Posts Tagged MVC
Common Misconceptions of PHP
Posted by Craig_Strong in Design Structure, Development, Frameworks, Security, Software Reviews, Zend Framework on January 2nd, 2010
As we have just rolled over to 2010 I thought I would compile a list of 4 common questions often raised against PHP from people within the IT industry (no particular user groups). Each of these 4 statements were mentioned to me within 2009, but stem back many years in some cases. Some of these questions demonstrate plain ignorance in some cases, others just a little confusion as a result of lack of understanding or exposure. Therefore I hope this contributes to clearing up some obvious misconceptions by my provision of some brief answers.
- PHP is not a secure language
- PHP doesn’t have good support for OOP
- PHP is slow
- PHP is an amateur language
Believe it or not this was stated to me by a highly ranked person within the development community. I was very surprised that such a statement was put forward considering PHP is a scripting language and security is not a definitive answer, but an on going process in which every facet of IT must undergo constantly to remain secure. To clarify this is a case of blaming poor workmanship on the tools. Although some tools are better than others, in no way do I believe this statement to be true. PHP can be as strong as the best of them in terms of security and some of the worlds most secure systems including many systems of the financial services industry as an example which hold vast amount of sensitive information can be found to be written using PHP. When using a tool to build something, the end result is that of the craftsman effort, ability, knowledge and experience. Keeping the argument of operating system security out of this which would be hosting PHP, to obtain security you need good, experienced and security aware developers. I personally believe this misconception often raises it’s head because of other languages restrict development to the framework or coding environment and developers within these environments don’t have to confront some areas of security as a result of this. I don’t think it’s good for developers to rely upon security being dealt with away from their application by making it someone or something else’s responsibility. A good craftsman will make it their job to be aware of system security and test their application before release as well as include continuous monitoring and alerting tools to support the application. Obviously there are those which specialise in such areas and their knowledge should be referred to in times of doubt or curiosity via supporting texts and communities. PHP is as secure as the developer’s knowledge and testing/release procedure involved with it as with most other languages.
I’m surprised that some people still think this. Before the release of PHP5 including the Zend 2 Engine, which was 13/07/2004 this would have been true. However please keep up people, we are in 2010 now and OOP support for PHP has been in place for over 5 years! I haven’t written procedural code for years with the exception of the odd testing script and procedure. There are great libraries available as well for those looking to extend OOP ability including such libraries as SPL, PECL, PEAR to name but a few. There are also some very fast moving and powerful frameworks available fully supporting OOP including such Frameworks as Zend Framework, Symfony, CakePHP, Codeigniter. These are also become very popular and demand for such frameworks from the workplace is rapidly increasing (see my other post).
Yes believe it or not I have heard people claim this. PHP is pretty damn fast as a scripting language written in C. If people say PHP is slow, I don’t believe the have looked at the problem or debugged their code well enough. There are so many factors that influence speed such as the OS, memory, debug code, logging scripts, the implemented code, other applications on the server etc. If your PHP code is running slow, debug it and find the problem. It’s likely that the problem could sit with any of the above or it could be badly written code. There are good debug tools out there such as Xdebug which could save you some time finding the problem. Remember PHP is so versatile you can even extend it in C. If you are doing something very complex in PHP and by taking it down a layer might reduce some of the functions taking some time, you have the option to write an extension if needed. I personally have never had to do this, but have seen it done for a workplace specific extension and it worked perfectly and very quickly.
With full OOP support and factoring in that it’s one of if not the most widespread scripting language and as mentioned briefly in point 1 above, you can find PHP in almost all industries. Now I am not one to suggest the best technology is the most widespread (no names mentioned). However if PHP was a amateur language why is it so popular in so many professional industries which demand professional results. You can write pretty much anything you want using PHP and it can be as simple and complex as you want it to be. I have used Java quite a bit in the past and often find myself using the same code design texts to reference my PHP objects as my Java objects. I even apply the same design pattern sources for both languages. An example is the built in observer pattern interface in Java, (java.util.Observer) PHP also has this (SplObserver). Again I feel that stating that PHP is amateur is missing the point that PHP it’s a tool for the job. If amateurs use PHP you might get amateur results by the same token if professionals use it you get professional results, which is obviously the same as any other language.
Overall I think some of the questions or statements raised above are raised as a result of lack of understanding. As with most things in life some people scratch the surface of an area of interest and call themselves experts. The same experts make such judgements which create barriers for others. This could reading a text titled ‘Learn PHP in 24 hrs’ then calling oneself an experienced programmer or taking your driving test after a couple of lessons in a controlled environment and calling oneself an experienced driver confident enough to race with the likes of ‘Jenson Button’ and expect to win. Personally I have been using PHP for over a decade now and I am still learning new things everyday, particularly through exposure of different implementations. The language is moving fast with PHP6 arriving soon as well as many new and exciting related projects becoming available such as the array of frameworks which provide common interfaces to integrate with many different technologies. I would encourage anyone to look under the bonnet and get to know PHP in more depth and hopefully you will see the true power and capabilities of it.
How to explain MVC to a business and convince them it’s something they need
Posted by Craig_Strong in Design Structure on May 17th, 2009
A common occurrence many development teams will encounter is a where an older system not designed to scale well, will need to consider scale to support business demands. Businesses need to move quickly and purposefully to cope with consumer demand upon services as well as innovation induced development to compete within the market place.
It could be that your current system was designed to meet previous business goals and the extent of the specification was simply to complete a given task. You might be finding that recent business demands are taking a great deal of time to implement and that the smallest change is having huge impacts on the existing code structure. This could be as it is in so many systems, a result of tightly coupled code which is infected with design debt, or it could simply be that the original design of the systems structure didn’t consider growth and re-usability beyond the scope of the original spec.
If this sounds familiar to you, you’re probably spending a great deal of time on system maintenance and testing. The smallest changes are having huge impacts not only with relation to system integrity, but having a negative impact on the professional image of the development team. Depending on how far you have gone down this road, the business could be seeing IT as a wasteful, incompetent resource.
As you’re reading this post, it is likely that you’re thinking that to make things better you are looking at introducing MVC (Model, View Controller) into your system architecture. This MVC structure maybe something that is being encouraged by a chosen framework or simply a structure you wish to introduce into your existing system whilst refactoring your code. Either way to gain project time in most cases the business have to recognise the need for such a change and allow resources to be allocated to move towards this place where the grass is said to be much greener.
Now you are in a situation where the business already blames development teams for slower production times and pretty much for all problems and bugs that are inherit from a system which may have been subject to the ‘Big Ball of Mud‘ scenario. How can you go to the business asking for more time and resources to work on a project which unlike a product development has no physical delivery. After all if you are moving your system to MVC and/or using a framework there maybe no physical difference in the end product initially. Why would the business want this? Where is the ROI?
Respect the old code and the business
When approaching the business it’s best to be honest and upfront. There is no gain to be had blaming individuals for the current state of the system. It not only looks as if you’re diverting attention, but your colleagues aren’t going to appreciate you pointing the finger away from yourself in their direction. You should also remember at this point that it’s this system which has supported the business to date and is likely to be the same system that is supplying the current revenue stream. Although the system may need work, it has done it’s job to date.
Don’t hide the facts and don’t cushion the blow
The first rule here is to respect the business and tell them the truth. I’m sure you will be surprised to how much they actually know and that could be your first factor in common to working together towards the solution. There are plenty of examples out there on the web of successful companies who are and have been in the same situation of introducing MVC and/or Frameworks. It would be a good idea to use some of these examples as this will not only provide a knowledge pool of what did or didn’t work well, but will reassure the business that the problem the system is suffering is very common and there are clear paths forward. There is no gain to be had by raising an alarm defining how bad the current system is without researching and demonstrating clear ways forward. This won’t aid your case of supporting the development of a new structure. Use real cases and put forward some other success stories where this change has been successful to inspire the business.
How did we get into this mess
The old saying ‘Learn from your mistakes’ is relative to this exact moment. However to learn from your mistakes, you must recognise that you have made mistakes.
There are thousands of reasons why systems can incur significant design debt. Many of these reasons are comforting to know as they can happen naturally by the very nature of simply being active within successful business. It’s very likely the reason your looking to for a framework or MVC structure is that you want to support growth. Business growth has taken you to this point in time and that business growth is a commendable asset and a reassuring factor to be presented with.
Common factors of business growth that influence systems and incur design debt could be the following:
- The business has grown so fast, very little resources have been available to maintain the design.
- Corners have been cut in development to ensure products are released in a short time and therefore generate income quicker. The short cuts have never been revisited and therefore they become permanent. Additional development therefore have inherited the previous problems.
- The purpose of the system today is very different to when it was originally designed and limited effort was proposed to make the transition. Instead quick fix cultures were applied to change the identity of the system.
- Customers have become larger. As a service grows you might have moved from B2C to B2B or both. This can drastically change the demands on the system and the original business intentions/system did not consider this change or scale of change
- Limited knowledge available. In fast growing businesses the developers are expected to know all the answers without been given time to research. Therefore applying solutions are done through a limited knowledge base which is not given time to increase through training and investment.
No matter what your reasons are it would be a benefit for IT and the business to share and understand some of the reasons. Both sides understanding these will help prevent mistakes being repeated in the future, but will also contribute towards design and research to be key elements in future solutions.
Remember if your system is cracking at the seems as it can’t scale well, this could be because the business is growing fast. You would do well to respect the business for this and at the same time use this fact as a reason for current system problems. If the business is successful it’s likely they will take this on board and appreciate that speed of growth has affected development. This could provide you with the opening of working with the business to get the systems into a more robust agile condition.
Introduce MVC
Remember the business are non-technical and using jargon like frameworks and MVC is likely to confuse the listeners and as a result put up barriers. The reason you are proposing MVC as a solution is that you probably want a clear system structure which will be provide an environment which is easier to develop and maintain. However before you start getting this message across you need to explain what MVC is and what benefits it will offer.
Define the existing structure clearly
One of the reasons you might be looking for an MVC structure is that your current code structure involves code where the interface incorporates business logic, or the business logic is coupled with system logic and so on. Ignoring the reasons for this as we have briefly mentioned them above, explain this is the case to the business. The better you get the business to understand this situation the more likely they will sympathise with you and understand why there is higher maintenance times and deployment issues.
Some further reading can be found here:
http://en.wikipedia.org/wiki/Spaghetti_code
http://www.laputan.org/mud/
http://www.codinghorror.com/blog/archives/000589.html
Define MVC in layman’s terms
Remember you’re technically minded and close to the code. MVC to you is as clear as day, but saying to the business ‘Model, View, Contoller’ could give them the impression that you are suffering from some form tourette syndrome. MVC won’t mean much to the business even after you define them in relation to the code. To get the business to understand why this is the answer and least of all what it is, can be more of a task than expected in my experience. Even some fellow developers have difficulty understanding this on occasion.
To get the listener to understand what MVC is and why it works what I have tried in the pass is to apply MVC to a different industries where the listeners have had more involvement. An example that has worked for me in the past in a comparison to the property or even the vehicles. Most people have had dealing’s with builders, carpenters, plumbers, electricians or have watched the flood of property shows on the TV. This experience is a good platform to use and to explain why separation such as MVC works. I know you’re probably thinking that won’t work as it’s not the same as in software, but remember you’re not trying to train the business to become developers or have an in depth understanding of MVC, simply explaining to them that separation in production is required and that’s what an MVC structure offers.
To give an example of how you could describe this I have very briefly explained how separation works in property. Keep in mind this is focused on using the system not developing which could be a completely different angle of explaination.
View
The view in MVC is the presentation layer. This is what the end user of a product will see and interact with. A system can have multiple views of all different types ranging from command line output to rendered HTML. The view doesn’t consist of business logic in most clear designs. The interface is fit for purpose and is the area of interaction. Therefore you could simply output HTML for consumers to interact with or output SOAP/XML for businesses to interact with. Both use the same business logic behind the system otherwise known as the models and controllers.
In the world of property you could think of the view as the interior of a property or the outer layer of a property that the inhabitants interact with. The interior can be customised for purpose and the same property can have many different types of tenants. For example a property of a particular design could contain residential dwellings. The same internal space could easily be used as office space, where although in the same property has a different purpose. However the property structure is the same. Therefore the environment in which the users interact does not interfere with the structure of the building.
Controllers
The controller is where the magic happens and defines the business application logic. This could be where the user has sent a response from the view, then this response is used to process the internal workings of the request and processes the response back to the user. Taking a typical response where a user has requested to buy a book. The controller has the user id, payment details, shipping address and item choice. These elements are then processed through the business logic to complete a purchase. The data is passed through the system into the model layer and eventually after the entire request satisfies the business definitions, the order is constructed and the user receives their item.
If we compare this to a property, we could compare the ordering of a book online to turning on a light switch. A tenant will flick the switch to on just like ordering a book. The switch itself is an element in the view layer which sends the request to the controller just like clicking a checkout button on a web site. The business logic in this case is what the electrician installed and are embedded within the property designs. The switch is flicked, which completes the circuit. Electricity runs through all the wires including the fuse box straight through to the light bulb. Just like the user receiving a book, in this case the tenant receives light. The whole process behind the scenes involving the electricity cabling is not visible to the the tenant. They simply interact with the switch within the space and from there the controller handles the request.
Models
The models in MVC are the bottom most layer and handle the core logic of the system. In most cases this could be seen as the layer that interacts with the data source. In systems using MVC, the controller will pass information to the model in order to store and retrieve data. Following on from the example above controller definition, this is where the order details are stored. Additional data such as stock levels, physical location of product of the book amongst many things are all stored here. If that was the last book in stock ordered, the next request for this item may check if it’s available and disallow the order as the item is no longer available.
Sticking with out example of turning on a light switch, this level in our structure could be the electricity supply. When the tenant flicks the switch, the internal circuit must request electricity to power the request which is similar when the user requested data from the database, as in data is needed to process a request. If the dwelling isn’t connected to an electric supply, it cannot complete the process.
Business benefits from using MVC
After you get the message across explaining what MVC is, you will then have to see what benefits can be obtained from it. I’m not going to go into a huge amount of detail here are I’m sure you can apply benefits more accurately which are directly related to you actual situation. To list just some of the common benefits of an MVC based system here are a few examples:
- Different skill levels can work on different system levels. For example designers can work on the interface (View) with very little development knowledge and developers can work on the business logic (Controller) with very little concern for the design level. Then they simply integrate together on completion.
- As a result of the above separation projects can be managed easier and quicker. The designer can start the interfaces before the developer and vice versa. This development process can be parallel as opposed to being sequential therefore reducing development time.
- Easy to have multiple view types using the same business logic.
- Clear route through the system. You clearly know where there different levels of the system are. With a clear route of the system, logic can be shared and improved. This has added security benefits as you clearly know the permitted route from the data to the user and can have clear security checks along the route.
- Each layer is responsible for itself. (Relates to point 1) This means that you can have clean file structure which can be maintained and managed much easier and quicker than a tightly couple system where you may have lots of duplicate logic.
- Having a clear structure means development will be more transparent which should result in reduced development time, maintenance problems and release cycles if applied properly.
Get the message across
If you’re still reading this article you maybe either thinking the example above is a good idea or that it’s just plain silly. No matter what you’re thinking, the goal here is to get your message clearly. If this example doesn’t work for you, try finding a solution which will have the same affect. The point is for the business to support you and to consider repaying the design debt you will need them to understand what problems the current system suffers from and how you can improve things. MVC is just one of many ways forward, but they will need to understand MVC to give you the green light and have time to implement it and factor it in future projects.
This has been written from my own personal approach. However if you have something to add to this post in order to give it value, please provide some feedback. It will only improve things for the next reader.
