apache2::serverutil.3

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

.IX Subsection "restart_count"
How many times the server was restarted.
.PP
.Vb 1
\&  $restart_count = Apache2::ServerUtil::restart_count();
.Ve
.ie n .IP "ret: ""restart_count"" ( number )" 4
.el .IP "ret: \f(CWrestart_count\fR ( number )" 4
.IX Item "ret: restart_count ( number )"
.PD 0
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PD
.PP
The following demonstration should make it clear what values to expect
from this function. Let's add the following code to \fIstartup.pl\fR, so
it's run every time \fIhttpd.conf\fR is parsed:
.PP
.Vb 5
\&  use Apache2::ServerUtil ();
\&  my $cnt = Apache2::ServerUtil::restart_count();
\&  open my $fh, ">>/tmp/out" or die "$!";
\&  print $fh "cnt: $cnt\en";
\&  close $fh;
.Ve
.PP
Now let's run a series of server starts and restarts and look at what
is logged into \fI/tmp/out\fR:
.PP
.Vb 3
\&  % httpd \-k start
\&  cnt: 1
\&  cnt: 2
\&  
\&  % httpd \-k graceful
\&  cnt: 1
\&  cnt: 3
\&  
\&  % httpd \-k graceful
\&  cnt: 1
\&  cnt: 4
\&  
\&  % httpd \-k stop
\&  cnt: 1
.Ve
.PP
Remembering that Apache restarts itself immediately after
starting, we can
see that the \f(CW\*(C`restart_count\*(C'\fR goes from 1 to 2 during the server
start. Moreover we can see that every operation forces the parsing of
\&\fIhttpd.conf\fR and therefore reinitialization of mod_perl (and running
all the code found in \fIhttpd.conf\fR). This happens even when the
server is shutdown via \f(CW\*(C`httpd \-k stop\*(C'\fR.
.PP
What conclusions can be drawn from this demonstration:
.IP "\(bu" 4
\&\f(CW\*(C`Apache2::ServerUtil::restart_count()\*(C'\fR returns 1 every time some \f(CW\*(C`\-k\*(C'\fR
command is passed to Apache (or \f(CW\*(C`kill \-USR1\*(C'\fR or some alternative
signal is received).
.IP "\(bu" 4
At all other times the count will be 2 or higher. So for example on
graceful restart the count will be 3 or higher.
.PP
For example if you want to run something every time \f(CW\*(C`httpd \-k\*(C'\fR is run
you just need to check whether \f(CW\*(C`restart_count()\*(C'\fR returns 1:
.PP
.Vb 2
\&  my $cnt = Apache2::ServerUtil::restart_count();
\&  do_something() if $cnt == 1;
.Ve
.PP
To do something only when server restarts (\f(CW\*(C`httpd \-k start\*(C'\fR or
\&\f(CW\*(C`httpd \-k graceful)\*(C'\fR, check whether \f(CW\*(C`restart_count()\*(C'\fR is bigger than
1:
.PP
.Vb 2
\&  my $cnt = Apache2::ServerUtil::restart_count();
\&  do_something() if $cnt > 1;
.Ve
.ie n .Sh """server"""
.el .Sh "\f(CWserver\fP"
.IX Subsection "server"
Get the main server's object
.PP
.Vb 1
\&  $main_s = Apache2::ServerUtil\->server();
.Ve
.ie n .IP "obj: ""Apache2"" (class name)" 4
.el .IP "obj: \f(CWApache2\fR (class name)" 4
.IX Item "obj: Apache2 (class name)"
.PD 0
.ie n .IP "ret: $main_s\fR ( \f(CW""Apache2::ServerRec object"" )" 4
.el .IP "ret: \f(CW$main_s\fR ( \f(CWApache2::ServerRec object\fR )" 4
.IX Item "ret: $main_s ( Apache2::ServerRec object )"
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PD
.ie n .Sh """server_root"""
.el .Sh "\f(CWserver_root\fP"
.IX Subsection "server_root"
returns the value set by the top-level \f(CW\*(C`ServerRoot\*(C'\fR directive.
.PP
.Vb 1
\&  $server_root = Apache2::ServerUtil::server_root();
.Ve
.ie n .IP "ret: $server_root ( string )" 4
.el .IP "ret: \f(CW$server_root\fR ( string )" 4
.IX Item "ret: $server_root ( string )"
.PD 0
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PD
.ie n .Sh """server_root_relative"""
.el .Sh "\f(CWserver_root_relative\fP"
.IX Subsection "server_root_relative"
Returns the canonical form of the filename made absolute to
\&\f(CW\*(C`ServerRoot\*(C'\fR:
.PP
.Vb 1
\&  $path = Apache2::ServerUtil::server_root_relative($pool, $fname);
.Ve
.ie n .IP "arg1: $pool\fR ( \f(CW""APR::Pool object"" )" 4
.el .IP "arg1: \f(CW$pool\fR ( \f(CWAPR::Pool object\fR )" 4
.IX Item "arg1: $pool ( APR::Pool object )"
Make sure that you read the following explanation and understand well
which pool object you need to pass before using this function.
.ie n .IP "opt arg2: $fname ( string )" 4
.el .IP "opt arg2: \f(CW$fname\fR ( string )" 4
.IX Item "opt arg2: $fname ( string )"
.PD 0
.ie n .IP "ret: $path ( string )" 4
.el .IP "ret: \f(CW$path\fR ( string )" 4
.IX Item "ret: $path ( string )"
.PD
The concatenation of \f(CW\*(C`ServerRoot\*(C'\fR and the \f(CW$fname\fR.
.Sp
If \f(CW$fname\fR is not specified, the value of \f(CW\*(C`ServerRoot\*(C'\fR is returned
with a trailing \f(CW\*(C`/\*(C'\fR. (it's the same as using \f(CW\*(Aq\*(Aq\fR as \f(CW$fname\fR's
value).
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PP
\&\f(CW$fname\fR is appended to the value of \f(CW\*(C`ServerRoot\*(C'\fR and returned. For
example:
.PP
.Vb 1
\&  my $dir = Apache2::ServerUtil::server_root_relative($r\->pool, \*(Aqlogs\*(Aq);
.Ve
.PP
You must be extra-careful when using this function. If you aren't sure
what you are doing don't use it.
.PP
It's much safer to build the path by yourself using use
\&\f(CW\*(C`Apache2::ServerUtil::server_root()\*(C'\fR, For
example:
.PP
.Vb 2
\&  use File::Spec::Functions qw(catfile);
\&  my $path = catfile Apache2::ServerUtil::server_root, qw(t logs);
.Ve
.PP
In this example, no memory allocation happens on the Apache-side and
you aren't risking to get a memory leak.
.PP
The problem with \f(CW\*(C`server_root_relative\*(C'\fR is that Apache allocates
memory to concatenate the path string. The memory is allocated from
the pool object. If you call this method on the server pool object
it'll allocate the memory from it.  If you do that at the server
startup, it's perfectly right, since you will do that only
once. However if you do that from within a request or a connection
handler, you create a memory leak every time it is called \*(-- as the
memory gets allocated from the server pool, it will be freed only when
the server is shutdown. Therefore if you need to build a relative to
the root server path for the duration of the request, use the request
pool:
.PP
.Vb 2
\&  use Apache2::RequestRec ();
\&  Apache2::ServerUtil::server_root_relative($r\->pool, $fname);
.Ve
.PP
If you need to have the path for the duration of a connection
(e.g. inside a protocol handler), you should use:
.PP
.Vb 2
\&  use Apache2::Connection ();
\&  Apache2::ServerUtil::server_root_relative($c\->pool, $fname);
.Ve
.PP
And if you want it for the scope of the server file:
.PP
.Vb 3
\&  use Apache2::Process ();
\&  use Apache2::ServerUtil ();
\&  Apache2::ServerUtil::server_root_relative($s\->process\->pool, $fname);
.Ve
.PP
Moreover, you could have encountered the opposite problem, where you
have used a short-lived pool object to construct the path, but tried
to use the resulting path variable, when that pool has been destructed
already. In order to avoid mysterious segmentation faults, mod_perl
does a wasteful copy of the path string when returning it to you \*(--
another reason to avoid using this function.
.ie n .Sh """set_handlers"""
.el .Sh "\f(CWset_handlers\fP"
.IX Subsection "set_handlers"
Set a list of handlers to be called for a given phase. Any previously
set handlers are forgotten.
.PP
.Vb 4
\&  $ok = $s\->set_handlers($hook_name => \e&handler);
\&  $ok = $s\->set_handlers($hook_name => [\e&handler, \e&handler2]);
\&  $ok = $s\->set_handlers($hook_name => []);
\&  $ok = $s\->set_handlers($hook_name => undef);
.Ve
.ie n .IP "obj: $s\fR ( \f(CW""Apache2::ServerRec object"" )" 4
.el .IP "obj: \f(CW$s\fR ( \f(CWApache2::ServerRec object\fR )" 4
.IX Item "obj: $s ( Apache2::ServerRec object )"
.PD 0
.ie n .IP "arg1: $hook_name ( string )" 4
.el .IP "arg1: \f(CW$hook_name\fR ( string )" 4
.IX Item "arg1: $hook_name ( string )"
.PD
the phase to set the handlers in
.ie n .IP "arg2: $handlers ( \s-1CODE\s0 ref or \s-1SUB\s0 name or an \s-1ARRAY\s0 ref )" 4
.el .IP "arg2: \f(CW$handlers\fR ( \s-1CODE\s0 ref or \s-1SUB\s0 name or an \s-1ARRAY\s0 ref )" 4
.IX Item "arg2: $handlers ( CODE ref or SUB name or an ARRAY ref )"
a reference to a single handler \s-1CODE\s0 reference or just a name of the
subroutine (fully qualified unless defined in the current package).
.Sp
if more than one passed, use a reference to an array of \s-1CODE\s0 refs
and/or subroutine names.
.Sp
if the argument is \f(CW\*(C`undef\*(C'\fR or \f(CW\*(C`[]\*(C'\fR the list of handlers is reset to
zero.
.ie n .IP "ret: $ok ( boolean )" 4
.el .IP "ret: \f(CW$ok\fR ( boolean )" 4
.IX Item "ret: $ok ( boolean )"
returns a true value on success, otherwise a false value
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PP
See also:
\&\f(CW\*(C`$r\->add_config\*(C'\fR
.PP
Examples:
.PP
A single handler:
.PP
.Vb 1
\&  $r\->set_handlers(PerlChildExitHandler => \e&handler);
.Ve
.PP
Multiple handlers:
.PP
.Vb 1
\&  $r\->set_handlers(PerlFixupHandler => [\*(AqFoo::Bar::handler\*(Aq, \e&handler2]);
.Ve
.PP
Anonymous functions:
.PP
.Vb 1
\&  $r\->set_handlers(PerlLogHandler => sub { return Apache2::Const::OK });
.Ve
.PP
Reset any previously set handlers:
.PP
.Vb 1
\&  $r\->set_handlers(PerlCleanupHandler => []);
.Ve
.PP
or
.PP
.Vb 1
\&  $r\->set_handlers(PerlCleanupHandler => undef);
.Ve
.SH "Unsupported API"
.IX Header "Unsupported API"
\&\f(CW\*(C`Apache2::ServerUtil\*(C'\fR also provides auto-generated Perl interface for
a few other methods which aren't tested at the moment and therefore
their \s-1API\s0 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 \s-1API\s0.
.ie n .Sh """error_log2stderr"""
.el .Sh "\f(CWerror_log2stderr\fP"
.IX Subsection "error_log2stderr"
Start sending \s-1STDERR\s0 to the error_log file
.PP
.Vb 1
\&  $s\->error_log2stderr();
.Ve
.ie n .IP "obj: $s\fR ( \f(CW""Apache2::ServerRec object"" )" 4
.el .IP "obj: \f(CW$s\fR ( \f(CWApache2::ServerRec object\fR )" 4
.IX Item "obj: $s ( Apache2::ServerRec object )"
The current server
.IP "ret: no return value" 4
.IX Item "ret: no return value"
.PD 0
.IP "since: 2.0.00" 4
.IX Item "since: 2.0.00"
.PD
.PP
This method may prove useful if you want to start redirecting \s-1STDERR\s0
to the error_log file before Apache does that on the startup.
.SH "See Also"
.IX Header "See Also"
mod_perl 2.0 documentation.
.SH "Copyright"
.IX Header "Copyright"
mod_perl 2.0 and its core modules are copyrighted under
The Apache Software License, Version 2.0.
.SH "Authors"
.IX Header "Authors"
The mod_perl development team and numerous
contributors.