PHP and COM

Wez Furlong < [email_address] >

Plan

What is COM?

What's it good for?

How do I use it?

Instantiation... and Monikers

Exceptions

Typelibraries

Variants

.Net Interop

ActiveScript

Persistence (experimental)

Common Object Model

Frequently mislabeled as Component Object Model

Specifies programming interfaces for OO code

Those interfaces are programming language independent

Provides a mechanism for code re-use

OLE

A subset of these interfaces are collectively known as OLE: Object Linking and Embedding

They define a way to dynamically create and invoke methods on objects that implement those interfaces

PHP COM is really PHP OLE

COM Servers

A COM Server is some module that exposes a COM interface via creatable classes

In-Proc (DLL) => fast

Out-of-Proc (EXE) => not so fast

DCOM => on another machine

Your code sees these as the same thing

What's it good for?

Talking to other applications and libraries

Most win32 software vendors provide a COM interface

Can be used to transition from ASP to PHP

Can use “easy” languages to extend PHP

How do I use it?

$word = new COM(“Word.Application”); $word->visible = true; $word->Documents->Add(); $word->Selection->TypeText(“hello”); $word->ActiveDocument->SaveAs(“test.doc”); $word->Quit();

Instantiation

$word = new COM(“Word.Application”, array( ‘Server’ => ‘otherbox’, ‘Username’ => ‘foo’, ‘Password’ => ‘bar’ ), CP_UTF8);

Exceptions

try { $o = new COM(“…”); } catch (com_exception $e) { print “failed to create: $e”; }

$e->getCode() corresponds to weird hex number (will show example later)

Typelibraries

Import constants from a COM server as regular PHP constants.

Manually

com_load_typelib(‘Word.Application’);

echo wdGoToBookmark;

From php.ini:

com.typelib_file=C:mytypelibs.txt

Variants

PHP COM is really PHP Variant

Variant is win32 equivalent of PHP typeless variables

JIT conversion in PHP 5

OLE default properties

$doc = $word->ActiveDocument;

print $doc; // prints document title

Variant Arrays

$user = new COM( “LDAP://cn=user,ou=test,dc=php,dc=net”);

$arr = $user->GetEx(“otherHomePhone”);

for ($i = 0; $i < count($arr); $i++) { print $arr[$i] . “ ”; }

Iterators

Set domainObject = GetObject("WinNT://Domain")

For Each obj in domainObject Response.Write obj.Name & "<br />“ Next

$domainObject = new COM("WinNT://Domain");

foreach ($domainObject as $obj) { echo $obj->Name . "<br />"; }

Variant Functions

Arithmetic

variant_add variant_sub

variant_mul variant_div

Casting

variant_set_type (VT_BSTR etc.)

variant_get_type

variant_date_from_timestamp

variant_date_to_timestamp

VB-like behaviour

.Net Interop

.Net is modern replacement for VB

Uses similar concepts to COM

MS provide an “Interop” layer to map .Net assemblies into COM

$stack = new DOTNET(‘mscorlib’, ‘System.Collections.Stack’);

$stack->push(‘.Net’);

$stack->Push(‘Hello ’);

echo $stack->pop() . $stack->pop();

Some Sample Scripts

Look at some common tasks implemented in PHP

Gotchas?

WMI for system monitoring

$wmi = new COM( “WinMgmts:{impersonationLevel=impersonate}” .“//{$hostname}/root/cimv2” );

$cpus = $wmi->ExecQuery( "Select * from Win32_Processor");

foreach ($cpus as $cpu) { printf(“%s %dMHz %d%% ”, $cpu->Name, $cpu->MaxClockSpeed, $cpu->LoadPercentage); }

ADO DB

Useful for transitioning ASP

Often faster to use odbc or native drivers

$conn = new COM(‘ADODB.Connection’); $conn->Open($dsn); $conn->Execute(‘update …’);

$rs = new COM(‘ADODB.Recordset’); $rs->Open(‘select foo from bar’, $conn);

while (!$rs->EOF()) { echo $rs->Fields(‘foo’); $rs->MoveNext(); }

MS Office (Word)

$word = new COM(“Word.Application”);

$word->visible = true;

$word->Documents->Add();

$word->Selection->TypeText(“hello ” . $_SESSION[‘username’]);

$word->ActiveDocument->SaveAs(“test.doc”);

$word->Quit();

Shmop mutex

Use a single instance of Word

Use mutex to control access to it

extension=php_shmop.dll

Need to be running ISAPI or Apache module on win2k and later

Shmop mutex 2

function try_mutex($timeout) { $t = time(); do { $mtx = shmop_open(42, “cwn”, 0644, 1); if ($mtx) return $mtx; usleep(200000); // 0.2 seconds } while (time() < $t + $timeout); return false; }

function drop_mutex($mtx) { shmop_delete($mtx); }

Shmop mutex 3

com_get_active_object() returns a handle to an instance from the Running Object Table

function get_one() { try { $w = com_get_active_object(‘Word.Application’); return $w; } catch (com_exception $e) { if ($e->getCode() == MK_E_UNAVAILABLE) return new COM(‘Word.Application’); throw $e; } }

Shmop mutex 4

$mtx = try_mutex(3); if (!$mtx) { .. Try again later … } $word = get_one(); $word->Documents->Add(); $word->Selection->TypeText(“foo”); $word->ActiveDocument->SaveAs($filename); $word->ActiveDocument->Close(); drop_mutex($mtx); readfile($filename);

Create a server app

The shmop idea is prone to failure if something bad happens to a request that holds the mutex

An alternative is to run a separate process as a tcp server and queue requests to it

PHP 5 makes this easy

Client for Word Daemon

$daemon = stream_socket_client(‘127.0.0.1:4000’);

if ($daemon) {

fwrite($daemon, serialize($data));

$result = fgets($daemon);

}

Word Daemon

$w = new COM(‘Word.Application’); $s = stream_socket_server(‘127.0.0.1:4000’); while (true) { $client = stream_socket_accept($s); $data = unserialize(stream_get_contents($client)); generate_word_doc($data); fwrite($client, “DONE ”); fclose($client); }

With Events

COM event handling framework is build from ‘Connection Points’

A source object is implements IConnectionPointContainer

A sink object (callback handler) implements a dispinterface

dispinterfaces allow a loose handler implementation; perfect for scripting languages

turning on events

bool com_event_sink($object,

$sinkobject [, $sinkname]);

Plumbs in event handling;

Events from $object are sunk into $sinkobject

Sinking events from IE

$ie = new COM("InternetExplorer.Application");

$ie->Visible = true;

$ie->Navigate("http://www.php.net");

IE Events 2

class IEEvents { var $dom = null; function DocumentComplete($dom, $url) { echo “$url complete ”; $this->dom = $dom; } }

IE Events 3

$sink = new IEEvents; $ie = new COM("InternetExplorer.Application"); $ie->Visible = true; com_event_sink($ie, $sink, ‘DWebBrowserEvents2’); $ie->Navigate("http://www.php.net"); while (!$sink->dom) { com_message_pump(4000); }