74 lines
3.6 KiB
Markdown
74 lines
3.6 KiB
Markdown
[](https://travis-ci.org/FredStober/tinyBT)
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[](https://codecov.io/github/FredStober/tinyBT?branch=master)
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tiny Bittorrent client
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======================
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The goal is to supply an easy to use and simple to understand implementation
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of the BitTorrent specifications in python with no external dependencies
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except for the python standard library.
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The implementation is spread over several files, each implementing
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a single component.
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- krpc.py - implements the basic UDP Kademila-RPC protocol layer
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- dht.py - contains the code for accessing the Mainline DHT using KRPC
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KRPC Implementation
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-------------------
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The KRPCPeer only exposes three methods:
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- __init__((host, port), query_handler)
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That takes the (host, port) tuple where it should listen and the second
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argument is the function that processes incoming messages.
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- shutdown()
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Shutdown of all threads and connections of the KRPC peer.
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- send_krpc_query((host, port), method, **kwargs)
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This method sends a query to a remote host specified by a (host, pool) tuple.
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The name and arguments to call on the remote host is given as well.
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An async result holder is returned, that allows to wait for a reply.
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DHT Implementation
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------------------
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The DHT class offers the 4 DHT methods described in BEP #5 - each takes the
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remote host in the form of a (host, port) tuple as the first argument. The
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other arguments are the same as described in the specification. They all return
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an async result holder with the unprocessed data from the remote host:
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- ping(target_connection, sender_id)
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- find_node(target_connection, sender_id, search_id)
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- get_peers(target_connection, sender_id, info_hash)
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- announce_peer(target_connection, sender_id, info_hash, port, token, implied_port = None)
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In addition, some additional helper functions are made available - these
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functions take care of updating the routing table and are blocking calls with
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a user specified timeout:
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- dht_ping(connection, timeout = 5)
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Returns the complete result dictionary of the call.
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- dht_find_node(search_id, timeout = 5, retries = 2)
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Searches iteratively for nodes with the given id
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and yields the connection tuple if found.
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- dht_get_peers(info_hash, timeout = 5, retries = 2)
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Searches iteratively for nodes with the given info_hash
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and yields the connection tuple if found.
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- dht_announce_peer(info_hash, implied_port = 1)
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Registers the availabilty of the info_hash on this node
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to all peers that supplied a token while searching for it.
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The final three functions are used to start and shutdown the local DHT Peer
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and allow access to the discovered external connection infos:
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- __init__(listen_connection, bootstrap_connection = ('router.bittorrent.com', 6881),
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user_setup = {}, user_router = None)
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The constructor needs to know what address and port to listen on and which node to use
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as a bootstrap node. The run interval and some other parameters of the maintainance
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threads can be configured as well via the user_setup parameter. The default values are:
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{'discover_t': 180, 'check_t': 30, 'check_N': 10}.
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It is possible to provide a user implemntation for the DHT node router with the user_router
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parameter
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- shutdown()
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Start shutdown of the local DHT peer and all associated maintainance threads.
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- get_external_connection()
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Return the discovered external connection infos
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