Christopher JonesOffline Processing in PHP with Advanced Queuing (16.5.2013, 20:14 UTC)

Offloading slow batch tasks to an external process is a common method of improving website responsiveness. One great way to initiate such background tasks in PHP is to use Oracle Streams Advanced Queuing in a producer-consumer message passing fashion. Oracle AQ is highly configurable. Messages can queued by multiple producers. Different consumers can filter messages. From PHP, the PL/SQL interface to AQ is used. There are also Java, C and HTTPS interfaces, allowing wide architectural freedom.

The following example simulates an application user registration system where the PHP application queues each new user's street address. An external system monitoring the queue can then fetch and process that address. In real life the external system might initiate a snail-mail welcome letter, or do further, slower automated validation on the address.

The following SQL*Plus script qcreate.sql creates a new Oracle user demoqueue with permission to create and use queues. A payload type for the address is created and a queue is set up for this payload.

-- qcreate.sql

connect / as sysdba
drop user demoqueue cascade;

create user demoqueue identified by welcome;
grant connect, resource to demoqueue;
grant aq_administrator_role, aq_user_role to demoqueue;
grant execute on dbms_aq to demoqueue;
grant create type to demoqueue;

connect demoqueue/welcome@localhost/orcl

-- The data we want to queue
create or replace type user_address_type as object (
  name        varchar2(10),
  address     varchar2(50)
);
/

-- Create and start the queue
begin
 dbms_aqadm.create_queue_table(
   queue_table        =>  'demoqueue.addr_queue_tab',
   queue_payload_type =>  'demoqueue.user_address_type');
end;
/

begin
 dbms_aqadm.create_queue(
   queue_name         =>  'demoqueue.addr_queue',
   queue_table        =>  'demoqueue.addr_queue_tab');
end;
/

begin
 dbms_aqadm.start_queue(
   queue_name         => 'demoqueue.addr_queue',
   enqueue            => true);
end;
/

The script qhelper.sql creates two useful helper functions to enqueue and dequeue messages:

-- qhelper.sql
-- Helpful address enqueue/dequeue procedures

connect demoqueue/welcome@localhost/orcl

-- Put an address in the queue
create or replace procedure my_enq(name_p in varchar2, address_p in varchar2) as
  user_address       user_address_type;
  enqueue_options    dbms_aq.enqueue_options_t;
  message_properties dbms_aq.message_properties_t;
  enq_id             raw(16);
begin
  user_address := user_address_type(name_p, address_p);
  dbms_aq.enqueue(queue_name         => 'demoqueue.addr_queue',
                  enqueue_options    => enqueue_options,
                  message_properties => message_properties,
                  payload            => user_address,
                  msgid              => enq_id);
  commit;
end;
/
show errors

-- Get an address from the queue
create or replace procedure my_deq(name_p out varchar2, address_p out varchar2) as
  dequeue_options    dbms_aq.dequeue_options_t;
  message_properties dbms_aq.message_properties_t;
  user_address       user_address_type;
  enq_id             raw(16);
begin
  dbms_aq.dequeue(queue_name         => 'demoqueue.addr_queue',
                  dequeue_options    => dequeue_options,
                  message_properties => message_properties,
                  payload            => user_address,
                  msgid              => enq_id);
  name_p    := user_address.name;
  address_p := user_address.address;
  commit;
end;
/
show errors

The script newuser.php is the part of the PHP application that handles site registration for a new user. It queues a message containing their address and continues executing:

<?php
// newuser.php

$c = oci_connect("demoqueue", "welcome", "localhost/orcl");

// The new user details
$username = 'Fred';
$address  = '500 Oracle Parkway';

// Enqueue the address for later offline handling
$s = oci_parse($c, "begin my_enq(:username, :address); end;");
oci_bind_by_name($s, ":username", $username, 10);
oci_bind_by_name($s, ":address",  $address,  50);
$r = oci_execute($s);

// Continue executing
echo "Welcome $username\n";

?>

It executes an anonymous PL/SQL block to create and enqueue the address message. The immediate script output is simply the echoed welcome message:

Welcome Fred

Once this PHP script is executed, any application can dequeue the new message at its leisure. For example, the following SQL*Plus commands call the helper my_deq() dequeue function and displays the user details:

-- getuser.sql

connect demoqueue/welcome@localhost/orcl

set serveroutput on
declare
  name varchar2(10);
  address varchar2(50);
begin
  my_deq(name, address);
  dbms_output.put_line('Name     : ' || name);
  dbms_output.put_line('Address  : ' || address);
end;
/

The

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Qafoo - PHPSlides: Behat & Beautiful APIs (16.5.2013, 06:14 UTC)
Last Wednesday I did a little talk marathon by first presenting a Webinar on Behavior Driven Development with Behat and afterwards going straight to Cologne for the Symfony Usergroup, where I spoke about Designing Beautiful APIs. Find the slides of my talks here.
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Pádraic BradyPublishing Security Disclosures In Consumable Formats For Simpler Aggregation and Security Checking (15.5.2013, 14:43 UTC)
English: Decentralised cooperation, many-to-ma...

This is a branch off from a separate discussion on the PHP-FIG mailing list about other ways the Framework Interoperability Group can encourage and foster wider interoperability among its member projects (and by extension, the whole PHP community). I’ll start by noting two interesting developments in recent months and one long standing best practice.

1. Launch of the SensioLabs Security Advisory Checker

The SensioLabs Security Advisor Checker is described on its website as follows.

You manage your PHP project dependencies with Composer, right? But are you sure that your project does not depend on a package with known security issues? The SensioLabs security advisories checker is a simple tool, available as a web service or as an online application, that uses the information from your composer.lock file to check for known security vulnerabilities. This checker is a frontend for the security advisories database.

The service operates by having people submit vulnerability data, as YAML files, to a centralised Github repository through pull requests. The upside is that the vulnerability data can be peer reviewed and centrally dispersed either online or via a service API. The downside is that you need to find vulnerability disclosures and people to submit them. The service currently covers Symfony, Zend Framework, Doctrine, Twig and FriendsOfSymfony bundles. It’s a tiny sample of packages available through Composer. I’m also not entirely sure if it’s sufficiently fine grained to report vulnerabilities on a project’s sub-packages where you have no direct dependency on the aggregate package (e.g. using zendframework/zend-db instead of zendframework/zendframework). That said, this is a working model of a service for checking your dependencies.

That said, the service exhibits an ambitious idea – projects sharing their vulnerability disclosures or advisories in a way that allows for automatically checking if any of your projects need to have their dependencies updated for security reasons.

2. OWASP‘s Top 10 security risks for 2013 includes “A9 – Using Components with Known Vulnerabilities”

This is a new entry onto OWASP’s Top 10 (which is currently at release candidate status for 2013). In summary, it recognises that applications are becoming ever more dependent on code not developed internally. We’ve had web application frameworks for years. Composer and Github have unleashed a storm of accessible libraries, bundles, modules, and other units of reuse that have revealed Not Invented Here (NIH Syndrome) as a psychological problem in ways not previously possible.

As reliance on externally controlled dependencies increases, so too does the risk of your applications using insecure dependencies. This is a risk that requires a lot of work to mitigate. For each dependency, you need to do a security review (no, I’m not kidding), check for security disclosures (whether voluntary or involuntary) and ensure that you end up rolling out to production with safe versions.

Quoting from the OWASP advice on preventing the use of components with known vulnerabilities…

One option is not to use compone

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Paul ReinheimerHow we organize our websites (15.5.2013, 13:19 UTC)

We recently migrated Where’s it Up to our fancy new hardware, it took a bit more effort than planned (some pains surrounding our use of MongoDB) but I’m incredibly happy with how things have ended up. As mentioned earlier we’ve purchased our own hardware, and have racked it with Peer 1 here in Toronto. We’ve installed a hypervisor, and are running different VMs for critical services: MySQL, Mongo, Web Production, Web Development, etc.

Our websites sit under /var/www, so Where’s it Up resides at /var/www/wheresitup.com/. Under that directory we have /noweb/apache/ which contains both wheresitup.com and dev.wheresitup.com, configuration files for apache. The entire /var/www/wheresitup.com directory tree resides nicely in our version control system. We hand off key configuration options to our websites through the use of Apache’s SetEnv, things like SetEnv mysql_host dev.mysql, these apache configuration options represent the only difference between the two code bases.

I’ve written or maintained code that implied the state (Dev/Production/Stage) based on the Host, directory, or other factors in the past. I much prefer grabbing an explicit constant. It feels cleaner, I don’t have to read up on which variables could have been manipulated by an attacker, and I can ask the exact question I want answered: Is this dev, rather than “is the url the one that means this is dev”.

This allows us to match our Development and Production virtual machines very closely, the only difference between the two is which apache configuration file is sym-linked under /etc/apache2/conf/sites-enabled. Clearly WebDev links to the dev.wheresitup.com file, and WebProd links to wheresitup.com. We actually cloned one machine to produce the other.

Keeping the configuration files so close also makes a lot of sense to me. If I’m adding a new constant on Dev, the immediate presence of Prod reminds me that I’ll need to add it there as well. Storing the entire site: PHP code, supporting apache configuration, etc, all in once place makes it easy to avoid forgetting anything (which is easy when it's a different file on a different server). The only exception is SSL certificates. We currently host a number of our projects with GitHub, and trust them as we might, we’re not willing to hand those to anyone else.

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Brandon SavageDealing with duplicated code (15.5.2013, 11:00 UTC)
We’ve all seen it: we’re working along, and we come across code that just has a feel to it. It’s like déjà vu. You’ve seen this code before. You open another file – sure enough, there it is. The same code. Almost line for line. In large code bases, it’s likely that there are dozens [...]
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Christopher JonesGetting Started with PHP Zend Framework 2 for Oracle DB (14.5.2013, 18:56 UTC)

This post shows the changes to the ZF2 tutorial application to allow it to run with Oracle Database 11gR2.

Oracle Database SQL identifiers are case insensitive by default so "select Abc from Xyz" is the same as "select abc from xyz". However the identifier metadata returned to programs like PHP is standardized to uppercase by default. After executing either query PHP knows that column "ABC" was selected from table "XYZ".

In PHP code, array indices and object attributes need to match the schema identifier case that is returned by the database. This is either done by using uppercase indices and attributes in the PHP code, or by forcing the SQL schema to case-sensitively use lower-case names.

The former approach is more common, and is shown here.

The instructions for creating the sample ZF2 application are here. Follow those steps as written, making the substitutions shown below.

Schema

In Oracle 11gR2, the schema can be created like:

DROP USER ZF2 CASCADE;

CREATE USER ZF2 IDENTIFIED BY WELCOME
    DEFAULT TABLESPACE USERS QUOTA UNLIMITED ON USERS
    TEMPORARY TABLESPACE TEMP;

GRANT CREATE SESSION
    , CREATE TABLE
    , CREATE PROCEDURE
    , CREATE SEQUENCE
    , CREATE TRIGGER
    , CREATE VIEW
    , CREATE SYNONYM
    , ALTER SESSION
TO ZF2;

CONNECT ZF2/WELCOME

CREATE TABLE ALBUM (
  ID NUMBER NOT NULL,
  ARTIST VARCHAR2(100) NOT NULL,
  TITLE VARCHAR2(100) NOT NULL,
  PRIMARY KEY (ID)
);

CREATE SEQUENCE ALBUMSEQ;

CREATE TRIGGER ALBUMTRIGGER BEFORE INSERT ON ALBUM FOR EACH ROW
BEGIN
  :NEW.ID := ALBUMSEQ.NEXTVAL;
END;
/

INSERT INTO ALBUM (ARTIST, TITLE)
    VALUES ('The  Military  Wives', 'In  My  Dreams');
INSERT INTO ALBUM (ARTIST, TITLE)
    VALUES ('Adele', '21');
INSERT INTO ALBUM (ARTIST, TITLE)
    VALUES ('Bruce  Springsteen', 'Wrecking Ball (Deluxe)');
INSERT INTO ALBUM (ARTIST, TITLE)
    VALUES ('Lana  Del  Rey', 'Born  To  Die');
INSERT INTO ALBUM (ARTIST, TITLE)
    VALUES ('Gotye', 'Making  Mirrors');

COMMIT;

Driver and Credentials

The driver and credentials are Oracle-specific. Always use the OCI8 adapter in ZF, since it is more stable and has better scalability. Specifying a character set will make connection faster.

zf2-tutorial/config/autoload/global.php:
 return array(
     'db' => array(
-        'driver'         => 'Pdo',
-        'dsn'            => 'mysql:dbname=zf2tutorial;host=localhost',
-        'driver_options' => array(
-            PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\''
-        ),
+        'driver'         => 'OCI8',
+        'connection_string' => 'localhost/orcl',
+        'character_set' => 'AL32UTF8',
     ),
     'service_manager' => array(
         'factories' => array(
zf2-tutorial/config/autoload/local.php:
 return array(
     'db' => array(
-        'username' => 'YOUR USERNAME HERE',
-        'password' => 'YOUR USERNAME HERE',
+        'username' => 'ZF2',
+        'password' => 'WELCOME',
     ),
     // Whether or not to enable a configuration cache.
     // If enabled, the merged configuration will be cached and used in

Attribute & Index Changes

The rest of the application changes are just to handle the case of the Oracle identifiers correctly.

zf2-tutorial/module/Album/Module.php
                     $dbAdapter = $sm->get('Zend\Db\Adapter\Adapter');
                     $resultSetPrototype = new ResultSet();
                     $resultSetPrototype->setArrayObjectPrototype(new Album());
-                    return new TableGateway('album', $dbAdapter, null, $resultSetPrototype);
+                    return new TableGateway('ALBUM', $dbAdapter, null, $resultSetPrototype);
                 },
             ),
         );
zf2-tutorial/module/Album/view/album/album/add.phtml
 $form->prepare();
 
 echo $this->form()->openTag($form);
-echo $this->formHidden($form->get('id'));
-echo $this->formRow($form->get('title'));
-echo $this->formRow($form->get('artist'));
+echo $this->formHidden($form->get('ID'));
+echo $this->formRow($form->get('TITLE'));
+echo $this->formRow($form->get('ARTIST'));
 echo $this->formSubmit($form->get('submit'));
 echo $this->form()->closeTag();
zf2-tutorial/module/Album/view/album/album/delete.phtml
 <h1><?php echo $this->escapeHtml($title); ?></h1>
 
 <p>Are you sure that you want to delete
-'<?php echo $this->escapeHtml($album->title); ?>' by
-'<?php echo $this->escapeHtml($album->artist); ?>'?
+'<?php echo $this->escapeHtml($album->TITLE); ?>' by
+'<?php echo $this->esc

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Simon HolywellImprove PHP session cookie security (14.5.2013, 10:42 UTC)
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Brandon SavageCompiling PHP 5.5 From Scratch (13.5.2013, 11:00 UTC)
There’s always a lag behind new releases of PHP and releases of packages for operating systems such as Ubuntu. This lag time means that you could be kept from upgrading to the latest and greatest PHP for a year or more, unless you use an outside repository like Dotdeb. Of course, even when using one [...]
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Evert PotEscaping in iCalendar and vCard (10.5.2013, 15:57 UTC)

The #1 bug report in my vObject library (a library to parse and create iCalendar and vCard objects in PHP) is that it does a bad job escaping/un-escaping of values.

In particular, it double-escapes certain values, changing things like ; into \\; and in other cases it's a bit too liberal un-escaping.

It's gotten to a point where I got so frustrated about this bug, I've been working all week on a new version of the parser.

Determined to do things right this time, I wanted to make sure I complied with all the relevant standards, in particular:

When I first wrote the vObject I naively thought that these formats were more or less the same. On the surface it does indeed seem that way, everything does seem to follow this basic structure:

BEGIN:VCARD
VERSION:4.0
FN:Evert Pot
END:VCARD

The nuances and slight difference between the specifications are enough to drive a simple person to madness though.

Just on the topic of ecaping values (the part after the :) the specifications have the following to say:

vCard 2.1

vCard 2.1, as well as the other specs have a concept of 'compound' or multi-value properties. An example:

BEGIN:VCARD
VERSION:2.1
N:Pot;Evert;Middle;Dr.;M.D.
END:VCARD

As you can see, the N property has multiple values. Any of these values may also contain a ;, which must be escaped as \;. So we also cannot blindly encode a string and automatically add backslashes to any ; we see.

The semi-colons should only be escaped in the ADR, ORG and N fields, but we can assume that backslashed semi-colons may also appear in other values.

Any property may have a parameter, a parameter looks a bit like this:

BEGIN:VCARD
VERSION:2.1
NOTE;ENCODING=QUOTED-PRINTABLE:Handsome guy, for sure..
END:VCARD

A parameter in vCard starts with a ;, has a name and a value. Only the colon may be escaped in parameters, using \:.

If you somehow wanted to encode a real backslash though, there's no mention of escaping it as a double-backslash.

If you need newlines in any values, quoted-printable encoding must be used. Other specs all encode newlines as \n or \N.

vCard 3.0

rfc2425 says that backslashes (\\), newlines (\N or \n) and comma's (\,) must always be escaped, no exceptions.. Well except when the comma is used as a delimiter for multiple values.

rfc2426 add semi-colon (\;) to this list, except when it's used as a delimiter. Semi-colon is used as a delimiter in the N, ADR, GEO and ORG fields. NICKNAME and CATEGORIES use comma's.

vCard also says that individual parts of ADR, and N may also contain multiple values themselves, which are themselves split by a comma.

Quoted-printable is now deprecated, and should no longer be used.

Parameters have also changed. The new rule is that parameters must not contain ;, : or ", unless they are surrounded by double-quotes, in which case only " may not appear. Escaping of the colon character (\:) has disappeared.

vCard 4.0

vCard 4 changes the interpretation of 3.0 a bit, and now states that semi-colons may be escaped, depending on the property.

The implication is that we need to maintain lists of properties, if they support multiple- or compound-values and which delimiter they use (, or ;).

Semi-colons are now used by N, ADR, ORG and CLIENTPIDMAP. Comma's are used by NICKNAME, RELATED, CATEGORIES and PID.

Even though the spec does say that comma's must always be escaped, it does appear to violate this rule in it's own examples, specifically the example for GEO (which is no longer a compound float value, but a url).

iCalendar 2.0

iCalendar 2

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Brandon SavageMaking better object oriented design decisions (10.5.2013, 11:00 UTC)
Last week I finished up the first section of The Object Oriented PHP Masterclass. The class was great, and I learned about as much from my students as they learned from me. One of the most common questions I got from my students was “how do I make decisions about how to design my object [...]
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