Project App Development

This document details instructions and guidelines for developing project apps to be used with the SODAR Core framework. This also applies for modifying existing Django apps into project apps.

Hint

The package example_project_app in the projectroles repository provides a concrete minimal example of a working project app.

Project App Basics

Characteristics of a project app:

Provides a functionality related to a project.
Is dynamically included in project views by projectroles using plugins.
Uses the project-based role and access control provided by projectroles.
Is (optionally) included in projectroles search.
Provides a dynamically included element (e.g. content overview) for the project details page.
Appears in the project menu sidebar in the default projectroles templates.
Can be archived or unarchived to enable/disable read-only mode.

Requirements for setting up a project app:

Implement project relations and SODAR UUIDs in the app’s Django models.
Use provided mixins, keyword arguments and conventions in views.
Extend projectroles base templates in your templates.
Implement specific templates for dynamic inclusion by Projectroles.
Create plugins.py with a project app plugin implementation.
Create rules.py with rules for access permissions.

Fulfilling these requirements is detailed further in this document.

Prerequisites

This documentation assumes you have a Django site with the projectroles app set up, either started with sodar-django-site or by integrating SODAR Core on an existing site (see projectroles integration). The instructions can be applied either to modify a previously existing app, or to set up a fresh app generated in the standard way with ./manage.py startapp.

It is also assumed that apps are more or less created according to best practices defined by Two Scoops, with the use of Class-Based Views being a requirement.

Models

In order to hook up your Django models into projects, there are two requirements: implementing a project foreign key and a UUID field.

Project Foreign Key

Add a ForeignKey field for the projectroles.models.Project model, either called project or accessible with a get_project() function implemented in your model.

If the project foreign key for your model is not project, make sure to define a get_project_filter_key() method. It should return the name of the field to use as key for filtering your model by project.

Note

If your app contains a complex model structure with e.g. nested models using foreign keys, it’s not necessary to add this to all your models, just the topmost one(s) used e.g. in URL kwargs.

Model UUID Field

To provide a unique identifier for objects in the SODAR context, add a UUIDField with the name of sodar_uuid into your model.

Note

SODAR Core links to objects in URLs, links and forms using UUIDs instead of database private keys. This is strongly recommended for all Django models in apps using the SODAR Core framework.

Note

When updating an existing Django model with an existing database, the sodar_uuid field needs to be populated. See instructions in Django documentation on how to create the required migrations.

Model Example

Below is an example of a projectroles-compatible Django model:

import uuid
from django.db import models
from projectroles.models import Project

class SomeModel(models.Model):
    some_field = models.CharField(
        help_text='Your own field'
    )
    project = models.ForeignKey(
        Project,
        related_name='some_objects',
        help_text='Project to which this object belongs',
    )
    sodar_uuid = models.UUIDField(
        default=uuid.uuid4,
        unique=True,
        help_text='SomeModel SODAR UUID',
    )

Note

The related_name field is optional, but recommended as it provides an easy way to lookup objects of a certain type related to a project. For example the project foreign key in a model called Document could feature e.g. related_name='documents'.

Rules File

Create a file rules.py in your app’s directory. You should declare at least one basic permission for enabling a user to view the app data for the project. This can be named e.g. {APP_NAME}.view_data. Common predicates for the rules file can be found in projectroles.rules. They can be extended within your app if needed.

import rules
from projectroles import rules as pr_rules

rules.add_perm(
    'example_project_app.view_data',
    pr_rules.is_project_owner
    | pr_rules.is_project_delegate
    | pr_rules.is_project_contributor
    | pr_rules.is_project_guest,
)

Hint

The rules.is_superuser predicate is often redundant, as permission checks are skipped for Django superusers. However, it can be handy if you e.g. want to define a rule allowing only superuser access for now, with the potential for adding other predicates later.

Hint

For permissions dealing with modifying data, you are strongly recommend to use the can_modify_project_data predicate. For more, see Project Archiving.

ProjectAppPlugin

Create a file plugins.py in your app’s directory. In the file, declare a ProjectAppPlugin class implementing projectroles.plugins.ProjectAppPluginPoint. Within the class, implement member variables and functions as instructed in comments and docstrings.

from projectroles.plugins import ProjectAppPluginPoint
from .urls import urlpatterns

class ProjectAppPlugin(ProjectAppPluginPoint):
    """Plugin for registering app with Projectroles"""
    name = 'yourprojectapp'
    title = 'Your Project App'
    urls = urlpatterns
    # ...

The following variables and functions are mandatory:

name: Plugin name. If only introducing a single plugin in your app, this should match the app name. For multiple plugins within a single app, additional plugins should start with the app name, e.g. yourapp_xxx. This ensures the correct highlighting of active apps in the UI. Note that the name variables of plugins are expected to be unique, although not currently strictly enforced.
title: Plugin title to be displayed in the UI.
urls: URL patterns, usually imported from the app’s urls.py file. For multiple plugins within the same app providing UI views, it is recommended to only provide the UI view URLs relevant to the plugin in question. This ensures the correct highlighting of active apps in the UI.
icon: Iconify collection and icon name (e.g. mdi:home).
entry_point_url_id: View ID for the app entry point (NOTE: The view must take the project sodar_uuid as a kwarg named project).
description: Verbose description of the app.
app_permission: Basic permission for viewing app data in the related project (see above).
search_enable: Boolean for enabling/disabling app search.
details_template: Path to template to be included in the project details page, usually called {APP_NAME}/_details_card.html.
details_title: Title string to be displayed in the project details page for the app details template.
plugin_ordering: Number to define the ordering of the app on the project menu sidebar and the details page.

Implementing the following is optional:

app_settings: Implement if project, user or project_user (Settings specific to a project and user) specific settings for the app are needed. See the plugin point definition for an example.
search_types: Implement if searching the data of the app is enabled.
search_template: Implement if searching the data of the app is enabled.
project_list_columns: Optional custom columns do be shown in the project list. See the plugin point definition for an example.
category_enable: Whether the app should also be made available for categories. Defaults to False and should only be overridden when required. For an example of a project app enabled in categories, see Timeline.
info_settings: List of names for app-specific Django settings to be displayed for administrators in the siteinfo app.
get_object_link(): Return object link for a Timeline event.
get_extra_data_link(): Return extra data link for a Timeline event.
search(): Function called when searching for data related to the app if search is enabled.
get_statistics(): Return statistics for the siteinfo app. See details in the siteinfo documentation.
get_project_list_value(): A function which must be implemented if project_list_columns are defined, to retrieve a column cell value for a specific project.
handle_project_update(): A function for enabling carrying out specific tasks within your app when the project is updated in projectroles. This is a work-in-progress functionality to be expanded later.

Once you have implemented the rules.py and plugins.py files and added the app and its URL patterns to the Django site configuration, you can create the project app plugin in the Django database with the following command:

$ ./manage.py syncplugins

You should see the following output to ensure the plugin was successfully registered:

Registering Plugin for {APP_NAME}.plugins.ProjectAppPlugin

For info on how to implement the specific required views/templates, see the rest of this document.

Hint

If you want to define multiple plugins within a single app, see the Multi-Plugin Apps documentation.

Views

Certain guidelines must be followed in developing Django web UI views for them to be successfully used with projectroles.

URL Keyword Arguments

In order to link a view to project and check user permissions using mixins, the URL keyword arguments must include an argument which matches one of the following conditions:

Contains a kwarg project which corresponds to the sodar_uuid member value of a projectroles.models.Project object
Contains a kwarg corresponding to the sodar_uuid of another Django model, which must contain a member field project which is a foreign key for a Projectroles.models.Project object. The kwarg must be named after the Django model of the referred object (in lowercase).
Same as above, but the Django model provides a get_project() function which returns a Projectroles.models.Project object.
Contains a kwarg corresponding to a model in another app. The app must be specified in the URL kwarg as app__model.

Examples:

urlpatterns = [
    # Direct reference to the Project model
    url(
        regex=r'^(?P<project>[0-9a-f-]+)$',
        view=views.ProjectDetailView.as_view(),
        name='detail',
    ),
    # RoleAssignment model has a "project" member which is also OK
    url(
        regex=r'^members/update/(?P<roleassignment>[0-9a-f-]+)$',
        view=views.RoleAssignmentUpdateView.as_view(),
        name='role_update',
    ),
    # Reference to a model in another app
    url(
        regex=r'^example/path/(?P<filesfolders__folder>[0-9a-f-]+)$',
        view=views.ExampleView.as_view(),
        name='example_ext_model',
    ),
]

Path URL syntax from Django v2+ is also supported. Examples:

urlpatterns = [
    # Direct reference to the Project model
    path(
        route='path-url/<uuid:project>',
        view=views.ExampleView.as_view(),
        name='example_path_url',
    ),
    # Reference to a model in another app
    path(
        route='path-ext/<uuid:filesfolders__folder>',
        view=views.ExampleView.as_view(),
        name='example_path_ext',
    ),
]

Mixins

The projectroles.views module provides several useful mixins for augmenting your view classes to add projectroles functionality. These can be found in the projectroles.views module.

The most commonly used mixins:

LoginRequiredMixin: Override of the standard Django mixin which may also allow anonymous guests if so configured in SODAR Core. If you plan on supporting anonymous users on your site, you must use this mixing instead of the original one in Django.
LoggedInPermissionMixin: Ensure correct redirection of users on no permissions. Can also be used to customize messages displayed to the user.
ProjectPermissionMixin: Provides a Project object for permission checking based on URL kwargs.
ProjectContextMixin: Provides a Project object into the view context based on URL kwargs.

See example_project_app.views.ExampleView for an example.

Templates

Template Structure

It is strongly recommended to extend projectroles/project_base.html in your project app templates. Just start your template with the following line:

{% extends 'projectroles/project_base.html' %}

The following template blocks are available for overriding or extending when applicable:

title: Page title.
css: Custom CSS (extend with {{ block.super }}).
projectroles_extend: Your app content goes here.
javascript: Custom Javascript (extend with {{ block.super }}).
head_extend: Optional block if you need to include additional content inside the HTML <head> element.

Within the projectroles_extend block, it is recommended to use the following div classes, both extending the Bootstrap 4 container-fluid class:

sodar-subtitle-container: Container for the page title.
sodar-content-container: Container for the actual content of your app.

If you do not want to include the project title header to your project templates, you can replace the projectroles_extend block with a projectroles block.

Warning

When customizing your templates, make sure you are not accidentally nesting built-in blocks within each other by e.g. placing the css block inside the projectroles or projectroles_extend block. Doing so may cause the page to render incorrectly or includes to fail.

Rules

To control user access within a template with permissions introduced in rules.py, do it as follows:

{% load rules %}
{% has_perm 'app.do_something' request.user project as can_do_something %}

This checks if the current user from the HTTP request has permission for app.do_something in the current project retrieved from the page context.

Common Template Tags

General purpose template tags are available in projectroles/templatetags/projectroles_common_tags.py. Include them to your template as follows:

{% load projectroles_common_tags %}

See the template tag API documentation for detailed instructions on using different tags in your templates.

Example

Minimal example for a project app template:

{% extends 'projectroles/project_base.html' %}

{% load projectroles_common_tags %}
{% load rules %}

{% block title %}
  Page Title
{% endblock title %}

{% block head_extend %}
  {# OPTIONAL: extra content under <head> goes here #}
{% endblock head_extend %}

{% block css %}
  {{ block.super }}
  {# OPTIONAL: Extend or override CSS here #}
{% endblock css %}

{% block projectroles_extend %}

  {# Page subtitle #}
  <div class="container-fluid sodar-subtitle-container">
    <h3>
      <i class="iconify" data-icon="mdi:rocket-launch"></i>
      App and/or Page Title
    </h3>
  </div>

  {# App content #}
  <div class="container-fluid sodar-page-container">
    <p>Your app content goes here!</p>
  </div>

{% endblock projectroles_extend %}

{% block javascript %}
  {{ block.super }}
  {# OPTIONAL: include additional Javascript here #}
{% endblock javascript %}

See example_project_app/example.html for a working and fully commented example of a minimal template.

Hint

If you include some controls on your sodar-subtitle-container class and want it to remain sticky on top of the page while scrolling, use row instead of container-fluid and add the bg-white sticky-top classes to the element.

General Guidelines for Views and Templates

General guidelines and hints for developing views and templates are discussed in this section.

Referring to Project Type

SODAR Core allows customizing the display name for the project type from the default “project” or “category”. For more information, see Projectroles Customization.

It is thus recommended that instead of hard coding “project” or “category” in your views or templates, use the get_display_name() function to refer to project type.

In templates, this can be achieved with a custom template tag. Example:

{% load projectroles_common_tags %}
{% get_display_name project.type title=True plural=False %}

In views and other Python code, the similar function can be accessed through utils.py:

from projectroles.utils import get_display_name
display_name = get_display_name(project.type, plural=False)

Hint

If not dealing with a Project object, you can provide the PROJECT_TYPE_* constant from SODAR_CONSTANTS. In templates, it’s most straightforward to use “CATEGORY” and “PROJECT”.

Specific Views and Templates

A few specific views/templates are expected to be implemented.

App Entry Point

As described in the Plugins chapter, an app entry point view is to be defined in the ProjectAppPlugin. This is mandatory.

The view must take a project URL kwarg which corresponds to a Project.sodar_uuid.

For an example, see example_project_app.views.ExampleView and the associated template.

Project Details Element

A sub-template to be included in the project details page (the project’s “front page” provided by projectroles, where e.g. overview of app content is shown).

Traditionally these files are called _details_card.html, but you can name them as you wish and point to the related template in the details_template variable of your plugin.

It is expected to have the content in a card-body container:

<div class="card-body">
  {# Content goes here #}
</div>

Project Search API and Template

If you want to implement search in your project app, you need to implement the search() method in your plugin as well as a template for displaying the results.

Hint

Implementing search can be complex. If you have access to the main SODAR repository, apps in that project might prove useful examples.

The search() Function

See the signature of search() in projectroles.plugins.ProjectAppPluginPoint. The arguments are as follows:

search_terms

One or more terms to be searched for (list of strings). Expected to be combined with OR operators in your search logic.
Multiple search terms or phrases containing whitespaces can be provided via the Advanced Search view.

user

User object for user initiating search.

search_type

The type of object to search for (string, optional).
Used to restrict search to specific types of objects.
You can specify supported types in the plugin’s search_types list.
Examples: file, sample..

keywords

Special search keywords, e.g. “exact”.
NOTE: Currently not implemented.

Note

Within this function, you are expected to verify appropriate access of the searching user yourself!

Warning

The old expected signature of providing a single search_term argument has been deprecated in v0.9 and will be removed in the next major release!

The return data is a dictionary, which is split by groups in case your app can return multiple different lists for data. This is useful where e.g. the same type of HTML list isn’t suitable for all returnable types. If only returning one type of data, you can just use e.g. all as your only category. Example of the result:

return {
    'all': {                     # 1-N categories to be included
        'title': 'List title',   # Title of the result list to be displayed
        'search_types': [],      # Object types included in this category
        'items': []              # The actual objects returned
        }
    }

Search Template

Projectroles will provide your template context the search_results object, which corresponds to the result dict of the aforementioned function. There are also includes for formatting the results list, which you are encouraged to use.

Example of a simple results template, in case of a single all category:

 {% if search_results.all.items|length > 0 %}

   {# Include standard search list header here #}
   {% include 'projectroles/_search_header.html' with search_title=search_results.all.title result_count=search_results.all.items|length %}

   {# Set up a table with your results #}
   <table class="table table-striped sodar-card-table sodar-search-table" id="sodar-ff-search-table">
     <thead>
       <tr>
         <th>Name</th>
         <th>Some Other Field</th>
       </tr>
    </thead>
    <tbody>
      {% for item in search_results.all.items %}
        <tr>
          <td>
            <a href="#link_to_somewhere_in your_app">{{ item.name }}</a>
          </td>
          <td>
            {{ item.some_other_field }}
          </td>
        </tr>
      {% endfor %}
    </tbody>
  </table>

  {# Include standard search list footer here #}
  {% include 'projectroles/_search_footer.html' %}

{% endif %}

API Views

API view usage in project apps is detailed in this section.

Rest API Views

To set up REST API views for project apps, it is recommended to use the base SODAR API view classes and mixins found in projectroles.views_api. These set up the recommended authentication methods, versioning through accept headers and project-based permission checks.

By default, the REST API views built on SODAR Core base classes support two methods of authentication: Knox tokens and Django session auth. These can of course be modified by overriding/extending the base classes.

For versioning we strongly recommend using accept header versioning, which is what is supported by the SODAR Core base classes. For this, supply your custom media type and version data using the corresponding SODAR_API_* settings. For details on these, see Projectroles Django Settings.

The base classes provide permission checks via SODAR Core project objects similar to UI view mixins.

Base REST API classes without a project context can also be used in site apps.

See the base REST API class documentation for details on the base REST API classes.

An example “hello world” REST API view for SODAR apps is available in example_project_app.views.HelloExampleProjectAPIView.

Note

Internal SODAR Core REST API views, specifically ones used in apps provided by the django-sodar-core package, use different media type and versioning from views to be implemented on your site. This is to prevent version number clashes and not require changes from your API when SODAR Core is updated.

For implementing your own API views, make sure to use the SODARAPI* base classes, not the CoreAPI classes. Similarly, in testing make sure to use the base class helpers of the site API instead of the core API.

Ajax API Views

To set up Ajax API views for the UI, it is recommended to use the base Ajax view classes found in projectroles.views_ajax. These views only support Django session authentication by default, so Knox token authentication will not work. Versioning is omitted. Base views without project permission checks can also be used in site apps.

If you want to enable anonymous access to an Ajax API view when PROJECTROLES_ALLOW_ANONYMOUS is enabled in your site’s Django settings, you can use the allow_anonymous property of the view.

See the base AJAX API view documentation for more information on using these base classes.

Example:

from projectroles.views_ajax import SODARBaseProjectAjaxView

class ExampleAjaxAPIView(SODARBaseProjectAjaxView):

permission_required = 'projectroles.view_project'

def get(self, request):
    # ...

If you want to wrap a REST API view into an Ajax API view, you can use SODARBaseAjaxMixin and your original view as base to ensure appropriate access control.

Serializers

Base serializers for SODAR Core based API views are available in projectroles.serializers. They provide Project context where needed, as well as setting default fields such as sodar_uuid which should be always used in place of pk.

See the serializer API documentation for details on using base serializer classes.

Project Archiving

Projects can be set to archived mode. If a project is archived, it is expected for apps to disable their data modifying functionality and prevent access to views used to alter app data. There may of course be some exceptions in your use case.

For most cases, your app should already be controlling user access to data modifying views and UI elements by checking permissions set in the rules.py module within the app. In these cases, you can simply add the can_modify_project_data predicate into any permission dealing with modifying project app data. An example from the filesfolders app:

from projectroles import rules as pr_rules  # To access common predicates

# Allow adding data to project
rules.add_perm(
    'filesfolders.add_data',
    pr_rules.can_modify_project_data
    & (
        pr_rules.is_project_owner
        | pr_rules.is_project_delegate
        | pr_rules.is_project_contributor
    ),
)

In cases not covered by the permissions, you can check a project’s archive status via the Project.archive field.

For an example how to implement and test archiving support in your project app, see the code and unit tests in Filesfolders App.

The archiving and unarchiving functionality will also call ProjectModifyPluginMixin.perform_project_archive() and its corresponding revert method when the archival status for a project is changed. If your site e.g. manages data in an external database, you may implement these methods for additional actions to be taken.

Note

In the current implementation, categories can not be archived. This may be implemented later.

Note

The usage of backend apps like sodarcache and timeline are not limited by the project archive status, your app logic should handle it instead.

Removing a Project App

Removing a project app from your Django site can be slightly more complicated than removing a normal non-SODAR-supporting Django application. Following the procedure detailed here you are able to cleanly remove a project app which has been in use on your site.

The instructions apply to project apps you have created yourself as well as project apps included in the django-sodar-core package, with the exception of projectroles which can not be removed from a SODAR based site.

Warning

Make sure to perform these steps in the order they are presented here. Otherwise you may risk serious problems with your site functionality or your database!

Note

Just in case, it is recommended to make a backup of your Django database before proceeding.

First you should delete all Timeline references to objects in your app. This is not done automatically as, by design, the references are kept even after the original objects are deleted. Go to the Django shell via management command using shell or shell_plus and enter the following. Replace app_name with the name of your application as specified in its ProjectAppPlugin.

from timeline.models import ProjectEvent
ProjectEvent.objects.filter(app='app_name').delete()

Next you should delete existing database objects defined by the models in your app. This is also most easily done via the Django shell. Example:

from yourapp.models import YourModel
YourModel.objects.all().delete()

After the objects have been deleted, reset the database migrations of your application.

$ ./manage.py migrate yourapp zero

Once this has been executed successfully, you should delete the plugin object for your application. Returning to the Django shell, type the following:

from djangoplugins.models import Plugin
Plugin.objects.get(name='app_name').delete()

Finally, you should remove the references to the removed app in the Django configuration.

App dependency in config/settings/base.py:

LOCAL_APPS = [
# The app you are removing
'yourapp.apps.YourAppConfig',
# ...
]

App URL patterns in config/urls.py:

urlpatterns = [
    # Your app's URLs
    url(r'^yourapp/', include('yourapp.urls')),
    # ...
]

Once you have performed the aforementioned database operations and deployed a version of your Django site with the application dependency and URL patterns removed, the project app should be cleanly removed from your site.