Create smartly structured PHP programs_PHP Tutorial

I've wanted to write this article for a long time, but never had the time to finish it. I'm not here to tell you how to do it. I hope this article is just an introduction to discuss with you how to build an effective and flexible network application.

After 2-3 years of developing web applications, my development experience has become more vivid. Looking back at the code I used to write for Geocrawler, I can’t believe it is mine. Due to the GPL, the source code in PHPBuilder is also mixed.

Recently, as an experienced PHP developer, I have been helping write SourceForge, and I think this shows the scope of the final result. Good code should be divided into multiple parts, with appropriate library and function calls, a clear database structure, and each part of the site is relatively independent from other parts.

However, this is still not the best. If I could redo it, I would focus more on separating the HTML layer from the data layer, achieving this through objects and clear function libraries.

Beautiful Graphics

I know managers like to use beautiful graphs and charts to describe them, which will leave the best impression on us. Using this idea of ​​hiding behind a structure, you can separate your logic from appearance, which means that any complex program can be expressed in an "API/Data Access Layer".

Instead of putting security checks, updated sentences, etc. in the HTML layer, it is better to put them as a whole in your API layer. And this HTML layer only contains simple function calls and returned arrays, objects or other custom objects, as well as some collections of database retrieval results, etc.

If you do this, the top level will be very thin and you can easily create and maintain it.

In the following example, this HTML interface only has some direct calls to functions in the API layer, some HTML tool libraries (it can generate a pop-up box, etc.), and some calls from the database abstraction layer. Database manipulation methods (you don't need to bind to a specific database). Basics

The most basic aspects of flexible PHP program structure are the following:

Database independence
Interface independence
Portability
Object-oriented or at least should be Composed of function libraries

Are there others?
Of course there are some other things, but I think those are too big, maybe you can point them out yourself.


Let’s talk about each of them in detail.

1. Database independence

You never know where your site will run, of course when you create it, you want it to be big and have a high flow. So you don't want to tie yourself to MS Access or any other lightweight database system. Although you can't plug into various database systems immediately, you can potentially switch between them easily. You have a few different options for abstracting away your database calls. A peculiar approach in PHP is that you have to write different code for each different database system, because the access functions for each different database in PHP are different. To get around this, you can use an abstract database access layer, like PHPLib, the next version of PEAR, and the one we describe in SourceForge.

2. Interface irrelevance

Is the technology of an application more important or the site it runs on? We don't really know. I never believed this - HTML is a standard. Especially for a web application, changes to the interface mean we always have to rewrite. But if your application is large and complex, you have to establish some other interfaces for your database, as long as you don't want to copy & paste your access check and other codes everywhere in your site program. This also means that if you design your application correctly, you can easily rewrite your site to adapt to WAP by simply writing a small WAP interface and having it call your database access object. . But if you don't design your program well, changing your HTML version to WAP version is a complicated project.

I also brought this idea into SourceForge. We have a huge user base who sends/receives bugs, tasks, etc. for us. First, we pointed out that all of this would be interfaced through our web pages, and then, due to pressure from Eric Raymond and others, we decided to use XML for the external interface to the database.

Fortunately, we separated the core logic code of the program from its interface in April. I'll try to express how we do it, hopefully it will be helpful to you in your work.

The SourceForge bug tracker and other tools are split into two libraries - the HTML library and the data access library. This data access library checks the correctness of the entered values, handles security checks, and returns TRUE or FALSE on success/failure.

Due to simplification reasons, this example is not based on a complete object model, so I have to explain this base class and some of its derived classes, etc. I think this example will give you the most common idea.Examples of HTML libraries

//connect to database
require ("database.php");

//common utils like header/footer HTML
require ("html. php");

//data access library
require ("bug_data.php");

echo site_header("Page Title");

echo " Updating a bug
";

if (bug_data_update($field1,$field2,$field3)) {

echo " Update Failed! ";

} else {

echo " Updated Bug Successfully ";
//echo the global error string
echo $feedback;
}

echo site_footer();

?>


Example of Data access library

3. Portability

There is no doubt that you don’t want your code to be used only for a fixed site. We may change the color selection in the future , element names, fonts or whatever, this should set up a config file that is included by multiple pages. A better idea is that your site is modular and you don't need to copy&paste any single HTML file, which I prefer. Put these into a function and call them wherever needed

The same approach can be used for database passwords, database connection strings, etc. These can be put into an abstraction layer for database processing. >

4. Object-oriented/functional

We are not developing in COBOL, so this means that we can divide the process into multiple function calls. Each call is an automatic behavior. , sometimes just call a short section of other functions and return the result

A good example is to check whether the user is logged in on each page. You can use cookies or query the database to complete this function, but once If you want to change your validation system, you have to change every page, but you should be able to do this by changing an ordinary function in the function library. Any time you write a piece of code, if it is going to be used. More than one place, you should consider putting it in a library

What else?

Obviously there are many things I haven't talked about, tell me yours. ideas, I'll discuss them in the next article. In particular, if you wrote a large, complex application, I'd like to hear how you planned it and what you think would be different if you redo it. .

http://www.bkjia.com/PHPjc/314028.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/314028.htmlTechArticleI have wanted to write this article for a long time, but I have never had time to complete it. I'm not here to tell you how to do it. I hope this article is just an introduction to discuss with you how to build...