9 More Discussions You Might Find Interesting
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I need clarification on whether it is okay to set socket options on a listening socket
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Following is the scenario:-
-- Task 1 - is executing in a loop - polling a listen socket, lets call it 'fd', (whose file descriptor is global)... (2 Replies)
Discussion started by: jake24
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can someone provide an example, where if the parent process quits for any reason, then the child process will also close? (3 Replies)
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Is the last two line necessary?
#include <sys/types.h>
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#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
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int main(void)
{
struct sockaddr_in stSockAddr;
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Hello Friends,
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=========================================================================
$ prstat -a
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Hi,
I was porting ipv4 application to ipv6; i was done with TCP transports. Now i am facing problem with SCTp transport at runtime.
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Interesting issue. There was some discussion on the LKML last year regarding the potential problems in concurrent applications reusing file descriptors in various scenarios. The main issue is that the reuse of a file descriptor and reception of data in a threaded application can be confused pretty... (1 Reply)
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I have written a socker program. I have executed that program many times without closing the socket. So I want to find which all sockets binded with which file descriptor.
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please help me!.. (3 Replies)
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Hi all,
I have a HP-UX 11.23 that have a Server establishing connections on port 8888 .
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9. Programming
I have a SUN environment running an WebLogic that communicates w/a 3rd party running IIS. When the IIS site goes down (frequently), I am stuck with sockets in an ESTABLISHED state, and cannot seem to figure out how to avoid this. No exceptions are thrown as I can still open connections to the IIS... (1 Reply)
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Plack::Builder(3pm) User Contributed Perl Documentation Plack::Builder(3pm)
NAME
Plack::Builder - OO and DSL to enable Plack Middlewares
SYNOPSIS
# in .psgi
use Plack::Builder;
my $app = sub { ... };
builder {
enable "Deflater";
enable "Session", store => "File";
enable "Debug", panels => [ qw(DBITrace Memory Timer) ];
enable "+My::Plack::Middleware";
$app;
};
# use URLMap
builder {
mount "/foo" => builder {
enable "Foo";
$app;
};
mount "/bar" => $app2;
mount "http://example.com/" => builder { $app3 };
};
# using OO interface
my $builder = Plack::Builder->new();
$builder->add_middleware('Foo', opt => 1);
$app = $builder->mount('/app' => $app);
$app = $builder->to_app($app);
DESCRIPTION
Plack::Builder gives you a quick domain specific language (DSL) to wrap your application with Plack::Middleware subclasses. The middleware
you're trying to use should use Plack::Middleware as a base class to use this DSL, inspired by Rack::Builder.
Whenever you call "enable" on any middleware, the middleware app is pushed to the stack inside the builder, and then reversed when it
actually creates a wrapped application handler. "Plack::Middleware::" is added as a prefix by default. So:
builder {
enable "Foo";
enable "Bar", opt => "val";
$app;
};
is syntactically equal to:
$app = Plack::Middleware::Bar->wrap($app, opt => "val");
$app = Plack::Middleware::Foo->wrap($app);
In other words, you're supposed to "enable" middleware from outer to inner.
INLINE MIDDLEWARE
Plack::Builder allows you to code middleware inline using a nested code reference.
If the first argument to "enable" is a code reference, it will be passed an $app and is supposed to return another code reference which is
PSGI application that consumes $env in runtime. So:
builder {
enable sub {
my $app = shift;
sub {
my $env = shift;
# do preprocessing
my $res = $app->($env);
# do postprocessing
return $res;
};
};
$app;
};
is equal to:
my $mw = sub {
my $app = shift;
sub { my $env = shift; $app->($env) };
};
$app = $mw->($app);
URLMap support
Plack::Builder has a native support for Plack::App::URLMap with "mount" method.
use Plack::Builder;
my $app = builder {
mount "/foo" => $app1;
mount "/bar" => builder {
enable "Foo";
$app2;
};
};
See Plack::App::URLMap's "map" method to see what they mean. With builder you can't use "map" as a DSL, for the obvious reason :)
NOTE: Once you use "mount" in your builder code, you have to use "mount" for all the paths, including the root path ("/"). You can't have
the default app in the last line of "builder" like:
my $app = sub {
my $env = shift;
...
};
builder {
mount "/foo" => sub { ... };
$app; # THIS DOESN'T WORK
};
You'll get warnings saying that your mount configuration will be ignored. Instead you should use "mount "/" => ..." in the last line to set
the default fallback app.
builder {
mount "/foo" => sub { ... };
mount "/" => $app;
}
Note that the "builder" DSL returns a whole new PSGI application, which means
o "builder { ... }" should normally the last statement of a ".psgi" file, because the return value of "builder" is the application that
actually is executed.
o You can nest your "builder" block, mixed with "mount" (see URLMap support above):
builder {
mount "/foo" => builder {
mount "/bar" => $app;
}
}
will locate the $app under "/foo/bar" since the inner "builder" block puts it under "/bar" and it results a new PSGI application which
is located under "/foo" because of the outer "builder" block.
CONDITIONAL MIDDLEWARE SUPPORT
You can use "enable_if" to conditionally enable middleware based on the runtime environment. See Plack::Middleware::Conditional for
details.
SEE ALSO
Plack::Middleware Plack::App::URLMap Plack::Middleware::Conditional
perl v5.14.2 2012-05-17 Plack::Builder(3pm)