librelist archives

Add no-cache to response

From:

Karsten Hoffrath

Date:

2011-08-08 @ 21:12

Hi everyone,

i'm new to python and web development. I worked through the Quickstart
and Tutorial and begun working on a small project.
For this project i want to explicity set 'no-cache' on the response for
a particular view. I'm using render_template() to render a template.

Googeling and searching Stack Overflow doesn't yield anything useful.

Can someone please post an example how to do this?

Thanks in advance,
Karsten

See the documentation for make_response.

You want to use make_response to get a Response object and then you can set
headers like

res.headers['Cache-Control'] = ...

On Mon, Aug 8, 2011 at 4:12 PM, Karsten Hoffrath <khoffrath@khoffrath.de>wrote:

> Hi everyone,
>
> i'm new to python and web development. I worked through the Quickstart
> and Tutorial and begun working on a small project.
> For this project i want to explicity set 'no-cache' on the response for
> a particular view. I'm using render_template() to render a template.
>
> Googeling and searching Stack Overflow doesn't yield anything useful.
>
> Can someone please post an example how to do this?
>
> Thanks in advance,
> Karsten
>

Thanks for your reply, i will give it a try tonight.

Karsten

Am 09.08.2011 03:16, schrieb Jay Baker:
> See the documentation for make_response.
> 
> You want to use make_response to get a Response object and then you can 
set headers like
> 
> res.headers['Cache-Control'] = ...
> 
> On Mon, Aug 8, 2011 at 4:12 PM, Karsten Hoffrath <khoffrath@khoffrath.de
> <mailto:khoffrath@khoffrath.de>> wrote:
> 
>     Hi everyone,
> 
>     i'm new to python and web development. I worked through the Quickstart
>     and Tutorial and begun working on a small project.
>     For this project i want to explicity set 'no-cache' on the response for
>     a particular view. I'm using render_template() to render a template.
> 
>     Googeling and searching Stack Overflow doesn't yield anything useful.
> 
>     Can someone please post an example how to do this?
> 
>     Thanks in advance,
>     Karsten
> 
> 

Hi,

As said, you can set headers on the response objects.  Either by using
make_response to explicitly get one or in a decorator:

Method 1:

@app.route('/nocache')
def something_not_cached():
    resp = make_response(render_template(...))
    resp.cache_control.no_cache = True
    return resp

Or you write a decorator:

@app.route('/nocache')
@nocache
def something_not_cached():
    return render_template(...)

And here is the decorator:

from flask import make_response
from functools import update_wrapper

def nocache(f):
    def new_func(*args, **kwargs):
        resp = make_response(f(*args, **kwargs))
        resp.cache_control.no_cache = True
        return resp
    return update_wrapper(new_func, f)

resp.cache_control is an accessor for the Cache-Control header, you can
also modify the header directly:

resp.headers['Cache-Control'] = 'no-cache'


Regards,
Armin

Hi,

wow, thanks for the detailled reply. I implemented the decorator but i
should read up on decorators ;)

Thanks
Karsten

Am 09.08.2011 12:26, schrieb Armin Ronacher:
> Hi,
> 
> As said, you can set headers on the response objects.  Either by using
> make_response to explicitly get one or in a decorator:
> 
> Method 1:
> 
> @app.route('/nocache')
> def something_not_cached():
>     resp = make_response(render_template(...))
>     resp.cache_control.no_cache = True
>     return resp
> 
> Or you write a decorator:
> 
> @app.route('/nocache')
> @nocache
> def something_not_cached():
>     return render_template(...)
> 
> And here is the decorator:
> 
> from flask import make_response
> from functools import update_wrapper
> 
> def nocache(f):
>     def new_func(*args, **kwargs):
>         resp = make_response(f(*args, **kwargs))
>         resp.cache_control.no_cache = True
>         return resp
>     return update_wrapper(new_func, f)
> 
> resp.cache_control is an accessor for the Cache-Control header, you can
> also modify the header directly:
> 
> resp.headers['Cache-Control'] = 'no-cache'
> 
> 
> Regards,
> Armin