unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (Debian-5.0)
Page:
Section:
Apropos / Subsearch:
optional field

libapache2-mod-perl2-2UsleirbaCpoancthrei2b-umtoedd-pPeerrll2-D2o.c0u.m4e:n:tdaotcis::api::APR::Socket(3pm)



NAME
       APR::Socket - Perl API for APR sockets

Synopsis
         use APR::Socket ();

         ### set the socket to the blocking mode if it isn't already
         ### and read in the loop and echo it back
         use APR::Const -compile => qw(SO_NONBLOCK);
         if ($sock->opt_get(APR::Const::SO_NONBLOCK)) {
             $sock->opt_set(APR::Const::SO_NONBLOCK => 0);
         }
         # read from/write to the socket (w/o handling possible failures)
         my $wanted = 1024;
         while ($sock->recv(my $buff, $wanted)) {
             $sock->send($buff);
         }

         ### get/set IO timeout and try to read some data
         use APR::Const -compile => qw(TIMEUP);
         # timeout is in usecs!
         my $timeout = $sock->timeout_get();
         if ($timeout < 10_000_000) {
             $sock->timeout_set(20_000_000); # 20 secs
         }
         # now read, while handling timeouts
         my $wanted = 1024;
         my $buff;
         my $rlen = eval { $sock->recv($buff, $wanted) };
         if ($@ && ref $@ && $@ == APR::Const::TIMEUP) {
             # timeout, do something, e.g.
             warn "timed out, will try again later";
         }
         else {
             warn "asked for $wanted bytes, read $rlen bytes\n";
             # do something with the data
         }

         # non-blocking io poll
         $sock->opt_set(APR::Const::SO_NONBLOCK => 1);
         my $rc = $sock->poll($c->pool, 1_000_000, APR::Const::POLLIN);
         if ($rc == APR::Const::SUCCESS) {
             # read the data
         }
         else {
             # handle the condition
         }

Description
       "APR::Socket" provides the Perl interface to APR sockets.

API
       "APR::Socket" provides the following methods:

   "opt_get"
       Query socket options for the specified socket

         $val = $sock->opt_get($opt);

       obj: $sock ( "APR::Socket object" )
           the socket object to query

       arg1: $opt ( "APR::Const constant" )
           the socket option we would like to configure.  Here are the
           available socket options.

       ret: $val ( integer )
           the currently set value for the socket option you've queried for

       excpt: "APR::Error"
       since: 2.0.00

       Examples can be found in the socket options constants section. For
       example setting the IO to the blocking mode.

   "opt_set"
       Setup socket options for the specified socket

         $sock->opt_set($opt, $val);

       obj: $sock ( "APR::Socket object" object )
           the socket object to set up.

       arg1: $opt ( "APR::Const" constant )
           the socket option we would like to configure.  Here are the
           available socket options.

       arg2: $val ( integer )
           value for the option. Refer to the socket options section to learn
           about the expected values.

       ret: no return value
       excpt: "APR::Error"
       since: 2.0.00

       Examples can be found in the socket options constants section. For
       example setting the IO to the blocking mode.

   "poll"
       Poll the socket for events:

           $rc = $sock->poll($pool, $timeout, $events);

       obj: $sock ( "APR::Socket object" )
           The socket to poll

       arg1: $pool ( "APR::Pool object" )
           usually "$c->pool".

       arg2: $timeout ( integer )
           The amount of time to wait (in milliseconds) for the specified
           events to occur.

       arg3: $events ( "APR::Const :poll constants" )
           The events for which to wait.

           For example use "APR::Const::POLLIN" to wait for incoming data to
           be available, "APR::Const::POLLOUT" to wait until it's possible to
           write data to the socket and "APR::Const::POLLPRI" to wait for
           priority data to become available.

       ret: $rc ( "APR::Const constant" )
           If "APR::Const::SUCCESS" is received than the polling was
           successful. If not -- the error code is returned, which can be
           converted to the error string with help of "APR::Error::strerror".

       since: 2.0.00

       For example poll a non-blocking socket up to 1 second when reading data
       from the client:

         use APR::Socket ();
         use APR::Connection ();
         use APR::Error ();

         use APR::Const -compile => qw(SO_NONBLOCK POLLIN SUCCESS TIMEUP);

         $sock->opt_set(APR::Const::SO_NONBLOCK => 1);

         my $rc = $sock->poll($c->pool, 1_000_000, APR::Const::POLLIN);
         if ($rc == APR::Const::SUCCESS) {
             # Data is waiting on the socket to be read.
             # $sock->recv(my $buf, BUFF_LEN)
         }
         elsif ($rc == APR::Const::TIMEUP) {
             # One second elapsed and still there is no data waiting to be
             # read. for example could try again.
         }
         else {
             die "poll error: " . APR::Error::strerror($rc);
         }

   "recv"
       Read incoming data from the socket

         $len = $sock->recv($buffer, $wanted);

       obj: $sock ( "APR::SockAddr object" object )
           The socket to read from

       arg1: $buffer ( SCALAR )
           The buffer to fill. All previous data will be lost.

       arg2: $wanted ( int )
           How many bytes to attempt to read.

       ret: $len ( number )
           How many bytes were actually read.

           $buffer gets populated with the string that is read. It will
           contain an empty string if there was nothing to read.

       excpt: "APR::Error"
           If you get the '(11) Resource temporarily unavailable' error
           (exception "APR::Const::EAGAIN") (or another equivalent, which
           might be different on non-POSIX systems), then you didn't ensure
           that the socket is in a blocking IO mode before using it. Note that
           you should use "APR::Status::is_EAGAIN" to perform this check
           (since different error codes may be returned for the same event on
           different OSes). For example if the socket is set to the non-
           blocking mode and there is no data right away, you may get this
           exception thrown. So here is how to check for it and retry a few
           times after short delays:

             use APR::Status ();
             $sock->opt_set(APR::Const::SO_NONBLOCK, 1);
             # ....
             my $tries = 0;
             my $buffer;
             RETRY: my $rlen = eval { $socket->recv($buffer, SIZE) };
             if ($@)
                 die $@ unless ref $@ && APR::Status::is_EAGAIN($@);
                 if ($tries++ < 3) {
                     # sleep 250msec
                     select undef, undef, undef, 0.25;
                     goto RETRY;
                 }
                 else {
                     # do something else
                 }
             }
             warn "read $rlen bytes\n"

           If timeout was set via "timeout_set|/C_timeout_set_", you may need
           to catch the "APR::Const::TIMEUP" exception. For example:

             use APR::Const -compile => qw(TIMEUP);
             $sock->timeout_set(1_000_000); # 1 sec
             my $buffer;
             eval { $sock->recv($buffer, $wanted) };
             if ($@ && $@ == APR::Const::TIMEUP) {
                 # timeout, do something, e.g.
             }

           If not handled -- you may get the error '70007: The timeout
           specified has expired'.

           Another error condition that may occur is the '(104) Connection
           reset by peer' error, which is up to your application logic to
           decide whether it's an error or not. This error usually happens
           when the client aborts the connection.

             use APR::Const -compile => qw(ECONNABORTED);
             my $buffer;
             eval { $sock->recv($buffer, $wanted) };
             if ($@ == APR::Const::ECONNABORTED) {
                 # ignore it or deal with it
             }

       since: 2.0.00

       Here is the quick prototype example, which doesn't handle any errors
       (mod_perl will do that for you):

         use APR::Socket ();

         # set the socket to the blocking mode if it isn't already
         use APR::Const -compile => qw(SO_NONBLOCK);
         if ($sock->opt_get(APR::Const::SO_NONBLOCK)) {
             $sock->opt_set(APR::Const::SO_NONBLOCK => 0);
         }
         # read from/write to the socket (w/o handling possible failures)
         my $wanted = 1024;
         while ($sock->recv(my $buffer, $wanted)) {
             $sock->send($buffer);
         }

       If you want to handle errors by yourself, the loop may look like:

         use APR::Const -compile => qw(ECONNABORTED);
         # ...
         while (1) {
             my $buf;
             my $len = eval { $sock->recv($buf, $wanted) };
             if ($@) {
                 # handle the error, e.g. to ignore aborted connections but
                 # rethrow any other errors:
                 if ($@ == APR::Const::ECONNABORTED) {
                     # ignore
                     last;
                 }
                 else {
                     die $@; # retrow
                 }
             }

             if ($len) {
                 $sock->send($buffer);
             }
             else {
                 last;
             }
         }

   "send"
       Write data to the socket

         $wlen = $sock->send($buf, $opt_len);

       obj: $sock ( "APR::Socket object" )
           The socket to write to

       arg1: $buf ( scalar )
           The data to send

       opt arg2: $opt_len ( int )
           There is no need to pass this argument, unless you want to send
           less data than contained in $buf.

       ret: $wlen ( integer )
           How many bytes were sent

       since: 2.0.00

       For examples see the "recv" item.

   "timeout_get"
       Get socket timeout settings

         $usecs = $sock->timeout_get();

       obj: $sock ( "APR::Socket object" )
           The socket to set up.

       ret: $usecs ( number)
           Currently set timeout in microseconds (and also the blocking IO
           behavior). See ("APR::timeout_set") for possible values and their
           meaning.

       excpt: "APR::Error"
       since: 2.0.00

   "timeout_set"
       Setup socket timeout.

         $sock->timeout_set($usecs);

       obj: $sock ( "APR::Socket object" )
           The socket to set up.

       arg1: $usecs ( number )
           Value for the timeout in microseconds and also the blocking IO
           behavior.

           The possible values are:

           t > 0
               "send()" and "recv()" throw ("APR::Const::TIMEUP" exception) if
               specified time elapses with no data sent or received.

               Notice that the positive value is in micro seconds. So if you
               want to set the timeout for 5 seconds, the value should be:
               5_000_000.

               This mode sets the socket into a non-blocking IO mode.

           t == 0
               "send()" and "recv()" calls never block.

           t < 0
               "send()" and "recv()" calls block.

               Usually just -1 is used for this case, but any negative value
               will do.

               This mode sets the socket into a blocking IO mode.

           ret: no return value
       excpt: "APR::Error"
       since: 2.0.00

Unsupported API
       "APR::Socket" also provides auto-generated Perl interface for a few
       other methods which aren't tested at the moment and therefore their API
       is a subject to change. These methods will be finalized later as a need
       arises. If you want to rely on any of the following methods please
       contact the the mod_perl development mailing list so we can help each
       other take the steps necessary to shift the method to an officially
       supported API.

   "bind"
       META: Autogenerated - needs to be reviewed/completed

       Bind the socket to its associated port

         $ret = $sock->bind($sa);

       obj: $sock ( "APR::Socket object" )
           The socket to bind

       arg1: $sa ( "APR::SockAddr object" )
           The socket address to bind to

       ret: $ret ( integer )
       since: subject to change

       This may be where we will find out if there is any other process using
       the selected port.

   "close"
       META: Autogenerated - needs to be reviewed/completed

       Close a socket.

         $ret = $sock->close();

       obj: $sock ( "APR::Socket object" )
           The socket to close

       ret: $ret ( integer )
       since: subject to change

   "connect"
       META: Autogenerated - needs to be reviewed/completed

       Issue a connection request to a socket either on the same machine or a
       different one.

         $ret = $sock->connect($sa);

       obj: $sock ( "APR::Socket object" )
           The socket we wish to use for our side of the connection

       arg1: $sa ( "APR::SockAddr object" )
           The address of the machine we wish to connect to.  If NULL, APR
           assumes that the sockaddr_in in the apr_socket is completely filled
           out.

       ret: $ret ( integer )
       since: subject to change

   "listen"
       META: Autogenerated - needs to be reviewed/completed

       Listen to a bound socket for connections.

         $ret = $sock->listen($backlog);

       obj: $sock ( "APR::Socket object" )
           The socket to listen on

       arg1: $backlog ( integer )
           The number of outstanding connections allowed in the sockets listen
           queue.  If this value is less than zero, the listen queue size is
           set to zero.

       ret: $ret ( integer )
       since: subject to change

   "recvfrom"
       META: Autogenerated - needs to be reviewed/completed

         $ret = $from->recvfrom($sock, $flags, $buf, $len);

       obj: $from ( "APR::SockAddr object" )
           The apr_sockaddr_t to fill in the recipient info

       arg1: $sock ( "APR::SockAddr object" )
           The socket to use

       arg2: $flags ( integer )
           The flags to use

       arg3: $buf ( integer )
           The buffer to use

       arg4: $len ( string )
           The length of the available buffer

       ret: $ret ( integer )
       since: subject to change

   "sendto"
       META: Autogenerated - needs to be reviewed/completed

         $ret = $sock->sendto($where, $flags, $buf, $len);

       obj: $sock ( "APR::Socket object" )
           The socket to send from

       arg1: $where ( "APR::Socket object" )
           The apr_sockaddr_t describing where to send the data

       arg2: $flags ( integer )
           The flags to use

       arg3: $buf ( scalar )
           The data to send

       arg4: $len ( string )
           The length of the data to send

       ret: $ret ( integer )
       since: subject to change

See Also
       mod_perl 2.0 documentation.

Copyright
       mod_perl 2.0 and its core modules are copyrighted under The Apache
       Software License, Version 2.0.

Authors
       The mod_perl development team and numerous contributors.



perl v5.10.0           libapache2-mod-perl2-2.0.4::docs::api::APR::Socket(3pm)