Upgrading to newer releases

Just like any software, weppy is changing over time, and most of these changes we introduce don't require you to change anything into your application code to profit from a new release.

Sometimes, indeed, there are changes in weppy source code that do require some changes or there are possibilities for you to improve your own code quality, taking advantage of new features in weppy.

This section of the documentation reports all the main changes in weppy from one release to the next and how you can (or you should) update your application's code to have the less painful upgrade experience.

Just as a remind, you can update weppy using easy_install:

$ easy_install -U weppy

or pip:

$ pip install -U weppy

Version 0.8

weppy 0.8 introduces some minor breaking changes you should be aware of, and some new features you might been interested into.

Breaking changes

Default serialization and validation of datetime fields

In weppy 0.8 the default serialization and validation of datetime fields has been changed in order to be compliant to the RFC3339 standard. This is due to better embrace developers who uses weppy to write REST APIs, and more generally, to simplify the compatibility with the Javascript world and third party services.

Practically speaking, while in weppy 0.7 and below versions, the format of datetime objects in serialization and validation was like this:

    "dt": "2016-10-31 15:37:30.997128"

in weppy 0.8 is changed to:

    "dt": "2016-10-31T15:37:30.997128+00:00"

Note that this also affects the format in forms, so if you want to stick with the previous notation for validation, add a format option to your validation rules:

class SomeModel(Model):
    dt = Field('datetime')

    validation = {
        'dt': {'is':
            {'datetime': {'format': '%Y-%m-%d %H:%M:%S'}}}

Upgraded default postgres adapters

The pyDAL library contains three different adapters for postgres databases, and the default one appears to be quite old.

In order to enhance performance and reliability of weppy ORM above postgres setups, we changed the default adapter to be the newest one. The main breaking differences between the adapters are the postgres types used for fields:

field type weppy 0.7 weppy 0.8
list:string TEXT TEXT[]

Since the migrator won't see the change, you have two ways to adapt your old code to weppy 0.8:

  • run a custom migration where you manually migrate the affected columns to the new types and use the new adapter
  • change the adapter in your database configuration from postgres to postgres3 in order to use the old adapter

has_one relations in join and including selections

In weppy 0.7 and below versions, when you performed some select with a join of a has_one relation, it appeared to be a list:

>>> rows = User.all().join('profile').select()
>>> rows[0].profile
[<Row {...}>]

In weppy 0.8 this is correctly added to the row attribute as a Row object instead of a list with a single Row object.

Please check your code for these conditions and update it accordingly.

New features

With weppy 0.8 we introduced some new features:

  • the forms now support and display readable-only fields
  • the 'in' validator now supports a 'dbset' notation to validate the presence of the record into a specific database set
  • the migrator now supports bigint fields

Version 0.7

weppy 0.7 introduces some deprecations you should be aware of, and some new features you might been interested into.

Deprecation of virtual decorators in models

In the previous versions, the decorators used to make computation on existing fields and to define virtual attributes and methods for the row were available as computation, virtualfield and fieldmethod. Since we think this naming was not the best option, in weppy 0.7 these decorators were renamed as follows:

old name new name
computation compute
virtualfield rowattr
fieldmethod rowmethod

We think the new nomenclature is more self-explainatory and will make the code of weppy applications more readable.

All these variables are deprecated in weppy 0.7, so you can still use them, but we really suggest to update your application code to the new naming since the old ones will be definitely removed in the next version.

New features

weppy 0.7 introduces official support to database indexes, integrating them with your models and the migration engine, read more about them in the appropriate chapter of the documentation.

Also, with weppy 0.7 we introduced some other small new features:

  • has_one and has_many helpers now support scope and where options
  • has_one and has_many helpers now can be used as decorators to create custom relations
  • fields of type password now have a default validation
  • the shell command now loads the entire application context instead of just the application object
  • a routes command is now available to easily get the routing table of the entire application

Version 0.6

weppy 0.6 introduces some deprecations and changes you should be aware of, and some new features you might been interested into.

Next paragraphs describe all this relevant changes.

Deprecation of expose

Since the first version of weppy, the decorator used to expose functions outside was, indeed, expose:

def foo():

def bar():

Since the majority of frameworks use, instead, the route word for the same purpose, and we wanted to make easier for developers to move from one framework to another, we also adopted this naming. With weppy 0.6 you should change all your expose calls with route:

def foo():

def bar():

All the usages remain the same of expose.
Since it's deprecated, you can still use expose in weppy 0.6, but you have to remember this will be definitely removed in the next version.

Drepecation of vars in request, forms and urls

In the previous versions, the parameters of the url's query string and the ones contained in the request body were stored in the request.get_vars, request.post_vars and request.vars attributes. Since this naming could be quite misleading for developers, in weppy 0.6 these attributes were renamed as follows:

old name new name
vars params
get_vars query_params
post_vars body_params

We think the new nomenclature is more self-explainatory and will make the code of weppy applications more readable.

Following the same rationale, we also changed the Form.vars and Form.input_vars in Form.parameters and Form.input_parameters.
Also the named vars parameter of the url() method is changed to params to avoid confusion.

All these variables are deprecated in weppy 0.6, so you can still use them, but we really suggest to update your application code to the new naming since the old ones will be definitely removed in the next version.

Breaking changes

weppy 0.6 introduces some minor breaking changes: here we list the upgrades you should perform on your application in order to have the same behavior with the new version of the framework.

Relations with has_one

In weppy 0.5 the has_one helper produced nested rows on the results of select operations for these kind of relations: this behavior is changed in weppy 0.6 in order to prevent performance issues. In fact, in the new version of the framework, the attribute responsible of the relation on the selected rows is now a Set.

The immediate consequence is that you have to change the code of your application when you want to effectively access the referred row with a call of the attribute:

# weppy 0.5
referred_row = row.hasonerelation
# weppy 0.6
referred_row = row.hasonerelation()

You can find more about this in the appropriate chapter of the documentation.

Model virtual decorators

The virtualfield and fieldmethods decorators were changed in order to bind the current model when accessing the row. This change was performed in order to simplify the code in these methods, since in weppy 0.5 you had to write code like this:

class Post(Model):
    title = Field()

    def build_short_title(self, row):
        # notice we have to access the field using the tablename
        return row.posts.title[:100]

In weppy 0.6 you can rewrite the decorated method just like this:

def build_short_title(self, row):
    return row.title[:100]

You can restore the old behavior using the current_model_only parameter:

@fieldmethod('short_title', current_model_only=False)

More details are available under the appropriate chapter of the documentation.

Methods of has_many sets

In weppy 0.5 the sets produced by has_many relations had an add with different behaviors depending on the via options:

  • without the via option, the add method was performing an insert of an object referred to the current row
  • with the via option, the add method was performing an insert of a record on the join table, reffered to the other two tables

Since weppy 0.6 introduces the create method on these sets, now the behavior of the add method is always the same, since it always accepts a record of the related table and will just create the relation with it.

If you used the add method of the has_many sets without via option in your application, you should change these calls with the create one.

You can find more about this in the appropriate chapter of the documentation.

New features

weppy 0.6 introduces some big new features you may take advantage of:

Also, with weppy 0.6 we introduced a lot of small new features on the ORM:

Since we introduced a lot of changes on the ORM, we also completely rewritten the involved chapters of the documentation. You may check them out in order to have a deepen view of all the features of the weppy ORM.

Version 0.5

weppy 0.5 introduces python 3 support. Fortunately, there are no changes in the main code that require changes in your application code.

Internally, weppy dropped an old library for utf8 utilities, needed for the translator. Since this part of weppy had been rewritten for python 3 support, the usage of that library (Utf8 class) is no longer required. If you used it in your own code, please make the appropriate changes in order to drop it.

Version 0.4

weppy 0.4 introduces a lot of major changes that break backward compatibility on the DAL, Auth, validation and forms modules among all the prior versions. These changes are a consequence of the introduction of a real ORM inside weppy (while prior versions just had a layer of abstraction over the database).

Please also keep in mind that weppy 0.4 dropped support of python 2.6.x. Please upgrade your python interpreter to 2.7.

Next paragraphs describe the relevant changes for your application in order to upgrade the code from weppy 0.3.

Field class without name parameter

The Field class previously required a name as first parameter. In weppy 0.4 the name is injected by weppy depending on the name of the variable you use for store the field instance.

As an immediate consequence, fields are now Model attributes, instead of elements of the fields attribute which is no more available. Your model should be upgraded from the old notation:

class Thing(Model):
    fields = [
        Field('value', 'integer')

to the new (and more convenient):

class Thing(Model):
    name = Field()
    value = Field('integer')

You should also update all your Form instances, since you should pass a dict of fields instead of a list as first parameter, so from:

form = Form([Field('name'), Field('value', 'integer')])


form = Form({'name': Field(), 'value': Field('int')})

Renamed attributes in Model class

We changed the nomenclature of the Model class attributes to a proper one. Here is the complete list of old names vs the new ones:

old name new name
validators validation
defaults default_values
updates update_values
representation repr_values
visibility form_rw
labels form_labels
comments form_info
widgets form_widgets

Please, update your models to the new structure.
Also, note that the previously available attribute Model.entity is now the more appropriate Model.table.

New validation system

weppy 0.4 introduces a totally refactored validation mechanism, and a new syntax for validation. In particular, the suggested syntax now uses dictionaries instead of lists of validator classes for validation.

Since this change removed quite a lot of previously available validators, we suggest you to convert your validation to the new system, which is documented in the appropriate chapter.

If you still want to use the old notation, here is the list of changes in validators classes:

validator change
isIntInRange removed
isFloatInRange removed
isDecimalInRange removed
isDateInRange removed
isDatetimeInRange removed
isEmailList removed
isListOf renamed into isList
isStrong deprecated (available under weppy.validators._old)
inDb deprecated (available under weppy.validators._old)
notInDb deprecated (available under weppy.validators._old)
FilenameMatches deprecated (available under weppy.validators._old)
anyOf renamed to Any
Slug renamed to Urlify

also, we added new validators that replace the removed ones:

validator in place of
inRange all the old range validators
inDB inDb
notInDB notInDb

Changes in Auth tables

Since weppy 0.4 introduces a new naming convention for models and tables, the old authorization tables were rewritten.

The first consequence is that new Auth tables have changed names:

old name new name
auth_user auth_users
auth_group auth_groups
auth_membership auth_memberships
auth_permission auth_permissions
auth_event auth_events

Moreover, we also changed the name of the columns involved in relations, in particular:

  • auth_memberships have changed user_id and group_id to user and authgroup
  • auth_permissions have changed group_id to authgroup
  • auth_events have changed user_id to user

We suggest you to manually do these changes executing the proper sql commands with your database.

If you're not sure on what to do, we also provide a migration script, which tries to migrate the data. Please, do a full backup of your database before running the script. You can use it as follows:

  • Download the script weppy04upgrade and put it in the directory of your application
  • Run the command weppy --app yourappname shell (with your application name) and in the console:
>>> from yourappname import app, db
>>> from weppy_04_upgrade import before_upgrade
>>> before_upgrade(app, db)
  • Rewrite your models to apply the correct changes mentioned above
  • Run the command weppy --app yourname shell (with your application name) and in the console:
>>> from yourappname import app, db, auth
>>> from weppy_04_upgrade import after_upgrade
>>> after_upgrade(app, db, auth)

Then your auth tables should be good. The script created a 03dump.json into your application folder that you can safely delete among with the script itself.

New features

weppy 0.4 also introduces some new features you may want to take advantage of:

  • Field class now support pythonic naming for old integer and boolean types: you can now write int and bool
  • Model class now auto-generate the name for the table, if not specified (read more in the DAL chapter)
  • belongs_to, has_one and has_many apis are now available for relations in your models (read more in the DAL chapter)
  • You can now disable default validation in Field and Model (read more in the DAL chapter)
  • The abort helper now also accept a body parameter which allows you to customize the body of the returned HTTP error

Version 0.3

weppy 0.3 introduces a caching system for the templates. This change add a new configuration value under app.config.templates_auto_reload which is default set to False.
This means that, under default behavior, in production weppy won't re-process the template files when modified, unless you reload the wsgi process. If you want to have the old behavior, so that weppy re-process the template file when it's modified, simply set the templates_auto_reload variable to True.
Also remind that when your application is in debug mode – which means when it's loaded with the builtin wsgi server – the configuration setting is ignored and templates are auto reloaded by default.

Version 0.2

weppy 0.2 introduces some major changes in the code that break backward compatibility among the 0.1 developer preview. These changes were made to simplify the coding flow for developers and to have more consistent APIs.

If you're upgrading your application from weppy 0.1, next paragraphs describe the relevant changes for your application.

sdict in place of Storage

The Storage class previously available under weppy.storage has moved to the more convenient sdict one. sdict behaves exactly the same as Storage, you just need to update references you have in your application, and the imports. You can import sdict directly from weppy writing:

from weppy import sdict

DAL changes

weppy 0.2 uses new pyDAL package instead of the old fork of the web2py's DAL. Due to this new implementation, we removed the old ModelsDAL class and unified the two classes under the DAL one. Moreover, the weppy.dal.modules package will no longer exists, so you should rewrite all your imports since everything that was in that package can be imported directly from weppy.dal:

from weppy.dal import DAL, Field, Model, after_insert

Also, the old ModelsDAL.define_datamodels() method is now available as DAL.define_models(), please update the relevant line in your application:

db.define_models([MyModel1, MyModel2])

Finally, the Model class now has only one setup method instead of the old list of set_ methods. Please use only this method to configure your tables.

Auth module changes

Due to ModelsDAL and DAL merge, we did the same to ModelsAuth. Now you should use Auth with the usermodel parameter, like this:

auth = Auth(app, db, usermodel=User)


We renamed all the validators available in weppy. We changed the nomenclature we were keeping from web2py to a simpler one (under our point of view at least). Here is the complete list of old names vs the new ones:

old name new name
IS_ALPHANUMERIC isAlphanumeric
IS_TIME isTime
IS_DATE isDate
IS_DATETIME isDatetime
IS_EMAIL isEmail
IS_URL isUrl
IS_IMAGE isImage
IS_IPV4 isIPv4
IS_IPV6 isIPv6
IS_STRONG isStrong
IS_LENGTH hasLength
IS_MATCH Matches
ANY_OF anyOf

Please not that we also removed the IS_EXPR validator. The reason for the removal is that we had to run an exec on the expression, which is not a so good operation, and you can actually achieve the same result writing your own validator. As an example, if you were writing this before:


you can better define a custom validator:

from weppy.validators import Validator

class EndsWithAsd(Validator):
    def __call__(self, value):
        if str(value).endswith('asd'):
            return (value, None)
        return (value, "value has to end with 'asd'")

Streaming files from DAL

We renamed the old stream_file() method under weppy.helpers to the more convenient stream_dbfile(), plase update the lines involved in your code.
The usage remains the same.

New features

weppy 0.2 also introduces some new features you may want to take advantage of:

  • json POST requests are now parsed to make the message data available into request.post_vars. If you want to use this feature, ensure to send the content to weppy with the Content-Type header set to "application/json".
  • SessionFSManager is now available to store sessions on server's filesystem. For the complete usage please check the Session chapter of the documentation.
  • stream_file() method under weppy.helpers allows you to stream a file stored into your application path, simply passing the location as the parameter: stream_file("myfiles/book.pdf").
  • xml is now available under services to allow rendering content as XML