PHP Embedded View as Markdown

Johannes Schlueter wrote:

Hi Mark,

Is there a way from within the embedded system to destroy all created
variables so that the environment is the same as when it was started or do
we need to shutdown the embedded engine and start it up again?

PHP was designed as an language running as an module inside an webserver to
run multiple, independent, request, one after each other. So PHP supports
reinitilizing the engine without restarting everything. Look around for
php_request_startup() and php_request_shutdown() and how they are used.

Also a problem they are coming up with occasionally is that the php engine
will crash when

php_embed_init(argc, argv PTSRMLS_CC);

is called, they havent found any reproducible steps yet. Could this be
caused by shutting down and starting up the emdedded engine from within the
same app? I have asked and the application isnt multi threaded.

Here one can't say much without any details (relevant code and backtrace)

php_embed_* are afaik wrapping up the complete engine und request init and
shutdown. If you want to do multiple independent requests you should take an
a bit closer look on the SAPI layer to use the functions I mentioned above.

If you want an example of doing request startup/shutdown multithreaded
with the embed SAPI and are willing to wade through a bit of XS, you can
check out the PHP::Interpreter Perl module (on CPAN:
http://search.cpan.org/dist/PHP-Interpreter/). That links against the
embed SAPI but uses the native engine calls for handling request
mortality. You could also check out Sara's runkit in PECL, I think that
does similar stuff.

George

Here one can't say much without any details (relevant code and backtrace)

php_embed_* are afaik wrapping up the complete engine und request init and
shutdown. If you want to do multiple independent requests you should take an
a bit closer look on the SAPI layer to use the functions I mentioned above.

I thought that would be the case, thanks for the info provided, I will
pass that on to our c++ guys.

There are quite a few "embedding PHP in an application"-examples in
php-src/sapi. If you don't like reading that code wait some weeks and you
might get Sara Golemon's not yet released book (ISBN: 067232704X) about
"Extending and Embedding PHP" if that's to late you might want to fetch
George Schlossnagle's (ISBN: 0672325616) which is anyways a good read about
"Advanced PHP Programming" and has a few chapters about PHP internals like
the SAPI layer.

Thanks, those books sound interesting, I guess I will buy both since you
can never have enough reference material IMO.

Thanks for your time.

Regards

Mark

you might get Sara Golemon's not yet released book (ISBN: 067232704X) about
"Extending and Embedding PHP"

I just did a search on Amazon for the above ISBN and it returned a book
as follows

Extending and Embedding PHP - Wez Furlong, George Schlossnagle
Paperback 448 pages (March 2005)
Publisher: Sams
Language: English
ISBN: 067232704X

Is this the right book as it has a publish date of March 2005.

Regards

Mark

Hi All

I am back again :-)

Here one can't say much without any details (relevant code and
backtrace)

The c++ guys are still having some problems and they have given me some
more info..

The app is init'd using the following

__declspec(dllexport) void InitPHPEngine(const CString& sStartupDir)
{
static bool bInitialised = false;

if (!bInitialised)
{

int argc = 1;
char *argv[2] = {"Actinic", NULL};

php_embed_module.ub_write = ub_write; // output is redirected to our
callback function
php_embed_module.log_message = log_message;
php_embed_module.sapi_error = sapi_error;
php_embed_module.php_ini_path_override = ".\";
php_embed_init(argc, argv PTSRMLS_CC); // init the engine
CString sInit = PHP_INIT_SCRIPT;

if (!sStartupDir.IsEmpty()) // if startup dir is defined
{
CString sPath;
sPath.Format("chdir("%s");",
CTextUtils::MakeStringSafeForQuotedPerlFragment(sStartupDir));
sInit += sPath;
}

zend_eval_string(sInit.GetBuffer(), NULL, "main" TSRMLS_CC);
bInitialised = true;
}
}

They then have a method

BOOL PHPEvalString(const CString& sCode, zval *pzvalResult, bool
bExpression)
{

CString sPreparedCode;
if (bExpression) // we should apply a trick for expressions
{
sPreparedCode.Format(_T("%s ? true : false"), sCode);
}
else
{
sPreparedCode = sCode;
gsPhpOutput.Empty();
gsPhpOutput.GetBuffer(sCode.GetLength()); // preallocate the string -
hopefully the result has similar length as the original script, so
probably that's a good guess
gsPhpOutput.ReleaseBuffer(); // doesn't release the extra bytes
}
char* pcScript = sPreparedCode.GetBuffer(sPreparedCode.GetLength());

zend_first_try
{
PG(during_request_startup) = 0;
int nResult;
if (bExpression)
{
nResult = zend_eval_string(pcScript, pzvalResult, "main" TSRMLS_CC);
}
else
{
nResult = zend_eval_string(pcScript, NULL, "main" TSRMLS_CC);
}

if (nResult == FAILURE)
{
return FALSE;
}
}
zend_catch
{
return FALSE;
}
zend_end_try();

return TRUE;
}

Therefore they want to shut down the request after the line

nResult = zend_eval_string(pcScript, NULL, "main" TSRMLS_CC);

and restart it for the next call

But doing

nResult = zend_eval_string(pcScript, NULL, "main" TSRMLS_CC);
TSRMLS_FETCH();
php_request_shutdown(NULL);
php_request_startup(TSRMLS_C);

Causes an immediate crash when it reaches php_request_startup(TSRMLS_C); :(

Also because init, eval and shutdown are in separate functions tsrm_ls
is defined as static in the app.

The also sent me the following backtrace if its of any use..

php4ts.dll!00d45b61()
php4ts.dll!00d45622()
user32.dll!77d6ebe2()
php4ts.dll!00d43e16()

ActPHPRunner.dll!PHPEvalString(const
ATL::CStringT<char,StrTraitMFC_DLL<char,ATL::ChTraitsCRT<char> > > &
sCode={...}, _zval_struct * pzvalResult=0x0012e558, bool
bExpression=false) Line 372 + 0x7c C++

Any advice is greatly appreciated.

Regards

Mark

HI Michael

I have made an unaccepted php_embed extension available at
http://www.badcode.be/~descript/PHP/php_embed/
Take a look at the example :
http://www.badcode.be/~descript/PHP/php_embed/examples/pembed_new.c
I use this part of code on my software with C++
If you have questions ...

Great many thanks, I think I am finally starting to understand how this
all works.. Look out world... c++ newbie coming through :-D

Regards

Mark