@auth.requires for functions

[Andrea Fae']

For example I have this type of functions:

# sono autorizzati i vari manager a seconda della sede

@auth.requires(auth.has_membership('Total-manager') | auth.has_membership('Conegliano-studente') | auth.has_membership('Pordenone-manager') | auth.has_membership('Pordenone-studente') | auth.has_membership('Udine-studente'))

def appuntamenti_studente():

     # recupero lo studente selezionato

    studente = request.args(0)

    # recupero il gruppo

    # query per recuperare il nome  dello studente

    query_nome_studente = db.auth_user.id == studente

    # recupero nome e cognome dello studente

    row = db(query_nome_studente).select(db.auth_user.first_name,db.auth_user.last_name).first()

    #seleziono gli eventi dello studente

    query = (db.evento.studenti.contains(studente))

    eventi_stud = db(query).select()

    # imposto la grid per far vedere gli eventi dello studente

    exportcls = dict(csv_with_hidden_cols=False, html=False, json=False, tsv_with_hidden_cols=False, tsv=False)

    # solo se lo studente corrisponde a chi si è loggato

    if (str(auth.user.id) == studente):

        #print 'sono al form normale'

        form = SQLFORM.grid(query, args=[studente], fields=[db.evento.titolo, db.evento.inizio,db.evento.fine,db.evento.risorsa, db.evento.materia,db.evento.docente],create=False, details=False, editable=False, deletable=False, maxtextlength=60, exportclasses = exportcls)

    else:

        redirect(URL('default','index'))

    return locals()

I'm testing different "fixed" values in the @auth.requires, but they can be more or less depending on how many roles are in the db. I'd like to do this dynamically from the db, extracting and compising this @auth.requires line in dynamic way. Is it possible? Do you have any examples? Thank you

[Anthony]

First, when using auth.requires(), it is best to put the test inside a lambda (or standard function) so it will not be evaluated until the decorated function is actually called (otherwise, the test will be evaluated whenever the controller file is accessed).

Anyway, you can do something like this:

list_of_roles = ['role1', 'role2', 'role3'] # You could get this list via a database query

@auth.requires(lambda: any(auth.has_membership(role) for role in list_of_roles))
def myfunc():
    ...

Anthony

[Andrea Fae']

But... "any"? I need some more information about lambda I think....where to find this syntax with any?

where is written what you told about evaluation?

Thank you very much

[Marvi Benedet]

https://docs.python.org/2/library/functions.html#any

def any(iterable):
    for element in iterable:
        if element:
            return True
    return False

so any() return true if one (or more) of the elements is True.

this:

auth.has_membership(role) for role in list_of_roles

try all the roles in the list.

so if one of the auth.has_membership() return true, the lamba function return true.

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[Andrea Fae']

Thanks

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[Anthony]

On Thursday, April 20, 2017 at 8:36:46 AM UTC-4, Andrea Fae' wrote:

But... "any"? I need some more information about lambda I think....where to find this syntax with any?

where is written what you told about evaluation?

Remember, web2py is a Python framework -- many of the things you see are simply Python (both "any" and "lambda" are plain Python constructs). Note, it doesn't have to be a lambda function -- the point is simply that if you pass a function of any kind to auth.requires(), it will call that function later (when the function it decorates is actually called) rather than immediately (when the decorator itself is defined -- which happens whenever the controller file is executed). So, by putting the test inside a function, you defer the execution of the test until it is actually needed. Because the auth.has_membership() calls each require a database select, you don't want to run those calls unless absolutely necessary. This recommendation is mentioned here: http://web2py.com/books/default/chapter/29/09/access-control#Decorators.

Anthony

[Andrea Fae']

Hello, if I have to get the list from database, where I need to put the code? At the start of default.py where I use the functions? Thanks

Il giorno mercoledì 19 aprile 2017 17:30:06 UTC+2, Anthony ha scritto:

[Andrea Fae']