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

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 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]
 *CubicWeb* does not define its own templating language as this was
 not our goal. Based on our experience, we realized that
 we could gain productivity by letting designers use design tools
 and developpers develop without the use of the templating language
 as an intermediary that could not be anyway efficient for both parties.
 Python is the templating language that we use in *CubicWeb*, but again,
 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 ?
 -----------------------------------------------------------------------------
 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.
 When doing development, you need a real language and template
 languages are not real languages.
 Using Python instead of a template langage for describing the user interface
 makes it 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 LGPL license to prevent me from doing X ?
 ------------------------------------------------------------
 LGPL means that *if* you redistribute your application, you need to
 redistribute the changes you made to CubicWeb under the LGPL licence.
 Publishing a web site has nothing to do with redistributing
 source code. A fair amount of companies use modified LGPL code
 for internal use. And someone could publish a *CubicWeb* component
 under a BSD licence for others to plug into a LGPL framework without
 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 ?
 --------------------------------------------
 It is constantly evolving, piece by piece.  The framework has evolved since
 2001 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 ?
 -----------------------------------------------------
 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 as a query language has been in our backlog for years.
+With version 3.4, CubicWeb has support for SPARQL.
 That RQL language is what is going to make a difference with django-
 like frameworks for several reasons.
 1. accessing data is *much* easier with it. One can write complex
 queries with RQL that would be tedious to define and hard to maintain
 using an object/filter suite of method calls.
 2. it offers an abstraction layer allowing your applications to run
 on multiple back-ends. That means not only various SQL backends
 (postgresql, sqlite, mysql), but also multiple databases at the
 same time, and also non-SQL data stores like LDAP directories and
 subversion/mercurial repositories (see the `vcsfile`
 component). Google App Engine is yet another supported target for
 RQL.
 [copy answer from forum, explain why similar to sparql and why better
 than django and SQL]
 which ajax library is CubicWeb using ?
 How is security implemented ?
 ------------------------------
-This is an example of how it works in our framework::
+This is an example of how it works in our framework:
+.. sourcecode:: python
 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.
-::
+.. sourcecode:: python
 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",
+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?]
 What is `Error while publishing rest text ...` ?
 ------------------------------------------------
 While modifying the description of an entity, you get an error message in
 the instance `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
 Traceback (most recent call last):
 File "/home/user/src/blogdemo/cubicweb/common/rest.py", line 217, in rest_publish
 File "/usr/lib/python2.5/codecs.py", line 817, in open
 file = __builtin__.open(filename, mode, buffering)
 TypeError: __init__() takes at most 3 arguments (4 given)
+This can be fixed by applying the patch described in :
-This can be fixed by applying the patch described in :
+http://code.google.com/p/googleappengine/issues/detail?id=48
-http://code.google.com/p/googleappengine/issues/detail?id=48
 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
 movements.
 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 ?
 ----------------------------------------------------------------------------------
 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` ?
 ----------------------------------------------------------------
 `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 ?
 ------------------------------------------------------
 It depends on what has been modified in the schema.
 * Update the permissions and properties of an entity or a relation:
 ``sync_schema_props_perms('MyEntityOrRelation')``.
 * Add an attribute: ``add_attribute('MyEntityType', 'myattr')``.
 * Add a relation: ``add_relation_definition('SubjRelation', 'MyRelation', 'ObjRelation')``.
 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 ::
 # login of the CubicWeb user account to use for anonymous user (if you want to
 # allow anonymous)
 anonymous-user=anon
 # password of the CubicWeb user account matching login
 anonymous-password=anon
 You also must ensure that this `anon` user is a registered user of
 the DB backend. If not, you can create through the administation
 interface of your instance by adding a user with the role `guests`.
 This could be the admin account (for development
 purposes, of course).
 .. note::
 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 instance 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.
 By default all instance will look for a ``logo.png`` to be
 rendered in the logo section.
 .. image:: ../images/lax-book.06-main-template-logo.en.png
 2. In your cube directory, you can specify which file to use for the logo.
 This is configurable in ``mycube/data/external_resources``: ::
 LOGO = DATADIR/path/to/mylogo.gif
 where DATADIR is ``mycube/data``.
 How to configure a 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: ::
 [ldapuser]
 adapter=ldapuser
 # ldap host
 host=myhost
 # base DN to lookup for usres
 user-base-dn=ou=People,dc=mydomain,dc=fr
 # user search scope
 user-scope=ONELEVEL
 # classes of user
 user-classes=top,posixAccount
 # attribute used as login on authentication
 user-login-attr=uid
 # name of a group in which ldap users will be by default
 user-default-group=users
 # map from ldap user attributes to cubicweb attributes
 user-attrs-map=gecos:email,uid:login
 Any change applied to configuration file requires to restart your
 instance.
 I get NoSelectableObject exceptions, how do I debug selectors ?
 ---------------------------------------------------------------
 You just need to put the appropriate context manager around view/component
-selection (one standard place in in vreg.py) : ::
+selection (one standard place in in vreg.py):
+.. sourcecode:: python
 def possible_objects(self, registry, *args, **kwargs):
 """return an iterator on possible objects in a registry for this result set
 actions returned are classes, not instances
 try:
 yield self.select(vobjects, *args, **kwargs)
 except NoSelectableObject:
 continue
-Don't forget the 'from __future__ improt with_statement' at the
+Don't forget the 'from __future__ import with_statement' at the module
-module top-level.
+top-level.
-This will yield additional WARNINGs, like this:
+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 ?
 ----------------------------------------
 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=systempropertiesform``
 and then set ``ui.date`` and/or ``ui.datetime``.
-Then in the view code, use::
+Then in the view code, use:
+.. sourcecode:: python
 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 instance is configured with ``pyro-server=yes``, otherwise
-you would not be able to use dbapi. ::
+you would not be able to use dbapi.
+.. sourcecode:: python
 from cubicweb import dbapi
 cnx = dbapi.connection(database='instance-id', user='admin', password='admin')
 cur = cnx.cursor()
 cnx.commit()
 What is the CubicWeb datatype corresponding to GAE datastore's UserProperty ?
 -----------------------------------------------------------------------------
 If you take a look at your instance 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 ::
+your entity and the Euser entity. As in:
+.. sourcecode:: python
 class TodoItem(EntityType):
 text = String()
 todo_by = SubjectRelation('Euser')
-[XXX check that cw handle users better by
+[XXX check that cw handle users better by mapping Google Accounts to local Euser
-mapping Google Accounts to local Euser entities automatically]
+entities automatically]
 How to reset the password for user joe ?
 ----------------------------------------
-You need to generate a new encrypted password::
+If you want to reset the admin password for ``myinstance``, do::
+$ cubicweb-ctl reset-admin-pwd myinstance
+You need to generate a new encrypted password::
 $ python
 >>> from cubicweb.server.utils import crypt_password
 >>> crypt_password('joepass')
 'qHO8282QN5Utg'
 >>>
 and paste it in the database::
 $ psql mydb
 mydb=> update cw_cwuser set cw_upassword='qHO8282QN5Utg' where cw_login='joe';
 UPDATE 1
 I've just created a user in a group and it doesn't work !
 ---------------------------------------------------------
 You are probably getting errors such as ::
 remove {'PR': 'Project', 'C': 'CWUser'} from solutions since your_user has no read access to cost
 This is because you have to put your user in the "users" group. The user has to be in both groups.

changeset 2547	f32af375339d
parent 2535	c7b736929a58
child 4748	135329e51713