AirDC++ is an open-source file-sharing client for Windows that connects people through Direct Connect hubs. It lets users make selected folders available to a community, search or browse other members' files, and download files or whole directories directly from their computers. Hub chat provides a place to communicate with the people sharing that content.
Hubs
A hub brings users together and carries searches and chat messages. The files themselves remain on members' computers: when a download starts, AirDC++ establishes a connection to the user providing it. At least one hub connection is needed to exchange files, and the content available depends on the users connected to that community.
AirDC++ supports the Advanced Direct Connect protocol and the older NMDC protocol. Their capabilities differ. In particular, exchanging portions of unfinished downloads is available in ADC hubs, while NMDC hubs no longer support that function.
Share profiles
The shared collection begins with local directories the user chooses. AirDC++ can assign different share profiles to favorite hubs, so each community can see a different selection of folders. This separates what is offered to one group from what is offered to another without requiring the same collection everywhere.
Directory refreshes update the contents exposed to other users. An individual root folder or subdirectory can be refreshed without processing the entire share. Files and directories downloaded into a shared location can become available to others when their downloads finish, allowing incoming content to join the collection.
File searches
AirDC++ searches the content offered by other users and sorts results by relevance. Search controls include file types and maximum file age, while result filters help narrow the returned items. A result can be added to the download queue, and searches for alternate sources can find other users offering queued content.
Filelists
A user's filelist provides another way to find content when its folder arrangement is more useful than a search term. AirDC++ supports partial lists that retrieve directory contents as those directories are opened, rather than requiring the user's complete collection to be downloaded first. The folder view can therefore be browsed progressively, including while file transfers from that user are running.
Download bundles
AirDC++ groups queued downloads into bundles, keeping a requested directory and its files together in the queue. Bundle and file priorities control which work should proceed first. Bundles can also be paused for a chosen period, and the queue retains completed downloads alongside unfinished work.
A file can be downloaded in segments from several users at the same time. AirDC++ also supports multiple transfer connections to one user. These are different arrangements: one gathers pieces from several sources, while the other opens additional connections to the same source. The transfer rate still depends on the available peers and their connections.
For compatible ADC transfers, clients can exchange information about the pieces they have already downloaded. This lets users contribute portions of a file before their own copy is complete. Unfinished content is kept out of ordinary search results and filelists, so browsing a share does not present those partial copies as finished files.
Direct chat
Public messages appear in the hub's main conversation, while private chats address a particular user. AirDC++ can also establish a direct encrypted private-message channel between clients. That channel carries the conversation separately from hub chat and supports typing and message-seen notifications.
Web control
The Windows application includes an optional web interface as well as its desktop interface. After its web server and a login account are configured, the running client can be accessed through a browser on another device, including a phone. This provides another interface to the client handling the shares and transfers on the Windows computer.
AirDC++ also exposes a JSON Web API for scripts and supports installable extensions. These can connect automated tasks, such as searches and downloads, to the file-sharing client instead of requiring every operation to be performed manually in its interface.
