues or suggestions, please open an issue on this repository.
Authors
Marco Gil, marcogil93@gmail.com