Building a Module¶

Warning

This tutorial requires having installed Flectra

Start/Stop the Flectra server¶

Flectra uses a client/server architecture in which clients are web browsers accessing the Flectra server via RPC.

Business logic and extension is generally performed on the server side, although supporting client features (e.g. new data representation such as interactive maps) can be added to the client.

In order to start the server, simply invoke the command flectra-bin in the shell, adding the full path to the file if necessary:

flectra-bin

The server is stopped by hitting Ctrl-C twice from the terminal, or by killing the corresponding OS process.

Build an Flectra module¶

Both server and client extensions are packaged as modules which are optionally loaded in a database.

Flectra modules can either add brand new business logic to an Flectra system, or alter and extend existing business logic: a module can be created to add your country’s accounting rules to Flectra’s generic accounting support, while the next module adds support for real-time visualisation of a bus fleet.

Everything in Flectra thus starts and ends with modules.

Composition of a module¶

An Flectra module can contain a number of elements:

Business objects

Declared as Python classes, these resources are automatically persisted by Flectra based on their configuration

Object views

Definition of business objects UI display

Data files

XML or CSV files declaring the model metadata :

views or reports,
configuration data (modules parametrization, security rules),
demonstration data
and more

Web controllers

Handle requests from web browsers

Static web data

Images, CSS or javascript files used by the web interface or website

Module structure¶

Each module is a directory within a module directory. Module directories are specified by using the --addons-path option.

Tip

most command-line options can also be set using a configuration file

An Flectra module is declared by its manifest.

A module is also a Python package with a __init__.py file, containing import instructions for various Python files in the module.

For instance, if the module has a single mymodule.py file __init__.py might contain:

from . import mymodule

Flectra provides a mechanism to help set up a new module, flectra-bin has a subcommand scaffold to create an empty module:

$ flectra-bin scaffold <module name> <where to put it>

The command creates a subdirectory for your module, and automatically creates a bunch of standard files for a module. Most of them simply contain commented code or XML. The usage of most of those files will be explained along this tutorial.

Exercise

Module creation

Use the command line above to create an empty module Open Academy, and install it in Flectra.

Object-Relational Mapping¶

A key component of Flectra is the ORM layer. This layer avoids having to write most SQL by hand and provides extensibility and security services2.

Business objects are declared as Python classes extending Model which integrates them into the automated persistence system.

Models can be configured by setting a number of attributes at their definition. The most important attribute is _name which is required and defines the name for the model in the Flectra system. Here is a minimally complete definition of a model:

from flectra import models
class MinimalModel(models.Model):
    _name = 'test.model'

Model fields¶

Fields are used to define what the model can store and where. Fields are defined as attributes on the model class:

from flectra import models, fields

class LessMinimalModel(models.Model):
    _name = 'test.model2'

    name = fields.Char()

Common Attributes¶

Much like the model itself, its fields can be configured, by passing configuration attributes as parameters:

name = field.Char(required=True)

Some attributes are available on all fields, here are the most common ones:

string (unicode, default: field’s name): The label of the field in UI (visible by users).
required (bool, default: False): If True, the field can not be empty, it must either have a default value or always be given a value when creating a record.
help (unicode, default: ''): Long-form, provides a help tooltip to users in the UI.
index (bool, default: False): Requests that Flectra create a database index on the column.

Simple fields¶

There are two broad categories of fields: “simple” fields which are atomic values stored directly in the model’s table and “relational” fields linking records (of the same model or of different models).

Example of simple fields are Boolean, Date, Char.

Reserved fields¶

Flectra creates a few fields in all models1. These fields are managed by the system and shouldn’t be written to. They can be read if useful or necessary:

id (Id): The unique identifier for a record in its model.
create_date (Datetime): Creation date of the record.
create_uid (Many2one): User who created the record.
write_date (Datetime): Last modification date of the record.
write_uid (Many2one): user who last modified the record.

Special fields¶

By default, Flectra also requires a name field on all models for various display and search behaviors. The field used for these purposes can be overridden by setting _rec_name.

Exercise

Define a model

Define a new data model Course in the openacademy module. A course has a title and a description. Courses must have a title.

Data files¶

Flectra is a highly data driven system. Although behavior is customized using Python code part of a module’s value is in the data it sets up when loaded.

Tip

some modules exist solely to add data into Flectra

Module data is declared via data files, XML files with <record> elements. Each <record> element creates or updates a database record.

<flectra>

        <record model="{model name}" id="{record identifier}">
            <field name="{a field name}">{a value}</field>
        </record>

</flectra>

model is the name of the Flectra model for the record.
id is an external identifier, it allows referring to the record (without having to know its in-database identifier).
<field> elements have a name which is the name of the field in the model (e.g. description). Their body is the field’s value.

Data files have to be declared in the manifest file to be loaded, they can be declared in the 'data' list (always loaded) or in the 'demo' list (only loaded in demonstration mode).

Exercise

Define demonstration data

Create demonstration data filling the Courses model with a few demonstration courses.

Tip

The content of the data files is only loaded when a module is installed or updated.

After making some changes, do not forget to use flectra-bin -u openacademy to save the changes to your database.

Actions and Menus¶

Actions and menus are regular records in database, usually declared through data files. Actions can be triggered in three ways:

by clicking on menu items (linked to specific actions)
by clicking on buttons in views (if these are connected to actions)
as contextual actions on object

Because menus are somewhat complex to declare there is a <menuitem> shortcut to declare an ir.ui.menu and connect it to the corresponding action more easily.

<record model="ir.actions.act_window" id="action_list_ideas">
    <field name="name">Ideas</field>
    <field name="res_model">idea.idea</field>
    <field name="view_mode">tree,form</field>
</record>
<menuitem id="menu_ideas" parent="menu_root" name="Ideas" sequence="10"
          action="action_list_ideas"/>

Danger

The action must be declared before its corresponding menu in the XML file.

Data files are executed sequentially, the action’s id must be present in the database before the menu can be created.

Exercise

Define new menu entries

Define new menu entries to access courses under the OpenAcademy menu entry. A user should be able to :

display a list of all the courses
create/modify courses

Basic views¶

Views define the way the records of a model are displayed. Each type of view represents a mode of visualization (a list of records, a graph of their aggregation, …). Views can either be requested generically via their type (e.g. a list of partners) or specifically via their id. For generic requests, the view with the correct type and the lowest priority will be used (so the lowest-priority view of each type is the default view for that type).

View inheritance allows altering views declared elsewhere (adding or removing content).

Generic view declaration¶

A view is declared as a record of the model ir.ui.view. The view type is implied by the root element of the arch field:

<record model="ir.ui.view" id="view_id">
    <field name="name">view.name</field>
    <field name="model">object_name</field>
    <field name="priority" eval="16"/>
    <field name="arch" type="xml">
        <!-- view content: <form>, <tree>, <graph>, ... -->
    </field>
</record>

Danger

The view’s content is XML.

The arch field must thus be declared as type="xml" to be parsed correctly.

Tree views¶

Tree views, also called list views, display records in a tabular form.

Their root element is <tree>. The simplest form of the tree view simply lists all the fields to display in the table (each field as a column):

<tree string="Idea list">
    <field name="name"/>
    <field name="inventor_id"/>
</tree>

Form views¶

Forms are used to create and edit single records.

Their root element is <form>. They are composed of high-level structure elements (groups, notebooks) and interactive elements (buttons and fields):

<form string="Idea form">
    <group colspan="4">
        <group colspan="2" col="2">
            <separator string="General stuff" colspan="2"/>
            <field name="name"/>
            <field name="inventor_id"/>
        </group>

        <group colspan="2" col="2">
            <separator string="Dates" colspan="2"/>
            <field name="active"/>
            <field name="invent_date" readonly="1"/>
        </group>

        <notebook colspan="4">
            <page string="Description">
                <field name="description" nolabel="1"/>
            </page>
        </notebook>

        <field name="state"/>
    </group>
</form>

Exercise

Customise form view using XML

Create your own form view for the Course object. Data displayed should be: the name and the description of the course.

Exercise

Notebooks

In the Course form view, put the description field under a tab, such that it will be easier to add other tabs later, containing additional information.

Form views can also use plain HTML for more flexible layouts:

<form string="Idea Form">
    <header>
        <button string="Confirm" type="object" name="action_confirm"
                states="draft" class="oe_highlight" />
        <button string="Mark as done" type="object" name="action_done"
                states="confirmed" class="oe_highlight"/>
        <button string="Reset to draft" type="object" name="action_draft"
                states="confirmed,done" />
        <field name="state" widget="statusbar"/>
    </header>
    <sheet>
        <div class="oe_title">
            <label for="name" class="oe_edit_only" string="Idea Name" />
            <h1><field name="name" /></h1>
        </div>
        <separator string="General" colspan="2" />
        <group colspan="2" col="2">
            <field name="description" placeholder="Idea description..." />
        </group>
    </sheet>
</form>

Search views¶

Search views customize the search field associated with the list view (and other aggregated views). Their root element is <search> and they’re composed of fields defining which fields can be searched on:

<search>
    <field name="name"/>
    <field name="inventor_id"/>
</search>

If no search view exists for the model, Flectra generates one which only allows searching on the name field.

Exercise

Search courses

Allow searching for courses based on their title or their description.

Relations between models¶

A record from a model may be related to a record from another model. For instance, a sale order record is related to a client record that contains the client data; it is also related to its sale order line records.

Exercise

Create a session model

For the module Open Academy, we consider a model for sessions: a session is an occurrence of a course taught at a given time for a given audience.

Create a model for sessions. A session has a name, a start date, a duration and a number of seats. Add an action and a menu item to display them. Make the new model visible via a menu item.

Relational fields¶

Relational fields link records, either of the same model (hierarchies) or between different models.

Relational field types are:

Many2one(other_model, ondelete='set null')

A simple link to an other object:

print foo.other_id.name

Inheritance¶

Model inheritance¶

Flectra provides two inheritance mechanisms to extend an existing model in a modular way.

The first inheritance mechanism allows a module to modify the behavior of a model defined in another module:

add fields to a model,
override the definition of fields on a model,
add constraints to a model,
add methods to a model,
override existing methods on a model.

The second inheritance mechanism (delegation) allows to link every record of a model to a record in a parent model, and provides transparent access to the fields of the parent record.

View inheritance¶

Instead of modifying existing views in place (by overwriting them), Flectra provides view inheritance where children “extension” views are applied on top of root views, and can add or remove content from their parent.

An extension view references its parent using the inherit_id field, and instead of a single view its arch field is composed of any number of xpath elements selecting and altering the content of their parent view:

<!-- improved idea categories list -->
<record id="idea_category_list2" model="ir.ui.view">
    <field name="name">id.category.list2</field>
    <field name="model">idea.category</field>
    <field name="inherit_id" ref="id_category_list"/>
    <field name="arch" type="xml">
        <!-- find field description and add the field
             idea_ids after it -->
        <xpath expr="//field[@name='description']" position="after">
          <field name="idea_ids" string="Number of ideas"/>
        </xpath>
    </field>
</record>

expr

An XPath expression selecting a single element in the parent view. Raises an error if it matches no element or more than one

position

Operation to apply to the matched element:

inside: appends xpath’s body at the end of the matched element
replace: replaces the matched element with the xpath’s body, replacing any $0 node occurrence in the new body with the original element
before: inserts the xpath’s body as a sibling before the matched element
after: inserts the xpaths’s body as a sibling after the matched element
attributes: alters the attributes of the matched element using special attribute elements in the xpath’s body

Tip

When matching a single element, the position attribute can be set directly on the element to be found. Both inheritances below will give the same result.

<xpath expr="//field[@name='description']" position="after">
    <field name="idea_ids" />
</xpath>

<field name="description" position="after">
    <field name="idea_ids" />
</field>

Exercise

Alter existing content

Using model inheritance, modify the existing Partner model to add an instructor boolean field, and a many2many field that corresponds to the session-partner relation
Using view inheritance, display this fields in the partner form view

Domains¶

In Flectra, Search domains are values that encode conditions on records. A domain is a list of criteria used to select a subset of a model’s records. Each criteria is a triple with a field name, an operator and a value.

For instance, when used on the Product model the following domain selects all services with a unit price over 1000:

[('product_type', '=', 'service'), ('unit_price', '>', 1000)]

By default criteria are combined with an implicit AND. The logical operators & (AND), | (OR) and ! (NOT) can be used to explicitly combine criteria. They are used in prefix position (the operator is inserted before its arguments rather than between). For instance to select products “which are services OR have a unit price which is NOT between 1000 and 2000”:

['|',
    ('product_type', '=', 'service'),
    '!', '&',
        ('unit_price', '>=', 1000),
        ('unit_price', '<', 2000)]

A domain parameter can be added to relational fields to limit valid records for the relation when trying to select records in the client interface.

Exercise

Domains on relational fields

When selecting the instructor for a Session, only instructors (partners with instructor set to True) should be visible.

Exercise

More complex domains

Create new partner categories Teacher / Level 1 and Teacher / Level 2. The instructor for a session can be either an instructor or a teacher (of any level).

Computed fields and default values¶

So far fields have been stored directly in and retrieved directly from the database. Fields can also be computed. In that case, the field’s value is not retrieved from the database but computed on-the-fly by calling a method of the model.

To create a computed field, create a field and set its attribute compute to the name of a method. The computation method should simply set the value of the field to compute on every record in self.

Danger

self is a collection

The object self is a recordset, i.e., an ordered collection of records. It supports the standard Python operations on collections, like len(self) and iter(self), plus extra set operations like recs1 + recs2.

Iterating over self gives the records one by one, where each record is itself a collection of size 1. You can access/assign fields on single records by using the dot notation, like record.name.

import random
from flectra import models, fields, api

class ComputedModel(models.Model):
    _name = 'test.computed'

    name = fields.Char(compute='_compute_name')

    def _compute_name(self):
        for record in self:
            record.name = str(random.randint(1, 1e6))

Dependencies¶

The value of a computed field usually depends on the values of other fields on the computed record. The ORM expects the developer to specify those dependencies on the compute method with the decorator depends(). The given dependencies are used by the ORM to trigger the recomputation of the field whenever some of its dependencies have been modified:

from flectra import models, fields, api

class ComputedModel(models.Model):
    _name = 'test.computed'

    name = fields.Char(compute='_compute_name')
    value = fields.Integer()

    @api.depends('value')
    def _compute_name(self):
        for record in self:
            record.name = "Record with value %s" % record.value

Exercise

Computed fields

Add the percentage of taken seats to the Session model
Display that field in the tree and form views
Display the field as a progress bar

Default values¶

Any field can be given a default value. In the field definition, add the option default=X where X is either a Python literal value (boolean, integer, float, string), or a function taking a recordset and returning a value:

name = fields.Char(default="Unknown")
user_id = fields.Many2one('res.users', default=lambda self: self.env.user)

Note

The object self.env gives access to request parameters and other useful things:

self.env.cr or self._cr is the database cursor object; it is used for querying the database
self.env.uid or self._uid is the current user’s database id
self.env.user is the current user’s record
self.env.context or self._context is the context dictionary
self.env.ref(xml_id) returns the record corresponding to an XML id
self.env[model_name] returns an instance of the given model

Exercise

Active objects – Default values

Define the start_date default value as today (see Date).
Add a field active in the class Session, and set sessions as active by default.

Onchange¶

The “onchange” mechanism provides a way for the client interface to update a form whenever the user has filled in a value in a field, without saving anything to the database.

For instance, suppose a model has three fields amount, unit_price and price, and you want to update the price on the form when any of the other fields is modified. To achieve this, define a method where self represents the record in the form view, and decorate it with onchange() to specify on which field it has to be triggered. Any change you make on self will be reflected on the form.

<!-- content of form view -->
<field name="amount"/>
<field name="unit_price"/>
<field name="price" readonly="1"/>

# onchange handler
@api.onchange('amount', 'unit_price')
def _onchange_price(self):
    # set auto-changing field
    self.price = self.amount * self.unit_price
    # Can optionally return a warning and domains
    return {
        'warning': {
            'title': "Something bad happened",
            'message': "It was very bad indeed",
        }
    }

For computed fields, valued onchange behavior is built-in as can be seen by playing with the Session form: change the number of seats or participants, and the taken_seats progressbar is automatically updated.

Exercise

Warning

Add an explicit onchange to warn about invalid values, like a negative number of seats, or more participants than seats.

Model constraints¶

Flectra provides two ways to set up automatically verified invariants: Python constraints and SQL constraints.

A Python constraint is defined as a method decorated with constrains(), and invoked on a recordset. The decorator specifies which fields are involved in the constraint, so that the constraint is automatically evaluated when one of them is modified. The method is expected to raise an exception if its invariant is not satisfied:

from flectra.exceptions import ValidationError

@api.constrains('age')
def _check_something(self):
    for record in self:
        if record.age > 20:
            raise ValidationError("Your record is too old: %s" % record.age)
    # all records passed the test, don't return anything

Exercise

Add Python constraints

Add a constraint that checks that the instructor is not present in the attendees of his/her own session.

SQL constraints are defined through the model attribute _sql_constraints. The latter is assigned to a list of triples of strings (name, sql_definition, message), where name is a valid SQL constraint name, sql_definition is a table_constraint expression, and message is the error message.

Exercise

Add SQL constraints

With the help of PostgreSQL’s documentation , add the following constraints:

CHECK that the course description and the course title are different
Make the Course’s name UNIQUE

Exercise

Exercise 6 - Add a duplicate option

Since we added a constraint for the Course name uniqueness, it is not possible to use the “duplicate” function anymore (Form ‣ Duplicate).

Re-implement your own “copy” method which allows to duplicate the Course object, changing the original name into “Copy of [original name]”.

Advanced Views¶

Tree views¶

Tree views can take supplementary attributes to further customize their behavior:

decoration-{$name}

allow changing the style of a row’s text based on the corresponding record’s attributes.

Values are Python expressions. For each record, the expression is evaluated with the record’s attributes as context values and if true, the corresponding style is applied to the row. Here are some of the other values available in the context:

uid: the id of the current user,
today: the current local date as a string of the form YYYY-MM-DD,
now: same as today with the addition of the current time. This value is formatted as YYYY-MM-DD hh:mm:ss.

{$name} can be bf (font-weight: bold), it (font-style: italic), or any bootstrap contextual color (danger, info, muted, primary, success or warning).

<tree string="Idea Categories" decoration-info="state=='draft'"
    decoration-danger="state=='trashed'">
    <field name="name"/>
    <field name="state"/>
</tree>

editable

Either "top" or "bottom". Makes the tree view editable in-place (rather than having to go through the form view), the value is the position where new rows appear.

Exercise

List coloring

Modify the Session tree view in such a way that sessions lasting less than 5 days are colored blue, and the ones lasting more than 15 days are colored red.

Calendars¶

Displays records as calendar events. Their root element is <calendar> and their most common attributes are:

color: The name of the field used for color segmentation. Colors are automatically distributed to events, but events in the same color segment (records which have the same value for their @color field) will be given the same color.
date_start: record’s field holding the start date/time for the event
date_stop (optional): record’s field holding the end date/time for the event
string: record’s field to define the label for each calendar event

<calendar string="Ideas" date_start="invent_date" color="inventor_id">
    <field name="name"/>
</calendar>

Exercise

Calendar view

Add a Calendar view to the Session model enabling the user to view the events associated to the Open Academy.

Search views¶

Search view <field> elements can have a @filter_domain that overrides the domain generated for searching on the given field. In the given domain, self represents the value entered by the user. In the example below, it is used to search on both fields name and description.

Search views can also contain <filter> elements, which act as toggles for predefined searches. Filters must have one of the following attributes:

domain: add the given domain to the current search
context: add some context to the current search; use the key group_by to group results on the given field name

<search string="Ideas">
    <field name="name"/>
    <field name="description" string="Name and description"
           filter_domain="['|', ('name', 'ilike', self), ('description', 'ilike', self)]"/>
    <field name="inventor_id"/>
    <field name="country_id" widget="selection"/>

    <filter name="my_ideas" string="My Ideas"
            domain="[('inventor_id', '=', uid)]"/>
    <group string="Group By">
        <filter name="group_by_inventor" string="Inventor"
                context="{'group_by': 'inventor_id'}"/>
    </group>
</search>

To use a non-default search view in an action, it should be linked using the search_view_id field of the action record.

The action can also set default values for search fields through its context field: context keys of the form search_default_field_name will initialize field_name with the provided value. Search filters must have an optional @name to have a default and behave as booleans (they can only be enabled by default).

Exercise

Search views

Add a button to filter the courses for which the current user is the responsible in the course search view. Make it selected by default.
Add a button to group courses by responsible user.

Gantt¶

Warning

The gantt view requires the web_gantt module which is present in the Professional edition version.

Horizontal bar charts typically used to show project planning and advancement, their root element is <gantt>.

<gantt string="Ideas"
       date_start="invent_date"
       date_stop="date_finished"
       progress="progress"
       default_group_by="inventor_id" />

Exercise

Gantt charts

Add a Gantt Chart enabling the user to view the sessions scheduling linked to the Open Academy module. The sessions should be grouped by instructor.

Graph views¶

Graph views allow aggregated overview and analysis of models, their root element is <graph>.

Note

Pivot views (element <pivot>) a multidimensional table, allows the selection of filers and dimensions to get the right aggregated dataset before moving to a more graphical overview. The pivot view shares the same content definition as graph views.

Graph views have 4 display modes, the default mode is selected using the @type attribute.

Bar (default)

a bar chart, the first dimension is used to define groups on the horizontal axis, other dimensions define aggregated bars within each group.

By default bars are side-by-side, they can be stacked by using @stacked="True" on the <graph>

Line

2-dimensional line chart

Pie

2-dimensional pie

Graph views contain <field> with a mandatory @type attribute taking the values:

row (default): the field should be aggregated by default
measure: the field should be aggregated rather than grouped on

<graph string="Total idea score by Inventor">
    <field name="inventor_id"/>
    <field name="score" type="measure"/>
</graph>

Warning

Graph views perform aggregations on database values, they do not work with non-stored computed fields.

Exercise

Graph view

Add a Graph view in the Session object that displays, for each course, the number of attendees under the form of a bar chart.

Kanban¶

Used to organize tasks, production processes, etc… their root element is <kanban>.

A kanban view shows a set of cards possibly grouped in columns. Each card represents a record, and each column the values of an aggregation field.

For instance, project tasks may be organized by stage (each column is a stage), or by responsible (each column is a user), and so on.

Kanban views define the structure of each card as a mix of form elements (including basic HTML) and QWeb.

Exercise

Kanban view

Add a Kanban view that displays sessions grouped by course (columns are thus courses).

Security¶

Access control mechanisms must be configured to achieve a coherent security policy.

Group-based access control mechanisms¶

Groups are created as normal records on the model res.groups, and granted menu access via menu definitions. However even without a menu, objects may still be accessible indirectly, so actual object-level permissions (read, write, create, unlink) must be defined for groups. They are usually inserted via CSV files inside modules. It is also possible to restrict access to specific fields on a view or object using the field’s groups attribute.

Access rights¶

Access rights are defined as records of the model ir.model.access. Each access right is associated to a model, a group (or no group for global access), and a set of permissions: read, write, create, unlink. Such access rights are usually created by a CSV file named after its model: ir.model.access.csv.

id,name,model_id/id,group_id/id,perm_read,perm_write,perm_create,perm_unlink
access_idea_idea,idea.idea,model_idea_idea,base.group_user,1,1,1,0
access_idea_vote,idea.vote,model_idea_vote,base.group_user,1,1,1,0

Exercise

Add access control through the Flectra interface

Create a new user “John Smith”. Then create a group “OpenAcademy / Session Read” with read access to the Session model.

Exercise

Add access control through data files in your module

Using data files,

Create a group OpenAcademy / Manager with full access to all OpenAcademy models
Make Session and Course readable by all users

Record rules¶

A record rule restricts the access rights to a subset of records of the given model. A rule is a record of the model ir.rule, and is associated to a model, a number of groups (many2many field), permissions to which the restriction applies, and a domain. The domain specifies to which records the access rights are limited.

Here is an example of a rule that prevents the deletion of leads that are not in state cancel. Notice that the value of the field groups must follow the same convention as the method write() of the ORM.

<record id="delete_cancelled_only" model="ir.rule">
    <field name="name">Only cancelled leads may be deleted</field>
    <field name="model_id" ref="crm.model_crm_lead"/>
    <field name="groups" eval="[(4, ref('sales_team.group_sale_manager'))]"/>
    <field name="perm_read" eval="0"/>
    <field name="perm_write" eval="0"/>
    <field name="perm_create" eval="0"/>
    <field name="perm_unlink" eval="1" />
    <field name="domain_force">[('state','=','cancel')]</field>
</record>

Exercise

Record rule

Add a record rule for the model Course and the group “OpenAcademy / Manager”, that restricts write and unlink accesses to the responsible of a course. If a course has no responsible, all users of the group must be able to modify it.

Wizards¶

Wizards describe interactive sessions with the user (or dialog boxes) through dynamic forms. A wizard is simply a model that extends the class TransientModel instead of Model. The class TransientModel extends Model and reuse all its existing mechanisms, with the following particularities:

Wizard records are not meant to be persistent; they are automatically deleted from the database after a certain time. This is why they are called transient.
Wizard records may refer to regular records or wizard records through relational fields(many2one or many2many), but regular records cannot refer to wizard records through a many2one field.

We want to create a wizard that allow users to create attendees for a particular session, or for a list of sessions at once.

Exercise

Define the wizard

Create a wizard model with a many2one relationship with the Session model and a many2many relationship with the Partner model.

Launching wizards¶

Wizards are simply window actions with a target field set to the value new, which opens the view (usually a form) in a separate dialog. The action may be triggered via a menu item, but is more generally triggered by a button.

An other way to launch wizards is through the Action menu of a tree or form view. This is done through the binding_model_id field of the action. Setting this field will make the action appear on the views of the model the action is “bound” to.

<record id="launch_the_wizard" model="ir.actions.act_window">
    <field name="name">Launch the Wizard</field>
    <field name="model">wizard.model.name</field>
    <field name="view_mode">form</field>
    <field name="target">new<field>
    <field name="binding_model_id" ref="model_context_model_ref"/>
</record>

Tip

While wizards use regular views and buttons, normally clicking any button in a form would first save the form then close the dialog. Because this is often undesirable in wizards, a special attribute special="cancel" is available which immediately closes the wizard without saving the form.

Exercise

Launch the wizard

Define a form view for the wizard.
Add the action to launch it in the context of the Session model.
Define a default value for the session field in the wizard; use the context parameter self._context to retrieve the current session.

Exercise

Add buttons to the wizard, and implement the corresponding method for adding the attendees to the given session.

Exercise

Modify the wizard model so that attendees can be registered to multiple sessions.

Internationalization¶

Each module can provide its own translations within the i18n directory, by having files named LANG.po where LANG is the locale code for the language, or the language and country combination when they differ (e.g. pt.po or pt_BR.po). Translations will be loaded automatically by Flectra for all enabled languages. Developers always use English when creating a module, then export the module terms using Flectra’s gettext POT export feature (Settings ‣ Translations ‣ Import/Export ‣ Export Translation without specifying a language), to create the module template POT file, and then derive the translated PO files. Many IDE’s have plugins or modes for editing and merging PO/POT files.

Tip

The Portable Object files generated by Flectra are published on Transifex, making it easy to translate the software.

|- idea/ # The module directory
   |- i18n/ # Translation files
      | - idea.pot # Translation Template (exported from Flectra)
      | - fr.po # French translation
      | - pt_BR.po # Brazilian Portuguese translation
      | (...)

Tip

By default Flectra’s POT export only extracts labels inside XML files or inside field definitions in Python code, but any Python string can be translated this way by surrounding it with the function flectra._() (e.g. _("Label"))

Exercise

Translate a module

Choose a second language for your Flectra installation. Translate your module using the facilities provided by Flectra.

Reporting¶

Printed reports¶

Flectra uses a report engine based on QWeb, Twitter Bootstrap and Wkhtmltopdf.

A report is a combination two elements:

an ir.actions.report which configures various basic parameters for the report (default type, whether the report should be saved to the database after generation,…)

<record id="account_invoices" model="ir.actions.report">
    <field name="name">Invoices</field>
    <field name="model">account.invoice</field>
    <field name="report_type">qweb-pdf</field>
    <field name="report_name">account.report_invoice</field>
    <field name="report_file">account.report_invoice</field>
    <field name="attachment_use" eval="True"/>
    <field name="attachment">(object.state in ('open','paid')) and
        ('INV'+(object.number or '').replace('/','')+'.pdf')</field>
    <field name="binding_model_id" ref="model_account_invoice"/>
    <field name="binding_type">report</field>
</record>

Tip

Because it largerly a standard action, as with Wizards it is generally useful to add the report as a contextual item on the tree and / or form views of the model being reported on via the binding_model_id field.

Here we are also using binding_type in order for the report to be in the report contextual menu rather than the action one. There is no technical difference but putting elements in the right place helps users.

A standard QWeb view for the actual report:

<t t-call="web.html_container">
    <t t-foreach="docs" t-as="o">
        <t t-call="web.external_layout">
            <div class="page">
                <h2>Report title</h2>
            </div>
        </t>
    </t>
</t>

the standard rendering context provides a number of elements, the most important being:

docs: the records for which the report is printed
user: the user printing the report

Because reports are standard web pages, they are available through a URL and output parameters can be manipulated through this URL, for instance the HTML version of the Invoice report is available through http://localhost:7073/report/html/account.report_invoice/1 (if account is installed) and the PDF version through http://localhost:7073/report/pdf/account.report_invoice/1.

Danger

If it appears that your PDF report is missing the styles (i.e. the text appears but the style/layout is different from the html version), probably your wkhtmltopdf process cannot reach your web server to download them.

If you check your server logs and see that the CSS styles are not being downloaded when generating a PDF report, most surely this is the problem.

The wkhtmltopdf process will use the web.base.url system parameter as the root path to all linked files, but this parameter is automatically updated each time the Administrator is logged in. If your server resides behind some kind of proxy, that could not be reachable. You can fix this by adding one of these system parameters:

report.url, pointing to an URL reachable from your server (probably http://localhost:7073 or something similar). It will be used for this particular purpose only.
web.base.url.freeze, when set to True, will stop the automatic updates to web.base.url.

Exercise

Create a report for the Session model

For each session, it should display session’s name, its start and end, and list the session’s attendees.

Dashboards¶

Exercise

Define a Dashboard

Define a dashboard containing the graph view you created, the sessions calendar view and a list view of the courses (switchable to a form view). This dashboard should be available through a menuitem in the menu, and automatically displayed in the web client when the OpenAcademy main menu is selected.

WebServices¶

The web-service module offer a common interface for all web-services :

XML-RPC
JSON-RPC

Business objects can also be accessed via the distributed object mechanism. They can all be modified via the client interface with contextual views.

Flectra is accessible through XML-RPC/JSON-RPC interfaces, for which libraries exist in many languages.

XML-RPC Library¶

The following example is a Python 3 program that interacts with an Flectra server with the library xmlrpc.client:

import xmlrpc.client

root = 'http://%s:%d/xmlrpc/' % (HOST, PORT)

uid = xmlrpc.client.ServerProxy(root + 'common').login(DB, USER, PASS)
print("Logged in as %s (uid: %d)" % (USER, uid))

# Create a new note
sock = xmlrpc.client.ServerProxy(root + 'object')
args = {
    'color' : 8,
    'memo' : 'This is a note',
    'create_uid': uid,
}
note_id = sock.execute(DB, uid, PASS, 'note.note', 'create', args)

Exercise

Add a new service to the client

Write a Python program able to send XML-RPC requests to a PC running Flectra (yours, or your instructor’s). This program should display all the sessions, and their corresponding number of seats. It should also create a new session for one of the courses.

JSON-RPC Library¶

The following example is a Python 3 program that interacts with an Flectra server with the standard Python libraries urllib.request and json. This example assumes the Productivity app (note) is installed:

import json
import random
import urllib.request

HOST = 'localhost'
PORT = 7073
DB = 'openacademy'
USER = 'admin'
PASS = 'admin'

def json_rpc(url, method, params):
    data = {
        "jsonrpc": "2.0",
        "method": method,
        "params": params,
        "id": random.randint(0, 1000000000),
    }
    req = urllib.request.Request(url=url, data=json.dumps(data).encode(), headers={
        "Content-Type":"application/json",
    })
    reply = json.loads(urllib.request.urlopen(req).read().decode('UTF-8'))
    if reply.get("error"):
        raise Exception(reply["error"])
    return reply["result"]

def call(url, service, method, *args):
    return json_rpc(url, "call", {"service": service, "method": method, "args": args})

# log in the given database
url = "http://%s:%s/jsonrpc" % (HOST, PORT)
uid = call(url, "common", "login", DB, USER, PASS)

# create a new note
args = {
    'color': 8,
    'memo': 'This is another note',
    'create_uid': uid,
}
note_id = call(url, "object", "execute", DB, uid, PASS, 'note.note', 'create', args)

Examples can be easily adapted from XML-RPC to JSON-RPC.

Note

There are a number of high-level APIs in various languages to access Flectra systems without explicitly going through XML-RPC or JSON-RPC, such as:

1: it is possible to disable the automatic creation of some fields
2: writing raw SQL queries is possible, but requires care as it bypasses all Flectra authentication and security mechanisms.