=head1 NAME
APR::Socket - Perl API for APR sockets
=head1 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
}
=head1 Description
C<APR::Socket> provides the Perl interface to APR sockets.
=head1 API
C<APR::Socket> provides the following methods:
=head2 C<opt_get>
Query socket options for the specified socket
$val = $sock->opt_get($opt);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
the socket object to query
=item arg1: C<$opt>
( C<L<APR::Const constant|docs::2.0::api::APR::Const/C__socket_>> )
the socket option we would like to configure. Here are the
L<available socket options|docs::2.0::api::APR::Const/C__socket_>.
=item ret: C<$val> ( integer )
the currently set value for L<the socket
option|docs::2.0::api::APR::Const/C__socket_> you've queried for
=item excpt: C<L<APR::Error|docs::2.0::api::APR::Error>>
=item since: 2.0.00
=back
Examples can be found in L<the socket options constants
section|docs::2.0::api::APR::Const/C__socket_>. For example L<setting
the IO to the blocking
mode|docs::2.0::api::APR::Const/C_APR__Const__SO_NONBLOCK_>.
=head2 C<opt_set>
Setup socket options for the specified socket
$sock->opt_set($opt, $val);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> object )
the socket object to set up.
=item arg1: C<$opt>
( C<L<APR::Const|docs::2.0::api::APR::Const/C__socket_>> constant )
the socket option we would like to configure. Here are the
L<available socket options|docs::2.0::api::APR::Const/C__socket_>.
=item arg2: C<$val> ( integer )
value for the option. Refer to the L<socket
options|docs::2.0::api::APR::Const/C__socket_> section to learn about
the expected values.
=item ret: no return value
=item excpt: C<L<APR::Error|docs::2.0::api::APR::Error>>
=item since: 2.0.00
=back
Examples can be found in L<the socket options constants
section|docs::2.0::api::APR::Const/C__socket_>. For example L<setting
the IO to the blocking
mode|docs::2.0::api::APR::Const/C_APR__Const__SO_NONBLOCK_>.
=head2 C<poll>
Poll the socket for events:
$rc = $sock->poll($pool, $timeout, $events);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to poll
=item arg1: C<$pool>
( C<L<APR::Pool object|docs::2.0::api::APR::Pool>> )
usually C<L<$c-E<gt>pool|docs::2.0::api::Apache2::Connection/C_pool_>>.
=item arg2: C<$timeout> ( integer )
The amount of time to wait (in milliseconds) for the specified events
to occur.
=item arg3: C<$events> ( C<L<APR::Const :poll
constants|docs::2.0::api::APR::Const/C__poll_>> )
The events for which to wait.
For example use
C<L<APR::Const::POLLIN|docs::2.0::api::APR::Const/C_APR__Const__POLLIN_>> to wait
for incoming data to be available,
C<L<APR::Const::POLLOUT|docs::2.0::api::APR::Const/C_APR__Const__POLLOUT_>> to wait
until it's possible to write data to the socket and
C<L<APR::Const::POLLPRI|docs::2.0::api::APR::Const/C_APR__Const__POLLPRI_>> to wait
for priority data to become available.
=item ret: C<$rc>
( C<L<APR::Const constant|docs::2.0::api::APR::Const>> )
If C<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
C<L<APR::Error::strerror|docs::2.0::api::APR::Error/C_strerror_>>.
=item since: 2.0.00
=back
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);
}
=head2 C<recv>
Read incoming data from the socket
$len = $sock->recv($buffer, $wanted);
=over 4
=item obj: C<$sock>
( C<L<APR::SockAddr object|docs::2.0::api::APR::SockAddr>> object )
The socket to read from
=item arg1: C<$buffer> ( SCALAR )
The buffer to fill. All previous data will be lost.
=item arg2: C<$wanted> ( int )
How many bytes to attempt to read.
=item ret: C<$len> ( number )
How many bytes were actually read.
C<$buffer> gets populated with the string that is read. It will
contain an empty string if there was nothing to read.
=item excpt: C<L<APR::Error|docs::2.0::api::APR::Error>>
If you get the C<'(11) Resource temporarily unavailable'> error
(exception
C<L<APR::Const::EAGAIN|docs::2.0::api::APR::Const/C_APR__Const__EAGAIN_>>)
(or another equivalent, which might be different on non-POSIX
systems), then you didn't ensure that the socket is in L<a blocking IO
mode|/C_opt_set_> before using it. Note that you should use
C<L<APR::Status::is_EAGAIN|docs::2.0::api::APR::Status/C_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 C<timeout_set|/C_timeout_set_>, you may need to
catch the
C<L<APR::Const::TIMEUP|docs::2.0::api::APR::Const/C_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 C<'70007: The timeout
specified has expired'>.
Another error condition that may occur is the C<'(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
}
=item since: 2.0.00
=back
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;
}
}
=head2 C<send>
Write data to the socket
$wlen = $sock->send($buf, $opt_len);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to write to
=item arg1: C<$buf> ( scalar )
The data to send
=item opt arg2: C<$opt_len> ( int )
There is no need to pass this argument, unless you want to send less
data than contained in C<$buf>.
=item ret: C<$wlen> ( integer )
How many bytes were sent
=item since: 2.0.00
=back
For examples see the C<L<recv|/C_recv_>> item.
=head2 C<timeout_get>
Get socket timeout settings
$usecs = $sock->timeout_get();
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to set up.
=item ret: C<$usecs> ( number)
Currently set timeout in microseconds (and also the blocking IO
behavior). See (C<L<APR::timeout_set|/C__timeout_set_>>) for possible
values and their meaning.
=item excpt: C<L<APR::Error|docs::2.0::api::APR::Error>>
=item since: 2.0.00
=back
=head2 C<timeout_set>
Setup socket timeout.
$sock->timeout_set($usecs);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to set up.
=item arg1: C<$usecs> ( number )
Value for the timeout in microseconds and also the blocking IO
behavior.
The possible values are:
=over
=item t E<gt> 0
C<L<send()|/C__send_>> and C<L<recv()|/C__recv_)>> throw
(C<L<APR::Const::TIMEUP|docs::2.0::api::APR::Const/C__APR__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.
=item t == 0
C<L<send()|/C__send_>> and C<L<recv()|/C__recv_)>> calls never block.
=item t E<lt> 0
C<L<send()|/C__send_>> and C<L<recv()|/C__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.
=item ret: no return value
=back
=item excpt: C<L<APR::Error|docs::2.0::api::APR::Error>>
=item since: 2.0.00
=back
=head1 Unsupported API
C<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 L<the mod_perl development mailing
list|maillist::dev> so we can help each other take the steps necessary
to shift the method to an officially supported API.
=head2 C<bind>
META: Autogenerated - needs to be reviewed/completed
Bind the socket to its associated port
$ret = $sock->bind($sa);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to bind
=item arg1: C<$sa>
( C<L<APR::SockAddr object|docs::2.0::api::APR::SockAddr>> )
The socket address to bind to
=item ret: C<$ret> ( integer )
=item since: subject to change
=back
This may be where we will find out if there is any other process
using the selected port.
=head2 C<close>
META: Autogenerated - needs to be reviewed/completed
Close a socket.
$ret = $sock->close();
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to close
=item ret: C<$ret> ( integer )
=item since: subject to change
=back
=head2 C<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);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket we wish to use for our side of the connection
=item arg1: C<$sa>
( C<L<APR::SockAddr object|docs::2.0::api::APR::SockAddr>> )
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.
=item ret: C<$ret> ( integer )
=item since: subject to change
=back
=head2 C<listen>
META: Autogenerated - needs to be reviewed/completed
Listen to a bound socket for connections.
$ret = $sock->listen($backlog);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to listen on
=item arg1: C<$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.
=item ret: C<$ret> ( integer )
=item since: subject to change
=back
=head2 C<recvfrom>
META: Autogenerated - needs to be reviewed/completed
$ret = $from->recvfrom($sock, $flags, $buf, $len);
=over 4
=item obj: C<$from>
( C<L<APR::SockAddr object|docs::2.0::api::APR::SockAddr>> )
The apr_sockaddr_t to fill in the recipient info
=item arg1: C<$sock>
( C<L<APR::SockAddr object|docs::2.0::api::APR::SockAddr>> )
The socket to use
=item arg2: C<$flags> ( integer )
The flags to use
=item arg3: C<$buf> ( integer )
The buffer to use
=item arg4: C<$len> ( string )
The length of the available buffer
=item ret: C<$ret> ( integer )
=item since: subject to change
=back
=head2 C<sendto>
META: Autogenerated - needs to be reviewed/completed
$ret = $sock->sendto($where, $flags, $buf, $len);
=over 4
=item obj: C<$sock>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The socket to send from
=item arg1: C<$where>
( C<L<APR::Socket object|docs::2.0::api::APR::Socket>> )
The apr_sockaddr_t describing where to send the data
=item arg2: C<$flags> ( integer )
The flags to use
=item arg3: C<$buf> ( scalar )
The data to send
=item arg4: C<$len> ( string )
The length of the data to send
=item ret: C<$ret> ( integer )
=item since: subject to change
=back
=head1 See Also
L<mod_perl 2.0 documentation|docs::2.0::index>.
=head1 Copyright
mod_perl 2.0 and its core modules are copyrighted under
The Apache Software License, Version 2.0.
=head1 Authors
L<The mod_perl development team and numerous
contributors|about::contributors::people>.
=cut
