graceful

graceful is an elegant Python REST toolkit built on top of falcon framework. It is highly inspired by Django REST framework - mostly by how object serialization is done but more emphasis here is put on API to be self-descriptive.

Features:

• generic classes for list and single object resources
• simple but extendable pagination
• simple but extendable authentication and authorization
• structured responses with content/meta separation
• declarative fields and parameters
• self-descriptive-everything: API description accessible both in python and through OPTIONS requests
• painless validation
• 100% tests coverage
• falcon>=0.3.0 (tested up to 1.4.x)
• python3 exclusive (tested from 3.3 to 3.6)

Community behind graceful is starting to grow but we don't have any mailing list yet. There was one on Librelist but no one used it and it seems that librelist became dead (see GitHub issue #36). For now let's use gitter chat until we decide on something new. Chat is available here.

python3 only

Important: graceful is python3 exclusive because right now should be a good time to forget about python2. There are no plans for making graceful python2 compatible although it would be pretty straightforward to do so with existing tools (like six).

usage

For extended tutorial and more information please refer to guide included in documentation.

Anyway here is simple example of working API made made with graceful:

import falcon

from graceful.serializers import BaseSerializer
from graceful.fields import IntField, RawField
from graceful.parameters import StringParam
from graceful.resources.generic import (
    RetrieveAPI,
    PaginatedListAPI,
)

api = application = falcon.API()

# lets pretend that this is our backend storage
CATS_STORAGE = [
    {"id": 0, "name": "kitty", "breed": "saimese"},
    {"id": 1, "name": "lucie", "breed": "maine coon"},
    {"id": 2, "name": "molly", "breed": "sphynx"},
]


# this is how we represent cats in our API
class CatSerializer(BaseSerializer):
    id = IntField("cat identification number", read_only=True)
    name = RawField("cat name")
    breed = RawField("official breed name")


class Cat(RetrieveAPI):
    """
    Single cat identified by its id
    """
    serializer = CatSerializer()

    def get_cat(self, cat_id):
        try:
            return [
                cat for cat in CATS_STORAGE if cat['id'] == int(cat_id)
            ][0]
        except IndexError:
            raise falcon.HTTPNotFound


    def retrieve(self, params, meta, **kwargs):
        cat_id = kwargs['cat_id']
        return self.get_cat(cat_id)

class CatList(PaginatedListAPI):
    """
    List of all cats in our API
    """
    serializer = CatSerializer()

    breed = StringParam("set this param to filter cats by breed")

    def list(self, params, meta, **kwargs):
        if 'breed' in params:
            filtered = [
                cat for cat in CATS_STORAGE
                if cat['breed'] == params['breed']
            ]
            return filtered
        else:
            return CATS_STORAGE

api.add_route("/v1/cats/{cat_id}", Cat())
api.add_route("/v1/cats/", CatList())

Assume this code is in python module named example.py. Now run it with gunicorn:

gunicorn -b localhost:8888 example

And you're ready to query it (here with awesome httpie tool):

$ http localhost:8888/v0/cats/?breed=saimese
HTTP/1.1 200 OK
Connection: close
Date: Tue, 16 Jun 2015 08:43:05 GMT
Server: gunicorn/19.3.0
content-length: 116
content-type: application/json

{
    "content": [
        {
            "breed": "saimese",
            "id": 0,
            "name": "kitty"
        }
    ],
    "meta": {
        "params": {
            "breed": "saimese",
            "indent": 0
        }
    }
}

Or access API description issuing OPTIONS request:

$ http OPTIONS localhost:8888/v0/cats
HTTP/1.1 200 OK
Connection: close
Date: Tue, 16 Jun 2015 08:40:00 GMT
Server: gunicorn/19.3.0
allow: GET, OPTIONS
content-length: 740
content-type: application/json

{
    "details": "List of all cats in our API",
    "fields": {
        "breed": {
            "details": "official breed name",
            "label": null,
            "spec": null,
            "type": "string"
        },
        "id": {
            "details": "cat identification number",
            "label": null,
            "spec": null,
            "type": "int"
        },
        "name": {
            "details": "cat name",
            "label": null,
            "spec": null,
            "type": "string"
        }
    },
    "methods": [
        "GET",
        "OPTIONS"
    ],
    "name": "CatList",
    "params": {
        "breed": {
            "default": null,
            "details": "set this param to filter cats by breed",
            "label": null,
            "required": false,
            "spec": null,
            "type": "string"
        },
        "indent": {
            "default": "0",
            "details": "JSON output indentation. Set to 0 if output should not be formated.",
            "label": null,
            "required": false,
            "spec": null,
            "type": "integer"
        }
    },
    "path": "/v0/cats",
    "type": "list"
}

contributing

Any contribution is welcome. Issues, suggestions, pull requests - whatever. There is only short set of rules that guide this project development you should be aware of before submitting a pull request:

• Only requests that have passing CI builds (Travis) will be merged.
• Code is checked with flakes8 and pydocstyle during build so this implicitly means that compliance with PEP-8 and PEP-257 is mandatory.
• No changes that decrease coverage will be merged.

One thing: if you submit a PR please do not rebase it later unless you are asked for that explicitly. Reviewing pull requests that suddenly had their history rewritten just drives me crazy.

license

See LICENSE file.