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add_configadd_version_componentdir_configexists_config_defineget_handlersget_server_builtget_server_versiongroup_idis_perl_option_enabledmethod_registerpush_handlersrestart_countserverserver_rootserver_root_relativeserver_shutdown_cleanup_registerset_handlersuser_id
Apache2::ServerUtil - Perl API for Apache server record utils
use Apache2::ServerUtil ();
$s = Apache2::ServerUtil->server;
# push config
$s->add_config(['ServerTokens off']);
# add components to the Server signature
$s->add_version_component("MyModule/1.234");
# access PerlSetVar/PerlAddVar values
my $srv_cfg = $s->dir_config;
# check command line defines
print "this is mp2"
if Apache2::ServerUtil::exists_config_define('MODPERL2');
# get PerlChildExitHandler configured handlers
@handlers = @{ $s->get_handlers('PerlChildExitHandler') || []};
# server build and version info:
$when_built = Apache2::ServerUtil::get_server_built();
$version = Apache2::ServerUtil::get_server_version();
# ServerRoot value
$server_root = Apache2::ServerUtil::server_root();
# get 'conf/' dir path (avoid using this function!)
my $dir = Apache2::ServerUtil::server_root_relative($r->pool, 'conf');
# set child_exit handlers
$r->set_handlers(PerlChildExitHandler => \&handler);
# server level PerlOptions flags lookup
$s->push_handlers(ChildExit => \&child_exit)
if $s->is_perl_option_enabled('ChildExit');
# extend HTTP to support a new method
$s->method_register('NEWGET');
# register server shutdown callback
Apache2::ServerUtil::server_shutdown_register_cleanup(sub { Apache2::Const::OK });
# do something only when the server restarts
my $cnt = Apache2::ServerUtil::restart_count();
do_something_once() if $cnt > 1;
# get the resolved ids from Group and User entries
my $user_id = Apache2::ServerUtil->user_id;
my $group_id = Apache2::ServerUtil->group_id;
Apache2::ServerUtil provides the Apache server object utilities API.
Apache2::ServerUtil provides the following functions and/or methods:
add_configDynamically add Apache configuration:
$s->add_config($lines);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$lines ( ARRAY ref )
An ARRAY reference containing configuration lines per element, without the new line terminators.
See also:
$r->add_config|docs::2.0::api::Apache2::RequestUtil/C_add_config_
For example:
Add a configuration section at the server startup (e.g. from startup.pl):
use Apache2::ServerUtil ();
my $conf = <<'EOC';
PerlModule Apache2::MyExample
<Location /perl>
SetHandler perl-script
PerlResponseHandler Apache2::MyExample
</Location>
EOC
Apache2::ServerUtil->server->add_config([split /\n/, $conf]);
add_version_componentAdd a component to the version string
$s->add_version_component($component);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$component ( string )
The string component to add
This function is usually used by modules to advertise themselves to
the world. It's picked up by such statistics collectors, like
netcraft.com, which accomplish that by connecting to various servers
and grabbing the server version response header (Server). Some
servers choose to fully or partially conceal that header.
This method should be invoked in the
PerlPostConfigHandler|docs::2.0::user::handlers::server/C_PerlPostConfigHandler_
phase, which will ensure that the Apache core version number will
appear first.
For example let's add a component ``Hikers, Inc/0.99999'' to the server string at the server startup:
use Apache2::ServerUtil ();
use Apache2::Const -compile => 'OK';
Apache2::ServerUtil->server->push_handlers(
PerlPostConfigHandler => \&add_my_version);
sub add_my_version {
my ($conf_pool, $log_pool, $temp_pool, $s) = @_;
$s->add_version_component("Hikers, Inc/0.99999");
return Apache2::Const::OK;
}
or of course you could register the
PerlPostConfigHandler|docs::2.0::user::handlers::server/C_PerlPostConfigHandler_
handler directly in httpd.conf
Now when the server starts, you will something like:
[Thu Jul 15 12:15:28 2004] [notice] Apache/2.0.51-dev (Unix) mod_perl/1.99_15-dev Perl/v5.8.5 Hikers, Inc/0.99999 configured -- resuming normal operations
Also remember that the ServerTokens directive value controls
whether the component information is displayed or not.
dir_config$s->dir_config() provides an interface for the per-server
variables specified by the PerlSetVar and PerlAddVar directives,
and also can be manipulated via the
APR::Table|docs::2.0::api::APR::Table methods.
$table = $s->dir_config(); $value = $s->dir_config($key); @values = $s->dir_config($key); $s->dir_config($key, $val);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$key ( string )
Key string
$val ( string )
Value string
Depends on the passed arguments, see further discussion
The keys are case-insensitive.
$t = $s->dir_config();
dir_config() called in a scalar context without the $key argument
returns a HASH reference blessed into the APR::Table class. This
object can be manipulated via the APR::Table methods. For available
methods see APR::Table.
@values = $s->dir_config($key);
If the $key argument is passed in the list context a list of all
matching values will be returned. This method is ineffective for big
tables, as it does a linear search of the table. Thefore avoid using
this way of calling dir_config() unless you know that there could be
more than one value for the wanted key and all the values are wanted.
$value = $s->dir_config($key);
If the $key argument is passed in the scalar context only a single
value will be returned. Since the table preserves the insertion order,
if there is more than one value for the same key, the oldest value
assosiated with the desired key is returned. Calling in the scalar
context is also much faster, as it'll stop searching the table as soon
as the first match happens.
$s->dir_config($key => $val);
If the $key and the $val arguments are used, the set() operation
will happen: all existing values associated with the key $key (and
the key itself) will be deleted and $value will be placed instead.
$s->dir_config($key => undef);
If $val is undef the unset() operation will happen: all existing
values associated with the key $key (and the key itself) will be
deleted.
exists_config_defineCheck for a definition from the server startup command line
(e.g. -DMODPERL2)
$result = Apache2::ServerUtil::exists_config_define($name);
$name ( string )
The define string to check for
$result ( boolean )
true if defined, false otherwise
For example:
print "this is mp2"
if Apache2::ServerUtil::exists_config_define('MODPERL2');
get_handlersReturns a reference to a list of handlers enabled for a given phase.
$handlers_list = $s->get_handlers($hook_name);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$hook_name ( string )
a string representing the phase to handle.
$handlers_list (ref to an ARRAY of CODE refs)
a list of references to the handler subroutines
See also:
$r->add_config|docs::2.0::api::Apache2::RequestUtil/C_get_handlers_
For example:
A list of handlers configured to run at the child_exit phase:
@handlers = @{ $s->get_handlers('PerlChildExitHandler') || []};
get_server_builtGet the date and time that the server was built
$when_built = Apache2::ServerUtil::get_server_built();
$when_built ( string )
The server build time string
get_server_versionGet the server version string
$version = Apache2::ServerUtil::get_server_version();
$version ( string )
The server version string
group_idGet the group id corresponding to the Group directive in
httpd.conf:
$gid = Apache2::ServerUtil->group_id;
Apache2::ServerUtil (class name)
$gid ( integer )
On Unix platforms returns the gid corresponding to the value used in
the Group directive in httpd.conf. On other platforms returns 0.
is_perl_option_enabledcheck whether a server level PerlOptions flag is enabled or not.
$result = $s->is_perl_option_enabled($flag);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$flag ( string )
$result ( boolean )
For example to check whether the ChildExit hook is enabled (which
can be disabled with PerlOptions -ChildExit) and configure some
handlers to run if enabled:
$s->push_handlers(ChildExit => \&child_exit)
if $s->is_perl_option_enabled('ChildExit');
See also: PerlOptions and the equivalent function for directory level PerlOptions flags.
method_registerRegister a new request method, and return the offset that will be associated with that method.
$offset = $s->method_register($methname);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$methname ( string )
The name of the new method to register (in addition to the already
supported GET, HEAD, etc.)
$offset ( integer )
An int value representing an offset into a bitmask. You can probably ignore it.
This method allows you to extend the HTTP protocol to support new
methods, which fit the HTTP paradigm. Of course you will need to
write a client that understands that protocol extension. For a good
example, refer to the MyApache2::SendEmail example presented in
the PerlHeaderParserHandler
section|docs::2.0::user::handlers::http/PerlHeaderParserHandler>,
which demonstrates how a new method EMAIL is registered and used.
push_handlersAdd one or more handlers to a list of handlers to be called for a given phase.
$ok = $s->push_handlers($hook_name => \&handler); $ok = $s->push_handlers($hook_name => [\&handler, \&handler2]);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$hook_name ( string )
the phase to add the handlers to
$handlers ( CODE ref or SUB name or an ARRAY ref )
a single handler CODE reference or just a name of the subroutine (fully qualified unless defined in the current package).
if more than one passed, use a reference to an array of CODE refs and/or subroutine names.
$ok ( boolean )
returns a true value on success, otherwise a false value
See also:
$r->add_config|docs::2.0::api::Apache2::RequestUtil/C_push_handlers_
Examples:
A single handler:
$s->push_handlers(PerlChildExitHandler => \&handler);
Multiple handlers:
$s->push_handlers(PerlChildExitHandler => ['Foo::Bar::handler', \&handler2]);
Anonymous functions:
$s->push_handlers(PerlLogHandler => sub { return Apache2::Const::OK });
restart_countHow many times the server was restarted.
$restart_count = Apache2::ServerUtil::restart_count();
restart_count ( number )
The following demonstration should make it clear what values to expect from this function. Let's add the following code to startup.pl, so it's run every time httpd.conf is parsed:
use Apache2::ServerUtil (); my $cnt = Apache2::ServerUtil::restart_count(); open my $fh, ">>/tmp/out" or die "$!"; print $fh "cnt: $cnt\n"; close $fh;
Now let's run a series of server starts and restarts and look at what is logged into /tmp/out:
% 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
Remembering that Apache restarts itself immediately after starting, we can
see that the restart_count goes from 1 to 2 during the server
start. Moreover we can see that every operation forces the parsing of
httpd.conf and therefore reinitialization of mod_perl (and running
all the code found in httpd.conf). This happens even when the
server is shutdown via httpd -k stop.
What conclusions can be drawn from this demonstration:
Apache2::ServerUtil::restart_count() returns 1 every time some -k
command is passed to Apache (or kill -USR1 or some alternative
signal is received).
At all other times the count will be 2 or higher. So for example on graceful restart the count will be 3 or higher.
For example if you want to run something every time httpd -k is run
you just need to check whether restart_count() returns 1:
my $cnt = Apache2::ServerUtil::restart_count(); do_something() if $cnt == 1;
To do something only when server restarts (httpd -k start or
httpd -k graceful), check whether restart_count() is bigger than
1:
my $cnt = Apache2::ServerUtil::restart_count(); do_something() if $cnt > 1;
serverGet the main server's object
$main_s = Apache2::ServerUtil->server();
Apache2::ServerUtil (class name)
$main_s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
server_rootreturns the value set by the top-level ServerRoot directive.
$server_root = Apache2::ServerUtil::server_root();
$server_root ( string )
server_root_relativeReturns the canonical form of the filename made absolute to
ServerRoot:
$path = Apache2::ServerUtil::server_root_relative($pool, $fname);
$pool
( APR::Pool object|docs::2.0::api::APR::Pool )
Make sure that you read the following explanation and understand well which pool object you need to pass before using this function.
$fname ( string )
$path ( string )
The concatenation of ServerRoot and the $fname.
If $fname is not specified, the value of ServerRoot is returned
with a trailing /. (it's the same as using '' as $fname's
value).
$fname is appended to the value of ServerRoot and returned. For
example:
my $dir = Apache2::ServerUtil::server_root_relative($r->pool, 'logs');
You must be extra-careful when using this function. If you aren't sure what you are doing don't use it.
It's much safer to build the path by yourself using use
Apache2::ServerUtil::server_root()|/C_Apache2__server_root_, For
example:
use File::Spec::Functions qw(catfile); my $path = catfile Apache2::ServerUtil::server_root, qw(t logs);
In this example, no memory allocation happens on the Apache-side and you aren't risking to get a memory leak.
The problem with server_root_relative is that Apache allocates
memory to concatenate the path string. The memory is allocated from
the pool object. If you call this method on the server pool object
it'll allocate the memory from it. If you do that at the server
startup, it's perfectly right, since you will do that only
once. However if you do that from within a request or a connection
handler, you create a memory leak every time it is called -- as the
memory gets allocated from the server pool, it will be freed only when
the server is shutdown. Therefore if you need to build a relative to
the root server path for the duration of the request, use the request
pool:
use Apache2::RequestRec (); Apache2::ServerUtil::server_root_relative($r->pool, $fname);
If you need to have the path for the duration of a connection (e.g. inside a protocol handler), you should use:
use Apache2::Connection (); Apache2::ServerUtil::server_root_relative($c->pool, $fname);
And if you want it for the scope of the server file:
use Apache2::Process (); use Apache2::ServerUtil (); Apache2::ServerUtil::server_root_relative($s->process->pool, $fname);
Moreover, you could have encountered the opposite problem, where you have used a short-lived pool object to construct the path, but tried to use the resulting path variable, when that pool has been destructed already. In order to avoid mysterious segmentation faults, mod_perl does a wasteful copy of the path string when returning it to you -- another reason to avoid using this function.
server_shutdown_cleanup_registerRegister server shutdown cleanup callback:
Apache2::ServerUtil::server_shutdown_cleanup_register($sub);
$sub ( CODE ref or SUB name )
This function can be used to register a callback to be run once at the
server shutdown (compared to
PerlChildExitHandler|docs::2.0::user::handlers::server/C_PerlChildExitHandler_
which will execute the callback for each exiting child process).
For example in order to arrange the function do_my_cleanups() to be
run every time the server shuts down (or restarts), run the following
code at the server startup:
Apache2::ServerUtil::server_shutdown_cleanup_register(\&do_my_cleanups);
It's necessary to run this code at the server startup (normally
startup.pl. The function will croak if run after the
PerlPostConfigHandler|docs::2.0::user::handlers::server/C_PerlPostConfigHandler_
phase.
set_handlersSet a list of handlers to be called for a given phase. Any previously set handlers are forgotten.
$ok = $s->set_handlers($hook_name => \&handler); $ok = $s->set_handlers($hook_name => [\&handler, \&handler2]); $ok = $s->set_handlers($hook_name => []); $ok = $s->set_handlers($hook_name => undef);
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
$hook_name ( string )
the phase to set the handlers in
$handlers ( CODE ref or SUB name or an ARRAY ref )
a reference to a single handler CODE reference or just a name of the subroutine (fully qualified unless defined in the current package).
if more than one passed, use a reference to an array of CODE refs and/or subroutine names.
if the argument is undef or [] the list of handlers is reset to
zero.
$ok ( boolean )
returns a true value on success, otherwise a false value
See also:
$r->add_config|docs::2.0::api::Apache2::RequestUtil/C_set_handlers_
Examples:
A single handler:
$r->set_handlers(PerlChildExitHandler => \&handler);
Multiple handlers:
$r->set_handlers(PerlFixupHandler => ['Foo::Bar::handler', \&handler2]);
Anonymous functions:
$r->set_handlers(PerlLogHandler => sub { return Apache2::Const::OK });
Reset any previously set handlers:
$r->set_handlers(PerlCleanupHandler => []);
or
$r->set_handlers(PerlCleanupHandler => undef);
user_idGet the user id corresponding to the User directive in
httpd.conf:
$uid = Apache2::ServerUtil->user_id;
Apache2::ServerUtil (class name)
$uid ( integer )
On Unix platforms returns the uid corresponding to the value used in
the User directive in httpd.conf. On other platforms returns 0.
Apache2::ServerUtil 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.
error_log2stderrStart sending STDERR to the error_log file
$s->error_log2stderr();
$s
( Apache2::ServerRec object|docs::2.0::api::Apache2::ServerRec )
The current server
This method may prove useful if you want to start redirecting STDERR to the error_log file before Apache does that on the startup.
mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0.