django-linkcheck

A fairly flexible app that will analyze and report on links in any model that you register with it.

Links can be bare (urls or image and file fields) or embedded in HTML (linkcheck handles the parsing). It's fairly easy to override methods of the Linkcheck object should you need to do anything more complicated (like generate URLs from slug fields etc).

You should run its management command via cron or similar to check external links regularly to see if their status changes. All links are checked automatically when objects are saved. This is handled by signals.

Minimal requirements

django-linkcheck requires Python 3.7 and Django 3.2.

Basic usage

1. Install app to somewhere on your Python path (e.g. pip install django-linkcheck).

2. Add 'linkcheck' to your settings.INSTALLED_APPS.

3. Add a file named linklists.py to every app (see an example in examples/linklists.py) that either:

   1. has models that contain content (e.g. url/image fields, chunks of markup or anything that gets transformed into a IMG or HREF when displayed
   2. can be the target of a link - i.e. is addressed by a url - in this case make sure it has an instance method named 'get_absolute_url'

4. Run ./manage.py migrate.

5. Add to your root url config:

   path('admin/linkcheck/', include('linkcheck.urls'))
   

6. View /admin/linkcheck/ from your browser.

We are aware that this documentation is on the brief side of things so any suggestions for elaboration or clarification would be gratefully accepted.

Linklist classes

The following class attributes can be added to your Linklist subclasses to customize the extracted links:

object_filter: a dictionary which will be passed as a filter argument to the filter applied to the default queryset of the target class. This allows you to filter the objects from which the links will be extracted. (example: {'active': True})

object_exclude: a dictionary which will be passed as a filter argument to the exclude applied to the default queryset of the target class. As with object_filter, this allows you to exclude objects from which the links will be extracted.

html_fields: a list of field names which will be searched for links.

url_fields: a list of URLField field names whose content will be considered as links. If the field content is empty and the field name is in ignore_empty, the content is ignored.

ignore_empty: a list of fields from url_fields. See the explanation above. (new in django-linkcheck 1.1)

image_fields: a list of ImageField field names whose content will be considered as links. Empty ImageField content is always ignored.

filter_callable: a callable which allows to pass a function as filter for your linklist class. It allows to apply more advanced filter operations. This function must be a class method and it should be passed the objects query set and return the filtered objects. Example usage in your linklists.py - only check latest versions:

@classmethod
def filter_callable(cls, objects):
    latest = Model.objects.filter(id=OuterRef('id')).order_by('-version')
    return objects.filter(version=Subquery(latest.values('version')[:1]))

Management commands

findlinks

This command goes through all registered fields and records the URLs it finds. This command does not validate anything. Typically run just after installing and configuring django-linkcheck.

checklinks

For each recorded URL, check and report the validity of the URL. All internal links are checked, but only external links that have not been checked during the last LINKCHECK_EXTERNAL_RECHECK_INTERVAL minutes are checked. This interval can be adapted per-invocation by using the --externalinterval (-e) command option (in minutes).

You can also limit the maximum number of links to be checked by passing a number to the --limit (--l) command option.

Settings

LINKCHECK_DISABLE_LISTENERS

A setting to totally disable linkcheck, typically when running tests. See also the context managers below.

LINKCHECK_EXTERNAL_RECHECK_INTERVAL

Default: 10080 (1 week in minutes)

Will not recheck any external link that has been checked more recently than this value.

LINKCHECK_EXTERNAL_REGEX_STRING

Default: r'^https?://'

A string applied as a regex to a URL to determine whether it's internal or external.

LINKCHECK_MEDIA_PREFIX

Default: '/media/'

Currently linkcheck tests whether links to internal static media are correct by wrangling the URL to be a local filesystem path.

It strips MEDIA_PREFIX off the interal link and concatenates the result onto settings.MEDIA_ROOT and tests that using os.path.exists

This 'works for me' but it is probably going to break for other people's setups. Patches welcome.

LINKCHECK_RESULTS_PER_PAGE

Controls pagination.

Pagination is slightly peculiar at the moment due to the way links are grouped by object.

LINKCHECK_MAX_URL_LENGTH

Default: 255

The length of the URL field. Defaults to 255 for compatibility with MySQL (see http://docs.djangoproject.com/en/dev/ref/databases/#notes-on-specific-fields )

LINKCHECK_CONNECTION_ATTEMPT_TIMEOUT

Default: 10

The timeout in seconds for each connection attempts. Sometimes it is useful to limit check time per connection in order to hold at bay the total check time.

SITE_DOMAIN and LINKCHECK_SITE_DOMAINS

Linkcheck tests external and internal using differently. Internal links use the Django test client whereas external links are tested using urllib2.

Testing internal links this as if they were external can cause errors in some circumstances so Linkcheck needs to know which external urls are to be treated as internal.

Linkcheck looks for either of the settings above. It only uses SITE_DOMAIN if LINKCHECK_SITE_DOMAINS isn't present

SITE_DOMAIN = "mysite.com"

would tell linkchecker to treat the following as internal links:

mysite.com www.mysite.com test.mysite.com

If you instead set LINKCHECK_SITE_DOMAINS to be a list or tuple then you can explicitly list the domains that should be treated as internal.

LINKCHECK_TOLERATE_BROKEN_ANCHOR

Default: True

Whether links with broken hash anchors should be marked as valid. Disable this if you want that links to anchors which are not contained in the link target's HTML source are marked as invalid.

django-filebrowser integration

If django-filebrowser is present on your path then linkcheck will listen to the post-upload, delete and rename signals and update itself according

Contributing

You can install all requirements of the development setup with the extra dev:

$ python3 -m venv .venv
$ source .venv/bin/activate
$ pip install -e .[dev]
$ django-admin compilemessages --ignore=.venv  # Optionally compile translation file

If you want to make use of the flake8 and isort pre-commit hooks, enable them with:

$ pre-commit install

Running tests

Tests can be run standalone by using the runtests.py script in linkcheck root:

$ python runtests.py

If you want to run linkcheck tests in the context of your project, you should include 'linkcheck.tests.sampleapp' in your INSTALLED_APPS setting.

Linkcheck gives you two context managers to enable or disable listeners in your own tests. For example:

def test_something_without_listeners(self):
    with listeners.disable_listeners():
        # Create/update here without linkcheck intervening.

In the case you defined the LINKCHECK_DISABLE_LISTENERS setting, you can temporarily enable it by:

def test_something_with_listeners(self):
    with listeners.enable_listeners():
        # Create/update here and see linkcheck activated.

Translations

At the moment this app is available in English and German. If you want to contribute translations for LOCALE, run:

django-admin makemessages --locale LOCALE

and edit the corresponding file in linkcheck/locale/LOCALE/LC_MESSAGES/django.po.