Module: DRb::DRbProtocol
Relationships & Source Files | |
Defined in: | lib/drb/drb.rb, lib/drb/drb.rb |
Overview
Module managing the underlying network protocol(s) used by drb.
By default, drb uses the DRbTCPSocket protocol. Other protocols can be defined. A protocol must define the following class methods:
[open(uri, config)] Open a client connection to the server at uri,
using configuration config. Return a protocol
instance for this connection.
[open_server(uri, config)] Open a server listening at uri,
using configuration config. Return a
protocol instance for this listener.
[uri_option(uri, config)] Take a URI, possibly containing an option
component (e.g. a trailing '?param=val'),
and return a [uri, option] tuple.
All of these methods should raise a DRbBadScheme error if the URI does not identify the protocol they support (e.g. “druby:” for the standard Ruby protocol). This is how the DRbProtocol
module, given a URI, determines which protocol implementation serves that protocol.
The protocol instance returned by #open_server must have the following methods:
- accept
-
Accept a new connection to the server. Returns a protocol instance capable of communicating with the client.
- close
-
Close the server connection.
- uri
-
Get the URI for this server.
The protocol instance returned by #open must have the following methods:
- send_request (ref, msg_id, arg, b)
-
Send a request to
ref
with the given message id and arguments. This is most easily implemented by calling DRbMessage.send_request, providing a stream that sits on top of the current protocol. - recv_reply
-
Receive a reply from the server and return it as a [success-boolean, reply-value] pair. This is most easily implemented by calling DRb.recv_reply, providing a stream that sits on top of the current protocol.
- alive?
-
Is this connection still alive?
- close
-
Close this connection.
The protocol instance returned by #open_server().accept() must have the following methods:
- recv_request
-
Receive a request from the client and return a [object, message, args, block] tuple. This is most easily implemented by calling DRbMessage.recv_request, providing a stream that sits on top of the current protocol.
- send_reply(succ, result)
-
Send a reply to the client. This is most easily implemented by calling DRbMessage.send_reply, providing a stream that sits on top of the current protocol.
- close
-
Close this connection.
A new protocol is registered with the DRbProtocol
module using the add_protocol method.
For examples of other protocols, see DRbUNIXSocket in drb/unix.rb, and HTTP0 in sample/http0.rb and sample/http0serv.rb in the full drb distribution.
Class Method Summary
-
.add_protocol(prot)
mod_func
Add a new protocol to the
DRbProtocol
module. - .open(uri, config, first = true) mod_func
- .open_server(uri, config, first = true) mod_func
-
.uri_option(uri, config, first = true)
mod_func
Parse uri into a [uri, option] pair.
Class Method Details
.add_protocol(prot) (mod_func)
Add a new protocol to the DRbProtocol
module.
# File 'lib/drb/drb.rb', line 725
def add_protocol(prot) @protocol.push(prot) end
.open(uri, config, first = true) (mod_func)
Open a client connection to DRb.uri with the configuration DRb.config.
The DRbProtocol module asks each registered protocol in turn to try to open the URI. Each protocol signals that it does not handle that URI by raising a DRbBadScheme error. If no protocol recognises the URI, then a DRbBadURI error is raised. If a protocol accepts the URI, but an error occurs in opening it, a DRbConnError is raised.
# File 'lib/drb/drb.rb', line 737
def open(uri, config, first=true) @protocol.each do |prot| begin return prot.open(uri, config) rescue DRbBadScheme rescue DRbConnError raise($!) rescue raise(DRbConnError, "#{uri} - #{$!.inspect}") end end if first && (config[:auto_load] != false) auto_load(uri) return open(uri, config, false) end raise DRbBadURI, 'can\'t parse uri:' + uri end
.open_server(uri, config, first = true) (mod_func)
Open a server listening for connections at DRb.uri with configuration DRb.config.
The DRbProtocol module asks each registered protocol in turn to try to open a server at the URI. Each protocol signals that it does not handle that URI by raising a DRbBadScheme error. If no protocol recognises the URI, then a DRbBadURI error is raised. If a protocol accepts the URI, but an error occurs in opening it, the underlying error is passed on to the caller.
# File 'lib/drb/drb.rb', line 765
def open_server(uri, config, first=true) @protocol.each do |prot| begin return prot.open_server(uri, config) rescue DRbBadScheme end end if first && (config[:auto_load] != false) auto_load(uri) return open_server(uri, config, false) end raise DRbBadURI, 'can\'t parse uri:' + uri end
.uri_option(uri, config, first = true) (mod_func)
Parse DRb.uri into a [uri, option] pair.
The DRbProtocol module asks each registered protocol in turn to try to parse the URI. Each protocol signals that it does not handle that URI by raising a DRbBadScheme error. If no protocol recognises the URI, then a DRbBadURI error is raised.
# File 'lib/drb/drb.rb', line 786
def uri_option(uri, config, first=true) @protocol.each do |prot| begin uri, opt = prot.uri_option(uri, config) # opt = nil if opt == '' return uri, opt rescue DRbBadScheme end end if first && (config[:auto_load] != false) auto_load(uri) return uri_option(uri, config, false) end raise DRbBadURI, 'can\'t parse uri:' + uri end