how to use auth.wiki "extra" and "env"

[dhmorgan]

I'm experimenting with auth.wiki() using the book's instructions; using web2py 2.60; created new simple app ("authwiki") via the admin wizard

I'm attempting to utilize "@(join:a,b,c)" in the body of my wiki page, having first set the controller to return auth.wiki(env=dict(join=lambda a,b,c:"%s-%s-%s" % (a,b,c)))

"@(join:a,b,c)" goes unrendered, as does "@join:a,b,c"

"@{join:a,b,c}" and "@{join:(a,b,c)} both produce an error indicating:

    ERROR: <lambda>() takes exactly 3 arguments (1 given)

In controllers/default.py: 

def index():

   return auth.wiki(env=dict(join=lambda a,b,c:"%s-%s-%s" % (a,b,c)))

I also tried the same using "extra" instead of "env" in the auth.wiki() call and got the same or similar results.

This is the actual body text:

- brackets and colon

    @{join:'how','you','doin'} 

- brackets, colon and parenths

    @{join:('how','you','doin')}

- parentheses and colon

    @(join:'how','you','doin')

- colon only

    @join:'how','you','doin'

[Massimo Di Pierro]

The correct syntax as far as the wiki is concerned is

@{join:a,b,c}

The problem is that MARKMIN identifies the call to "join" and the args "a,b,c" but it does not parse the args. You will have to do that:

def myjoin(vars):

     items = vars.split(',')

     if len(items)==3: return '-'.join(items)

     return 'Error!'

def index():

    return auth.wiki(env=dict(join=myjoin)

[Alan Etkin]

The correct syntax as far as the wiki is concerned is

@{join:a,b,c}

The problem is that MARKMIN identifies the call to "join" and the args "a,b,c" but it does not parse the args. You will have to do that:

def myjoin(vars):

     items = vars.split(',')

     if len(items)==3: return '-'.join(items)

     return 'Error!'

def index():

    return auth.wiki(env=dict(join=myjoin)

Then the book example needs to be fixed because the arguments are not parsed by the custom join function.

Also, it is confusing the use of the extra word in "... This calls the join function passed as extra with parameters ..." since there's an extra wiki argument used for additional markmin render functions (to process custom blocks), but that feature is not related to env.

[Massimo Di Pierro]

Tis gives us two options: fix the docs or change the code. I may be easier to fix the code. How about we do:

@{join:1,2,3} we first parse as c = {'a':'join','b':'1,2,3') then we do args = ast.literal_eval('(%s)' % c['b'] and then we call env[c['a']](*args)?

[Alan Etkin]

I have a possible correction here

https://github.com/mdipierro/web2py-book/pull/86

[dhmorgan]

Thank you both for helping me out here.

Changing the lambda, as indicated in the pending book correction, works.

in controller:

    def index(): 

        return auth.wiki(env=dict(join=lambda a:"-".join(a.split(","))))

in wiki page body:    

    @{join:'this',that','the other'}

    @{join:how,you,doin'} 

result:

    'this'-'that'-'the other'

    how-you-doin'

Danny

[Massimo Di Pierro]

I am thinking that for security reasons it may be better to leave the book un-changed and make it work as described by doing the parsing properly and safely.

[Alan Etkin]

I am thinking that for security reasons it may be better to leave the book un-changed and make it work as described by doing the parsing properly and safely.

Agree. Nevermind my patch then.

BTW: perhaps the new implementation could support also keyword arguments and basic types (ints, string, float)

[Massimo Di Pierro]

I agree. It should  also support the use of variable already passed to the MARKMIN environment. Yet it should not support expressions and python code. All of this may not be easy since we do not want to user eval.

[Alan Etkin]

El miércoles, 17 de julio de 2013 12:14:25 UTC-3, Massimo Di Pierro escribió:

I agree. It should  also support the use of variable already passed to the MARKMIN environment. Yet it should not support expressions and python code. All of this may not be easy since we do not want to user eval.

I have opened two issues (one for fixing the unparsed args and the other for the enhancements)

http://code.google.com/p/web2py/issues/detail?id=1589
http://code.google.com/p/web2py/issues/detail?id=1590