bt种子tracker服务器 bep协议规范

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bt种子tracker服务器 bep协议规范

trackers
Tracker GET requests have the following keys:

info_hash
The 20 byte sha1 hash of the bencoded form of the info value from the metainfo file. This value will almost certainly have to be escaped.

Note that this is a substring of the metainfo file. The info-hash must be the hash of the encoded form as found in the .torrent file, which is identical to bdecoding the metainfo file, extracting the info dictionary and encoding it if and only if the bdecoder fully validated the input (e.g. key ordering, absence of leading zeros). Conversely that means clients must either reject invalid metainfo files or extract the substring directly. They must not perform a decode-encode roundtrip on invalid data.

peer_id
A string of length 20 which this downloader uses as its id. Each downloader generates its own id at random at the start of a new download. This value will also almost certainly have to be escaped.
ip
An optional parameter giving the IP (or dns name) which this peer is at. Generally used for the origin if it's on the same machine as the tracker.
port
The port number this peer is listening on. Common behavior is for a downloader to try to listen on port 6881 and if that port is taken try 6882, then 6883, etc. and give up after 6889.
uploaded
The total amount uploaded so far, encoded in base ten ascii.
downloaded
The total amount downloaded so far, encoded in base ten ascii.
left
The number of bytes this peer still has to download, encoded in base ten ascii. Note that this can't be computed from downloaded and the file length since it might be a resume, and there's a chance that some of the downloaded data failed an integrity check and had to be re-downloaded.
event
This is an optional key which maps to started, completed, or stopped (or empty, which is the same as not being present). If not present, this is one of the announcements done at regular intervals. An announcement using started is sent when a download first begins, and one using completed is sent when the download is complete. No completed is sent if the file was complete when started. Downloaders send an announcement using stopped when they cease downloading.
Tracker responses are bencoded dictionaries. If a tracker response has a key failure reason, then that maps to a human readable string which explains why the query failed, and no other keys are required. Otherwise, it must have two keys: interval, which maps to the number of seconds the downloader should wait between regular rerequests, and peers. peers maps to a list of dictionaries corresponding to peers, each of which contains the keys peer id, ip, and port, which map to the peer's self-selected ID, IP address or dns name as a string, and port number, respectively. Note that downloaders may rerequest on nonscheduled times if an event happens or they need more peers.

https://www.bittorrent.org/beps/bep_0003.html