Confusion regarding @view_config return value usage

[wichert]

I have an existing view function that I am trying expose for another object as well. The original is defined like this:

@view_config(route_name='celebrity-style-link-search', context=CelebrityStyle,
        renderer='json', permission='authenticated')
def link_search(context, request):
    ....

To expose it for a different class as well I tried to call view_config directly:

magazine_link_search = (view_config(route_name='magazine-page-link-search',
        context=MagazinePage, renderer='json', permission='authenticated')
        (link_search))

That result in an error that the view conflicts with itself:

pyramid.exceptions.ConfigurationConflictError: Conflicting configuration actions
  For: ('view', <class 'customer.site.model.magazine.MagazinePage'>, '', None, <InterfaceClass pyramid.interfaces.IView>, None, None, None, 'magazine-page-link-search', None, False, None, None, None, None)
    ('/home/wichert/Work/customer.admin/src/customer/admin/ui/magazine.py', 149, '<module>', '(link_search))')
    ('/home/wichert/Work/customer.admin/src/customer/admin/ui/magazine.py', 149, '<module>', '(link_search))')

This appears to be due to the assignment. If I rewrite the code to remove the assignment to this:

(view_config(route_name='magazine-page-link-search',
        context=MagazinePage, renderer='json', permission='authenticated')
        (link_search))

thinks work normally. I do not understand why this would break since I am only calling view_config once here. Is this a venusian bug?

[mcdonc]

I'm marking this as "sprintable" so that someone can verify that Wiggy's example breaks (or doesn't) with the most recent venusian.

[mcdonc]

I'm marking this as "sprintable" so that someone can verify that Wiggy's example breaks (or doesn't) with the most recent venusian.

[witsch]

how about using

@view_config(route_name='magazine-page-link-search', context=MagazinePage,
        renderer='json', permission='authenticated')
def magazine_link_search(context, request):
    return link_search(context, request)

i know people will probably try to use the decorator directly (causing it to break), but i'd argue that the above is much cleaner to read anyway (so they shouldn't really :)). we're gonna check with the latest venusian nevertheless...

[witsch]

how about using

@view_config(route_name='magazine-page-link-search', context=MagazinePage,
        renderer='json', permission='authenticated')
def magazine_link_search(context, request):
    return link_search(context, request)

i know people will probably try to use the decorator directly (causing it to break), but i'd argue that the above is much cleaner to read anyway (so they shouldn't really :)). we're gonna check with the latest venusian nevertheless...

[witsch]

ftr, the issue still occurs with the latest pyramid (@f6ea2275f927e88d43fb2d105bce33d0ece0df16) and venusian (@11857ea4674cb01bf6cc82c6faddd62f3c8b35d1). steps to reproduce are:

• run the following from a pyramid checkout

$ tox -c hacking-tox.ini
$ git clone git@github.com:Pylons/venusian.git
$ cd venusian
$ ../env27/bin/python setup.py develop
$ cd ../env27

• append the line

alias_view = view_config(route_name='bar', renderer='json')(my_view)

to hacking/hacking/views.py as well as

config.add_route('bar', '/bar')

in hacking/hacking/__init__.py:main()

• run

$ bin/pserve hacking/development.ini

this results in

Traceback (most recent call last):
 ...
  File ".../env27/lib/python2.7/site-packages/pyramid/config/__init__.py", line 1199, in resolveConflicts
    raise ConfigurationConflictError(conflicts)
pyramid.exceptions.ConfigurationConflictError: Conflicting configuration actions
  For: ('view', None, '', 'bar', 'd41d8cd98f00b204e9800998ecf8427e')
    Line 9 of file .../env27/hacking/hacking/views.py:
        alias_view = view_config(route_name='bar', renderer='json')(my_view)
    Line 9 of file .../env27/hacking/hacking/views.py:
        alias_view = view_config(route_name='bar', renderer='json')(my_view)
  For: ('view', None, '', 'home', 'd41d8cd98f00b204e9800998ecf8427e')
    Line 4 of file .../env27/hacking/hacking/views.py:
        @view_config(route_name='home', renderer='templates/mytemplate.pt')
    Line 4 of file .../env27/hacking/hacking/views.py:
        @view_config(route_name='home', renderer='templates/mytemplate.pt')

[witsch]

ftr, the issue still occurs with the latest pyramid (@f6ea2275f927e88d43fb2d105bce33d0ece0df16) and venusian (@11857ea4674cb01bf6cc82c6faddd62f3c8b35d1). steps to reproduce are:

• run the following from a pyramid checkout

$ tox -c hacking-tox.ini
$ git clone git@github.com:Pylons/venusian.git
$ cd venusian
$ ../env27/bin/python setup.py develop
$ cd ../env27

• append the line

alias_view = view_config(route_name='bar', renderer='json')(my_view)

to hacking/hacking/views.py as well as

config.add_route('bar', '/bar')

in hacking/hacking/__init__.py:main()

• run

$ bin/pserve hacking/development.ini

this results in

Traceback (most recent call last):
 ...
  File ".../env27/lib/python2.7/site-packages/pyramid/config/__init__.py", line 1199, in resolveConflicts
    raise ConfigurationConflictError(conflicts)
pyramid.exceptions.ConfigurationConflictError: Conflicting configuration actions
  For: ('view', None, '', 'bar', 'd41d8cd98f00b204e9800998ecf8427e')
    Line 9 of file .../env27/hacking/hacking/views.py:
        alias_view = view_config(route_name='bar', renderer='json')(my_view)
    Line 9 of file .../env27/hacking/hacking/views.py:
        alias_view = view_config(route_name='bar', renderer='json')(my_view)
  For: ('view', None, '', 'home', 'd41d8cd98f00b204e9800998ecf8427e')
    Line 4 of file .../env27/hacking/hacking/views.py:
        @view_config(route_name='home', renderer='templates/mytemplate.pt')
    Line 4 of file .../env27/hacking/hacking/views.py:
        @view_config(route_name='home', renderer='templates/mytemplate.pt')

[witsch]

@wiggy, the decorator returns the view function as is, so it's possible to use it multiple times. i've quickly verified it during the sprint party... :)

so, turning your above example into:

@view_config(route_name='magazine-page-link-search', context=MagazinePage,
        renderer='json', permission='authenticated')
@view_config(route_name='celebrity-style-link-search', context=CelebrityStyle,
        renderer='json', permission='authenticated')
def link_search(context, request):
    ...

should do the trick. and i think it's much more readable, too! ;)

[witsch]

@wiggy, the decorator returns the view function as is, so it's possible to use it multiple times. i've quickly verified it during the sprint party... :)

so, turning your above example into:

@view_config(route_name='magazine-page-link-search', context=MagazinePage,
        renderer='json', permission='authenticated')
@view_config(route_name='celebrity-style-link-search', context=CelebrityStyle,
        renderer='json', permission='authenticated')
def link_search(context, request):
    ...

should do the trick. and i think it's much more readable, too! ;)

[wichert]

I could, but not without making my code ugly: I want to reuse a common view (for example something handle generate CORS OPTION request) in various places close to the right view.

[wichert]

I could, but not without making my code ugly: I want to reuse a common view (for example something handle generate CORS OPTION request) in various places close to the right view.

[pauleveritt]

@wichert I'm doing some housecleaning, is this ticket still worth keeping open?

[pauleveritt]

@wichert I'm doing some housecleaning, is this ticket still worth keeping open?

[wichert]

I do see some value in keeping this open, albeit at a very low priority.

[wichert]

I do see some value in keeping this open, albeit at a very low priority.

[mmerickel]

If this is really an issue then it should be reported to venusian. If someone does this we can close the issue here.

[mmerickel]

If this is really an issue then it should be reported to venusian. If someone does this we can close the issue here.