In preparation for the Zend Certification Exam (ZCE), Zend provides a great (sarcasm) online practice test that consists of 8 questions. That is right, 8 questions. A certification exam that consists of 70 questions and Zend offers 8 questions. And the other thing with the practice test, is that if you get 5 out of 8 correct, then you are “ready” to take the exam. Which I would not suggest, unless of course you have at least 1 year of real PHP experience coding, testing, even hacking. Plus, there is a good amount of DB stuff on the test, as well as security, streams, XML/Web Services and other stuff. I also suggest you pay (that is right, pay) for a set of practice exams. But I digress. Back to the Zend practice test. They give you 8 questions, then just tell you how many you got right/wrong. There is no feedback (like a real exam) on the practice test, which I think there ought to be. So I decided I would not only give you the answer, but why it is the answer. Following is the exam questions and the answers and why they are the answers.
Continue reading Zend Certification Practice Exam
Category Archives: PHP
Zend Certification
Another quick post this week, as I am bogged down in work and preparing for a Zend Certification Exam. I am going to be taking the exam for Zend Certified Engineer (ZCE). While I do not expect it to be much problem, these types of exams are usually worded in a way that may not give you all the basics.
I do highly recommend to visit the Zend site, download the exam prep book, and then also get a 5 pack of the test exams. The Zend store has the book and you can add on the practice exams for $17 (for 5 exams). The book explains the basics on the exam, things like network programming, XML and web services, and other items that will appear on the exam. Then if you get the 5 pack for the exam, you can take a practice test 5 times, and be able to get an idea of what the exam will be like.
Some of the questions seem like no brainers, but then there are times when the question has a key word, that makes the question mean something completely different than first appearances. One of the things I learned a long time ago, is that with these types of exams, the multiple choice has four to five questions that can be peared down quickly. Usually one is not going to be correct because of absurdity, one is going to sound like it is right, but for obvious reasons it is incorrect. Then there are the final 2 questions that can both be correct, but there is one answer they are looking for.
Sounds easy right? Would be if it was just like college, where you get to take a test, if you do not get a “pass” grade, then there are other things you can do to make up the score. With these exams, and this one in particular, it is $125 for one certification exam. You do not pass, not only are you out $125, you do not get anything, no certification of any kind. You need to pay again for another shot at the exam. So no matter how much you know a language, no matter how much you think you may know, always study and prepare. It never hurts and in the process, you may get to know more about the language than you did before.
CakePHP Auth error message
Today is just going to be a quick post. It is Labor Day here in the States and that means a whole heap of people are not going to be working, including me. So I am just messing around with some stuff in CakePHP as I am doing a side project for a local church to put up a calendar. Most of it is complete, but there was one thing that I wanted to change.
I am using the Auth component in my User model. I have allowed register, resetpass, and index. So when I go to view a user’s detailed profile, there is that message: “You are not authorized to access that location.” Which is a fine message and all, but I want it to be site specific, and also controller specific. So the Users controller will have a separate Auth error message than the Calendars controller. So here is what I did.
In the Users controller, I built a beforeFilter function. I set my authorized actions, set redirect to false. I also set a session level variable with the Auth, then I set the error message. There are a couple of messages you can set for the Users controller. You can set the loginError and the authError. The loginError will be the error when the user logs in and is unable to for whatever reason. The authError is what the user will see when they try to perform an action that is not allowed by them, whether it is because they are not logged in (as in my case) or you are using Auth to “authorize” an action.
So here is what it would look like:
function beforeFilter() {
parent::beforeFilter();
$this->Auth->allow('register', 'index', 'resetpass');
$this->Auth->autoRedirect = false;
$this->Auth->authorize = 'controller';
$this->set('my_id', $this->Auth->user('user_id'));
$this->Auth->authError = "Please log in first in order to preform that action.";
}
So when you want to change the standard Auth error message, just remember to set the “authError” to whatever message you would like. Happy Labor Day!
Access Control Lists (ACLs) Part 3
In the first part, the idea and theory behind an ACL was discussed. In part 2, the set up of AROs, ACOs, and ACLs via the command line was shown. Now in part three, we look at why this is so important. Because an interactive site with memberships should never be static, what happens when a new member signs up? What happens when a member is promoted to an “admin” level? And what happens when users change? This can all be happened via ACLs.
In part 2, existing member were set up as AROs. And with user accounts, we also have to set those up as ACOs. Then those AROs (people) need to have permissions set for the CRUD actions. (Create, Read, Update, Delete). These actions are specific to the ACO, or object they are trying to manipulate. So if a user wants to edit their own account, do they have permission? If a user wants to delete another person’s account, do they have permissions to? With setting up ACLs, this can be checked. But what do we do when a new person signs up for an account? We need to create the code to do this.
In the Users Controller, we need to make sure we use the ACL component is included. So include this in the controller:
class UsersController extends AppController {
var $name = 'Users';
var $components = array('Acl');
Also remember that the Auth and Security components are also very powerful components and should be included as well, but the above only shows where to include the components. Now with this in place, we can no address the add (or register) function of the controller.
Access Control Lists (ACLs) Part 2
In my last post, I covered a little bit about what an Access Control List (ACL) was. The Cookbook provides a great more detail.
To go along with the idea of the last post, the application has a few different areas: Users who are members of groups, Groups which have users as members, and Events that belong to either the user or the group. Since the creation of ACOs and AROs are basically the same for each area (Users, Groups, Events), I will detail some code for the Users area making use of ACLs.
The first thing we need to do is create an ARO grouping and an ACO grouping. Remember that AROs are the requester of an object. In this example, we can think of them as people. And people have different types of roles, which is what we need to create for the people. In this example application, there will be site admins (Admins), group leaders (Leaders) and regular members (Members). So we need to create this type of ARO. We can do this in a controller, and a page, or we can do this via the command line.
Access Control Lists (ACLs)
Access Control Lists, or ACLs, provide a good level of access control on any site. Code bases and platforms may use a different method of instituting ACLs and I am going to go through how CakePHP 1.2.x is handling them.
First is to understand what an ACL really is. The Cookbook has a good page explaining this type of concept. I highly recommend reading through this page. The whole concept behind this ACL can be divided in three parts:
- ACO – Access Control Object, object that is being requested
- ARO – Access Request Object, object that is putting in the request
- ACL – Access Control List, determines if an ARO can access an ACO.
In the Cookbook, they have a very good call out about the ACL, it is not authentication. No matter what code base, or platform you are on, never mistake this. The ACL verification only happens after the person logs in. They can be very powerful together, but authentication must happen first.
The next thing to understand is the way an ACL would look in a matrix. Again, the Cookbook provides a great example of this. The one thing that I would rather prefer, but understand why they do this, is the use of the example. Sure, we all like movies, and the Lord of the Rings is a great way to really explain different things, but it may be hard to switch that over to the real world of coding. So for this entry, I am going to use as an example, and Event Calendar.
Queries using CakePHP find()
CakePHP now has deprecated some queries. The findALL, findCount, etc etc etc. This now uses the find() method for all of these, and has a basic syntax for this. If it is basic, why blog about it then? Good question. The documentation is there in the API, and is there in the Cookbook, it took me some time to really get a good idea on an applicable example and took many times of “trial and error” to help me get along. Because finding is good, and will give you all the information you need, if it is a simple, 1 table find. If you need to query two or three tables, how does this work. So this will go into those as well.
The basic idea of find, as listed by the API is this:
find( array $conditions, array $fields, string $order, int $recursive );
This will find one record based on conditions, return the desired fields (or all of them if nothing is specified), order the results, and go so many levels deep (-1 for just the current table).
Continue reading Queries using CakePHP find()
Custom Pagination in CakePHP
To continue on last weeks thought of a “lite” forum, I needed 2 tables (Forums, Posts). Since this is a “lite” forum, I did not want to create a mid-table labeled topics, so I incorporated that in the Posts table. The other reasoning behind this, is that to create a hybrid forum/blog, the topic is really just a beginning post in the thread, so keep those in the Posts table, just mark it as a topic to differentiate this from the other posts.
I created two controllers, forums_controller.php and posts_controller.php. All of the links on the application will point to the forums_controller.php file. The models need to be created, forum.php and post.php, with the relationships.
The file user.php (User model) needs to have a “hasMany” relationship with Posts.
var $hasMany = array(
'Post' => array('className' => 'Post',
'foreignKey' => 'post_id',
'dependent' => false,
)
);
The Forum model needs a “hasMany” relationship with the Post model
var $hasMany = array(
'Post' => array('className' => 'Post',
'foreignKey' => 'forum_id',
'dependent' => false,
)
);
The Post model needs a “belongsTo relationship with both the Forum and User models.
var $belongsTo = array(
'Forum' => array('className' => 'Forum',
'foreignKey' => 'forum_id',
'conditions' => '',
'fields' => '',
'order' => ''
),
'User' => array('className' => 'User',
'foreignKey' => 'user_id',
'conditions' => '',
'fields' => '',
'order' => ''
)
);
Blogs, Forums and CakePHP
In one of my contracts, I am writing a full application with membership, conference signups, information pages, and a small little forum. This is all per the customer’s request. The solution I decided on, was CakePHP for the framework. It is not going to be a big, full site like a MySpace, or Facebook. It is a small local non-profit group who will be able to have its membership keep in touch via the site. So the main pages are not hard. Most of the pages will follow a simplistic CRUD (create, read, update and delete) format, with the site admins being able to create, update and delete most pages. But instead of having a static site, they wanted the membership to be able to interact with the authors of the pages, and themselves.
The pages are not hard to enable this. I could have just as easily installed a WordPress instance for the solution, themed it up, and be done. Which I was seriously considering, as this already has the permissions, updates, management, etc. However, they were not too happy with something like this. So I looked elsewhere. Drupal would provide a good out of the box solution, but there were problems with the modules, and it seemed to take too much overhead to get the groups, permissions and other CMS features set up for this small site. The next idea I looked at was going the CakePHP route. Continue reading Blogs, Forums and CakePHP
Don’t forget the basics
There was something I was asked to troubleshoot between two different environments. Most reputable places will give at least 2 different environments for application development, the best is to have at least three, development, stage, and production areas. I was asked resolve and fix an issue in the stage area, but it was not happening in the development area. Normally, I follow a few simple rules to get through this type of troubleshooting. Today, for some reason, I blew those off. Now this is not an end all be all type of list, and I use what is good for me and what I have learned. Other people may find different ways to do this, and find ways that work for them more. Here are some of the major items I check for with web applications in PHP.
- Check the Apache services, connection, or anything that would lead to just no resulting page whatsoever.
- Check the DB server, make sure the server is working, the connection is good, the data flow is there
- Check the permission of the database, the tables, the sequences, etc. Whatever is needed from the database, make sure the caller has permissions to do that task
- Check the code objects/PEAR packages/framework extensions are installed. If you have a recent version of PHP, then you should be good for PEAR, and if you have the most recent framework version (like Symfony, CakePHP or Zend) that should house them all, but never hurts to check
- Check instantiated objects, function calls, object variables, etc. Most of the time it could be a spelling error, or the call is made before the object is created
- I check the data being returned and the statements making the calls. What I am calling for may not be listed, or I may need to grab data from another table. This sometimes creates errors for other functions expecting an array and getting a character value.
- Dump the session, maybe the session variable was never set, or never started.
- Form data and POST variables are always good to give a good ol’ var_dump() or print_r().
Obviously this is not all of them, nor is this just a quick checklist. Some of these may take a while to go through, and may have a lot of details to peruse through to find the answer. This will not always give the answer the quickest ways, nor will it ever just shine the answer down to you. But it helps to isolate issues starting form the global level, work down to the application level, and then down to the code level. Plus, it helps eliminate the obvious problems first, so that when someone asks “is the printer is turned on?”, I don’t sit there looking stupid because “it is turned off” and I just never looked. But that is what happens at times.
Today, I completely forgot about permissions on a database. Sure, the code works in development, I have my hands all over that environment. But when it does not work in the staging area, I should have checked permissions instead of just lopping off my hand with endless queries to try and see where the code went wrong. Just one simple act of a GRANT permission to the application user calling the query would have fixed it. But I was forgetful and should have checked that first. Sometimes developers go down the wrong path. To stay down the wrong path, well, you can finish that one on your own.