Plugins

One of the most useful aspects of the Girder platform is its ability to be extended in almost any way by custom plugins. Developers looking for information on writing their own plugins should see the Plugin Development section. Below is a listing and brief documentation of some of Girder’s standard plugins that come pre-packaged with the application.

Authorized Uploads

This plugin allows registered users to grant access to others to upload data on their behalf via a secure URL. The secure URL allows a third party to upload a single file into the selected folder, even if that third party does not have a registered user in Girder.

To authorize an upload on behalf of your user:

  1. Navigate into any folder to which you have write access. From the Folder actions dropdown menu on the right, choose Authorize upload here. You will be taken to a page that allows generation of a secure, single-use URL. You can optionally specify a number of days until the URL expires; if none is specified, the user session lifetime is used, which defaults to 180 days.
  2. Click Generate URL, and your secure URL will appear below.
  3. Copy that URL and send it to the third party, and they will be taken to a simple page allowing them to upload the file without having to see any details of the normal Girder application.

Note

When an upload is authorized, it’s authorized into a particular folder, and inherits the access control configured on that folder.

Jobs

The jobs plugin is useful for representing long-running (usually asynchronous) jobs in the Girder data model. Since the notion of tracking batch jobs is so common to many applications of Girder, this plugin is very generic and is meant to be an upstream dependency of more specialized plugins that actually create and execute the batch jobs.

The job resource that is the primary data type exposed by this plugin has many common and useful fields, including:

  • title: The name that will be displayed in the job management console.
  • type: The type identifier for the job, used by downstream plugins opaquely.
  • args: Ordered arguments of the job (a list).
  • kwargs: Keyword arguments of the job (a dictionary).
  • created: Timestamp when the job was created
  • progress: Progress information about the job’s execution.
  • status: The state of the job, e.g. Inactive, Running, Success.
  • log: Log output from this job’s execution.
  • handler: An opaque value used by downstream plugins to identify what should handle this job.
  • meta: Any additional information about the job should be stored here by downstream plugins.

Jobs should be created with the createJob method of the job model. Downstream plugins that are in charge of actually scheduling a job for execution should then call scheduleJob, which triggers the jobs.schedule event with the job document as the event info.

The jobs plugin contains several built-in status codes within the girder.plugins.jobs.constants.JobStatus namespace. These codes represent various states a job can be in, which are:

  • INACTIVE (0)
  • QUEUED (1)
  • RUNNING (2)
  • SUCCESS (3)
  • ERROR (4)
  • CANCELED (5)

Downstream plugins that wish to expose their own custom job statuses must hook into the jobs.status.validate event for any new valid status value, which by convention must be integer values. To validate a status code, the default must be prevented on the event, and the handler must add a True response to the event. For example, a downstream plugin with a custom job status with the value 1234 would add the following hook:

from girder import events

def validateJobStatus(event):
    if event.info == 1234:
        event.preventDefault().addResponse(True)

def load(info):
    events.bind('jobs.status.validate', 'my_plugin', validateJobStatus):

Downstream plugins that want to hook into job updates must use a different convention than normal; for the sake of optimizing data transfer, job updates do not occur using the normal save method of Girder models. Therefore, plugins that want to listen to job updates should bind to either jobs.job.update (which is triggered prior to persisting the updates and can be used to prevent the update) or jobs.job.update.after (which is triggered after the update). Users of these events should be aware that the log field of the job will not necessarily be in sync with the persisted version, so if your event handler requires access to the job log, you should manually re-fetch the full document in the handler.

Geospatial

TODO: Add migration notice

Google Analytics

The Google Analytics plugin enables the use of Google Analytics to track page views with the Girder one-page application. It is primarily a client-side plugin with the tracking ID stored in the database. Each routing change will trigger a page view event and the hierarchy widget has special handling (though it does not technically trigger routing events for hierarchy navigation).

To use this plugin, simply copy your tracking ID from Google Analytics into the plugin configuration page.

Homepage

The Homepage plugin allows the default Girder front page to be replaced by content written in Markdown format. After enabling this plugin, visit the plugin configuration page to edit and preview the Markdown.

Auto Join

The Auto Join plugin allows you to define rules to automatically assign new users to groups based on their email address domain. Typically, this is used in conjunction with email verification.

When a new user registers, each auto join rule is checked to see if the user’s email address contains the rule pattern as a substring (case insensitive).

If there is a match, the user is added to the group with the specified access level.

Download Statistics

This plugin tracks and records file download activity. The recorded information (downloads started, downloads completed, and total requests made) is stored on the file model:

file['downloadStatistics']['started']
file['downloadStatistics']['requested']
file['downloadStatistics']['completed']

DICOM Viewer

The DICOM Viewer plugin adds support for previewing DICOM files when viewing an item in girder. If multiple DICOM files are present in a single item, they are presented as multiple slices. The DICOM image is shown as well as a table of DICOM tags. The window center and width can be changed by the user. Controls allow the user to step through slices, auto-level the window, auto-zoom, or playback the slices at different speeds.

This plugin parses the DICOM tags when files are uploaded and stores them in the MongoDB database for quick retrieval. This is mostly used to sort multiple images by series and instance.

LDAP Authentication

This plugin allows administrators to configure the server so that users can log in against one or more LDAP servers. If the user fails to authenticate to any of the available LDAP servers, they will fall back to normal core authentication. Documentation of the LDAP standard in general can be found here.

Administrators can configure the ordered list of LDAP servers to try on the plugin configuration page. Each server in the list has several properties:

  • URI: The URI of the LDAP server. Example: ldaps://my.ldap.org:636.
  • Bind name: The Distinguished Name (DN) to use when connecting to the LDAP server to perform directory searches. Example: cn=me,cn=Users,dc=my,dc=ldap,dc=org.
  • Password: (Optional) The password to use when connecting to the LDAP server to perform directory searches.
  • Base DN: The Distinguished Name (DN) under which to search for users during login. Example: cn=Users,dc=my,dc=ldap,dc=org.
  • Search field: (Optional) This specifies what field should be searched in the directory for the login field entered by the user. The default value is the uid field, though some implementations would want to use, e.g. mail. It is assumed that the search field will uniquely identify at most one user in the directory under the Base DN.

Note

This plugin is known to work against LDAP version 3. Using it with older versions of the protocol might work, but is not tested at this time.

OAuth Login

This plugin allows users to log in using OAuth against a set of supported providers, rather than storing their credentials in the Girder instance. Specific instructions for each provider can be found below.

By using OAuth, Girder users can avoid registering a new user in Girder, leaving it up to the OAuth provider to store their password and provide details of their identity. The fact that a Girder user has logged in via an OAuth provider is stored in their user document instead of a password. OAuth users who need to authenticate with programmatic clients such as the girder-client python library should use API keys to do so.

Google

On the plugin configuration page, you must enter a Client ID and Client secret. Those values can be created in the Google Developer Console, in the APIS & AUTH > Credentials section. When you create a new Client ID, you must enter the AUTHORIZED_JAVASCRIPT_ORIGINS and AUTHORIZED_REDIRECT_URI fields. These must point back to your Girder instance. For example, if your Girder instance is hosted at https://my.girder.com, then you should specify the following values:

AUTHORIZED_JAVASCRIPT_ORIGINS: https://my.girder.com
AUTHORIZED_REDIRECT_URI: https://my.girder.com/api/v1/oauth/google/callback

After successfully creating the Client ID, copy and paste the client ID and client secret values into the plugin’s configuration page, and hit Save. Users should then be able to log in with their Google account when they click the log in page and select the option to log in with Google.

Extension

This plugin can also be extended to do more than just login behavior using the OAuth providers. For instance, if you wanted some sort of integration with a user’s Google+ circles, you would add a custom scope that the user would have to authorize during the OAuth login process.

from girder.plugins.oauth.providers.google import Google
Google.addScopes(['https://www.googleapis.com/auth/plus.circles.read'])

Then, you can hook into the event of a user logging in via OAuth. You can hook in either before the Girder user login has occurred, or afterward. In our case, we want to do it after the Girder user has been fetched (or created, if this is the first time logging in with these OAuth credentials).

def readCircles(event):
    # Read user's circles, do something with them
    if event.info['provider'] == 'google':
        token = event.info['token']
        user = event.info['user']
        ...

from girder import events
events.bind('oauth.auth_callback.after', 'my_plugin', readCircles)

Gravatar Portraits

This lightweight plugin makes all users’ Gravatar image URLs available for use in clients. When enabled, user documents sent through the REST API will contain a new field gravatar_baseUrl if the value has been computed. If that field is not set on the user document, instead use the URL /user/:id/gravatar under the Girder API, which will compute and store the correct Gravatar URL, and then redirect to it. The next time that user document is sent over the REST API, it should contain the computed gravatar_baseUrl field.

Terms of Use

This plugin allows collection admins to define a set of textual “Terms of Use”, which other users must accept before browsing within the collection. The terms may be set with markdown-formatted text, and users will be required to re-accept the terms whenever the content changes. Logged-in users have their acceptances stored and remembered permanently, while anonymous users have their acceptances stored only on the local browser.

Javascript clients

The Gravatar plugin’s javascript code extends the Girder web client’s girder.models.UserModel by adding the getGravatarUrl(size) method that adheres to the above behavior internally. You can use it on any user model with the _id field set, as in the following example:

import { getCurrentUser } from 'girder/auth';

const currentUser = getCurrentUser();
if (currentUser) {
    this.$('div.gravatar-portrait').css(
        'background-image', `url(${currentUser.getGravatarUrl(36)})`);
}

Note

Gravatar images are always square; the size parameter refers to the side length of the desired image in pixels.

Remote Worker

This plugin should be enabled if you want to use the Girder worker distributed processing engine to execute batch jobs initiated by the server. This is useful for deploying service architectures that involve both data management and scalable offline processing. This plugin provides utilities for sending generic tasks to worker nodes for execution. The worker itself uses celery to manage the distribution of tasks, and builds in some useful Girder integrations on top of celery. Namely,

  • Data management: This plugin provides python functions for building task input and output specs that refer to data stored on the Girder server, making it easy to run processing on specific folders, items, or files. The worker itself knows how to authenticate and download data from the server, and upload results back to it.
  • Job management: This plugin depends on the Jobs plugin. Tasks are specified as python dictionaries inside of a job document and then scheduled via celery. The worker automatically updates the status of jobs as they are received and executed so that they can be monitored via the jobs UI in real time. If the script prints any logging information, it is automatically collected in the job log on the server, and if the script raises an exception, the job status is automatically set to an error state.

Hashsum Download

The hashum_download plugin allows a file to be downloaded from Girder given a hash value and hash algorithm. Use this plugin when you have large data that you don’t want to keep in a software repository, but want to access that data from the repository, e.g. during a build or test of that software project. This plugin is written to satisfy the needs of CMake ExternalData. These docs describe how to use this plugin along with ExternalData, but the plugin could be used outside of that context. For more detailed documentation on how to use this in a software repository see the ITKExamples. This example project uses the Girder instance https://data.kitware.com.

Note

The use of the hashsum_download plugin with CMake ExternalData is only supported with a filesystem assetstore and SHA512 as the hash algorithm.

As every local Git repository contains a copy of the entire project history, it is important to avoid adding large binary files directly to the repository. Large binary files added and removed throughout a project’s history will cause the repository to become bloated and take up too much disk space, requiring excessive time and bandwidth to download.

A solution to this problem, when using the CMake build system, is to store binary files in a separate location outside the Git repository, then download the files at build time with CMake.

CMake uses the notion of a content link file, which contains an identifying hash calculated from the original data file. The content link file has the same name as the data file, with a “.sha512” extension appended to the file name, and should be stored in the Git repository. CMake will find these content link files at build time, download the corresponding data files from a list of server resources, and create symlinks or copies of the original files in the build tree, which is why the files are called “content links”.

What CMake calls a content link file, Girder calls a key file, as the notion of content link doesn’t apply in the context of Girder, and the hash value is a key into the original data file. When using the hashsum_download plugin, the data file is stored in Girder, with the SHA512 for the data added as metadata and provided as the key file, which can be downloaded from Girder and added to a project repository. The hashsum_plugin allows the data file to be downloaded based on the hash of the data. CMake ExternalData provides tooling to connect with a Girder instance, download the actual data file pointed to by the content link (key) file by passing the hash to Girder, and provide a local file path to access the data file contents.

Usage by a software project maintainer

Again, for more background, using the example Girder instance https://data.kitware.com, see the ITKExamples. Also see the CMake External Data documentation for CMake project configuration help.

In your project, you must set ExternalData_URL_TEMPLATES to a girder url, e.g. “https://data.kitware.com/api/v1/file/hashsum/%(algo)/%(hash)/download”.

See the ITK configuration for an example application of ExternalData_URL_TEMPLATES.

Project contributors will add data files to a Girder instance in arbitrary folders. At a project release and on a regular basis, perhaps nightly, the data should be archived in a new Girder folder to ensure its persistence. A script that provides this functionality is available, as is an example folder produced by the script for a release.

Usage by a software project contributor

Upload a file to a Girder instance, which will create a Girder Item to house the file. Navigate to the Item, then click on the i (information) icon next to the file, which will show the id, and since the hashsum_download plugin is enabled, the sha512 field will also be displayed. Click on the key icon to download a hashfile, which will be the full sha512 of the file, with the same name as the file, and an extension of .sha512, and you can use this key file as your CMake content link. E.g., upload my_datafile.txt and download the my_data.txt.sha512 file, then check the my_data.txt.sha512 file into your source repository.

You can use the Girder API to get the hash of the file given the file id, with the endpoint api/v1/file/<file id>/hashsum_file/sha512, where the file id comes from the specific file in Girder.

You can also use the API to download the file based on the hash returned by the previous endpoint, with an endpoint /api/v1/file/hashsum/sha512/<file sha512 hash>/download, where the sha512 hash comes from the specific file in Girder.