cubicweb: comparison doc/book/en/annexes/faq.rst

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-:a721966779be
+:cba9f175da2d
 http://groups.google.com/group/google-appengine/browse_frm/thread/d791ce17e2716147/eb078f8cfe8426e0
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 http://groups.google.com/group/google-appengine/browse_frm/thread/f48cf6099973aef5/c28cd6934dd72457
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-* Why does not CubicWeb have a template language ?
+Why does not CubicWeb have a template language ?
+------------------------------------------------
 There are enough template languages out there. You can use your
 preferred template language if you want. [explain how to use a
 template language]
 it does not prevent you from using a templating language.
 The reason template languages are not used in this book is that
 experience has proved us that using pure python was less cumbersome.
-* Why do you think using pure python is better than using a template language ?
+Why do you think using pure python is better than using a template language ?
+-----------------------------------------------------------------------------
 Python is an Object Oriented Programming language and as such it
 already provides a consistent and strong architecture and syntax
 a templating language would not reach.
 easier to maintain with real functions/classes/contexts
 without the need of learning a new dialect. By using Python,
 we use standard OOP techniques and this is a key factor in a
 robust application.
-* Why do you use the GPL license to prevent me from doing X ?
+Why do you use the GPL license to prevent me from doing X ?
+-----------------------------------------------------------
 GPL means that *if* you redistribute your application, you need to
 redistribute it *and* the changes you made *and* the code _linked_
 to it under the GPL licence.
 any problem. The only thing we are trying to prevent here is someone
 taking the framework and packaging it as closed source to his own
 clients.
-* CubicWeb looks pretty recent. Is it stable ?
+CubicWeb looks pretty recent. Is it stable ?
+--------------------------------------------
 It is constantly evolving, piece by piece.  The framework has
 evolved over the past seven years and data has been migrated from
 one schema to the other ever since. There is a well-defined way to
 handle data and schema migration.
-* Why is the RQL query language looking similar to X ?
+Why is the RQL query language looking similar to X ?
+-----------------------------------------------------
 It may remind you of SQL but it is higher level than SQL, more like
 SPARQL. Except that SPARQL did not exist when we started the project.
 Having SPARQL has a query language has been in our backlog for years.
 RQL.
 [copy answer from forum, explain why similar to sparql and why better
 than django and SQL]
-* which ajax library
+which ajax library
+------------------
 [we use jquery and things on top of that]
-* `Error while publishing rest text ...`
+`Error while publishing rest text ...`
+--------------------------------------
 While modifying the description of an entity, you get an error message in
 the application `Error while publishing ...` for Rest text and plain text.
 The server returns a traceback like as follows ::
 2008-10-06 15:05:08 - (cubicweb.rest) ERROR: error while publishing ReST text
 This can be fixed by applying the patch described in :
 http://code.google.com/p/googleappengine/issues/detail?id=48
-* What are hooks used for?
+What are hooks used for?
+------------------------
 Hooks are executed around (actually before or after) events.  The
 most common events are data creation, update and deletion.  They
 permit additional constraint checking (those not expressible at the
 schema level), pre and post computations depending on data
 As such, they are a vital part of the framework.
 Other kinds of hooks, called Operations, are available
 for execution just before commit.
-* When should you define an HTML template rather than define a graphical component?
+When should you define an HTML template rather than define a graphical component?
+---------------------------------------------------------------------------------
 An HTML template cannot contain code, hence it is only about static
 content.  A component is made of code and operations that apply on a
 well defined context (request, result set). It enables much more
 dynamic views.
-* What is the difference between `AppRsetObject` and `AppObject` ?
+What is the difference between `AppRsetObject` and `AppObject` ?
+----------------------------------------------------------------
 `AppRsetObject` instances are selected on a request and a result
 set. `AppObject` instances are directly selected by id.
-* How to update a database after a schema modification?
+How to update a database after a schema modification?
+-----------------------------------------------------
 It depends on what has been modified in the schema.
 * Update of an attribute permissions and properties:
 ``synchronize_eschema('MyEntity')``.
 * Add an attribute: ``add_attribute('MyEntityType', 'myattr')``.
 * Add a relation: ``add_relation_definition('SubjRelation', 'MyRelation', 'ObjRelation')``.
-* How to create an anonymous user?
+How to create an anonymous user?
+--------------------------------
 This allows to bypass authentication for your site. In the
 ``all-in-one.conf`` file of your instance, define the anonymous user
 as follows ::
 While creating a new instance, you can decide to allow access
 to anonymous user, which will automatically execute what is
 decribed above.
-* How to change the application logo?
+How to change the application logo?
+-----------------------------------
 There are two ways of changing the logo.
 1. The easiest way to use a different logo is to replace the existing
 ``logo.png`` in ``myapp/data`` by your prefered icon and refresh.
 LOGO = DATADIR/path/to/mylogo.gif
 where DATADIR is ``mycubes/data``.
-* How to configure LDAP source?
+How to configure LDAP source?
+-------------------------------
 Your instance's sources are defined in ``/etc/cubicweb.d/myapp/sources``.
 Configuring an LDAP source is about declaring that source in your
 instance configuration file such as: ::
 user-attrs-map=gecos:email,uid:login
 Any change applied to configuration file requires to restart your
 application.
-* I get NoSelectableObject exceptions: how do I debug selectors ?
+I get NoSelectableObject exceptions: how do I debug selectors ?
+---------------------------------------------------------------
 You just need to put the appropriate context manager around view/component
 selection: ::
 from cubicweb.common.selectors import traced_selection
 This will yield additional WARNINGs, like this: ::
 2009-01-09 16:43:52 - (cubicweb.selectors) WARNING: selector one_line_rset returned 0 for <class 'cubicweb.web.views.basecomponents.WFHistoryVComponent'>
-* How to format an entity date attribute?
+How to format an entity date attribute?
+---------------------------------------
 If your schema has an attribute of type Date or Datetime, you might
 want to format it. First, you should define your preferred format using
 the site configuration panel ``http://appurl/view?vid=systemepropertiesform``
 and then set ``ui.date`` and/or ``ui.datetime``.
 Then in the view code, use::
 self.format_date(entity.date_attribute)
+Can PostgreSQL and CubicWeb authentication work with kerberos ?
+----------------------------------------------------------------
+If you have postgresql set up to accept kerberos authentication, you can set
+the db-host, db-name and db-user parameters in the `sources` configuration
+file while leaving the password blank. It should be enough for your instance
+to connect to postgresql with a kerberos ticket.
+How to load data from a script?
+-------------------------------
+The following script aims at loading data within a script assuming pyro-nsd is
+running and your application is configured with ``pyro-server=yes``, otherwise
+you would not be able to use dbapi. ::
+from cubicweb import dbapi
+cnx = dbapi.connection(database='instance-id', user='admin', password='admin')
+cur = cnx.cursor()
+for name in ('Personal', 'Professional', 'Computers'):
+cur.execute('INSERT Blog B: B name %s', name)
+cnx.commit()
+What is the CubicWeb datatype corresponding to GAE datastore's UserProperty?
+----------------------------------------------------------------------------
+If you take a look at your application schema and
+click on "display detailed view of metadata" you will see that there
+is a Euser entity in there. That's the one that is modeling users. The
+thing that corresponds to a UserProperty is a relationship between
+your entity and the Euser entity. As in ::
+class TodoItem(EntityType):
+text = String()
+todo_by = SubjectRelation('Euser')
+[XXX check that cw handle users better by
+mapping Google Accounts to local Euser entities automatically]
+How to implement security?
+--------------------------
+This is an example of how it works in our framework::
+class Version(EntityType):
+"""a version is defining the content of a particular project's
+release"""
+# definition of attributes is voluntarily missing
+permissions = {'read': ('managers', 'users', 'guests',),
+'update': ('managers', 'logilab', 'owners',),
+'delete': ('managers', ),
+'add': ('managers', 'logilab',
+ERQLExpression('X version_of PROJ, U in_group G, PROJ
+require_permission P, P name "add_version", P require_group G'),)}
+The above means that permission to read a Version is granted to any
+user that is part of one of the groups 'managers', 'users', 'guests'.
+The 'add' permission is granted to users in group 'managers' or
+'logilab' and to users in group G, if G is linked by a permission
+entity named "add_version" to the version's project.
+::
+class version_of(RelationType):
+"""link a version to its project. A version is necessarily linked
+to one and only one project. """
+# some lines voluntarily missing
+permissions = {'read': ('managers', 'users', 'guests',),
+'delete': ('managers', ),
+'add': ('managers', 'logilab',
+RRQLExpression('O require_permission P, P name "add_version",
+'U in_group G, P require_group G'),) }
+You can find additional information in the section :ref:`security`.
+[XXX what does the second example means in addition to the first one?]

branch	tls-sprint
changeset 1715	cba9f175da2d
parent 1599	38a1d0f190e2
parent 1714	a721966779be
child 1808	aa09e20dd8c0