Example of mvc mode implementation in php

Example of mvc mode implementation in php

{Some_text} {Some_more_text} They do not make sense in the document. they represent that PHP will replace it with something else. If you agree to this loose description of the view, you will agree that the vast majority of template schemes do not effectively separate views and models. The template tag will be replaced with what is stored in the model. When you implement a View, ask yourself a few questions: "Is it easy to replace all views ?" "How long does it take to implement a new view ?" "Is it easy to replace the description language of the view? (For example, replacing HTML documents with SOAP documents in the same view )" II. Model) The model represents the program logic. (Business layer is often called in enterprise applications )) In general, the model task is to convert the original data into data that contains some meaning, and the data will be displayed by the view. Generally, the model encapsulates data queries and may use abstract data classes (data access layer) to perform queries. For example, if you want to calculate the annual rainfall in the UK (just to find a good holiday place for yourself), the model will receive the daily rainfall for ten years, calculate the average value, and pass it to the view. III. controller) Simply put, the controller is the first part of the HTTP request to be called in a Web application. It checks received requests, such as GET variables, and makes appropriate feedback. Before writing your first controller, it is difficult for you to write other php code. The most common usage is the structure of a switch statement in index. php: Switch ($ _ GET ['viewpage']) { Case "news ": $ Page = new NewsRenderer; Break; Case "links ": $ Page = new LinksRenderer; Break; Default: $ Page = new HomePageRenderer; Break; } $ Page-> display (); ?> This code mix process-oriented and object-oriented code, but this is usually the best choice for small websites. The code above can be optimized. The controller is actually a control used to trigger the binding between the data of the model and the View elements. Here is a simple example of using the MVC mode. First, we need a database category class, which is a common class. /** * A simple class for querying MySQL */ Class DataAccess { /** * Private * $ Db stores a database resource */ Var $ db; /** * Private * $ Query stores a query resource */ Var $ query; // Query resource //! A constructor. /** * Constucts a new DataAccess object * @ Param $ host string hostname for dbserver * @ Param $ user string dbserver user * @ Param $ pass string dbserver user password * @ Param $ db string database name */ Function DataAccess ($ host, $ user, $ pass, $ db ){ $ This-> db = mysql_pconnect ($ host, $ user, $ pass ); Mysql_select_db ($ db, $ this-> db ); } //! An accessor /** * Fetches a query resources and stores it in a local member * @ Param $ SQL string the database query to run * @ Return void */ Function fetch ($ SQL ){ $ This-> query = mysql_unbuffered_query ($ SQL, $ this-> db); // Perform query here } //! An accessor /** * Returns an associative array of a query row * @ Return mixed */ Function getRow (){ If ($ row = mysql_fetch_array ($ this-> query, MYSQL_ASSOC )) Return $ row; Else Return false; } } ?> Put the model on it. /** * Fetches "products" from the database * Link: http://bbs.it-home.org */ Class ProductModel { /** * Private * $ Dao an instance of the DataAccess class */ Var $ dao; //! A constructor. /** * Constucts a new ProductModel object * @ Param $ dbobject an instance of the DataAccess class */ Function ProductModel (& $ dao ){ $ This-> dao = & $ dao; } //! A manipulator /** * Tells the $ dboject to store this query as a resource * @ Param $ start the row to start from * @ Param $ rows the number of rows to fetch * @ Return void */ Function listProducts ($ start = 1, $ rows = 50 ){ $ This-> dao-> fetch ("SELECT * FROM products LIMIT". $ start. ",". $ rows ); } //! A manipulator /** * Tells the $ dboject to store this query as a resource * @ Param $ id a primary key for a row * @ Return void */ Function listProduct ($ id ){ $ This-> dao-> fetch ("SELECT * FROM products where productid = '". $ id ."'"); } //! A manipulator /** * Fetches a product as an associative array from the $ dbobject * @ Return mixed */ Function getProduct (){ If ($ product = $ this-> dao-> getRow ()) Return $ product; Else Return false; } } ?> Note: Between the model and the data pipeline class, the interaction between the model and the data pipeline class will never be more than one row-no multiple rows are transmitted, and the program will soon slow down. For classes in the usage mode, the same program only needs to keep one Row in the memory -- others are handed over to saved query resources -- in other words, we asked MYSQL to keep the results for us. Next is the view (the following code removes the html content ). /** * Binds product data to HTML rendering * Link: http://bbs.it-home.org */ Class ProductView { /** * Private * $ Model an instance of the ProductModel class */ Var $ model; /** * Private * $ Output rendered HTML is stored here for display */ Var $ output; //! A constructor. /** * Constucts a new ProductView object * @ Param $ model an instance of the ProductModel class */ Function ProductView (& $ model ){ $ This-> model = & $ model; } //! A manipulator /** * Builds the top of an HTML page * @ Return void */ Function header (){ } //! A manipulator /** * Builds the bottom of an HTML page * @ Return void */ Function footer (){ } //! A manipulator /** * Displays a single product * @ Return void */ Function productItem ($ id = 1 ){ $ This-> model-> listProduct ($ id ); While ($ product = $ this-> model-> getProduct ()){ // Bind data to HTML } } //! A manipulator /** * Builds a product table * @ Return void */ Function productTable ($ rownum = 1 ){ $ Rowsperpage = '20 '; $ This-> model-> listProducts ($ rownum, $ rowsperpage ); While ($ product = $ this-> model-> getProduct ()){ // Bind data to HTML } } //! An accessor /** * Returns the rendered HTML * @ Return string */ Function display (){ Return $ this-> output; } } ?> Finally, the controller implements the view as a subclass. /** * Controls the application */ Class ProductController extends ProductView { //! A constructor. /** * Constucts a new ProductController object * @ Param $ model an instance of the ProductModel class * @ Param $ getvars the incoming http get method variables */ Function ProductController (& $ model, $ getvars = null ){ ProductView: ProductView ($ model ); $ This-> header (); Switch ($ getvars ['View']) { Case "product ": $ This-> productItem ($ getvars ['id']); Break; Default: If (empty ($ getvars ['rownum']) { $ This-> productTable (); } Else { $ This-> productTable ($ getvars ['rownum']); } Break; } $ This-> footer (); } } ?> Note: This is not the only way to implement MVC-for example, you can use controllers to implement models and integrate views at the same time. This is just a way to demonstrate the mode. The index. php file looks like this: Require_once ('Lib/DataAccess. php '); Require_once ('Lib/ProductModel. php '); Require_once ('Lib/ProductView. php '); Require_once ('Lib/ProductController. php '); $ Dao = & new DataAccess ('localhost', 'user', 'pass', 'dbname '); $ ProductModel = & new ProductModel ($ dao ); $ ProductController = & new ProductController ($ productModel, $ _ GET ); Echo $ productController-> display (); ?> There are some techniques for using controllers. you can do this in PHP: $ this-> {$ _ GET ['method']} ($ _ GET ['param']); we recommend that you define the namespace format (namespace) of the program URL so that it will be more standard, for example: "Index. php? Class = ProductView & method = productItem & id = 4" The controller can be processed as follows: $ View = new $ _ GET ['class']; $ View-> {$ _ GET ['method'] ($ _ GET ['id']); Sometimes it is not easy to establish a controller, for example, when the development speed and adaptability need to be weighed. A good place to be inspired is Apache group's Java Struts. its controller is completely defined by the XML document.