Есть плагин к Valknut
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HTTP plugin
The http plugin allows you to control Valknut via a web browser. This could be really useful if you don't always have physical access to the machine running the client, and a graphical remote control method like VNC is not suitable.
Currently the http plugin allows you to see the current state of Valknut, display and cancel transfers and connect to hubs. There is no way at the moment to search or browse filelists, or add new downloads.
By default, the http plugin listens on port 1480 and only accepts connections from localhost. Connecting to
http://localhost:1480/ will present you with a login prompt. The default username is "dcgui" and the password is "admin". Once you are logged in you can change the password and security settings. The configuration of the plugin is stored in ~/.dc/plugin/http.xml
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видел в действии, совершенно бесполезен.
И посмотрите тут
http://trac.transmissionbt.com/wiki/WebInterface
Ето вебдоступ к Transmission. Напишите результат.
Сам интересовался данным вопросом, одно время. По поводу самостоятельного Web DC клиента
поисковики находили только проект phpdccli, проект заброшен без единого релиза.