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ive seen many third party mvcs or frameworks such as codeignitor , cakephp, and so on. what i want to know is what are their purposes? ive created my own framework call it an mvc or framework (in my opinion their all the same). in my framework i have all the classes in one folder called classes and all functions in another. its all organized and when a new project comes in i am able to complete it fast. i have looked at the applications that i mentioned and it seems to have huge articles and tutorials to study. what is the purpose? why not study the main language such as php, javascript/ajax or jquery, and so on then build something that you know the ins and outs of so that any project comes your way you know what to do. ive known some people who use cakephp and for every project they get stuck and need to figure out what to do. another guy i knew worked with joomla and every basic company website that came his way he would reverse engineer joomla to make it work with the site. are people using these applications because they lack knowledge in the languages? or sometimes have no choice but to make a site while lacking language and put something together.
ps: i dont want to say which is better or argue, i want to understand and see if im missing anything.
Standardized frameworks make it easy to adapt and reuse blocks of code. By using a framework such as Zend, Cake, Joomla, etc. you can find repositories of pre-made scripts and components that easily plug into your existing site.
Not only that but frameworks will (in most cases) handle a lot of complicated, repetitive tasks that are standard across most websites. Frameworks will in most cases scaffold CRUD classes against your database automatically and support a clean separation of logic and view.
Frameworks aren't for everyone and I would actually recommend that newcomers to programming or PHP learn the basic syntax and object structure. Doing so will give you a stronger understanding of how your framework behaves and make it easier for you to modify/override the existing structure. Every framework is different, and some are better suited than others for particular tasks. You should do research and testing to see which one fits your needs.
One other benefit that hasn't been mentioned yet is that using a standard framework gives some shared knowledge between developers. If you build a project with your home-grown "framework" and then someone else has to maintain it in the future, they have to totally learn your methods from scratch. However, if you had used CakePHP, and they already have experience with CakePHP, they're going to have a pretty good base to start with. That can make a huge difference in the amount of time it takes them to get comfortable with a new system.
If you want to setup a project quickly, without having to know too much about everything underneath, using one of these frameworks can be very useful. You know, to some extent at least, that they're pretty well built and reliable, and it saves you a lot of time opposed to creating everything yourself. Most of them are also easily extendable to add functionality you might need.
But you're right, it's always a good thing to learn about all the basics. That way it's a lot easier to know what these frameworks exactly do, and more importantly, why and how. And knowing that makes it easier to choose the right framework for you and extend it in a proper and efficient way.
But in the end you'll learn from both approaches, the difference being that with an existing framework you can get start working with a site (almost) right away.
I too use my own home-built framework that took many months to develop, but for every project I still weigh the pros and cons of using a 3rd party framework. The decision usually comes down to the specifics of what I want to achieve. For example, in database-centric applications, I use my own framework because the ORM solutions of most of the well-known frameworks are just downright terrible and inefficient, but for something simple like a Blog, Codeigniter might be my choice (just because I hate Wordpress, which isn't even a framework but I have to mention here how horrible it is).
But keep in mind that while you know the ins and outs of your own framework, if anyone else has to maintain your project later on it will be difficult especially if you don't document. Big frameworks like CakePHP, Kohana, Symfony, etc. are fairly well known and it's easy to find others who have experience with them. Plus if you need help, all you have to do is post on their forums and chances are you'll have a good answer.
Another point is the maintenance of a home-built framework. More often than not this comes second to developing new sites or maintaining old ones, whereas a standard framework has a team of developers behind it. Any security issues in the framework are addressed and patched more rapidly and you can usually just upgrade the framework and keep your code intact.
So, I'm very tempted to rewrite my application using a php framework, as I think it'll make it easier for folks to get involved, as well as improving the design of the app.
CakePHP looks like the best of the PHP web frameworks. Does anyone have any experiences of it? What are the caveats I should consider going from handcoded PHP to using a framework?
Not depending on the framework you'll chose, the first thing you have to know is that :
it'll take some time for you to know it
you'll do crapping things, during that time ^^
so, take into account the fact it'll take some time before you are fully operational :-)
I think those points are the most under-estimated points : using a framework takes not much time... Using it well and to the full extend of its abilities takes... Well, a couple of months, maybe... Which means, when you are at the end of your project you'll say "I should rewrite that with all the stuff I learned while re-writing it the first time" :-D
What it means is : learn what the framework can do, learn how to use it, and use it for a while on small applications, before starting rewriting your big one !
Then, there is probably no "best framework" : one framework may be very well suited for one project, and another one may be best for a second, different project.
I've never worked with CakePHP ; I really like Zend Framework. But that is a personal opinion, and O know people who really like symfony ; they are not wrong : symfony is great -- and I am not wrong either ^^
Still, we sometimes agree on some things ; like the fact that Doctrine (default ORM layer of symfony) is really great stuff, and we tend to use in both symfony and ZF-based projects...
If motivated, you can take a look at many posts on SO, about frameworks... Here are a couple of those :
What PHP framework would you choose for a new application and why?
Is Symfony a good framework to learn?
What, in your mind, is the best PHP MVC framework?
Is Symfony a better choice than Zend for a web development shop (10+) because it is a full stack framework?
Best PHP framework for an experienced PHP developer?
Good luck with those ^^
("Which framework" is a quite pationnating -- and subjective -- question ^^ )
CakePHP has it's good parts but there is no "best" framework. Here's a thread with some clues about what's good in most popular PHP frameworks.
If you never used MVC frameworks before (and Cake is MVC framework) I think you should first familiaze yourself with MVC architecture.
"CakePHP looks like the best of the PHP
web frameworks."
This is subjective. You should compare the pros/cons of other PHP frameworks that will suit your needs.
These posts may help you:
https://stackoverflow.com/questions/2648/what-php-framework-would-you-choose-for-a-new-application-and-why
Why do I need to use a popular framework?
https://stackoverflow.com/questions/249984/php-framework-decision-analysis-paralysis
FWIW, I used it for a time when I was doing some php development. I found it easy to use, and the rapid development aspect was great, and I would imagine has just gotten better in the last 3 years. There is a ton of help in the irc channel, and the documentation is good. I didn't stick around in PHP long enough to become an expert. However, I was just starting out as a programmer then, and ran into Larry Masters (the creator, aka phpnut) and he was just a good person to talk to about design principles, and an all around nice guy. Then again you don't have to be a super nice guy to write a good web framework (I'm looking at you DHH).
Most of the frameworks "bind" you to them, meaning you have to do things their way. If you want to do something they weren't designed to do, you usually have to hack it. For example, how many PHP frameworks currently support Facebook Connect?
Personally I prefer "frameworks" that you can use only the parts you want. Zend is like this, Doctrine and Propel are ORM that are designed to be used with other code. For example, the Symfony framework can use either.
Finally, I haven't found a popular PHP framework that scales well.
I have used cakephp for a couple of projects. From the moment I learned it I have never written php again without it (unless is fun code in which I want to try some new stuff, or learn other design ideas away from MVC). As mentioned, learning it will take some time. How much time it takes really depends on your background. If you have used another MVC framework for a web scripting language then you will learn it really quick; RoR developers will pick it up within hours/days. If you don't have experience with MVC frameworks then it might take you a little bit, but it will really save you time later on the road (including in that project you start with).
Until today, I still learn new things about CakePHP every time I start a new project on it, although I do dig into a lot of its source code (you definitely don't need to do this, documentation and help boards are more than enough).
I definitely recommend you looking into it. It will save you a lot of time and get your head thinking in a different way (if you are not used to the MVC).
Best of luck.
CakePHP's convention over configuration approach has a few advantages once you learn them:
it helps to keep you code organised and understandable
makes it easier for multiple developers to collaborate on the same application
makes it possible for developers to understand other developers' applications
You have two main options when rewriting a legacy application in CakePHP:
change the database schema to reflect the conventions - resulting in less code
code your models to interface with the legacy database - this book goes into all the details
Either way, once you have done the above, it's pretty much plain sailing, and a good learning experience.
This isn't a question about what framework to use. I've learned both Rails and Django, and I write all of my webapps in PHP. My question is why bother with the frameworks? It's always taken me longer to use a framework than to reuse old MySQL code and build "models" with phpMyAdmin. I also like writing everything myself, because I know what's going on. I can still reuse functions, etc. and do things how I want, and this freedom seems to be missing from most frameworks.
I'm not saying that my way is right; in fact, I'm trying to figure out where my logic fails. The hype can't be just thin air. What am I missing?
The basic idea of a framework is to allow you to work at a higher level of abstruction and write only the code you have to write to implement your specific requirements. All the other repetitive stuff is handled for you by the framework, and probably with far fewer bugs and security holes than if you did it yourself.
It may feel like it takes longer to learn a framework than to just do it yourself using basic language features and standard APIs, but it's simply not true - not if the framework is good and the app is non-trivial, and especially not once you have learned the framework (using a different one for each new project would of course be idiotic) and factor in the time it would take to find and eliminate all the bugs and correct all the design mistakes that have long since been found, eliminated and corrected in the framework by its developer community.
Almost every developer has cowboy coder instincts that tell him "Doing things yourself is much more fun than using code others have written, and I'm sure I'm good enough to get it right the first time, so it will even be faster and better!". These instincts are almost always wrong.
Frameworks allow you to concentrate on the application itself rather than worrying about the boilerplate code that you'd otherwise have to write for every application. They allow you to structure you site in a much more logical (mostly object-oriented) way, using tried and tested design patters such as model-view-controller. The code in framework is generally more mature and of a higher standard than code you would write yourself for one-off projects as framework have a large community of developers perfecting the code perfecting the code over year. This means that framework-driven sites often perform better and are much more secure.
You also mentioned you like writing things yourself - I know where you're coming from. My solution to this was to write my own framework - I get to reuse and improve my code with every project I do and I know the entire codebase inside out.
Writing it your self may make it easier for you to understand things your self but unfortunately it can make it much harder for other developers to understand what is happening. Frameworks will often be better documented and have a larger community that can support a new developer that is working on the app that you wrote.
I think a big part of it is what you focus on. Frameworks standardize the parts that you shouldn't have to keep revisiting, which helps you focus on the application as a whole. If you reuse your own code all the time you're already using your own makeshift framework.
Your comparing a framework (Rails) to a language (PHP). A framework is going to give you pre-built components so you can spend time on what makes your project unique.
You may already have a code base that helps do this for you. Check out some of the PHP frameworks since that's where you are more comfortable. Take a look at CakePHP, CodeIgnitor and/or Zend Framework.
If you are building many small apps/sites, using a framework may make your life easier.
I think a good step for you is to create your own framework with the code you've programmed so far. ;)
Try to make your code parametrizeable, in other words: create components which you can reuse in different parts of a website (for instance: styled containers), or in different websites (form generators/validators).
You can even go further and create base-classes from which you extend new classes to build your websites. (for instance: data objects with generic select/insert/update/delete methods).
I bet this gives you the best view on why frameworks are so damn handy ;)
It'll take you longer to initially use a framework for the same reasons a PHP developer would take longer to initially use Ruby - you're not familiar with it.
Once you're familiar with them, frameworks can offer the ability to skip the mundane and focus on actually writing the important parts of the app.
You should also just use a PHP based framework like Symfony or CakePHP using them should reduce your production time considerably.
One reason to use a frame work is code separation. Take symfony for example. The model is all done with propel or doctrine libraries. Very little SQL needed. You instantiate a new object and user getters and setters, to store your data, and instead of writing SQL in your page code you create functions in the objects related to the query. When you need to access the same kind of data on different pages you are asking the model for it, keeping the business logic with the model where it should be, so there's never any difference. All the work is done in the "action controller function". You get all the data you need, and then put as little php in the display, basically just echoing the variables you got in the action controller, (with the exception of some for loops and if statements for conditionals. I have found this a more efficient way to code, and on my 2nd project saw the production time cut in half.
You don't need to learn a new language python/ruby just to use a great framework, just have to fin one that works for you.
First, PHP has frameworks too, so the question as stated misses the point.
Yes, you can write your own framework, and as Kris said, there's no shame in that. However, part of the leverage of code reuse is the collective value of the efforts of many. It's not just about reusing your own code. Frameworks encapsulate the common tasks and patterns we all share and provide well tested solutions with many iterations of improvements from the community. No individual effort is going to measure up to that, no matter who you are.
If you roll your own, it will only become world class due to the collective effort of world class people, and that will only happen if your idea merits the attention. The top frameworks out there are already proven on those criteria.
DHH is a smart guy, but the Rails we have today never could have been realized by him alone. Not even close.
If you like "writing everything yourself" as you say, then choose a framework with a core philosophy that matches yours, and start making core contributions in the areas where you can see room for improvement.
Depending on the functions of your Web Application, it can be faster to develop without a framework. For example when the Webapp is just some kind of data viewer.
But as soon as you begin to implement more advanced functions, you are much more efficient with a framework.
Try do do this from scratch:
- proper Form validation
- Handling of multiple Language and Date/Time formatting
- Authentication
See a framework as free tools and stable implemented function for you to use.
Sounds to me like you have already written your own framework in php, since you do mention code reuse.
I can imagine it being easier to use your own set of wheels instead of adapting to someone else's. No shame in that.
Frameworks are there mainly to help people who are semi-new to PHP (or the specific language it is built on) to be able to build a website to an extent that it is secure and easy enough to add on extra parts to the site without having to know a lot about the specifics like security, MySQL (or other database types). In my opinion it is a fairly good way to help break coders into a language, allowing for the fact that the framework isn't too complex of course.
EDIT The reason behind me saying they are for beginners is because myself, as a beginner has used frameworks to break myself into languages a lot better.
I have a relatively simple application up and working with some basic functionality which i have built as a bit of a project. I would like to now build on that, and add some more complex features, including login.
The code has got quite complex, and it's written in plain php, so all the presentation code is mixed in with the logic. I have decided that before I go any further I'd like to re factor it to separate this out, so it's easier to maintain and add to. I've been researching MVC and think that's the way i should be going.
I had decided to give the zend framework a go, and have spent a while trying to get to grips with it, however I have found the learning curve extremely steep as I have no object oriented experience.
Is there another framework or option that anyone could recommend? I am considering having a look at cake based on reading other posts in this forum but I'd accept any guidance - my "requirments" are
easiest to learn for non OO experience
includes some login / authentication features
handles database interaction with mysql easily.
All suggestions appreciated!
As stated very eloquently here already, frameworks are good until you want to do something they're not suited for, plus they can abstract the language to the point where you're effectively learning them rather than the language you're coding in.
I would encourage you to roll your own. If you understand the principles of MVC and you have a fair-to-middling knowledge of PHP then it won't be too hard (there's already several pointers around), plus you'll come out of it far further ahead than if you'd just used someone else's.
Smarty templating engine.
http://www.smarty.net/
I've personally used Symfony. It's a very complete and well-supported framework which is relatively easy to get started with. My experience with frameworks is that for simpler projects they can be quite a burdon.
The people at my workplace swear by Cake. It does seems to be quite flexible and certainly fast to develop with once you know it. However, I would echo da5id and say that it's always safest to build your own - you know exactly how it works, you get some good PHP experience (instead of Cake experience), and you don't have to spend hours either fighting with it to get it do do what you want, or reading up on how to use it in the first place.
I am not at all convinced that "MVC" really exists as a paradigm in PHP incidentally - the V and the C are so hopelessly intertwined in most cases because the form is the view.
Build yourself a code generator that will output PHP classes based on your database tables. If you're really clever you can get it to inspect the database for relationships and even build the joins in PHP too. Then create a second set of classes that each inherit from the table-based-class that lets you customize its behaviour. Rely on these secondary classes in your business code. (It's a form of the Generation Gap pattern)
In addition to being a framework, Fat-Free also has its own templating engine that goes beyond just variable substitution. It allows you to invoke functions and class/object methods along with familiar PHP-like expressions.
I've been a PHP developer for many years now, with many tools under my belt; tools that I've either developed myself, or free-to-use solutions that I have learned to trust.
I looked into CodeIgniter recently, and discovered that they have many classes and helper routines to aid with development, yet saw nothing in the examples that I couldn't do just as easily with my own tools. Simple things like DB abstractions, Email helpers, etc. There was some interesting code relating to routes - mapping urls to the right controllers; but even that's not particularly difficult to code yourself if you've ever written an MVC style web app with pretty urls.
Even after looking through some of the other popular frameworks, I still see nothing that would be that much of a time-saver. Even looking at the forums, I see people struggling to get the tools to work for them. I do understand how they would be more useful for junior developers, since full system design skills take a while to understand and appreciate fully.
Yet, I'm often told that I should use an off-the-shelf framework to produce my solutions, but I still remain unconvinced. What's the real benefit to someone like myself? Am I just being elitist, or is this a common opinion?
Edit: Looking at some of the answers here, should I perhaps consider packaging up my toolset as its very own framework, writing some documentation and posting tutorials? If I'm hesitant to take on other's frameworks, would opening it up and getting more eyes on it help to improve my own skills/tools?
Frameworks have several advantages:
You don't have to write everything. In your case, this is less of a help because you have your own framework which you have accumulated over the years.
Frameworks provide standardized and tested ways of doing things. The more users there are of a given framework, the more edge cases that have been encountered and coded for. Your own code may, or may not, be battle hardened in the same way.
Others can be recruited onto a project with a standard framework and have access to the documentation, examples and experience with that framework. Your own snippets may or may not be fully documented or have examples of use... but isn't much chance that others are comfortable with them initially.
EDIT:
With regards to your idea of packaging up your own framework, the benefit of cleaning it up for public consumption can be larger than the benefit of getting others to use it.
The reason is simple: you will have to re-evaluate your assumptions about each component, how they fit together and how clear each piece is to understand. Once you publish your framework, your success will be strongly dependent on how easy it is to get up and running with.
Big wins with little effort are essential for adoption (those wins will encourage people to delve further into the framework). Ruby on Rails in an example of a framework that gives such big wins with little effort, and then has hidden layers of features that would have overwhelmed someone just getting started. (The question of the quality of RoR apps is not the point, the point is about adoption speed).
After people adopt a framework, it is about the ease of continued use. Little details like consistent parameter use patterns make all the difference here. If one class has many parameters on every method, while another has setters that are expected to be called before invoking methods, you will lose users because they can't get a "feel" for what is expected in a given case without resorting to the documents.
If both ease-of-adoption and ease-of-living-with issues are addressed properly, you only have to get lucky for people to adopt your framework. If those issues are not addressed properly, even an initial interest in the framework will wane quickly. The reason is that there are many frameworks: you will need to stand out to gain the advantages of having others using your kit (as they rightfully are as wary of your framework as you are of others).
Here's another reason not to create your own framework. Linus' Law - "Given enough eyeballs, all bugs are shallow". In other words, the more people who use a given framework, the more solid and bug-free it is likely to be.
Have you seen how many web frameworks there are for Java? Back in the day, it was fashionable for any half-decent developer/architect to write their own custom web framework. And at the end of the day, 95% of them looked like a custom implementation of Struts (the most popular Java web framework at the time). So they basically created a Struts clone that was: 1) proprietary; and 2) not as well documented and tested.
Let's face it - writing our own customer framework is fun, but what happens next? It becomes a maintenance burden to keep up with the framework yourself (or the poor soul who replaces you). And maintaining software is much, much more costly, especially when it comes to custom frameworks. Is the company in business to solve domain problems or in the business of maintaining frameworks?
I forget who said it, but I once heard a great quote - "The first rule to creating your own framework is: don't". Somebody else has probably gone through the effort of doing so and probably done the same work you would have done. Save yourself the time, effort, and testing.
There's many comments here as to the advantages of using a framework, and certainly I think in a good many cases they are perfectly correct.
HOWEVER
All frameworks come with the downside that they have a domain of problems that can be fitted into them. If your problem is well inside the scope of the domain then using a framework isn't an issue, and most of the time it's readily apparent if your problem is well outside the domain so you don't give it a thought. Issues arise when you try to force a problem into a framework that it just doesn't quite fit into or has some unusual non-standard feature - in which case you complete 90% of the code really fast then spend all the time you've saved figuring out how to bend or extend the framework so it can accomplish some obscure requirement. Because in these case your solution/extension has to plug into the framework it can often be more difficult to code than if you'd come to it independently.
In the wrong circumstances this can actually be disastrous. For example if a client asks for a project that you believe will fit into a framework solution and you quote accordingly, then after completing 90% you find the gotcha then you can be really up the creek, especially if it's some feature that the client is insistent upon (and it always is). These issues tend to arise because it is not always apparent from the word go where the gotchas might lie, particularly if you're using a framework you are less familiar with (and you have to from time to time).
This is really the same problem as arises with deploying any third party software in a project. Myself from experience I have no qualms about using frameworks or similar, but given the choice I will always go for the lightest, thinnest, wrapper I can find that will do what I need. That way I gain the advantages, whilst knowing that if issues do arise (and they are generally less likely to with a thinner wrapper) then figuring out how to work around them is likely to be simpler than learning an extensive code-base to the point where I can safely modify it.
The framework code is likely to be well-tested and relatively free of bugs. By using it you save yourself time testing/maintaining your own code to do the same thing.
And any time saved is good. Laziness pays off in programming.
One thing that you will be missing out on is all of the Validation that goes into a popular framework.
Your routines simply don't have the same exposure that the popular libraries have.
You may have a point.... however I wouldn't underestimate the power of many, as an example phpBB is as far as i'm concerned the bb solution to use. Why? Because there are many, many thousands of posts on their support boards and many people using it who are knowledgeable and can help people solve problems.
Therefore the only reason in your case to use a popular framework is the many others that use it, report bugs against it, fix it and support it. It'll be tricky to get the same coverage on your own libraries.
I would go against the grain here, and say, you should use your own custom framework, If the software you are building is the core of your business. As Joel would say, "Find the dependencies - and eliminate them". If you are just putting up a little website for your company, and you business isn't maintaining websites, then go ahead and use a framework. But when that website is your business, then you shouldn't depend on a framework from somebody else to let you get the job done.
I think the main reason is that when you use a common framework, there are a lot of people who are instantly familiar with your product.
Apart from that I think it's most important that whatever tools you use actually get the job done. If it happens to be familiar to other people, then that's a bonus.
I agree you should use your own custom framework. Not only is it easier for you to understand, but it provides the ultimate in job security!
Three reasons I can think of immediately:
A well-known framework will be familiar to other developers who may have to work on your project
A well-known framework will have resources like books, discussion boards, and other experts that can be used for finding out more information
Managers will often have a "don't reinvent the wheel" philosophy. In fact, existing solutions have probably solved the same problems that you'd discover if you create your own solution.
All of that said, there may still be a place for your own solutions. We wouldn't have so many frameworks (or scripting languages) to choose from if no one started something new.
Any experienced developer can build a framework -- the challenging part is convincing others that it's worth using. You'll need to create documentation and tutorials for it for those who plan to use or maintain it. You'll probably need to create a demo site to prove that its useful and actually works like it's supposed to.
That alone can be a considerable investment, not including bugs that could pop up in between. When its all said it done, it could be worth spending time learning another framework instead of making your own.
You mentioned CodeIgniter -- I personally feel like that's a pretty framework -- it doesn't get much more barebones than that.
What you essentially have is your own framework. So, it isn't a time-saver FOR YOU, because you have already spent the time to develop the framework. If you didn't have that to build from, it would certainly be easier and faster to use an existing framework than to roll your own.
What you need to look at is whether or not your framework is better than other options out there, and whether your familiarity with your own code outweighs having other eyes looking at it, and other people using it in enough different ways that the likelihood of any problems being found and corrected is much higher.
Also, if your framework is so much better than everyone elses', you might consider opening yours up to the community ;)
As you probably know: "time is money". So by using a popular framework with a lot of helpers, a lot of code examples on web and a big community you do more in less time.
Sometimes it if ok to use frameworks because you become more productive, but in some advanced and difficult projects it may happen so that the framework stays in your way and you have to find workarounds.
I think there is no definitive answer. You should put in balance the pros and cons and take the right decision for your project.
Usually I adopt popular frameworks very fast but not in critical parts of the projects and in time I extend their usage.
I think that if you don't see a need to use a framework then don't.
The reason I use a framework for example Django for python or Rails for Ruby or Webforms and MVC for ASP.net is because they make it easier and faster to write applications for them. In the case of Ruby and Python not using a framework for me would make me go crazy.
If you have something that works and don't see a need to use a framework I would say stick with what you feel is best. But, I would still keep up to date with frameworks.
I think they are more useful if you are starting from scratch and don't have the time to write your own. If you already have a codebase you developed over the years, they may be much less useful, but it may still be useful to take a look and see what they did.
For example, I am sure major game development shops are not using third-party tools, engines and frameworks, not because they are not sufficient, but they already have built their own since the 80's or whatever.
Plus, if you are using an off-the-shelf component, there is no way to exceed it in its particular area. If you need to be a market leader in a particular dimension, you should be building your own solution in that dimension, so you can lead. If you don't need this capability, using a third-party component that is just as good as yours may be a good solution as long as it is an easy transition. Time to train in the new tool and living with its idiosyncrasies may or may not be worth it though.
The other thing to consider is that if you can build something, you truly understand it. Otherwise, you don't. Now, you don't need to fully understand stuff to use them, so long as they "just work", but we all know how that goes... :)
Can you solve the problems you are given have with your code faster and more reliably than public frameworks?
If yes, then keep using your own.
If no, then find the framework that does a better job and run with it for that project.
It all comes down to which codebase gets the job done better(for the value of better given by the client. ;) )
Disadvantages.
Most frame works are not object orientated. (code igniter does show some promiss)
Most of the code is done via includes. trying to track down the problem is like pulling on a thread on a sweater, and having to unravel the entire garment to fully understand the creation.
Most frame works have poorly written documentation.
Most frame works try to do many many many things.
I find from my experience developing with frame works that it takes a good 3-6 months to get on top of the code base. And its only after that period of time that you will find out weather you are trying to fit a square peg into a round hole. Given that most php projects want to be finished before that period has elapsed, it will cost employers more to get any project using a big "frame work" to fruition.
Many of the php Frame works were written for php 4, and were written in a different enviroment. They have been extended greatly, but are showing their origins. The use of global constraints is particularly prevalent. I am hoping that php 6 puts most of them to death. Code igniter escapes most of this, but it is new, and has object orientated parts.
Some frame works have written code that is not needed, and causes problems.. eg: CAKE has a most excellent model view controller, but its session handling is a disaster. Unfortunately frame works are not written in a modular way. Often its an all or nothing option.
MOst programers "hack" the frame work to get it to do what they want. This leaves future programers sractching their heads. It also makes "upgrading" the frame work a impossibility.
I have yet to see a frame work that implements unit testing. (how do you know that you have not broken it).
give me a well written object any time. At least them you know the scope right off the bat.
Advantages are that it's already written and tested by multiple people therefore less likely to be bug prone.
Disadvantages are that it's not built specifically for your application and therefore will most likely perform worse.
All in all, I can't really see much reason to use one considering you already have your own...although it may be worth releasing that open source so others are able to bug check and recommend improvements.