Module peer_worker
A managed PPSPP UDP-based Peer.
Behaviours: gen_server.
Description
The peer_worker provides a wrapper around the standard gen_udp server
spawning an additional erlang process for every received datagram.
At startup, the peer_worker registers itself in the gproc registry
with the assigned UDP port.
Note that every port has a 1-to-1 association to a specific swarm, comprising options, IP, and port. The main reason for this is to be able to pass these swarm options through to the packet decoder when checking that the requested hash is available in this swarm or not, without requiring additional lookups.
Data Types
state()
state() = {ppspp_options:options(), inet:port_number(), port()}
Function Index
| code_change/3 | Default gen_server API. |
| get_url/1 | Create a URL for this endpoint that another peer could connect to. |
| handle_call/3 | Default gen_server API. |
| handle_cast/2 | Default gen_server API. |
| handle_info/2 | Receives UDP datagrams from gen_udp server and spawns a subsidiary
process to manage it. |
| init/1 | Initialises the peer_worker and associated UDP port. |
| pid_to_port/1 | Looks up the port for a given pid. |
| start_link/2 | Start the peer with given port number and ppspp options which includes the root hash and chunk addressing specification. |
| stop/1 | Stops the server, given a corresponding UDP port. |
| terminate/2 | Closes down the peer_worker. |
| where_is/1 | Looks up the pid for a given port Returns an error tuple if the port cannot be found in the registry. |
Function Details
code_change/3
code_change(OldVsn :: term(), State :: [state()], Extra :: term()) ->{ok, [state()]}
Default gen_server API.
get_url/1
get_url(Port :: inet:port_number()) -> {ok, string()}
Create a URL for this endpoint that another peer could connect to.
As there is no official spec for URLs yet, I made one up. See url.md.
A simple example is ppspp://example.net:7777/c89800bf
handle_call/3
handle_call(Message :: any(),From :: {pid(), any()},State :: [state()]) ->{reply, ok, state()}
Default gen_server API.
handle_cast/2
handle_cast(Message :: stop | any(), State :: [state()]) ->{noreply, state()}
Default gen_server API.
handle_info/2
handle_info(Packet :: term(), State :: [state()]) ->{noreply, [state()]} |{stop, {error, term()}, term()}
Receives UDP datagrams from gen_udp server and spawns a subsidiary
process to manage it. Returns noreply tuple.
init/1
init(X1 :: [inet:port_number() | ppspp_options:options()]) ->{ok, [state()]}
Initialises the peer_worker and associated UDP port.
Registers the worker with provided swarm options and UDP port in gproc.
pid_to_port/1
pid_to_port(Pid :: pid()) ->{ok, inet:port_number()} | {error, term()}
Looks up the port for a given pid. Returns an error tuple if the port cannot be found in the registry.
start_link/2
start_link(Port :: inet:port_number(),Swarm_Options :: ppspp_options:options()) ->ignore | {error, term()} | {ok, pid()}
Start the peer with given port number and ppspp options which includes the root hash and chunk addressing specification. These are required during subsequent packet parsing, even if the peer itself supports multiple swarms.
stop/1
stop(Port :: inet:port_number()) -> ok | {error, any()}
Stops the server, given a corresponding UDP port. Returns an error tuple if the port is no longer active.
terminate/2
terminate(Reason :: term(), X2 :: [state()]) -> ok
Closes down the peer_worker. Returns reason and brief statistics.
where_is/1
where_is(Port :: inet:port_number()) ->{ok, pid()} | {error, term()}
Looks up the pid for a given port Returns an error tuple if the port cannot be found in the registry.