.. _searchformat: .. currentmodule:: flask.ext.restless Making search queries ===================== Clients can make :http:method:`get` requests on individual instances of a model (for example, :http:get:`/api/person/1`) and on collections of all instances of a model (:http:get:`/api/person`). To get all instances of a model that meet some criteria, clients can make :http:method:`get` requests with a query parameter specifying a search. The search functionality in Flask-Restless is relatively simple, but should suffice for many cases. Quick examples -------------- The following are some quick examples of creating search queries with different types of clients. Find more complete documentation in subsequent sections. In these examples, each client will search for instances of the model ``Person`` whose names contain the letter "y". Using the Python `requests `_ library:: import requests import json url = 'http://127.0.0.1:5000/api/person' headers = {'Content-Type': 'application/json'} filters = [dict(name='name', op='like', val='%y%')] params = dict(q=json.dumps(dict(filters=filters))) response = requests.get(url, params=params, headers=headers) assert response.status_code == 200 print(response.json()) Using `jQuery `_: .. sourcecode:: javascript var filters = [{"name": "id", "op": "like", "val": "%y%"}]; $.ajax({ url: 'http://127.0.0.1:5000/api/person', data: {"q": JSON.stringify({"filters": filters})}, dataType: "json", contentType: "application/json", success: function(data) { console.log(data.objects); } }); Using `curl `_: .. sourcecode:: bash curl \ -G \ -H "Content-type: application/json" \ -d "q={\"filters\":[{\"name\":\"name\",\"op\":\"like\",\"val\":\"%y%\"}]}" \ http://127.0.0.1:5000/api/person The ``examples/`` directory has more complete versions of these examples. .. _queryformat: Query format ------------ The query parameter ``q`` must be a JSON string. It can have the following mappings, all of which are optional: ``filters`` A list of objects of one of the following forms:: {"name": , "op": , "val": } or:: {"name": , "op": , "field": } In the first form, ```` is one of the strings described in the :ref:`operators` section, the first ```` is the name of the field of the model to which to apply the operator, ```` is a value to be used as the second argument to the given operator. In the second form, the second ```` is the field of the model that should be used as the second argument to the operator. ```` may alternately specify a field on a related model, if it is a string of the form ``__``. If the field name is the name of a relation and the operator is ``"has"`` or ``"any"``, the ``"val"`` argument can be a dictionary with the arguments representing another filter to be applied as the argument for ``"has"`` or ``"any"``. The returned list of matching instances will include only those instances that satisfy all of the given filters. Filter objects can also be arbitrary Boolean formulas. For example:: {"or": [, {"and": [, ...]}, ...]} ``limit`` A positive integer which specifies the maximum number of objects to return. ``offset`` A positive integer which specifies the offset into the result set of the returned list of instances. ``order_by`` A list of objects of the form:: {"field": , "direction": } where ```` is a string corresponding to the name of a field of the requested model and ```` is either ``"asc"`` for ascending order or ``"desc"`` for descending order. ```` may alternately specify a field on a related model, if it is a string of the form ``__``. ``group_by`` A list of objects of the form:: {"field": } where ```` is a string corresponding to the name of a field of the requested model. ```` may alternately specify a field on a related model, if it is a string of the form ``__``. .. versionadded:: 0.16.0 ``single`` A Boolean representing whether a single result is expected as a result of the search. If this is ``true`` and either no results or multiple results meet the criteria of the search, the server responds with an error message. If a filter is poorly formatted (for example, ``op`` is set to ``'=='`` but ``val`` is not set), the server responds with :http:statuscode:`400`. .. versionchanged:: 0.17.0 Removed the ``disjunction`` mapping in favor of a more robust Boolean expression system. .. _operators: Operators --------- The operator strings recognized by the API incude: * ``==``, ``eq``, ``equals``, ``equals_to`` * ``!=``, ``neq``, ``does_not_equal``, ``not_equal_to`` * ``>``, ``gt``, ``<``, ``lt`` * ``>=``, ``ge``, ``gte``, ``geq``, ``<=``, ``le``, ``lte``, ``leq`` * ``in``, ``not_in`` * ``is_null``, ``is_not_null`` * ``like`` * ``has`` * ``any`` These correspond to SQLAlchemy column operators as defined `here `_. Examples -------- Consider a ``Person`` model available at the URL ``/api/person``, and suppose all of the following requests are :http:get:`/api/person` requests with query parameter ``q``. Attribute greater than a value ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ On request: .. sourcecode:: http GET /api/person?q={"filters":[{"name":"age","op":"ge","val":10}]} HTTP/1.1 Host: example.com the response will include only those ``Person`` instances that have ``age`` attribute greater than or equal to 10: .. sourcecode:: http HTTP/1.1 200 OK { "num_results": 8, "total_pages": 3, "page": 2, "objects": [ {"id": 1, "name": "Jeffrey", "age": 24}, {"id": 2, "name": "John", "age": 13}, {"id": 3, "name": "Mary", "age": 18} ] } Arbitrary Boolean expression of filters ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ On request: .. sourcecode:: http GET /api/person?q={"filters":[{"or":[{"name":"age","op":"lt","val":10},{"name":"age","op":"gt","val":20}]}]} HTTP/1.1 Host: example.com the response will include only those ``Person`` instances that have ``age`` attribute either less than 10 or greater than 20: .. sourcecode:: http HTTP/1.1 200 OK { "num_results": 3, "total_pages": 1, "page": 1, "objects": [ {"id": 4, "name": "Abraham", "age": 9}, {"id": 5, "name": "Isaac", "age": 25}, {"id": 6, "name": "Job", "age": 37} ] } Attribute between two values ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ On request: .. sourcecode:: http GET /api/person?q={"filters":[{"name":"age","op":"ge","val":10},{"name":"age","op":"le","val":20}]} HTTP/1.1 Host: example.com the response will include only those ``Person`` instances that have ``age`` attribute between 10 and 20, inclusive: .. sourcecode:: http HTTP/1.1 200 OK { "num_results": 6, "total_pages": 3, "page": 2, "objects": [ {"id": 2, "name": "John", "age": 13}, {"id": 3, "name": "Mary", "age": 18} ] } Expecting a single result ~~~~~~~~~~~~~~~~~~~~~~~~~ On request: .. sourcecode:: javascript GET /api/person?q={"filters":[{"name":"id","op":"eq","val":1}],"single":true} HTTP/1.1 Host: example.com the response will include only the sole ``Person`` instance with ``id`` equal to 1: .. sourcecode:: http HTTP/1.1 200 OK {"id": 1, "name": "Jeffrey", "age": 24} In the case that the search would return no results or more than one result, an error response is returned instead: .. sourcecode:: http GET /api/person?q={"filters":[{"name":"age","op":"ge","val":10}],"single":true} HTTP/1.1 Host: example.com .. sourcecode:: http HTTP/1.1 400 Bad Request {"message": "Multiple results found"} .. sourcecode:: http GET /api/person?q={"filters":[{"name":"id","op":"eq","val":-1}],"single":true} HTTP/1.1 Host: example.com .. sourcecode:: http HTTP/1.1 404 Bad Request {"message": "No result found"} Comparing two attributes ~~~~~~~~~~~~~~~~~~~~~~~~ On request: .. sourcecode:: http GET /api/person?q={"filters":[{"name":"age","op":"ge","field":"height"}]} HTTP/1.1 Host: example.com the response will include only those ``Person`` instances that have ``age`` attribute greater than or equal to the value of the ``height`` attribute: .. sourcecode:: http HTTP/1.1 200 OK { "num_results": 6, "total_pages": 3, "page": 2, "objects": [ {"id": 1, "name": "John", "age": 80, "height": 65}, {"id": 2, "name": "Mary", "age": 73, "height": 60} ] } Comparing attribute of a relation ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ On request: .. sourcecode:: http GET /api/person?q={"filters":[{"name":"computers__manufacturer","op":"any","val":"Apple"}],"single":true} HTTP/1.1 Host: example.com response will include only those ``Person`` instances that are related to any ``Computer`` model that is manufactured by Apple: .. sourcecode:: http HTTP/1.1 200 OK { "num_results": 6, "total_pages": 3, "page": 2, "objects": { "id": 1, "name": "John", "computers": [ { "id": 1, "manufacturer": "Dell", "model": "Inspiron 9300"}, { "id": 2, "manufacturer": "Apple", "model": "MacBook"} ] }, { "id": 2, "name": "Mary", "computers": [ { "id": 3, "manufacturer": "Apple", "model": "iMac"} ] } ] } Using ``has`` and ``any`` ~~~~~~~~~~~~~~~~~~~~~~~~~ Use the ``has`` and ``any`` operators to search for instances by fields on related instances. For example, you can search for all ``Person`` instances that have a related ``Computer`` with a certain ID number by using the ``any`` operator. For another example, you can search for all ``Computer`` instances that have an owner with a certain name by using the ``has`` operator. In general, use the ``any`` operator if the relation is a list of objects and use the ``has`` operator if the relation is a single object. For more information, see the SQLAlchemy documentation. On request: .. sourcecode:: http GET /api/person?q={"filters":[{"name":"computers","op":"any","val":{"name":"id","op":"gt","val":1}}]} HTTP/1.1 Host: example.com the response will include only those ``Person`` instances that have a related ``Computer`` instance with ``id`` field of value greater than 1: .. sourcecode:: http HTTP/1.1 200 OK { "num_results": 6, "total_pages": 3, "page": 2, "objects": [ {"id": 1, "name": "John", "age": 80, "height": 65, "computers": [...]}, {"id": 2, "name": "Mary", "age": 73, "height": 60, "computers": [...]} ] } On request: .. sourcecode:: http GET /api/computers?q={"filters":[{"name":"owner","op":"has","val":{"name":"vendor","op":"ilike","val":"%John%"}}]} HTTP/1.1 Host: example.com the response will include only those ``Computer`` instances that have an owner with ``name`` field that includes ``'John'``: .. sourcecode:: http HTTP/1.1 200 OK { "num_results": 6, "total_pages": 3, "page": 2, "objects": [ {"id": 1, "name": "pluto", vendor="Apple", ...}, {"id": 2, "name": "jupiter", vendor="Dell", ...} ] }