335 lines
10 KiB
Markdown
335 lines
10 KiB
Markdown
# Routing
|
|
|
|
Routing allows the user to specify handler functions for different URL endpoints.
|
|
|
|
A basic route looks like the following, where `app` is an instance of the
|
|
`Sanic` class:
|
|
|
|
```python
|
|
from sanic.response import json
|
|
|
|
@app.route("/")
|
|
async def test(request):
|
|
return json({ "hello": "world" })
|
|
```
|
|
|
|
When the url `http://server.url/` is accessed (the base url of the server), the
|
|
final `/` is matched by the router to the handler function, `test`, which then
|
|
returns a JSON object.
|
|
|
|
Sanic handler functions must be defined using the `async def` syntax, as they
|
|
are asynchronous functions.
|
|
|
|
## Request parameters
|
|
|
|
Sanic comes with a basic router that supports request parameters.
|
|
|
|
To specify a parameter, surround it with angle quotes like so: `<PARAM>`.
|
|
Request parameters will be passed to the route handler functions as keyword
|
|
arguments.
|
|
|
|
```python
|
|
from sanic.response import text
|
|
|
|
@app.route('/tag/<tag>')
|
|
async def tag_handler(request, tag):
|
|
return text('Tag - {}'.format(tag))
|
|
```
|
|
|
|
To specify a type for the parameter, add a `:type` after the parameter name,
|
|
inside the quotes. If the parameter does not match the specified type, Sanic
|
|
will throw a `NotFound` exception, resulting in a `404: Page not found` error
|
|
on the URL.
|
|
|
|
```python
|
|
from sanic.response import text
|
|
|
|
@app.route('/number/<integer_arg:int>')
|
|
async def integer_handler(request, integer_arg):
|
|
return text('Integer - {}'.format(integer_arg))
|
|
|
|
@app.route('/number/<number_arg:number>')
|
|
async def number_handler(request, number_arg):
|
|
return text('Number - {}'.format(number_arg))
|
|
|
|
@app.route('/person/<name:[A-z]+>')
|
|
async def person_handler(request, name):
|
|
return text('Person - {}'.format(name))
|
|
|
|
@app.route('/folder/<folder_id:[A-z0-9]{0,4}>')
|
|
async def folder_handler(request, folder_id):
|
|
return text('Folder - {}'.format(folder_id))
|
|
|
|
```
|
|
|
|
## HTTP request types
|
|
|
|
By default, a route defined on a URL will be available for only GET requests to that URL.
|
|
However, the `@app.route` decorator accepts an optional parameter, `methods`,
|
|
which allows the handler function to work with any of the HTTP methods in the list.
|
|
|
|
```python
|
|
from sanic.response import text
|
|
|
|
@app.route('/post', methods=['POST'])
|
|
async def post_handler(request):
|
|
return text('POST request - {}'.format(request.json))
|
|
|
|
@app.route('/get', methods=['GET'])
|
|
async def get_handler(request):
|
|
return text('GET request - {}'.format(request.args))
|
|
|
|
```
|
|
|
|
There is also an optional `host` argument (which can be a list or a string). This restricts a route to the host or hosts provided. If there is a also a route with no host, it will be the default.
|
|
|
|
```python
|
|
@app.route('/get', methods=['GET'], host='example.com')
|
|
async def get_handler(request):
|
|
return text('GET request - {}'.format(request.args))
|
|
|
|
# if the host header doesn't match example.com, this route will be used
|
|
@app.route('/get', methods=['GET'])
|
|
async def get_handler(request):
|
|
return text('GET request in default - {}'.format(request.args))
|
|
```
|
|
|
|
There are also shorthand method decorators:
|
|
|
|
```python
|
|
from sanic.response import text
|
|
|
|
@app.post('/post')
|
|
async def post_handler(request):
|
|
return text('POST request - {}'.format(request.json))
|
|
|
|
@app.get('/get')
|
|
async def get_handler(request):
|
|
return text('GET request - {}'.format(request.args))
|
|
|
|
```
|
|
## The `add_route` method
|
|
|
|
As we have seen, routes are often specified using the `@app.route` decorator.
|
|
However, this decorator is really just a wrapper for the `app.add_route`
|
|
method, which is used as follows:
|
|
|
|
```python
|
|
from sanic.response import text
|
|
|
|
# Define the handler functions
|
|
async def handler1(request):
|
|
return text('OK')
|
|
|
|
async def handler2(request, name):
|
|
return text('Folder - {}'.format(name))
|
|
|
|
async def person_handler2(request, name):
|
|
return text('Person - {}'.format(name))
|
|
|
|
# Add each handler function as a route
|
|
app.add_route(handler1, '/test')
|
|
app.add_route(handler2, '/folder/<name>')
|
|
app.add_route(person_handler2, '/person/<name:[A-z]>', methods=['GET'])
|
|
```
|
|
|
|
## URL building with `url_for`
|
|
|
|
Sanic provides a `url_for` method, to generate URLs based on the handler method name. This is useful if you want to avoid hardcoding url paths into your app; instead, you can just reference the handler name. For example:
|
|
|
|
```python
|
|
@app.route('/')
|
|
async def index(request):
|
|
# generate a URL for the endpoint `post_handler`
|
|
url = app.url_for('post_handler', post_id=5)
|
|
# the URL is `/posts/5`, redirect to it
|
|
return redirect(url)
|
|
|
|
|
|
@app.route('/posts/<post_id>')
|
|
async def post_handler(request, post_id):
|
|
return text('Post - {}'.format(post_id))
|
|
```
|
|
|
|
Other things to keep in mind when using `url_for`:
|
|
|
|
- Keyword arguments passed to `url_for` that are not request parameters will be included in the URL's query string. For example:
|
|
```python
|
|
url = app.url_for('post_handler', post_id=5, arg_one='one', arg_two='two')
|
|
# /posts/5?arg_one=one&arg_two=two
|
|
```
|
|
- Multivalue argument can be passed to `url_for`. For example:
|
|
```python
|
|
url = app.url_for('post_handler', post_id=5, arg_one=['one', 'two'])
|
|
# /posts/5?arg_one=one&arg_one=two
|
|
```
|
|
- Also some special arguments (`_anchor`, `_external`, `_scheme`, `_method`, `_server`) passed to `url_for` will have special url building (`_method` is not support now and will be ignored). For example:
|
|
```python
|
|
url = app.url_for('post_handler', post_id=5, arg_one='one', _anchor='anchor')
|
|
# /posts/5?arg_one=one#anchor
|
|
|
|
url = app.url_for('post_handler', post_id=5, arg_one='one', _external=True)
|
|
# //server/posts/5?arg_one=one
|
|
# _external requires passed argument _server or SERVER_NAME in app.config or url will be same as no _external
|
|
|
|
url = app.url_for('post_handler', post_id=5, arg_one='one', _scheme='http', _external=True)
|
|
# http://server/posts/5?arg_one=one
|
|
# when specifying _scheme, _external must be True
|
|
|
|
# you can pass all special arguments one time
|
|
url = app.url_for('post_handler', post_id=5, arg_one=['one', 'two'], arg_two=2, _anchor='anchor', _scheme='http', _external=True, _server='another_server:8888')
|
|
# http://another_server:8888/posts/5?arg_one=one&arg_one=two&arg_two=2#anchor
|
|
```
|
|
- All valid parameters must be passed to `url_for` to build a URL. If a parameter is not supplied, or if a parameter does not match the specified type, a `URLBuildError` will be thrown.
|
|
|
|
## WebSocket routes
|
|
|
|
Routes for the WebSocket protocol can be defined with the `@app.websocket`
|
|
decorator:
|
|
|
|
```python
|
|
@app.websocket('/feed')
|
|
async def feed(request, ws):
|
|
while True:
|
|
data = 'hello!'
|
|
print('Sending: ' + data)
|
|
await ws.send(data)
|
|
data = await ws.recv()
|
|
print('Received: ' + data)
|
|
```
|
|
|
|
Alternatively, the `app.add_websocket_route` method can be used instead of the
|
|
decorator:
|
|
|
|
```python
|
|
async def feed(request, ws):
|
|
pass
|
|
|
|
app.add_websocket_route(my_websocket_handler, '/feed')
|
|
```
|
|
|
|
Handlers for a WebSocket route are passed the request as first argument, and a
|
|
WebSocket protocol object as second argument. The protocol object has `send`
|
|
and `recv` methods to send and receive data respectively.
|
|
|
|
WebSocket support requires the [websockets](https://github.com/aaugustin/websockets)
|
|
package by Aymeric Augustin.
|
|
|
|
|
|
## About `strict_slashes`
|
|
|
|
You can make `routes` strict to trailing slash or not, it's configurable.
|
|
|
|
```python
|
|
|
|
# provide default strict_slashes value for all routes
|
|
app = Sanic('test_route_strict_slash', strict_slashes=True)
|
|
|
|
# you can also overwrite strict_slashes value for specific route
|
|
@app.get('/get', strict_slashes=False)
|
|
def handler(request):
|
|
return text('OK')
|
|
|
|
# It also works for blueprints
|
|
bp = Blueprint('test_bp_strict_slash', strict_slashes=True)
|
|
|
|
@bp.get('/bp/get', strict_slashes=False)
|
|
def handler(request):
|
|
return text('OK')
|
|
|
|
app.blueprint(bp)
|
|
```
|
|
|
|
## User defined route name
|
|
|
|
You can pass `name` to change the route name to avoid using the default name (`handler.__name__`).
|
|
|
|
```python
|
|
|
|
app = Sanic('test_named_route')
|
|
|
|
@app.get('/get', name='get_handler')
|
|
def handler(request):
|
|
return text('OK')
|
|
|
|
# then you need use `app.url_for('get_handler')`
|
|
# instead of # `app.url_for('handler')`
|
|
|
|
# It also works for blueprints
|
|
bp = Blueprint('test_named_bp')
|
|
|
|
@bp.get('/bp/get', name='get_handler')
|
|
def handler(request):
|
|
return text('OK')
|
|
|
|
app.blueprint(bp)
|
|
|
|
# then you need use `app.url_for('test_named_bp.get_handler')`
|
|
# instead of `app.url_for('test_named_bp.handler')`
|
|
|
|
# different names can be used for same url with different methods
|
|
|
|
@app.get('/test', name='route_test')
|
|
def handler(request):
|
|
return text('OK')
|
|
|
|
@app.post('/test', name='route_post')
|
|
def handler2(request):
|
|
return text('OK POST')
|
|
|
|
@app.put('/test', name='route_put')
|
|
def handler3(request):
|
|
return text('OK PUT')
|
|
|
|
# below url are the same, you can use any of them
|
|
# '/test'
|
|
app.url_for('route_test')
|
|
# app.url_for('route_post')
|
|
# app.url_for('route_put')
|
|
|
|
# for same handler name with different methods
|
|
# you need specify the name (it's url_for issue)
|
|
@app.get('/get')
|
|
def handler(request):
|
|
return text('OK')
|
|
|
|
@app.post('/post', name='post_handler')
|
|
def handler(request):
|
|
return text('OK')
|
|
|
|
# then
|
|
# app.url_for('handler') == '/get'
|
|
# app.url_for('post_handler') == '/post'
|
|
```
|
|
|
|
## Build URL for static files
|
|
|
|
You can use `url_for` for static file url building now.
|
|
If it's for file directly, `filename` can be ignored.
|
|
|
|
```python
|
|
|
|
app = Sanic('test_static')
|
|
app.static('/static', './static')
|
|
app.static('/uploads', './uploads', name='uploads')
|
|
app.static('/the_best.png', '/home/ubuntu/test.png', name='best_png')
|
|
|
|
bp = Blueprint('bp', url_prefix='bp')
|
|
bp.static('/static', './static')
|
|
bp.static('/uploads', './uploads', name='uploads')
|
|
bp.static('/the_best.png', '/home/ubuntu/test.png', name='best_png')
|
|
app.blueprint(bp)
|
|
|
|
# then build the url
|
|
app.url_for('static', filename='file.txt') == '/static/file.txt'
|
|
app.url_for('static', name='static', filename='file.txt') == '/static/file.txt'
|
|
app.url_for('static', name='uploads', filename='file.txt') == '/uploads/file.txt'
|
|
app.url_for('static', name='best_png') == '/the_best.png'
|
|
|
|
# blueprint url building
|
|
app.url_for('static', name='bp.static', filename='file.txt') == '/bp/static/file.txt'
|
|
app.url_for('static', name='bp.uploads', filename='file.txt') == '/bp/uploads/file.txt'
|
|
app.url_for('static', name='bp.best_png') == '/bp/static/the_best.png'
|
|
|
|
```
|