1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
Metadata-Version: 2.3
Name: uvicorn
Version: 0.29.0
Summary: The lightning-fast ASGI server.
Project-URL: Changelog, https://github.com/encode/uvicorn/blob/master/CHANGELOG.md
Project-URL: Funding, https://github.com/sponsors/encode
Project-URL: Homepage, https://www.uvicorn.org/
Project-URL: Source, https://github.com/encode/uvicorn
Author-email: Tom Christie <tom@tomchristie.com>
License-Expression: BSD-3-Clause
License-File: LICENSE.md
Classifier: Development Status :: 4 - Beta
Classifier: Environment :: Web Environment
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: BSD License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Classifier: Programming Language :: Python :: 3.12
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
Classifier: Topic :: Internet :: WWW/HTTP
Requires-Python: >=3.8
Requires-Dist: click>=7.0
Requires-Dist: h11>=0.8
Requires-Dist: typing-extensions>=4.0; python_version < '3.11'
Provides-Extra: standard
Requires-Dist: colorama>=0.4; (sys_platform == 'win32') and extra == 'standard'
Requires-Dist: httptools>=0.5.0; extra == 'standard'
Requires-Dist: python-dotenv>=0.13; extra == 'standard'
Requires-Dist: pyyaml>=5.1; extra == 'standard'
Requires-Dist: uvloop!=0.15.0,!=0.15.1,>=0.14.0; (sys_platform != 'win32' and (sys_platform != 'cygwin' and platform_python_implementation != 'PyPy')) and extra == 'standard'
Requires-Dist: watchfiles>=0.13; extra == 'standard'
Requires-Dist: websockets>=10.4; extra == 'standard'
Description-Content-Type: text/markdown
<p align="center">
<img width="320" height="320" src="https://raw.githubusercontent.com/tomchristie/uvicorn/master/docs/uvicorn.png" alt='uvicorn'>
</p>
<p align="center">
<em>An ASGI web server, for Python.</em>
</p>
---
[](https://github.com/encode/uvicorn/actions)
[](https://pypi.python.org/pypi/uvicorn)
[](https://pypi.org/project/uvicorn)
**Documentation**: [https://www.uvicorn.org](https://www.uvicorn.org)
---
Uvicorn is an ASGI web server implementation for Python.
Until recently Python has lacked a minimal low-level server/application interface for
async frameworks. The [ASGI specification][asgi] fills this gap, and means we're now able to
start building a common set of tooling usable across all async frameworks.
Uvicorn supports HTTP/1.1 and WebSockets.
## Quickstart
Install using `pip`:
```shell
$ pip install uvicorn
```
This will install uvicorn with minimal (pure Python) dependencies.
```shell
$ pip install 'uvicorn[standard]'
```
This will install uvicorn with "Cython-based" dependencies (where possible) and other "optional extras".
In this context, "Cython-based" means the following:
- the event loop `uvloop` will be installed and used if possible.
- the http protocol will be handled by `httptools` if possible.
Moreover, "optional extras" means that:
- the websocket protocol will be handled by `websockets` (should you want to use `wsproto` you'd need to install it manually) if possible.
- the `--reload` flag in development mode will use `watchfiles`.
- windows users will have `colorama` installed for the colored logs.
- `python-dotenv` will be installed should you want to use the `--env-file` option.
- `PyYAML` will be installed to allow you to provide a `.yaml` file to `--log-config`, if desired.
Create an application, in `example.py`:
```python
async def app(scope, receive, send):
assert scope['type'] == 'http'
await send({
'type': 'http.response.start',
'status': 200,
'headers': [
(b'content-type', b'text/plain'),
],
})
await send({
'type': 'http.response.body',
'body': b'Hello, world!',
})
```
Run the server:
```shell
$ uvicorn example:app
```
---
## Why ASGI?
Most well established Python Web frameworks started out as WSGI-based frameworks.
WSGI applications are a single, synchronous callable that takes a request and returns a response.
This doesn’t allow for long-lived connections, like you get with long-poll HTTP or WebSocket connections,
which WSGI doesn't support well.
Having an async concurrency model also allows for options such as lightweight background tasks,
and can be less of a limiting factor for endpoints that have long periods being blocked on network
I/O such as dealing with slow HTTP requests.
---
## Alternative ASGI servers
A strength of the ASGI protocol is that it decouples the server implementation
from the application framework. This allows for an ecosystem of interoperating
webservers and application frameworks.
### Daphne
The first ASGI server implementation, originally developed to power Django Channels, is [the Daphne webserver][daphne].
It is run widely in production, and supports HTTP/1.1, HTTP/2, and WebSockets.
Any of the example applications given here can equally well be run using `daphne` instead.
```
$ pip install daphne
$ daphne app:App
```
### Hypercorn
[Hypercorn][hypercorn] was initially part of the Quart web framework, before
being separated out into a standalone ASGI server.
Hypercorn supports HTTP/1.1, HTTP/2, and WebSockets.
It also supports [the excellent `trio` async framework][trio], as an alternative to `asyncio`.
```
$ pip install hypercorn
$ hypercorn app:App
```
### Mangum
[Mangum][mangum] is an adapter for using ASGI applications with AWS Lambda & API Gateway.
---
<p align="center"><i>Uvicorn is <a href="https://github.com/encode/uvicorn/blob/master/LICENSE.md">BSD licensed</a> code.<br/>Designed & crafted with care.</i><br/>— 🦄 —</p>
[asgi]: https://asgi.readthedocs.io/en/latest/
[daphne]: https://github.com/django/daphne
[hypercorn]: https://github.com/pgjones/hypercorn
[mangum]: https://mangum.io
[trio]: https://trio.readthedocs.io
|
