How to show part of a page to a record’s team#

A template on a record’s page often shows something only to the people who work on the record, such as an edit link. You ask the template tag holds_level whether the viewer holds a level on the record, and the template needs no view code to work out the answer.

Before you start#

The record must be a project, dataset, sample or measurement. The levels are "view", "edit" and "manage", and each includes the ones before it. They are described in Contribution levels and record access.

Steps#

Load the library at the top of the template.
```
{% load plugin_tags %}
```
Ask for the level and store the answer.
```
{% holds_level "edit" object as can_edit %}
```
On a plugin page, object is the record. Use base_object when your view has an object of its own.

Show the part only when the answer is true.

{% if can_edit %}
  <a href="{% plugin_url 'contribution-list' %}">Manage contributors</a>
{% endif %}

If you need the same answer in Python, call the function.

from fairdm.plugins import holds_level

if holds_level(request, "edit", record):
    ...

The result#

The part appears for people who hold the level and is left out for everyone else.

The answer follows the rule the record’s own pages use: the view_<model>, change_<model> or delete_<model> permission that the level stands for. A level held on a record above counts, such as a dataset’s team on the dataset’s samples, and so does a portal role that holds the permission for the whole portal.

Check these limits before you rely on the tag:

A visitor who is not signed in holds no level, on a public record as on a private one. The tag tells you who is on the record’s team, not who may read the record.
The tag is False for anything that is not a project, dataset, sample or measurement.
A level that does not exist raises ValueError, so a mistyped one is found the first time the template renders.
The tag decides what a page shows. It never decides who may open another page. A link it hides still leads somewhere, and that page needs its own check or permission. See How to restrict a plugin to some users.

The answer for a record is remembered for the rest of the request. Ask about the record the page belongs to. For a list of records, work the answers out in the view. The tag is described in Template tags.