Class: EventMachine::Connection
- Inherits:
-
Object
- Object
- EventMachine::Connection
- Defined in:
- lib/em/connection.rb
Overview
EventMachine::Connection is a class that is instantiated by EventMachine's processing loop whenever a new connection is created. (New connections can be either initiated locally to a remote server or accepted locally from a remote client.) When a Connection object is instantiated, it mixes in the functionality contained in the user-defined module specified in calls to connect or start_server. User-defined handler modules may redefine any or all of the standard methods defined here, as well as add arbitrary additional code that will also be mixed in.
EventMachine manages one object inherited from EventMachine::Connection (and containing the mixed-in user code) for every network connection that is active at any given time. The event loop will automatically call methods on EventMachine::Connection objects whenever specific events occur on the corresponding connections, as described below.
This class is never instantiated by user code, and does not publish an initialize method. The instance methods of EventMachine::Connection which may be called by the event loop are:
- #post_init
- #connection_completed
- #receive_data
- #unbind
- #ssl_verify_peer (if TLS is used)
- #ssl_handshake_completed
All of the other instance methods defined here are called only by user code.
Direct Known Subclasses
DNS::Socket, DeferrableChildProcess, FileWatch, ProcessWatch, Protocols::HeaderAndContentProtocol, Protocols::HttpClient, Protocols::HttpClient2, Protocols::LineAndTextProtocol, Protocols::Postgres3, Protocols::SmtpClient, Protocols::SmtpServer, Protocols::Socks4
Instance Method Summary collapse
-
#close_connection(after_writing = false) ⇒ Object
EventMachine::Connection#close_connection is called only by user code, and never by the event loop.
-
#close_connection_after_writing ⇒ Object
A variant of #close_connection.
-
#comm_inactivity_timeout ⇒ Object
comm_inactivity_timeout returns the current value (float in seconds) of the inactivity-timeout property of network-connection and datagram-socket objects.
-
#comm_inactivity_timeout=(value) ⇒ Object
(also: #set_comm_inactivity_timeout)
Allows you to set the inactivity-timeout property for a network connection or datagram socket.
-
#connection_completed ⇒ Object
Called by the event loop when a remote TCP connection attempt completes successfully.
-
#detach ⇒ Object
Removes given connection from the event loop.
-
#error? ⇒ Boolean
Returns true if the connection is in an error state, false otherwise.
-
#get_idle_time ⇒ Object
The number of seconds since the last send/receive activity on this connection.
-
#get_peer_cert ⇒ String
If TLS is active on the connection, returns the remote X509 certificate as a string, in the popular PEM format.
-
#get_peername ⇒ Object
This method is used with stream-connections to obtain the identity of the remotely-connected peer.
-
#get_pid ⇒ Integer
Returns the PID (kernel process identifier) of a subprocess associated with this Connection object.
-
#get_proxied_bytes ⇒ Object
The number of bytes proxied to another connection.
- #get_sock_opt(level, option) ⇒ Object
-
#get_sockname ⇒ Object
Used with stream-connections to obtain the identity of the local side of the connection.
-
#get_status ⇒ Integer
Returns a subprocess exit status.
-
#notify_readable=(mode) ⇒ Object
Watches connection for readability.
-
#notify_readable? ⇒ Boolean
True if the connection is being watched for readability.
-
#notify_writable=(mode) ⇒ Object
Watches connection for writeability.
-
#notify_writable? ⇒ Boolean
Returns true if the connection is being watched for writability.
-
#pause ⇒ Object
Pause a connection so that #send_data and #receive_data events are not fired until #resume is called.
-
#paused? ⇒ Boolean
True if the connect was paused using #pause.
-
#pending_connect_timeout ⇒ Float
The duration after which a TCP connection in the connecting state will fail.
-
#pending_connect_timeout=(value) ⇒ Object
(also: #set_pending_connect_timeout)
Sets the duration after which a TCP connection in a connecting state will fail.
-
#post_init ⇒ Object
Called by the event loop immediately after the network connection has been established, and before resumption of the network loop.
-
#proxy_completed ⇒ Object
called when the reactor finished proxying all of the requested bytes.
-
#proxy_incoming_to(conn, bufsize = 0) ⇒ Object
EventMachine::Connection#proxy_incoming_to is called only by user code.
-
#proxy_target_unbound ⇒ Object
Called by the reactor after attempting to relay incoming data to a descriptor (set as a proxy target descriptor with enable_proxy) that has already been closed.
-
#receive_data(data) ⇒ Object
Called by the event loop whenever data has been received by the network connection.
-
#reconnect(server, port) ⇒ Object
Reconnect to a given host/port with the current instance.
-
#resume ⇒ Object
Resume a connection's #send_data and #receive_data events.
-
#send_data(data) ⇒ Object
Call this method to send data to the remote end of the network connection.
-
#send_datagram(data, recipient_address, recipient_port) ⇒ Object
Sends UDP messages.
-
#send_file_data(filename) ⇒ Object
Like #send_data, this sends data to the remote end of the network connection.
- #set_sock_opt(level, optname, optval) ⇒ Object
-
#ssl_handshake_completed ⇒ Object
Called by EventMachine when the SSL/TLS handshake has been completed, as a result of calling #start_tls to initiate SSL/TLS on the connection.
-
#ssl_verify_peer(cert) ⇒ Object
Called by EventMachine when :verify_peer => true has been passed to #start_tls.
-
#start_tls(args = {}) ⇒ Object
Call #start_tls at any point to initiate TLS encryption on connected streams.
-
#stop_proxying ⇒ Object
A helper method for disable_proxy.
-
#stream_file_data(filename, args = {}) ⇒ EventMachine::Deferrable
Open a file on the filesystem and send it to the remote peer.
-
#unbind ⇒ Object
called by the framework whenever a connection (either a server or client connection) is closed.
Instance Method Details
#close_connection(after_writing = false) ⇒ Object
EventMachine::Connection#close_connection is called only by user code, and never by the event loop. You may call this method against a connection object in any callback handler, whether or not the callback was made against the connection you want to close. close_connection schedules the connection to be closed at the next available opportunity within the event loop. You may not assume that the connection is closed when close_connection returns. In particular, the framework will callback the unbind method for the particular connection at a point shortly after you call close_connection. You may assume that the unbind callback will take place sometime after your call to close_connection completes. In other words, the unbind callback will not re-enter your code "inside" of your call to close_connection. However, it's not guaranteed that a future version of EventMachine will not change this behavior.
#close_connection will silently discard any outbound data which you have sent to the connection using #send_data but which has not yet been sent across the network. If you want to avoid this behavior, use #close_connection_after_writing.
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# File 'lib/em/connection.rb', line 265 def close_connection after_writing = false EventMachine::close_connection @signature, after_writing end |
#close_connection_after_writing ⇒ Object
A variant of #close_connection. All of the descriptive comments given for close_connection also apply to close_connection_after_writing, with one exception: if the connection has outbound data sent using send_dat but which has not yet been sent across the network, close_connection_after_writing will schedule the connection to be closed after all of the outbound data has been safely written to the remote peer.
Depending on the amount of outgoing data and the speed of the network, considerable time may elapse between your call to close_connection_after_writing and the actual closing of the socket (at which time the unbind callback will be called by the event loop). During this time, you may not call send_data to transmit additional data (that is, the connection is closed for further writes). In very rare cases, you may experience a receive_data callback after your call to #close_connection_after_writing, depending on whether incoming data was in the process of being received on the connection at the moment when you called #close_connection_after_writing. Your protocol handler must be prepared to properly deal with such data (probably by ignoring it).
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# File 'lib/em/connection.rb', line 302 def close_connection_after_writing close_connection true end |
#comm_inactivity_timeout ⇒ Object
comm_inactivity_timeout returns the current value (float in seconds) of the inactivity-timeout property of network-connection and datagram-socket objects. A nonzero value indicates that the connection or socket will automatically be closed if no read or write activity takes place for at least that number of seconds. A zero value (the default) specifies that no automatic timeout will take place.
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# File 'lib/em/connection.rb', line 589 def comm_inactivity_timeout EventMachine::get_comm_inactivity_timeout @signature end |
#comm_inactivity_timeout=(value) ⇒ Object Also known as: set_comm_inactivity_timeout
Allows you to set the inactivity-timeout property for a network connection or datagram socket. Specify a non-negative float value in seconds. If the value is greater than zero, the connection or socket will automatically be closed if no read or write activity takes place for at least that number of seconds. Specify a value of zero to indicate that no automatic timeout should take place. Zero is the default value.
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# File 'lib/em/connection.rb', line 599 def comm_inactivity_timeout= value EventMachine::set_comm_inactivity_timeout @signature, value.to_f end |
#connection_completed ⇒ Object
Called by the event loop when a remote TCP connection attempt completes successfully. You can expect to get this notification after calls to EventMachine.connect. Remember that EventMachine makes remote connections asynchronously, just as with any other kind of network event. This method is intended primarily to assist with network diagnostics. For normal protocol handling, use #post_init to perform initial work on a new connection (such as sending initial set of data). #post_init will always be called. This method will only be called in case of a successful completion. A connection attempt which fails will result a call to #unbind after the failure.
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# File 'lib/em/connection.rb', line 362 def connection_completed end |
#detach ⇒ Object
Removes given connection from the event loop. The connection's socket remains open and its file descriptor number is returned.
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# File 'lib/em/connection.rb', line 271 def detach EventMachine::detach_fd @signature end |
#error? ⇒ Boolean
Returns true if the connection is in an error state, false otherwise.
In general, you can detect the occurrence of communication errors or unexpected disconnection by the remote peer by handing the #unbind method. In some cases, however, it's useful to check the status of the connection using #error? before attempting to send data. This function is synchronous but it will return immediately without blocking.
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# File 'lib/em/connection.rb', line 339 def error? errno = EventMachine::report_connection_error_status(@signature) case errno when 0 false when -1 true else EventMachine::ERRNOS[errno] end end |
#get_idle_time ⇒ Object
The number of seconds since the last send/receive activity on this connection.
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# File 'lib/em/connection.rb', line 580 def get_idle_time EventMachine::get_idle_time @signature end |
#get_peer_cert ⇒ String
If TLS is active on the connection, returns the remote X509 certificate as a string, in the popular PEM format. This can then be used for arbitrary validation of a peer's certificate in your code.
This should be called in/after the #ssl_handshake_completed callback, which indicates that SSL/TLS is active. Using this callback is important, because the certificate may not be available until the time it is executed. Using #post_init or #connection_completed is not adequate, because the SSL handshake may still be taking place.
This method will return nil
if:
- EventMachine is not built with OpenSSL support
- TLS is not active on the connection
- TLS handshake is not yet complete
- Remote peer for any other reason has not presented a certificate
You can do whatever you want with the certificate String, such as load it as a certificate object using the OpenSSL library, and check its fields.
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# File 'lib/em/connection.rb', line 487 def get_peer_cert EventMachine::get_peer_cert @signature end |
#get_peername ⇒ Object
This method is used with stream-connections to obtain the identity of the remotely-connected peer. If a peername is available, this method returns a sockaddr structure. The method returns nil if no peername is available. You can use Socket.unpack_sockaddr_in and its variants to obtain the values contained in the peername structure returned from #get_peername.
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# File 'lib/em/connection.rb', line 538 def get_peername EventMachine::get_peername @signature end |
#get_pid ⇒ Integer
Returns the PID (kernel process identifier) of a subprocess associated with this Connection object. For use with EventMachine.popen and similar methods. Returns nil when there is no meaningful subprocess.
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# File 'lib/em/connection.rb', line 567 def get_pid EventMachine::get_subprocess_pid @signature end |
#get_proxied_bytes ⇒ Object
The number of bytes proxied to another connection. Reset to zero when EventMachine::Connection#proxy_incoming_to is called, and incremented whenever data is proxied.
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# File 'lib/em/connection.rb', line 243 def get_proxied_bytes EventMachine::get_proxied_bytes(@signature) end |
#get_sock_opt(level, option) ⇒ Object
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# File 'lib/em/connection.rb', line 275 def get_sock_opt level, option EventMachine::get_sock_opt @signature, level, option end |
#get_sockname ⇒ Object
Used with stream-connections to obtain the identity of the local side of the connection. If a local name is available, this method returns a sockaddr structure. The method returns nil if no local name is available. You can use Socket.unpack_sockaddr_in and its variants to obtain the values contained in the local-name structure returned from this method.
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# File 'lib/em/connection.rb', line 558 def get_sockname EventMachine::get_sockname @signature end |
#get_status ⇒ Integer
Returns a subprocess exit status. Only useful for EventMachine.popen. Call it in your #unbind handler.
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# File 'lib/em/connection.rb', line 575 def get_status EventMachine::get_subprocess_status @signature end |
#notify_readable=(mode) ⇒ Object
Watches connection for readability. Only possible if the connection was created using EventMachine.attach and had EventMachine.notify_readable/EventMachine.notify_writable defined on the handler.
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# File 'lib/em/connection.rb', line 671 def notify_readable= mode EventMachine::set_notify_readable @signature, mode end |
#notify_readable? ⇒ Boolean
Returns true if the connection is being watched for readability.
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# File 'lib/em/connection.rb', line 676 def notify_readable? EventMachine::is_notify_readable @signature end |
#notify_writable=(mode) ⇒ Object
Watches connection for writeability. Only possible if the connection was created using EventMachine.attach and had EventMachine.notify_readable/EventMachine.notify_writable defined on the handler.
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# File 'lib/em/connection.rb', line 684 def notify_writable= mode EventMachine::set_notify_writable @signature, mode end |
#notify_writable? ⇒ Boolean
Returns true if the connection is being watched for writability.
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# File 'lib/em/connection.rb', line 689 def notify_writable? EventMachine::is_notify_writable @signature end |
#pause ⇒ Object
Pause a connection so that #send_data and #receive_data events are not fired until #resume is called.
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# File 'lib/em/connection.rb', line 695 def pause EventMachine::pause_connection @signature end |
#paused? ⇒ Boolean
Returns true if the connect was paused using #pause.
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# File 'lib/em/connection.rb', line 708 def paused? EventMachine::connection_paused? @signature end |
#pending_connect_timeout ⇒ Float
The duration after which a TCP connection in the connecting state will fail. It is important to distinguish this value from #comm_inactivity_timeout, which looks at how long since data was passed on an already established connection. The value is a float in seconds.
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# File 'lib/em/connection.rb', line 610 def pending_connect_timeout EventMachine::get_pending_connect_timeout @signature end |
#pending_connect_timeout=(value) ⇒ Object Also known as: set_pending_connect_timeout
Sets the duration after which a TCP connection in a connecting state will fail.
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# File 'lib/em/connection.rb', line 618 def pending_connect_timeout= value EventMachine::set_pending_connect_timeout @signature, value.to_f end |
#post_init ⇒ Object
Called by the event loop immediately after the network connection has been established, and before resumption of the network loop. This method is generally not called by user code, but is called automatically by the event loop. The base-class implementation is a no-op. This is a very good place to initialize instance variables that will be used throughout the lifetime of the network connection.
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# File 'lib/em/connection.rb', line 81 def post_init end |
#proxy_completed ⇒ Object
called when the reactor finished proxying all of the requested bytes.
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# File 'lib/em/connection.rb', line 224 def proxy_completed end |
#proxy_incoming_to(conn, bufsize = 0) ⇒ Object
EventMachine::Connection#proxy_incoming_to is called only by user code. It sets up a low-level proxy relay for all data inbound for this connection, to the connection given as the argument. This is essentially just a helper method for enable_proxy.
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# File 'lib/em/connection.rb', line 232 def proxy_incoming_to(conn,bufsize=0) EventMachine::enable_proxy(self, conn, bufsize) end |
#proxy_target_unbound ⇒ Object
Called by the reactor after attempting to relay incoming data to a descriptor (set as a proxy target descriptor with EventMachine.enable_proxy) that has already been closed.
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# File 'lib/em/connection.rb', line 219 def proxy_target_unbound end |
#receive_data(data) ⇒ Object
Depending on the protocol, buffer sizes and OS networking stack configuration, incoming data may or may not be "a complete message". It is up to this handler to detect content boundaries to determine whether all the content (for example, full HTTP request) has been received and can be processed.
Called by the event loop whenever data has been received by the network connection. It is never called by user code. #receive_data is called with a single parameter, a String containing the network protocol data, which may of course be binary. You will generally redefine this method to perform your own processing of the incoming data.
Here's a key point which is essential to understanding the event-driven programming model: EventMachine knows absolutely nothing about the protocol which your code implements. You must not make any assumptions about the size of the incoming data packets, or about their alignment on any particular intra-message or PDU boundaries (such as line breaks). receive_data can and will send you arbitrary chunks of data, with the only guarantee being that the data is presented to your code in the order it was collected from the network. Don't even assume that the chunks of data will correspond to network packets, as EventMachine can and will coalesce several incoming packets into one, to improve performance. The implication for your code is that you generally will need to implement some kind of a state machine in your redefined implementation of receive_data. For a better understanding of this, read through the examples of specific protocol handlers in EventMachine::Protocols
The base-class implementation (which will be invoked only if you didn't override it in your protocol handler) simply prints incoming data packet size to stdout.
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# File 'lib/em/connection.rb', line 116 def receive_data data puts "............>>>#{data.length}" end |
#reconnect(server, port) ⇒ Object
Reconnect to a given host/port with the current instance
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# File 'lib/em/connection.rb', line 627 def reconnect server, port EventMachine::reconnect server, port, self end |
#resume ⇒ Object
Resume a connection's #send_data and #receive_data events.
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# File 'lib/em/connection.rb', line 701 def resume EventMachine::resume_connection @signature end |
#send_data(data) ⇒ Object
Call this method to send data to the remote end of the network connection. It takes a single String argument, which may contain binary data. Data is buffered to be sent at the end of this event loop tick (cycle).
When used in a method that is event handler (for example, #post_init or #connection_completed, it will send data to the other end of the connection that generated the event. You can also call #send_data to write to other connections. For more information see The Chat Server Example in the EventMachine tutorial.
If you want to send some data and then immediately close the connection, make sure to use #close_connection_after_writing instead of #close_connection.
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# File 'lib/em/connection.rb', line 324 def send_data data data = data.to_s size = data.bytesize if data.respond_to?(:bytesize) size ||= data.size EventMachine::send_data @signature, data, size end |
#send_datagram(data, recipient_address, recipient_port) ⇒ Object
Sends UDP messages.
This method may be called from any Connection object that refers to an open datagram socket (see EventMachine#open_datagram_socket). The method sends a UDP (datagram) packet containing the data you specify, to a remote peer specified by the IP address and port that you give as parameters to the method. Observe that you may send a zero-length packet (empty string). However, you may not send an arbitrarily-large data packet because your operating system will enforce a platform-specific limit on the size of the outbound packet. (Your kernel will respond in a platform-specific way if you send an overlarge packet: some will send a truncated packet, some will complain, and some will silently drop your request). On LANs, it's usually OK to send datagrams up to about 4000 bytes in length, but to be really safe, send messages smaller than the Ethernet-packet size (typically about 1400 bytes). Some very restrictive WANs will either drop or truncate packets larger than about 500 bytes.
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# File 'lib/em/connection.rb', line 514 def send_datagram data, recipient_address, recipient_port data = data.to_s size = data.bytesize if data.respond_to?(:bytesize) size ||= data.size EventMachine::send_datagram @signature, data, size, recipient_address, Integer(recipient_port) end |
#send_file_data(filename) ⇒ Object
Like #send_data, this sends data to the remote end of the network connection. #send_file_data takes a filename as an argument, though, and sends the contents of the file, in one chunk.
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# File 'lib/em/connection.rb', line 641 def send_file_data filename EventMachine::send_file_data @signature, filename end |
#set_sock_opt(level, optname, optval) ⇒ Object
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# File 'lib/em/connection.rb', line 279 def set_sock_opt level, optname, optval EventMachine::set_sock_opt @signature, level, optname, optval end |
#ssl_handshake_completed ⇒ Object
Called by EventMachine when the SSL/TLS handshake has been completed, as a result of calling #start_tls to initiate SSL/TLS on the connection.
This callback exists because #post_init and #connection_completed are not reliable for indicating when an SSL/TLS connection is ready to have its certificate queried for.
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# File 'lib/em/connection.rb', line 127 def ssl_handshake_completed end |
#ssl_verify_peer(cert) ⇒ Object
Called by EventMachine when :verify_peer => true has been passed to #start_tls. It will be called with each certificate in the certificate chain provided by the remote peer.
The cert will be passed as a String in PEM format, the same as in #get_peer_cert. It is up to user defined code to perform a check on the certificates. The return value from this callback is used to accept or deny the peer. A return value that is not nil or false triggers acceptance. If the peer is not accepted, the connection will be subsequently closed.
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# File 'lib/em/connection.rb', line 174 def ssl_verify_peer(cert) end |
#start_tls(args = {}) ⇒ Object
support passing an encryption parameter, which can be string or Proc, to get a passphrase
support passing key material via raw strings or Procs that return strings instead of
Call #start_tls at any point to initiate TLS encryption on connected streams. The method is smart enough to know whether it should perform a server-side or a client-side handshake. An appropriate place to call #start_tls is in your redefined #post_init method, or in the #connection_completed handler for an outbound connection.
for encrypted private keys. just filenames.
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# File 'lib/em/connection.rb', line 406 def start_tls args={} priv_key, cert_chain, verify_peer = args.values_at(:private_key_file, :cert_chain_file, :verify_peer) [priv_key, cert_chain].each do |file| next if file.nil? or file.empty? raise FileNotFoundException, "Could not find #{file} for start_tls" unless File.exists? file end EventMachine::set_tls_parms(@signature, priv_key || '', cert_chain || '', verify_peer) EventMachine::start_tls @signature end |
#stop_proxying ⇒ Object
A helper method for EventMachine.disable_proxy
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# File 'lib/em/connection.rb', line 237 def EventMachine::disable_proxy(self) end |
#stream_file_data(filename, args = {}) ⇒ EventMachine::Deferrable
Open a file on the filesystem and send it to the remote peer. This returns an object of type Deferrable. The object's callbacks will be executed on the reactor main thread when the file has been completely scheduled for transmission to the remote peer. Its errbacks will be called in case of an error (such as file-not-found). This method employs various strategies to achieve the fastest possible performance, balanced against minimum consumption of memory.
Warning: this feature has an implicit dependency on an outboard extension, evma_fastfilereader. You must install this extension in order to use #stream_file_data with files larger than a certain size (currently 8192 bytes).
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# File 'lib/em/connection.rb', line 663 def stream_file_data filename, args={} EventMachine::FileStreamer.new( self, filename, args ) end |
#unbind ⇒ Object
called by the framework whenever a connection (either a server or client connection) is closed. The close can occur because your code intentionally closes it (using #close_connection and #close_connection_after_writing), because the remote peer closed the connection, or because of a network error. You may not assume that the network connection is still open and able to send or receive data when the callback to unbind is made. This is intended only to give you a chance to clean up associations your code may have made to the connection object while it was open.
If you want to detect which peer has closed the connection, you can override #close_connection in your protocol handler and set an @ivar.
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# File 'lib/em/connection.rb', line 212 def unbind end |