The official Docker image is provided:

$ docker pull dahlia/nicovideo-translator

You need to provide a required environment variable GOOGLE_TRANSLATE_API_KEY to use Google Translate API, and may want to set an optional environment variable LANG which means the target language. The exposed port number is 8080:

$ docker run \
    -e GOOGLE_TRANSLATE_API_KEY=EiP3NSgLid81OjSwpOMkgV0rzD9SLHRqwqUwx2r \
    -e LANG=ko \
    -p 80:8080 \
    dahlia/nicovideo-translator

You can install it using cabal:

$ cabal install nicovideo-translator

To make the translator to intercept comments from Nico Nico comment server, you have to alias Nico Nico comment server domain (nmsg.nicovideo.jp) to your localhost (127.0.0.1). Open your hosts file using text editor (you probably need administrator permission), and then add the following line:

127.0.0.1    nmsg.nicovideo.jp

The translator behaves as a proxy server, so it has to be running while you watch Nico Nico videos. You can invoke the proxy server using CLI (you probably need administrator permission to listen 80 port):

$ nicovideo-translator EiP3NSgLid81OjSwpOMkgV0rzD9SLHRqwqUwx2r
Running on http://0.0.0.0:80/ (Press ^C to quit)
Upstream: nmsg.nicovideo.jp (202.248.110.173)

Note that it takes a Google Translate API key as its first argument.

You can terminate the server by pressing Ctrl-C.

It can optionally take the target language which is a two-letter e.g. en, ko through -l/--lang/--language option:

$ nicovideo-translator -l ko

It's written by Hong Minhee, and distributed under AGPLv3. You can find the source code from the Git repository:

$ git clone git://github.com/dahlia/nicovideo-translator

Please report bugs to the issue tracker if you find. Pull requests welcome!