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Date: Wed, 21 Dec 2005 11:49:56 -0400
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Subject: Change to timeout use
From: aschiffler@ic-agency.com (Andreas Schiffler)

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Hi all,

I am new to php source code hacking, but got into it for a particular 
reason: I need sub-second SOAP request timeouts.

To qualify the reasoning behind this sub-second timeout requirement a 
bit further, let me explain what it is used for: We are implementing a 
system that changes webcontent based on a remote SOAP service (i.e. 
customer database) and we want to never wait more than - say -  250ms 
for this to complete. Currently the best I can do is 1 sec connection 
timeout (in SoapClient() using the connection_timeout parameter) and 1 
sec socket-read timeout (using ini_set() on the default_socket_timeout 
parameter). Assuming the remote SOAP server is down or slow, every 
pagerender with the SOAP request in it would get delayed by at least 1 
sec, which is unacceptable in our case.

BTW, comparing the PHP situation with other SOAP implementations, we 
have typically millisecond timeouts available:
- Java (apachesoap): milliseconds
- Java (axis): milliseconds
- .NET: milliseconds
- perl (SOAP::Lite): seconds

Currently all socket/connection timeouts in PHP are implemented with 
second resolution. This is an unnecessary limitation in my view and I 
would love for this to be changed in mainstream PHP. I believe the 
effort to do so is minimal and has no impact to the users.

The timeout numbers are usually used to populate a "tv" struct - in the 
current PHP code only the tv.tv_sec is typically set.  So the change 
would simply be to promote default_socket_timeout (and similar 
variables) to a float and use the fractional part to properly populate 
tv.tv_usec with a microsecond number.

In fact I found locations where the default_socket_timeout parameter is 
assumed to be a float (ext/standard/fsock.c - line 66).
Also this simple code shows the local default_socket_context to accept a 
float parameter:
<?php
ini_set("default_socket_timeout",0.5);
phpinfo();
?>
while ext/standard/file.h - line 113 stores it as a long.
So a quick review of how this parameter is used throughout the code 
might be a-good-thing (TM) anyhow.

An example implementation of the new, float resulution timeout use for 
the SoapClient/SoapServer is a few lines in ext/soap/soap.c and 
ext/soap/php_http.c as follows:

soap.c
                if (zend_hash_find(ht, "connection_timeout", 
sizeof("connection
                    Z_TYPE_PP(tmp) == IS_DOUBLE && Z_DVAL_PP(tmp) > 0.0) {
                        add_property_double(this_ptr, 
"_connection_timeout", Z_
                }

php_http.c

        if (zend_hash_find(Z_OBJPROP_P(this_ptr), "_connection_timeout", 
sizeof
            Z_TYPE_PP(tmp) == IS_DOUBLE && Z_DVAL_PP(tmp) > 0.0) {
          tv.tv_sec = floor(Z_DVAL_PP(tmp));
          tv.tv_usec = (1000000.0*(Z_DVAL_PP(tmp)-floor(Z_DVAL_PP(tmp))));
          timeout = &tv;
        }

Similarly changes in the main PHP code could look something like this 
(assuming the var is a float):

main/streams/transport.c

    default_timeout.tv_sec = floor(FG(default_socket_timeout));
    default_timeout.tv_usec = (1000000.0 * 
(FG(default_socket_timeout)-floor(FG(default_socket_timeout))) );

The files that need to be changed are limited.
    grep -c default_socket_timeout ind . -name "*.[ch]" | grep -v :0
gives
  ./ext/imap/php_imap.c:4
  ./ext/standard/file.c:1
  ./ext/standard/file.h:1
  ./ext/standard/fsock.c:1
  ./ext/standard/streamsfuncs.c:2
  ./ext/openssl/xp_ssl.c:2
  ./main/streams/transports.c:2
  ./main/streams/xp_socket.c:3
  ./main/network.c:2

    grep -c default_socket_timeout ind . -name "*.[ch]" | grep -v :0
gives
 ./ext/ftp/ftp.c:2
 ./ext/curl/streams.c:1
 ./ext/soap/php_http.c:1
 ./ext/session/session.c:3
 ./ext/sockets/sockets.c:5
 ./ext/standard/uniqid.c:1
 ./ext/standard/lcg.c:1
 ./ext/standard/fsock.c:1
 ./ext/standard/streamsfuncs.c:4
 ./ext/openssl/xp_ssl.c:2
 ./main/streams/xp_socket.c:2
 ./main/network.c:2

Best regards
Andreas


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