Anki Server

NOTE: Maintenance of this project has moved to a new GitHub project.

Anki is a powerful Open Source flashcard application, which helps you quickly and easily memorize facts over the long term utilizing a spaced repetition algorithm.

Anki's main form is a desktop application (for Windows, Linux and MacOS) which can sync to a web version (AnkiWeb) and mobile versions for Android and iOS.

This is a personal Anki Server, which you can sync against instead of AnkiWeb.

It also includes a RESTful API, so that you could implement your own AnkiWeb-like site if you wanted.

It was originally developed to support the flashcard functionality on Bibliobird, a web application for language learning.

Installing the easy way!

If you have easy_install or pip on your system, you can simply run:

$ easy_install AnkiServer

Or using pip:

$ pip install AnkiServer

This will give you the latest released version!

However, if you want to try the latest bleeding edge version OR you want to help with development, you'll need to install from source. In that case, follow the instructions in the next two sections.

Setting up a virtualenv

If you want to install your Anki Server in an isolated Python environment using virtualenv, please follow these instructions before going on to the next section. If not, just skip to the "Installing" section below.

There are many reasons for installing into a virtualenv, rather than globally on your system:

• You can keep the Anki Server's dependencies seperate from other Python applications.
• You don't have permission to install globally on your system (like on a shared host).

Here are step-by-step instruction for setting up your virtualenv:

1. First, you need to install "virtualenv". If your system has easy_install or pip, this is just a matter of:

   $ easy_install virtualenv
   

   Or using pip:

   $ pip install virtualenv
   

   Or you can use your the package manager provided by your OS.

2. Next, create your a Python environment for running AnkiServer:

   $ virtualenv AnkiServer.env
   

3. (Optional) Enter the virtualenv to save you on typing:

   $ . AnkiServer.env/bin/activate
   

If you skip step 3, you'll have to type AnkiServer.env/bin/python instead of python and AnkiServer.env/bin/paster instead of paster in the following sections.

Also, remember that the environment change in step 3 only lasts as long as your current terminal session. You'll have to re-enter the environment if you enter that terminal and come back later.

Installing your Anki Server from source

1. Install all the dependencies we need using easy_install or pip:

   $ easy_install webob PasteDeploy PasteScript sqlalchemy simplejson
   

   Or using pip:

   $ pip install webob PasteDeploy PasteScript sqlalchemy simplejson
   

   Or you can use your the package manager provided by your OS.

2. Download and install libanki. You can find the latest release of Anki here:

   http://code.google.com/p/anki/downloads/list

   Look for a *.tgz file with a Summary of "Anki Source". At the time of this writing that is anki-2.0.11.tgz.

   Download this file and extract.

   Then either:

   1. Run the 'make install', or
   2. Copy the entire directory to /usr/share/anki

3. Make the egg info files (so paster can see our app):

   $ python setup.py egg_info
   

Configuring and running your Anki Server

1. Copy the example.ini to production.ini in your current directory and edit for your needs.

   1. If you installed from source, it'll be at the top-level.

   2. If you installed via 'easy_install' or 'pip', you'll find all the example configuration at python_prefix/lib/python2.X/site-packages/AnkiServer-2.X.X-py2.X.egg/examples (replacing python_prefix with the root of your Python and all the X with the correct versions). For example, it could be:

      /usr/lib/python2.7/site-packages/AnkiServer-2.0.0a6-py2.7.egg/examples/example.ini
      

3. Create user:

   $ ./ankiserverctl.py adduser <username>
   

4. Test the server by starting it debug mode:

   $ ./ankiserverctl.py debug
   

   If the output looks good, you can stop the server by pressing Ctrl-C and start it again in normal mode:

   $ ./ankiserverctl.py start
   

   To stop AnkiServer, run:

   $ ./ankiserverctl.py stop
   

Point the Anki desktop program at it

Unfortunately, there isn't currently any user interface in the Anki destop program to point it at your personal sync server instead of AnkiWeb, so you'll have to write a short "addon".

Create a file like this in your Anki/addons folder called "mysyncserver.py":

import anki.sync
anki.sync.SYNC_BASE = 'http://127.0.0.1:27701/'
anki.sync.SYNC_MEDIA_BASE = 'http://127.0.0.1:27701/msync/'

Be sure to change the SYNC_URL to point at your sync server. The address 127.0.0.1 refers to the local computer.

If you are using TLS, add these lines to the configuration to verify the certificate against a custom certificate chain:

# Path to the certificate chain file, relative to the Anki/addons directory
CERTPATH = 'server.pem'

# Override TLS certificate path
httpCon_anki = anki.sync.httpCon
def httpCon_patch():
    import os.path
    conn = httpCon_anki()
      conn.ca_certs = os.path.join(os.path.dirname(__file__), CERTPATH)
      return conn
anki.sync.httpCon = httpCon_patch

The certificate chain must include all intermediate certificates and the root certificate. For the popular free Let's encrypt CA, a sample certificate chain can be found here.

Unfortunately python-httplib2 (used by Anki's sync client for issuing HTTP requests) does not support SNI for telling the web server during the TLS handshake which certificate to use. This will result in certificate validation errors if your Anki Server instance runs behind a web server that serves multiple domains using different certificates. This has been fixed in the python-httplib2 source code and will be part of the upcoming 0.9.3 release. In the likely event that you are not using the latest version yet you will have to install the latest release from source using:

sudo pip install -e git+https://github.com/httplib2/httplib2.git#egg=httplib2

Alternatively you can try adding these lines, to disable certificate validation entirely:

# Override TLS certificate path
httpCon_anki = anki.sync.httpCon
def httpCon_patch():
      conn = httpCon_anki()
      conn.disable_ssl_certificate_validation = True
      return conn
anki.sync.httpCon = httpCon_patch

Restart Anki for your plugin to take effect. Now, everytime you sync, it will be to your personal sync server rather than AnkiWeb.

However, if you just want to switch temporarily, rather than creating an addon, you can set the SYNC_URL environment variable when running from the command-line (on Linux):

export SYNC_URL=http://127.0.0.1:27701/sync/
./runanki &

Point the mobile apps at it

As of AnkiDroid 2.6 the sync server can be changed in the settings:

1. Open the Settings screen from the menu
2. In the Advanced section, tap on Custom sync server
3. Check the Use custom sync server box
4. Change the Sync URL and Media sync URL to the values described above
5. The next sync should use the new sync server (if your previous username or password does not match AnkiDroid will ask you to log in again)

At the moment, there isn't any way to get the Anki iOS app to point at your personal sync server. 😕

Running with Supervisor

If you want to run your Anki server persistantly on a Linux (or other UNIX-y) server, Supervisor is a great tool to monitor and manage it. It will allow you to start it when your server boots, restart it if it crashes and easily access it's logs.

1. Install Supervisor on your system. If it's Debian or Ubuntu this will work:

   $ sudo apt-get install supervisor
   

   If you're using a different OS, please try these instructions.

2. Copy supervisor-anki-server.conf to /etc/supervisor/conf.d/anki-server.conf:

   $ sudo cp supervisor-anki-server.conf /etc/supervisor/conf.d/anki-server.conf
   

3. Modify /etc/supervisor/conf.d/anki-server.conf to match your system and how you setup your Anki Server in the section above.

4. Reload Supervisor's configuration:

   $ sudo supervisorctl reload
   

5. Check the logs from the Anki Server to make sure everything is fine:

   $ sudo supervisorctl tail anki-server
   

   If it's empty - then everything's fine! Otherwise, you'll see an error message.

Later if you manually want to stop, start or restart it, you can use:

$ sudo supervisorctl stop anki-server

$ sudo supervisorctl start anki-server

$ sudo supervisorctl restart anki-server

See the Supervisor documentation for more info!

Using with Apache

If you're already serving your website via Apache (on port 80) and want to also allow users to sync against a URL on port 80, you can forward requests from Apache to the Anki server.

On Bibliobird.com, I have a special anki.bibliobird.com virtual host which users can synch against. Here is an excerpt from my Apache conf:

<VirtualHost *:80>
    ServerAdmin [email protected]
    ServerName anki.bibliobird.com

    # The Anki server handles gzip itself!
    SetEnv no-gzip 1

    <Location />
        ProxyPass http://localhost:27701/
        ProxyPassReverse http://localhost:27701/
    </Location>
</VirtualHost>

It may also be possible to use mod_wsgi, however, I have no experience with that.

Using with nginx

If you happen to use nginx, you can use the following configuration to proxy requests from nginx to your Anki Server:

server {
    # Allow access via HTTP
    listen 80;
    listen [::]:80;

    # Allow access via HTTPS
    listen 443 ssl spdy;
    listen [::]:443 ssl spdy;

    # Set server names for access
    server_name anki.server.name;

    # Set TLS certificates to use for HTTPS access
    ssl_certificate     /path/to/fullchain.pem;
    ssl_certificate_key /path/to/privkey.pem;

    location / {
        # Prevent nginx from rejecting larger media files
        client_max_body_size 0;

        proxy_pass http://anki:27701;
        include proxy_params;
    }
}

AnkiDroid will not verify the TLS certificate, Anki Desktop will by default reject all but AnkiWeb's certificate, see the Anki addon section for how to change this.

How to get help

If you're having any problems installing or using Anki Server, please create an issue on GitHub (or find an existing issue about your problem):

https://github.com/dsnopek/anki-sync-server/issues

Be sure to let us know which operating system and version you're using and how you intend to use the Anki Server!