# flask-restplus-server-example

**Repository Path**: nameReallyGet/flask-restplus-server-example

## Basic Information

- **Project Name**: flask-restplus-server-example
- **Description**: git镜像 https://github.com/frol/flask-restplus-server-example.git
- **Primary Language**: Python
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2020-12-09
- **Last Updated**: 2022-05-12

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

[![Build Status](https://travis-ci.org/frol/flask-restplus-server-example.svg)](https://travis-ci.org/frol/flask-restplus-server-example)
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[![Codacy Coverage Status](https://api.codacy.com/project/badge/coverage/b0fc91ce77d3437ea5f107c4b7ccfa26)](https://www.codacy.com/app/frolvlad/flask-restplus-server-example)
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[![Heroku](http://heroku-badge.herokuapp.com/?app=flask-restplus-example-server&root=api/v1/&style=flat&svg=1)](http://flask-restplus-example-server.herokuapp.com/api/v1/)


RESTful API Server Example
==========================

This project showcases my vision on how the RESTful API server should be
implemented.

> **Author's vision update!**
>
> I used to use RESTful style APIs for quite a number of projects and this
> example was the finest foundation I ended up with, but I always felt
> limited by HTTP request-response nature and RESTful resources. Thus, I was
> looking for a new solution to the API problem space. I am currently happy
> with [WAMP-proto](https://wamp-proto.org/) specification
> ([here is my barebones demo](https://github.com/frol/wamp-demo)), so I can
> recommend it. I have also switched to Rust programming language. I am
> currently working on async/await-powered implementation of WAMP-proto in
> Rust. Stay tuned!

The goals that were achived in this example:

* RESTful API server should be self-documented using OpenAPI (fka Swagger)
  specifications, so interactive documentation UI is in place;
* Authentication is handled with OAuth2 and using Resource Owner Password
  Credentials Grant (Password Flow) for first-party clients makes it usable
  not only for third-party "external" apps;
* Permissions are handled (and automaticaly documented);
* PATCH method can be handled accordingly to
  [RFC 6902](http://tools.ietf.org/html/rfc6902);
* Extensive testing with good code coverage.

I had to patch Flask-RESTplus (see `flask_restplus_patched` folder), so it can
handle Marshmallow schemas and Webargs arguments.

Here is how it looks at this point of time ([live demo](http://flask-restplus-example-server.herokuapp.com/api/v1/)):

![Flask RESTplus Example API](https://raw.githubusercontent.com/frol/flask-restplus-server-example/master/docs/static/Flask_RESTplus_Example_API.png)


Single File Example
-------------------

This example should give you a basic understanding of what you can get with
Flask, SQLAlchemy, Marshmallow, Flask-RESTplus (+ my patched extension), and
OpenAPI.

```python
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_restplus_patched import Api, Namespace, Resource, ModelSchema

# Extensions initialization
# =========================
app = Flask(__name__)
db = SQLAlchemy(app)
api = Api(app)


# Database table definition (SQLAlchemy)
# ======================================
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(), nullable=False)


# Serialization/Deserialization schema definition
# ===============================================
class UserSchema(ModelSchema):
    class Meta:
        model = User


# "Users" resource RESTful API definitions
# ========================================
users_api = Namespace('users')
api.add_namespace(users_api)

@users_api.route('/')
class UsersList(Resource):

    @users_api.response(UserSchema(many=True))
    def get(self):
        return User.query.all()


@users_api.route('/<int:user_id>')
@users_api.resolve_object('user', lambda kwargs: User.query.get_or_404(kwargs.pop('user_id')))
class UserByID(Resource):

    @users_api.response(UserSchema())
    def get(self, user):
        return user


# Run the RESTful API server
# ==========================
if __name__ == '__main__':
    db.create_all()
    with db.session.begin(nested=True):
        db.session.add(User(name='user1'))
        db.session.add(User(name='user2'))
    app.run()
```

Save it, install the dependencies, and run it:

```
$ pip install -r app/requirements.txt
$ python server.py
```

Open http://127.0.0.1:5000 and examine the interactive documentation for your
new RESTful API server! You can use any HTTP tools (e.g. `cURL`, `wget`,
Python `requests`, or just a web browser) to communicate with it, or generate
specialized API client libraries for many programming languages using
[Swagger Codegen](https://github.com/swagger-api/swagger-codegen) (learn more
in the [API Integration](#api-integration) section).

Note, this whole repo features much more than that; it demonstrates how I would
organize a production-ready RESTful API server *project*, so stay tunned.


Project Structure
-----------------

### Root folder

Folders:

* `app` - This RESTful API Server example implementation is here.
* `flask_restplus_patched` - There are some patches for Flask-RESTPlus (read
  more in *Patched Dependencies* section).
* `migrations` - Database migrations are stored here (see `invoke --list` to
  learn available commands, and learn more about PyInvoke usage below).
* `tasks` - [PyInvoke](http://www.pyinvoke.org/) commands are implemented here.
* `tests` - These are [pytest](http://pytest.org) tests for this RESTful API
  Server example implementation.
* `docs` - It contains just images for the README, so you can safely ignore it.
* `deploy` - It contains some application stack examples.

Files:

* `README.md`
* `config.py` - This is a config file of this RESTful API Server example.
* `conftest.py` - A top-most pytest config file (it is empty, but it [helps to
  have a proper PYTHON PATH](http://stackoverflow.com/a/20972950/1178806)).
* `.coveragerc` - [Coverage.py](http://coverage.readthedocs.org/) (code
  coverage) config for code coverage reports.
* `.travis.yml` - [Travis CI](https://travis-ci.org/) (automated continuous
  integration) config for automated testing.
* `.pylintrc` - [Pylint](https://www.pylint.org/) config for code quality
  checking.
* `Dockerfile` - Docker config file which is used to build a Docker image
  running this RESTful API Server example.
* `.dockerignore` - Lists files and file masks of the files which should be
  ignored while Docker build process.
* `.gitignore` - Lists files and file masks of the files which should not be
  added to git repository.
* `LICENSE` - MIT License, i.e. you are free to do whatever is needed with the
  given code with no limits.

### Application Structure

```
app/
├── requirements.txt
├── __init__.py
├── extensions
│   └── __init__.py
└── modules
    ├── __init__.py
    ├── api
    │   └── __init__.py
    ├── auth
    │   ├── __init__.py
    │   ├── models.py
    │   ├── parameters.py
    │   └── views.py
    ├── users
    │   ├── __init__.py
    │   ├── models.py
    │   ├── parameters.py
    │   ├── permissions.py
    │   ├── resources.py
    │   └── schemas.py
    └── teams
        ├── __init__.py
        ├── models.py
        ├── parameters.py
        ├── resources.py
        └── schemas.py
```

* `app/requirements.txt` - The list of Python (PyPi) requirements.
* `app/__init__.py` - The entrypoint to this RESTful API Server example
  application (Flask application is created here).
* `app/extensions` - All extensions (e.g. SQLAlchemy, OAuth2) are initialized
  here and can be used in the application by importing as, for example,
  `from app.extensions import db`.
* `app/modules` - All endpoints are expected to be implemented here in logicaly
  separated modules. It is up to you how to draw the line to separate concerns
  (e.g. you can implement a monolith `blog` module, or split it into
  `topics`+`comments` modules).

### Module Structure

Once you added a module name into `config.ENABLED_MODULES`, it is required to
have `your_module.init_app(app, **kwargs)` function. Everything else is
completely optional. Thus, here is the required minimum:

```
your_module/
└── __init__.py
```

, where `__init__.py` will look like this:

```python
def init_app(app, **kwargs):
    pass
```

In this example, however, `init_app` imports `resources` and registeres `api`
(an instance of (patched) `flask_restplus.Namespace`). Learn more about the
"big picture" in the next section.


Where to start reading the code?
--------------------------------

The easiest way to start the application is by using PyInvoke command `app.run`
implemented in [`tasks/app/run.py`](tasks/app/run.py):

```
$ invoke app.run
```

The command creates an application by running
[`app/__init__.py:create_app()`](app/__init__.py) function, which in its turn:

1. loads an application config;
2. initializes extensions:
   [`app/extensions/__init__.py:init_app()`](app/extensions/__init__.py);
3. initializes modules:
   [`app/modules/__init__.py:init_app()`](app/modules/__init__.py).

Modules initialization calls `init_app()` in every enabled module
(listed in `config.ENABLED_MODULES`).

Let's take `teams` module as an example to look further.
[`app/modules/teams/__init__.py:init_app()`](app/modules/teams/__init__.py)
imports and registers `api` instance of (patched) `flask_restplus.Namespace`
from `.resources`. Flask-RESTPlus `Namespace` is designed to provide similar
functionality as Flask `Blueprint`.

[`api.route()`](app/modules/teams/resources.py) is used to bind a
resource (classes inherited from `flask_restplus.Resource`) to a specific
route.

Lastly, every `Resource` should have methods which are lowercased HTTP method
names (i.e. `.get()`, `.post()`, etc). This is where users' requests end up.


Dependencies
------------

### Project Dependencies

* [**Python**](https://www.python.org/) 2.7, 3.5+ / pypy2 (2.5.0)
* [**flask-restplus**](https://github.com/noirbizarre/flask-restplus) (+
  [*flask*](http://flask.pocoo.org/))
* [**sqlalchemy**](http://www.sqlalchemy.org/) (+
  [*flask-sqlalchemy*](http://flask-sqlalchemy.pocoo.org/)) - Database ORM.
* [**sqlalchemy-utils**](https://sqlalchemy-utils.rtdf.org/) - for nice
  custom fields (e.g., `PasswordField`).
* [**alembic**](https://alembic.rtdf.org/) - for DB migrations.
* [**marshmallow**](http://marshmallow.rtfd.org/) (+
  [*marshmallow-sqlalchemy*](http://marshmallow-sqlalchemy.rtfd.org/),
  [*flask-marshmallow*](http://flask-marshmallow.rtfd.org/)) - for
  schema definitions. (*supported by the patched Flask-RESTplus*)
* [**webargs**](http://webargs.rtfd.org/) - for parameters (input arguments).
  (*supported by the patched Flask-RESTplus*)
* [**apispec**](http://apispec.rtfd.org/) - for *marshmallow* and *webargs*
  introspection. (*integrated into the patched Flask-RESTplus*)
* [**oauthlib**](http://oauthlib.rtfd.org/) (+
  [*flask-oauthlib*](http://flask-oauthlib.rtfd.org/)) - for authentication.
* [**flask-login**](http://flask-login.rtfd.org/) - for `current_user`
  integration only.
* [**bcrypt**](https://github.com/pyca/bcrypt/) - for password hashing (used as
  a backend by *sqlalchemy-utils.PasswordField*).
* [**permission**](https://github.com/hustlzp/permission) - for authorization.
* [**Swagger-UI**](https://github.com/swagger-api/swagger-ui) - for interactive
  RESTful API documentation.

### Build Dependencies

I use [`pyinvoke`](http://pyinvoke.org) with custom tasks to maintain easy and
nice command-line interface. Thus, it is required to have `invoke` Python
package installed, and optionally you may want to install `colorlog`, so your
life become colorful.

### Patched Dependencies

* **flask-restplus** is patched to handle marshmallow schemas and webargs
  input parameters
  ([GH #9](https://github.com/noirbizarre/flask-restplus/issues/9)).
* **swagger-ui** (*the bundle is automatically downloaded on the first run*)
  just includes a pull-request to support Resource Owner Password Credentials
  Grant OAuth2 (aka Password Flow)
  ([PR #1853](https://github.com/swagger-api/swagger-ui/pull/1853)).


Installation
------------

### Using Docker

It is very easy to start exploring the example using Docker:

```bash
$ docker run -it --rm --publish 5000:5000 frolvlad/flask-restplus-server-example
```

[![](https://images.microbadger.com/badges/image/frolvlad/flask-restplus-server-example.svg)](http://microbadger.com/images/frolvlad/flask-restplus-server-example "Get your own image badge on microbadger.com")


### From sources

#### Clone the Project

```bash
$ git clone https://github.com/frol/flask-restplus-server-example.git
```

#### Setup Environment

It is recommended to use virtualenv or Anaconda/Miniconda to manage Python
dependencies. Please, learn details yourself.

You will need `invoke` package to work with everything related to this project.

```bash
$ pip install -r tasks/requirements.txt
```


#### Run Server

NOTE: All dependencies and database migrations will be automatically handled,
so go ahead and turn the server ON! (Read more details on this in Tips section)

```bash
$ invoke app.run
```

#### Deploy Server

In general, you deploy this app as any other Flask/WSGI application. There are
a few basic deployment strategies documented in the [`./deploy/`](./deploy/)
folder.


Quickstart
----------

Open online interactive API documentation:
[http://127.0.0.1:5000/api/v1/](http://127.0.0.1:5000/api/v1/)

Autogenerated swagger config is always available from
[http://127.0.0.1:5000/api/v1/swagger.json](http://127.0.0.1:5000/api/v1/swagger.json)

`example.db` (SQLite) includes 2 users:

* Admin user `root` with password `q`
* Regular user `user` with password `w`

NOTE: Use On/Off switch in documentation to sign in.


Authentication Details
----------------------

This example server features OAuth2 Authentication protocol support, but don't
be afraid of it! If you learn it, OAuth2 will save you from a lot of troubles.

### Authentication with Login and Password (Resource Owner Password Credentials Grant)

Here is how you authenticate with user login and password credentials using cURL:

```
$ curl 'http://127.0.0.1:5000/auth/oauth2/token?grant_type=password&client_id=documentation&username=root&password=q'
{
    "token_type": "Bearer",
    "access_token": "oqvUpO4aKg5KgYK2EUY2HPsbOlAyEZ",
    "refresh_token": "3UTjLPlnomJPx5FvgsC2wS7GfVNrfH",
    "expires_in": 3600,
    "scope": "auth:read auth:write users:read users:write teams:read teams:write"
}
```

That is it!

Well, the above request uses query parameters to pass client ID, user login and
password which is not recommended (even discouraged) for production use since
most of the web servers logs the requested URLs in plain text and we don't want
to leak sensitive data this way.  Thus, in practice you would use form
parameters to pass credentials:

```
$ curl 'http://127.0.0.1:5000/auth/oauth2/token?grant_type=password' -F 'client_id=documentation' -F 'username=root' -F 'password=q'
```

, or even pass `client_id` as Basic HTTP Auth:

```
$ curl 'http://127.0.0.1:5000/auth/oauth2/token?grant_type=password' --user 'documentation:' -F 'username=root' -F 'password=q'
```

You grab the `access_token` and put it into `Authorization` header
to request "protected" resources:

```
$ curl --header 'Authorization: Bearer oqvUpO4aKg5KgYK2EUY2HPsbOlAyEZ' 'http://127.0.0.1:5000/api/v1/users/me'
{
    "id": 1,
    "username": "root",
    "email": "root@localhost",
    "first_name": "",
    "middle_name": "",
    "last_name": "",
    "is_active": true,
    "is_regular_user": true,
    "is_admin": true,
    "created": "2016-10-20T14:00:35.912576+00:00",
    "updated": "2016-10-20T14:00:35.912602+00:00"
}
```

Once the access token expires, you can refresh it with `refresh_token`. To do
that, OAuth2 RFC defines Refresh Token Flow (notice that there is no need to
store user credentials to do the refresh procedure):

```
$ curl 'http://127.0.0.1:5000/auth/oauth2/token?grant_type=refresh_token' --user 'documentation:' -F 'refresh_token=3UTjLPlnomJPx5FvgsC2wS7GfVNrfH'
{
    "token_type": "Bearer",
    "access_token": "FwaS90XWwBpM1sLeAytaGGTubhHaok",
    "refresh_token": "YD5Rc1FojKX1ZY9vltMSnFxhm9qpbb",
    "expires_in": 3600,
    "scope": "auth:read auth:write users:read users:write teams:read teams:write"
}
```

### Authentication with Client ID and Secret (Client Credentials Grant)

Here is how you authenticate with user login and password credentials using cURL:

```
$ curl 'http://127.0.0.1:5000/auth/oauth2/token?grant_type=client_credentials' --user 'documentation:KQ()SWK)SQK)QWSKQW(SKQ)S(QWSQW(SJ*HQ&HQW*SQ*^SSQWSGQSG'
{
    "token_type": "Bearer",
    "access_token": "oqvUpO4aKg5KgYK2EUY2HPsbOlAyEZ",
    "expires_in": 3600,
    "scope": "teams:read users:read users:write teams:write"
}
```

The same way as in the previous section, you can grab the `access_token` and
access protected resources.


API Integration
---------------

One of the key point of using OpenAPI (Swagger) specification is that it
enables automatic code generation.
[Swagger Codegen project](https://github.com/swagger-api/swagger-codegen)
implements client library and server stub generators for over 18
programming languages! There are also many other projects with OpenAPI
specification support, so if you lack anything in the official tooling,
search for third-party solutions.

I have had a need to work with my API servers from Python and JavaScript, so
I started with Swagger Codegen Python and JavaScript generators. Very soon I
realized that most (if not all) Swagger Codegen generators lack OAuth2 support,
but other than that, the client libraries look fine (I have contributed a few
changes to Python and JavaScript generators over the time, and the nice thing
all the clients benefit from contributions into a single project). Thus,
@khorolets and I implemented hacky OAuth2 support for Python client and even
more hacky out-of-client helpers for JavaScript (hopefully, one day OAuth2
support will be contributed into the Swagger Codegen upstream).

To use Swagger Codegen, you only need a `swagger.json` file describing your API
server. You can get one by accessing http://127.0.0.1:5000/api/v1/swagger.json,
or by running an Invoke task:

```bash
$ invoke app.swagger
```

NOTE: Use stdout rediction to save the output into a file.

To further simplify the codegeneration, there is another Invoke task:

```bash
$ invoke app.swagger.codegen --language python --version 1.0.0
```

To run that, however, you will need Docker installed on your machine since we
use Swagger Codegen as a Docker image. Once that is completed, you will have a
Python client in the `clients/python/dist/` folder. The `javascript` client can
be generated just the same way. Read the generated `clients/*/dist/README.md`
to learn how to use those clients.

NOTE: As mentioned above, a slightly modified Swagger Codegen version is used
to enable OAuth2 support in Python client.


Integrations with Flask-* Projects
----------------------------------

Since this project is only an extension to Flask, most (if not all) Flask
plugins should work.

Verified compatible projects:
* flask-sqlalchemy
* flask-login
* flask-marshmallow
* flask-oauthlib
* flask-cors
* flask-limiter

### Example integration steps
  
#### flask-limiter

1. Add `flask-limiter` to end of the `app/requirements.txt` file, so it gets
installed when the application is deployed.
2. Apply the relevant changes to `app/extensions/__init__.py`:

    ```python
    # ... other imports.

    from flask_limiter import Limiter
    from flask_limiter.util import get_remote_address

    # change limiter configs per your project needs.
    limiter = Limiter(key_func=get_remote_address, default_limits=["1 per minute"])

    from . import api

    def init_app(app):
        """
        Application extensions initialization.
        """
        for extension in (
                # ... other extensions.
                limiter,  # Add this
            ):
            extension.init_app(app)
    ```
3. (Optional) Set endpoint-specific limits:

    ```python
    from app.extensions import limiter

    @api.route('/account/verify')
    class IdentityVerify(Resource):
        """
        Handle identity verification.
        """
        # Notice this is different from the simple example at the top of flask-limiter doc page.
        # The reason is explained here: https://flask-limiter.readthedocs.io/en/stable/#using-flask-pluggable-views
        decorators = [limiter.limit("10/second")] # config as you need. 

        @api.parameters(parameters.SomeParameters())
        @api.response(schemas.SomeSchema())
        def post(self, args):
            return {"verified": True}
    ```


Tips
----

Once you have invoke, you can learn all available commands related to this
project from:

```bash
$ invoke --list
```

Learn more about each command with the following syntax:

```bash
$ invoke --help <task>
```

For example:

```bash
$ invoke --help app.run
Usage: inv[oke] [--core-opts] app.run [--options] [other tasks here ...]

Docstring:
  Run DDOTS RESTful API Server.

Options:
  -d, --[no-]development
  -h STRING, --host=STRING
  -i, --[no-]install-dependencies
  -p, --port
  -u, --[no-]upgrade-db
```

Use the following command to enter ipython shell (`ipython` must be installed):

```bash
$ invoke app.env.enter
```

`app.run` and `app.env.enter` tasks automatically prepare all dependencies
(using `pip install`) and migrate database schema to the latest version.

Database schema migration is handled via `app.db.*` tasks group. The most
common migration commands are `app.db.upgrade` (it is automatically run on
`app.run`), and `app.db.migrate` (creates a new migration).

You can use [`better_exceptions`](https://github.com/Qix-/better-exceptions)
package to enable detailed tracebacks. Just add `better_exceptions` to the
`app/requirements.txt` and `import better_exceptions` in the `app/__init__.py`.


Marshmallow Tricks
------------------

There are a few helpers already available in the `flask_restplus_patched`:

* `flask_restplus_patched.parameters.Parameters` - base class, which is a thin
  wrapper on top of Marshmallow Schema.
* `flask_restplus_patched.parameters.PostFormParameters` - a helper class,
  which automatically mark all the fields that has no explicitly defined
  location to be form data parameters.
* `flask_restplus_patched.parameters.PatchJSONParameters` - a helper class for
  the common use-case of [RFC 6902](http://tools.ietf.org/html/rfc6902)
  describing JSON PATCH.
* `flask_restplus_patched.namespace.Namespace.parameters` - a helper decorator,
  which automatically handles and documents the passed `Parameters`.

You can find the examples of the usage throughout the code base (in
`/app/modules/*`).


### JSON Parameters

While there is an implementation for JSON PATCH Parameters, there are other
use-cases, where you may need to handle JSON as input parameters. Naturally,
JSON input is just a form data body text which is treated as JSON on a server
side, so you only need define a single variable called `body` with
`location='json'`:

```python
class UserSchema(Schema):
    id = base_fields.Integer(required=False)
    username = base_fields.String(required=True)


class MyObjectSchema(Schema):
    id = base_fields.Integer(required=True)
    priority = base_fields.String(required=True)
    owner = base_fields.Nested(UserSchema, required=False)


class CreateMyObjectParameters(Parameters):
    body = base_fields.Nested(MyObjectSchema, location='json', required=True)


api = Namespace('my-objects-controller', description="My Objects Controller", path='/my-objects')


@api.route('/')
class MyObjects(Resource):
    """
    Manipulations with My Objects.
    """

    @api.parameters(CreateMyObjectParameters())
    @api.response(MyObjectSchema())
    @api.response(code=HTTPStatus.CONFLICT)
    @api.doc(id='create_my_object')
    def post(self, args):
        """
        Create a new My Object.
        """
        return create_my_object(args)
```


Useful Links
============

* [Q&A about this project](https://github.com/frol/flask-restplus-server-example/issues?utf8=%E2%9C%93&q=is%3Aissue+label%3Aquestion)
* [Valuable extensions that didn't make into the upstream](https://github.com/frol/flask-restplus-server-example/issues?utf8=%E2%9C%93&q=label%3Aextension)
* "[The big Picture](https://identityserver.github.io/Documentation/docsv2/overview/bigPicture.html)" -
  short yet complete idea about how the modern apps should talk.
* "[Please. Don't PATCH Like An Idiot.](http://williamdurand.fr/2014/02/14/please-do-not-patch-like-an-idiot/)"
* "[A Concise RESTful API Design Guide](https://twincl.com/programming/*6af/rest-api-design)"
* "[Best Practices for Designing a Pragmatic RESTful API](http://www.vinaysahni.com/best-practices-for-a-pragmatic-restful-api)"
* "[My take on RESTful authentication](https://facundoolano.wordpress.com/2013/12/23/my-take-on-restful-authentication/)"
* "[Is it normal design to completely decouple backend and frontend web applications and allow them to communicate with (JSON) REST API?](http://softwareengineering.stackexchange.com/questions/337467/is-it-normal-design-to-completely-decouple-backend-and-frontend-web-applications)"