NAME
IO::Stream - ease non-blocking I/O streams based on EV
VERSION
This document describes IO::Stream version v2.0.1
SYNOPSIS
use EV;
use IO::Stream;
IO::Stream->new({
host => 'google.com',
port => 80,
cb => \&client,
wait_for => SENT|EOF,
in_buf_limit=> 102400,
out_buf => "GET / HTTP/1.0\nHost: google.com\n\n",
});
$EV::DIED = sub { warn $@; EV::unloop };
EV::loop;
sub client {
my ($io, $e, $err) = @_;
if ($err) {
$io->close();
die $err;
}
if ($e & SENT) {
print "request sent, waiting for reply...\n";
}
if ($e & EOF) {
print "server reply:\n", $io->{in_buf};
$io->close();
EV::unloop; # ALL DONE
}
}
DESCRIPTION
Non-blocking event-based low-level I/O is hard to get right. Code
usually error-prone and complex... and it very similar in all
applications. Things become much worse when you need to alter I/O
stream in some way - use proxies, encryption, SSL, etc.
This module designed to give user ability to work with I/O streams on
higher level, using input/output buffers (just scalars) and high-level
events like CONNECTED, SENT or EOF. As same time it doesn't hide
low-level things, and user still able to work on low-level without any
limitations.
PLUGINS
Architecture of this module make it ease to write plugins, which will
alter I/O stream in any way - route it through proxies, encrypt, log,
etc.
Here are few available plugins, you may find more on CPAN:
IO::Stream::Crypt::RC4, IO::Stream::Proxy::HTTPS,
IO::Stream::MatrixSSL::Client, IO::Stream::MatrixSSL::Server.
If you interested in writing own plugin, check source for "skeleton"
plugins: IO::Stream::Noop and IO::Stream::NoopAlias.
EXPORTS
This modules doesn't export any functions/methods/variables, but it
exports a lot of constants. There two groups of constants: events and
errors (which can be imported using tags ':Event' and ':Error'). By
default all constants are exported.
Events:
RESOLVED CONNECTED IN OUT EOF SENT
Errors:
EINBUFLIMIT
ETORESOLVE ETOCONNECT ETOWRITE
EDNS EDNSNXDOMAIN EDNSNODATA
EREQINBUFLIMIT EREQINEOF
Errors are similar to $! - they're dualvars, having both textual and
numeric values.
NOTE: Since v2.0.0 ETORESOLVE, EDNSNXDOMAIN and EDNSNODATA are not used
anymore (EDNS is used instead), but they're still exported for
compatibility.
OVERVIEW
You can create IO::Stream object using any "stream" fh (file, TTY, UNIX
socket, TCP socket, pipe, FIFO). Or, if you need TCP socket, you can
create IO::Stream object using host+port instead of fh (in this case
IO::Stream will do non-blocking host resolving, create TCP socket and
do non-blocking connect).
After you created IO::Stream object, it will handle read/write on this
fh, and deliver only high-level events you asked for into your
callback, where you will be able to operate with in/out buffers instead
of doing sysread()/syswrite() manually.
There no limitations on what you can do with fh after you've created
IO::Stream object - you can even do sysread()/syswrite() (but there no
reasons for you to do this anymore).
IMPORTANT! When you want to close this fh, you MUST use $io->close()
method for closing fh instead of doing close($fh). This is because
IO::Stream doesn't require from you to keep object returned by new(),
and without call to $io->close() IO::Stream object will continue to
exists and may receive/generate some events, which is not what you
expect after closing fh. Also, if you keep object returned by
IO::Stream->new() somewhere in your variables, you should either undef
all such variables after you called $io->close(), or you should use
Scalar::Util::weaken() on these variables after storing IO::Stream
object. (The same is applicable for all plugin objects too.)
EVENTS
RESOLVED
If you created IO::Stream object using {host}+{port} instead of {fh},
this event will be generated after resolving {host}. Resolved IP
address will be stored in {ip}.
CONNECTED
If you created IO::Stream object using {host}+{port} instead of {fh},
this event will be generated after connecting socket to {ip}:{port}.
IN
Generated after each successful read. IO::Stream may execute several
sysread() at once before generating IN event for optimization. Read
data will be stored in {in_buf}, and {in_bytes} counter will be
incremented by amount of bytes read.
EOF
Generated only ONCE when EOF reached (sysread() return 0). Also will
set {is_eof} to true.
OUT
Generated when some data from {out_buf} was written. Written bytes
either removed from {out_buf} or just increment {out_pos} by amount
of bytes written (see documentation about these fields below for more
details). Also increment {out_bytes} counter by amount of bytes
written.
Here 'written' may be somewhat virtual, while {out_buf}/{out_pos}
changes, the real data still can be in plugin buffers (if you use
plugins) and real syswrite() may not be called yet. To detect when
all data is really written you should use SENT event, not OUT.
SENT
Generated when all data from {out_buf} was written. It's usual and
safe to call $io->close() on SENT event.
TIMEOUTS
IO::Stream has 30-second timeouts for connect and write, to timeout DNS
resolve it use default AnyEvent::DNS timeout. If you need to timeout
other operations, you have to create own timers using EV::timer().
Current version doesn't allow you to change these timeouts.
SERVER
If you need to run TCP/UNIX-server socket, then you should handle that
socket manually. But you can create IO::Stream object for accept()'ed
socket:
my ($host, $port) = ('0.0.0.0', 1234);
socket my $srv_sock, AF_INET, SOCK_STREAM, 0;
setsockopt $srv_sock, SOL_SOCKET, SO_REUSEADDR, 1;
bind $srv_sock, sockaddr_in($port, inet_aton($host));
listen $srv_sock, SOMAXCONN;
fcntl $srv_sock, F_SETFL, O_NONBLOCK;
$srv_w = EV::io($srv_sock, EV::READ, sub {
if (accept my $sock, $srv_sock) {
IO::Stream->new({
fh => $sock,
cb => \&server,
wait_for => IN,
});
}
elsif ($! != EAGAIN) {
die "accept: $!";
}
});
INTERFACE
IO::Stream provide only three public methods: new(), write() and
close(). new() will create new object, close() will destroy it and
write() must be called when you want to modify (or just modified)
output buffer.
All other operations are done using IO::Stream object fields - for
simplicity and performance reasons. Moreover, you can keep your own
data in it. There convention on field names, to avoid conflicts:
/^_/
Fields with names started with underscore are for internal use by
IO::Stream, you shouldn't touch them or create your own field with
such names.
/^[a-z]/
Fields with names started with lower-case letter are part of
IO::Stream public interface - you allowed to read/write these fields,
but you should not store incorrect values in these fields. Check
"PUBLIC FIELDS" below for description of available fields and their
format.
/^[A-Z]/
You can store your own data in IO::Stream object using field names
started with upper-case letter. IO::Stream will not touch these
fields.
When some event arise which you're waited for, your callback will be
called with 3 parameters: IO::Stream object, event mask, and error (if
any):
sub callback {
my ($io, $e, $err) = @_;
}
METHODS
new
IO::Stream->new( \%opt );
Create and return IO::Stream object. You may not keep returned object -
you will get it in your callback (in first parameter) when some
interesting for your event happens, and will exists until to call
method close(). See OVERVIEW for more details.
Fields of %opt become fields of created IO::Stream object. There only
few fields required, but you can set any other fields too, and can also
set your custom fields (with names starting from upper-case letter).
Only required fields in %opt are {cb} and either {fh} or {host}+{port}.
The {wait_for} field also highly recommended to set when creating
object.
If {out_buf} will be set, then new() will automatically call write()
after creating object.
IO::Stream->new({
fh => \*STDIN,
cb => \&console,
wait_for => IN,
});
write
$io->write();
$io->write($data);
Method write() MUST be called after any modifications of {out_buf}
field, to ensure data in {out_buf} will be written to {fh} as soon as
it will be possible.
If {fh} available for writing when calling write(), then it will write
(may be partially) {out_buf} and may immediately call your callback
function delivering OUT|SENT events there. So, if you call write() from
that callback (as it usually happens), keep in mind it may be called
again while executing write(), and object state may significantly
change (it even may be close()'d) after it return from write() into
your callback.
The write($data) is just a shortcut for:
$io->{out_buf} .= $data;
$io->write();
close
$io->close()
Method close() will close {fh} and destroy IO::Stream object. See
OVERVIEW for more details.
PUBLIC FIELDS
If field marked *RO* that mean field is read-only and shouldn't be
changed.
Some field have default values (shown after equal sign).
Some field modified on events.
cb
method ='IO'
User callback which will be called when some listed in {wait_for}
events arise or error happens.
Field {cb} should be either CODE ref or object or class name. In last
two cases method named {method} will be called. Field {method} should
be string.
wait_for
Bitmask of events interesting for user. Can be changed at any time.
For example:
$io->{wait_for} = RESOLVED|CONNECTED|IN|EOF|OUT|SENT;
When some data will be read from {fh}, {wait_for} must contain IN
and/or EOF, or error EREQINEOF will be generated. So, it's better to
always have IN and/or EOF in {wait_for}.
If {wait_for} contain EOF and doesn't contain IN then {in_buf_limit}
must be defined or error EREQINBUFLIMIT will be generated.
fh *RO*
File handle for doing I/O. It's either provided by user to new(), or
created by new() (when user provided {host}+{port} instead).
host *RO*
port *RO*
If user doesn't provide {fh} to new(), he should provide {host} and
{port} instead. This way new() will create new TCP socket in {fh} and
resolve {host} and connect this {fh} to resolved {ip} and {port}.
Both resolving and connecting happens in non-blocking way, and will
result in delivering RESOLVED and CONNECTED events into user callback
(if user {wait_for} these events).
in_buf_limit =undef
Used to avoid DoS attach when user doesn't handle IN events and want
his callback called only on EOF event. Must be defined if user have
EOF without IN in {wait_for}.
Any value >0 will defined amount of bytes which can be read into
{in_buf} before EOF happens. When size of {in_buf} become larger than
{in_buf_limit}, error EINBUFLIMIT will be delivered to user callback.
In this case user can either remove some data from {in_buf} to make
it smaller than {in_buf_limit} or increase {in_buf_limit}, and
continue reading data.
NOT RECOMMENDED! Value 0 will switch off DoS protection, so there
will be no limit on amount of data to read into {in_buf} until EOF
happens.
out_buf =q{} # modified on: OUT
out_pos =undef # modified on: OUT
Data from {out_buf} will be written to {fh}.
If {out_pos} not defined, then data will be written from beginning of
{out_buf}, and after successful write written bytes will be removed
from beginning of {out_buf}.
If {out_pos} defined, it should be >= 0. In this case data will be
written from {out_pos} position in {out_buf}, and after successful
write {out_pos} will be incremented by amount of bytes written.
{out_buf} will not be changed!
out_bytes =0 # modified on: OUT
Each successful write will increment {out_bytes} by amount of written
bytes. You can change {out_bytes} in any way, but it should always be
a number.
in_buf =q{} # modified on: IN
Each successful read will concatenate read bytes to {in_buf}. You can
change {in_buf} in any way, but it should always be a string.
in_bytes =0 # modified on: IN
Each successful read will increment {in_bytes} by amount of read
bytes. You can change {in_bytes} in any way, but it should always be
a number.
ip *RO* =undef # modified on: RESOLVED
When you call new() with {host}+{port} instead of {fh} then IP
address resolved from {host} will be stored in {ip}, and event
RESOLVED will be generated.
is_eof *RO* =undef # modified on: EOF
When EOF event happens {is_eof} will be set to true value. This allow
you to detect is EOF already happens at any time, even if you doesn't
have EOF in {wait_for}.
plugin *RO* ={}
Allow you to set list of plugins when creating object with new(), and
later access these plugins.
This field is somewhat special, because when you call new() you
should set plugin to ARRAY ref, but in IO::Stream object {plugin} is
HASH ref:
my $io = IO::Stream->new({
host => 'www.google.com',
port => 443,
cb => \&google,
wait_for => EOF,
in_buf_limit=> 102400,
out_buf => "GET / HTTP/1.0\nHost: www.google.com\n\n",
plugin => [ # <------ it's ARRAY, but looks like HASH
ssl => IO::Stream::MatrixSSL::Client->new(),
proxy => IO::Stream::Proxy::HTTPS->new({
host => 'my.proxy.com',
port => 3218,
user => 'me',
pass => 'my pass',
}),
],
MyField1 => 'my data1',
MyField2 => \%mydata2,
});
# access the "proxy" plugin:
$io->{plugin}{proxy};
This is because when calling new() it's important to keep plugins in
order, but later it's easier to access them using names.
DIAGNOSTICS
Exceptions may be thrown only in new(). All other errors will be
delivered to user's callback in last parameter.
usage: IO::Stream->new({ cb=>, wait_for=>, [fh=>, | host=>, port=>,]
... })
You called new() with wrong parameters.
socket: %s
fcntl: %s
Error happens while creating new socket. Usually this happens because
you run out of file descriptors.
can't get file descriptor
Failed to get fileno() for your fh. Either fh doesn't open, or this
fh type is not supported (directory handle), or fh is not file handle
at all.
can't create second object for same fh
You can't have more than one IO::Stream object for same fh.
IO::Stream keep all objects created by new() until $io->close() will
be called. Probably you've closed fh in some way without calling
$io->close(), then new fh was created with same file descriptor
number, and you've tried to create IO::Stream object using new fh.
SEE ALSO
AnyEvent::Handle
SUPPORT
Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker at
https://github.com/powerman/perl-IO-Stream/issues. You will be notified
automatically of any progress on your issue.
Source Code
This is open source software. The code repository is available for
public review and contribution under the terms of the license. Feel
free to fork the repository and submit pull requests.
https://github.com/powerman/perl-IO-Stream
git clone https://github.com/powerman/perl-IO-Stream.git
Resources
* MetaCPAN Search
https://metacpan.org/search?q=IO-Stream
* CPAN Ratings
http://cpanratings.perl.org/dist/IO-Stream
* AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/IO-Stream
* CPAN Testers Matrix
http://matrix.cpantesters.org/?dist=IO-Stream
* CPANTS: A CPAN Testing Service (Kwalitee)
http://cpants.cpanauthors.org/dist/IO-Stream
AUTHOR
Alex Efros <powerman@cpan.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2008- by Alex Efros <powerman@cpan.org>.
This is free software, licensed under:
The MIT (X11) License