sanic/guide/content/en/guide/basics/routing.md

Routing

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So far we have seen a lot of this decorator in different forms.

But what is it? And how do we use it?

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```python
@app.route("/stairway")
    ...

@app.get("/to")
    ...

@app.post("/heaven")
    ...
```

Adding a route

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The most basic way to wire up a handler to an endpoint is with `app.add_route()`.

See [API docs](https://sanic.readthedocs.io/en/stable/sanic/api_reference.html#sanic.app.Sanic.url_for) for more details.

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```python
async def handler(request):
    return text("OK")

app.add_route(handler, "/test")
```

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By default, routes are available as an HTTP `GET` call. You can change a handler to respond to one or more HTTP methods.

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```python
app.add_route(
    handler,
    '/test',
    methods=["POST", "PUT"],
)
```

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Using the decorator syntax, the previous example is identical to this.

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```python
@app.route('/test', methods=["POST", "PUT"])
async def handler(request):
    return text('OK')
```

HTTP methods

Each of the standard HTTP methods has a convenience decorator.

GET

@app.get('/test')
async def handler(request):
    return text('OK')

MDN Docs

POST

@app.post('/test')
async def handler(request):
    return text('OK')

MDN Docs

PUT

@app.put('/test')
async def handler(request):
    return text('OK')

MDN Docs

PATCH

@app.patch('/test')
async def handler(request):
    return text('OK')

MDN Docs

DELETE

@app.delete('/test')
async def handler(request):
    return text('OK')

MDN Docs

HEAD

@app.head('/test')
async def handler(request):
    return empty()

MDN Docs

OPTIONS

@app.options('/test')
async def handler(request):
    return empty()

MDN Docs

.. warning::

By default, Sanic will **only** consume the incoming request body on non-safe HTTP methods (`POST`, `PUT`, `PATCH`, `DELETE`). If you want to receive data in the HTTP request on any other method, you will need to do one of the following two options:

**Option #1 - Tell Sanic to consume the body using `ignore_body`**
```python
@app.request("/path", ignore_body=False)
async def handler(_):
    ...
```

**Option #2 - Manually consume the body in the handler using `receive_body`**
```python
@app.get("/path")
async def handler(request: Request):
    await request.receive_body()
```

Path parameters

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Sanic allows for pattern matching, and for extracting values from URL paths. These parameters are then injected as keyword arguments in the route handler.

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```python
@app.get("/tag/<tag>")
async def tag_handler(request, tag):
    return text("Tag - {}".format(tag))
```

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You can declare a type for the parameter. This will be enforced when matching, and also will type cast the variable.

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```python
@app.get("/foo/<foo_id:uuid>")
async def uuid_handler(request, foo_id: UUID):
    return text("UUID - {}".format(foo_id))
```

Supported types

str

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**Regular expression applied**: `r"[^/]+"`  
**Cast type**: `str`  
**Example matches**:  

- `/path/to/Bob`
- `/path/to/Python%203`

Beginning in v22.3 `str` will *not* match on empty strings. See `strorempty` for this behavior.

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```python
@app.route("/path/to/<foo:str>")
async def handler(request, foo: str):
    ...
```

strorempty

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**Regular expression applied**: `r"[^/]*"`  
**Cast type**: `str`  
**Example matches**:

- `/path/to/Bob`
- `/path/to/Python%203`
- `/path/to/`

Unlike the `str` path parameter type, `strorempty` can also match on an empty string path segment.

*Added in v22.3*

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```python
@app.route("/path/to/<foo:strorempty>")
async def handler(request, foo: str):
    ...
```

int

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**Regular expression applied**: `r"-?\d+"`  
**Cast type**: `int`  
**Example matches**:  

- `/path/to/10`
- `/path/to/-10`

_Does not match float, hex, octal, etc_

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```python
@app.route("/path/to/<foo:int>")
async def handler(request, foo: int):
    ...
```

float

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**Regular expression applied**: `r"-?(?:\d+(?:\.\d*)?|\.\d+)"`  
**Cast type**: `float`  
**Example matches**:  

- `/path/to/10`
- `/path/to/-10`
- `/path/to/1.5`

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```python
@app.route("/path/to/<foo:float>")
async def handler(request, foo: float):
    ...
```

alpha

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**Regular expression applied**: `r"[A-Za-z]+"`  
**Cast type**: `str`  
**Example matches**:  

- `/path/to/Bob`
- `/path/to/Python`

_Does not match a digit, or a space or other special character_

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```python
@app.route("/path/to/<foo:alpha>")
async def handler(request, foo: str):
    ...
```

slug

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**Regular expression applied**: `r"[a-z0-9]+(?:-[a-z0-9]+)*"`  
**Cast type**: `str`  
**Example matches**:  

- `/path/to/some-news-story`
- `/path/to/or-has-digits-123`

*Added in v21.6*

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```python
@app.route("/path/to/<article:slug>")
async def handler(request, article: str):
    ...
```

path

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**Regular expression applied**: `r"[^/].*?"`  
**Cast type**: `str`  
**Example matches**:
- `/path/to/hello`
- `/path/to/hello.txt`
- `/path/to/hello/world.txt`

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```python
@app.route("/path/to/<foo:path>")
async def handler(request, foo: str):
    ...
```

.. warning::

Because this will match on `/`, you should be careful and thoroughly test your patterns that use `path` so they do not capture traffic intended for another endpoint. Additionally, depending on how you use this type, you may be creating a path traversal vulnerability in your application. It is your job to protect your endpoint against this, but feel free to ask in our community channels for help if you need it :)

ymd

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**Regular expression applied**: `r"^([12]\d{3}-(0[1-9]|1[0-2])-(0[1-9]|[12]\d|3[01]))"`  
**Cast type**: `datetime.date`  
**Example matches**:  

- `/path/to/2021-03-28`

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```python
@app.route("/path/to/<foo:ymd>")
async def handler(request, foo: datetime.date):
    ...
```

uuid

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**Regular expression applied**: `r"[A-Fa-f0-9]{8}-[A-Fa-f0-9]{4}-[A-Fa-f0-9]{4}-[A-Fa-f0-9]{4}-[A-Fa-f0-9]{12}"`  
**Cast type**: `UUID`  
**Example matches**:  

- `/path/to/123a123a-a12a-1a1a-a1a1-1a12a1a12345`

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```python
@app.route("/path/to/<foo:uuid>")
async def handler(request, foo: UUID):
    ...
```

ext

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**Regular expression applied**: n/a
**Cast type**: *varies*
**Example matches**:

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```python
@app.route("/path/to/<foo:ext>")
async def handler(request, foo: str, ext: str):
    ...
```

definition	example	filename	extension
<file:ext>	page.txt	"page"	"txt"
<file:ext=jpg>	cat.jpg	"cat"	"jpg"
<file:ext=jpg|png|gif|svg>	cat.jpg	"cat"	"jpg"
<file=int:ext>	123.txt	123	"txt"
<file=int:ext=jpg|png|gif|svg>	123.svg	123	"svg"
<file=float:ext=tar.gz>	3.14.tar.gz	3.14	"tar.gz"

File extensions can be matched using the special ext parameter type. It uses a special format that allows you to specify other types of parameter types as the file name, and one or more specific extensions as shown in the example table above.

It does not support the path parameter type.

Added in v22.3

regex

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**Regular expression applied**: _whatever you insert_  
**Cast type**: `str`  
**Example matches**:  

- `/path/to/2021-01-01`

This gives you the freedom to define specific matching patterns for your use case.

In the example shown, we are looking for a date that is in `YYYY-MM-DD` format.

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```python
@app.route(r"/path/to/<foo:([12]\d{3}-(0[1-9]|1[0-2])-(0[1-9]|[12]\d|3[01]))>")
async def handler(request, foo: str):
    ...
```

Regex Matching

More often than not, compared with complex routing, the above example is too simple, and we use a completely different routing matching pattern, so here we will explain the advanced usage of regex matching in detail.

Sometimes, you want to match a part of a route:

/image/123456789.jpg

If you wanted to match the file pattern, but only capture the numeric portion, you need to do some regex fun 😄:

app.route(r"/image/<img_id:(?P<img_id>\d+)\.jpg>")

Further, these should all be acceptable:

@app.get(r"/<foo:[a-z]{3}.txt>")                # matching on the full pattern
@app.get(r"/<foo:([a-z]{3}).txt>")              # defining a single matching group
@app.get(r"/<foo:(?P<foo>[a-z]{3}).txt>")       # defining a single named matching group
@app.get(r"/<foo:(?P<foo>[a-z]{3}).(?:txt)>")   # defining a single named matching group, with one or more non-matching groups

Also, if using a named matching group, it must be the same as the segment label.

@app.get(r"/<foo:(?P<foo>\d+).jpg>")  # OK
@app.get(r"/<foo:(?P<bar>\d+).jpg>")  # NOT OK

For more regular usage methods, please refer to Regular expression operations

Generating a URL

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Sanic provides a method to generate URLs based on the handler method name: `app.url_for()`. This is useful if you want to avoid hardcoding url paths into your app; instead, you can just reference the handler name.

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```python
@app.route('/')
async def index(request):
    # generate a URL for the endpoint `post_handler`
    url = app.url_for('post_handler', post_id=5)

    # Redirect to `/posts/5`
    return redirect(url)

@app.route('/posts/<post_id>')
async def post_handler(request, post_id):
    ...
```

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You can pass any arbitrary number of keyword arguments. Anything that is _not_ a request parameter will be implemented as a part of the query string.

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```python
assert app.url_for(
    "post_handler",
    post_id=5,
    arg_one="one",
    arg_two="two",
) == "/posts/5?arg_one=one&arg_two=two"
```

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Also supported is passing multiple values for a single query key.

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```python
assert app.url_for(
    "post_handler",
    post_id=5,
    arg_one=["one", "two"],
) == "/posts/5?arg_one=one&arg_one=two"
```

Special keyword arguments

See API Docs for more details.

app.url_for("post_handler", post_id=5, arg_one="one", _anchor="anchor")
# '/posts/5?arg_one=one#anchor'

# _external requires you to pass an argument _server or set SERVER_NAME in app.config if not url will be same as no _external
app.url_for("post_handler", post_id=5, arg_one="one", _external=True)
# '//server/posts/5?arg_one=one'

# when specifying _scheme, _external must be True
app.url_for("post_handler", post_id=5, arg_one="one", _scheme="http", _external=True)
# 'http://server/posts/5?arg_one=one'

# you can pass all special arguments at once
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'

Customizing a route name

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A custom route name can be used by passing a `name` argument while registering the route.

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```python
@app.get("/get", name="get_handler")
def handler(request):
    return text("OK")
```

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Now, use this custom name to retrieve the URL

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```python
assert app.url_for("get_handler", foo="bar") == "/get?foo=bar"
```

Websockets routes

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Websocket routing works similar to HTTP methods.

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```python
async def handler(request, ws):
    message = "Start"
    while True:
        await ws.send(message)
        message = await ws.recv()

app.add_websocket_route(handler, "/test")
```

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It also has a convenience decorator.

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```python
@app.websocket("/test")
async def handler(request, ws):
    message = "Start"
    while True:
        await ws.send(message)
        message = await ws.recv()
```

Read the websockets section to learn more about how they work.

Strict slashes

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Sanic routes can be configured to strictly match on whether or not there is a trailing slash: `/`. This can be configured at a few levels and follows this order of precedence:

1. Route
2. Blueprint
3. BlueprintGroup
4. Application

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```python
# provide default strict_slashes value for all routes
app = Sanic(__file__, strict_slashes=True)
```

```python
# overwrite strict_slashes value for specific route
@app.get("/get", strict_slashes=False)
def handler(request):
    return text("OK")
```

```python
# it also works for blueprints
bp = Blueprint(__file__, strict_slashes=True)

@bp.get("/bp/get", strict_slashes=False)
def handler(request):
    return text("OK")
```

```python
bp1 = Blueprint(name="bp1", url_prefix="/bp1")
bp2 = Blueprint(
    name="bp2",
    url_prefix="/bp2",
    strict_slashes=False,
)

# This will enforce strict slashes check on the routes
# under bp1 but ignore bp2 as that has an explicitly
# set the strict slashes check to false
group = Blueprint.group([bp1, bp2], strict_slashes=True)
```

Static files

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In order to serve static files from Sanic, use `app.static()`.

The order of arguments is important:

1. Route the files will be served from
2. Path to the files on the server

See [API docs](https://sanic.readthedocs.io/en/stable/sanic/api/app.html#sanic.app.Sanic.static) for more details.

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```python
app.static("/static/", "/path/to/directory/")
```

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It is generally best practice to end your directory paths with a trailing slash (`/this/is/a/directory/`). This removes ambiguity by being more explicit.

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You can also serve individual files.

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```python
app.static("/", "/path/to/index.html")
```

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It is also sometimes helpful to name your endpoint

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```python
app.static(
    "/user/uploads/",
    "/path/to/uploads/",
    name="uploads",
)
```

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Retrieving the URLs works similar to handlers. But, we can also add the `filename` argument when we need a specific file inside a directory.

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```python
assert app.url_for(
    "static",
    name="static",
    filename="file.txt",
) == "/static/file.txt"
```
```python
assert app.url_for(
    "static",
    name="uploads",
    filename="image.png",
) == "/user/uploads/image.png"

```

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If you are going to have multiple `static()` routes, then it is *highly* suggested that you manually name them. This will almost certainly alleviate potential hard to discover bugs.

```python
app.static("/user/uploads/", "/path/to/uploads/", name="uploads")
app.static("/user/profile/", "/path/to/profile/", name="profile_pics")
```

Auto index serving

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If you have a directory of static files that should be served by an index page, you can provide the filename of the index. Now, when reaching that directory URL, the index page will be served.

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```python
app.static("/foo/", "/path/to/foo/", index="index.html")
```

Added in v23.3

File browser

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When serving a directory from a static handler, Sanic can be configured to show a basic file browser instead using `directory_view=True`.

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```python
app.static("/uploads/", "/path/to/dir", directory_view=True)
```

You now have a browsable directory in your web browser:

Added in v23.3

Route context

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When a route is defined, you can add any number of keyword arguments with a `ctx_` prefix. These values will be injected into the route `ctx` object.

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```python
@app.get("/1", ctx_label="something")
async def handler1(request):
    ...

@app.get("/2", ctx_label="something")
async def handler2(request):
    ...

@app.get("/99")
async def handler99(request):
    ...

@app.on_request
async def do_something(request):
    if request.route.ctx.label == "something":
        ...
```

Added in v21.12