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1 Chapter 6 - Inside The Controller Layer 2 ======================================= 3 4 In symfony, the controller layer, which contains the code linking the business logic and the presentation, is split into several components that you use for different purposes: 5 6 * The front controller is the unique entry point to the application. It loads the configuration and determines the action to execute. 7 * Actions contain the applicative logic. They check the integrity of the request and prepare the data needed by the presentation layer. 8 * The request, response, and session objects give access to the request parameters, the response headers, and the persistent user data. They are used very often in the controller layer. 9 * Filters are portions of code executed for every request, before or after the action. For example, the security and validation filters are commonly used in web applications. You can extend the framework by creating your own filters. 10 11 This chapter describes all these components, but don't be intimidated by their number. For a basic page, you will probably need to write only a few lines in the action class, and that's all. The other controller components will be of use only in specific situations. 12 13 The Front Controller 14 -------------------- 15 16 All web requests are handled by a single front controller, which is the unique entry point to the whole application in a given environment. 17 18 When the front controller receives a request, it uses the routing system to match an action name and a module name with the URL typed (or clicked) by the user. For instance, the following request URL calls the `index.php` script (that's the front controller) and will be understood as a call to the action `myAction` of the module `mymodule`: 19 20 http://localhost/index.php/mymodule/myAction 21 22 If you are not interested in symfony's internals, that's all that you need to know about the front controller. It is an indispensable component of the symfony MVC architecture, but you will seldom need to change it. So you can jump to the next section unless you really want to know about the guts of the front controller. 23 24 ### The Front Controller's Job in Detail 25 26 The front controller does the dispatching of the request, but that means a little more than just determining the action to execute. In fact, it executes the code that is common to all actions, including the following: 27 28 1. Define the core constants. 29 2. Locate the symfony libraries. 30 3. Load and initiate the core framework classes. 31 4. Load the configuration. 32 5. Decode the request URL to determine the action to execute and the request parameters. 33 6. If the action does not exist, redirect to the 404 error action. 34 7. Activate filters (for instance, if the request needs authentication). 35 8. Execute the filters, first pass. 36 9. Execute the action and render the view. 37 10. Execute the filters, second pass. 38 11. Output the response. 39 40 ### The Default Front Controller 41 42 The default front controller, called `index.php` and located in the `web/` directory of the project, is a simple PHP file, as shown in Listing 6-1. 43 44 Listing 6-1 - The Default Production Front Controller 45 46 [php] 47 <?php 48 49 define('SF_ROOT_DIR', realpath(dirname(__FILE__).'/..')); 50 define('SF_APP', 'myapp'); 51 define('SF_ENVIRONMENT', 'prod'); 52 define('SF_DEBUG', false); 53 54 require_once(SF_ROOT_DIR.DIRECTORY_SEPARATOR.'apps'.DIRECTORY_SEPARATOR.SF_APP.DIRECTORY_SEPARATOR.'config'.DIRECTORY_SEPARATOR.'config.php'); 55 56 sfContext::getInstance()->getController()->dispatch(); 57 58 The constants definition corresponds to the first step described in the previous section. Then the front controller includes the application config.php, which takes care of steps 2 through 4. The call to the `dispatch()` method of the `sfController` object (which is the core controller object of the symfony MVC architecture) dispatches the request, taking care of steps 5 through 7. The last steps are handled by the filter chain, as explained later in this chapter. 59 60 ### Calling Another Front Controller to Switch the Environment 61 62 One front controller exists per environment. As a matter of fact, it is the very existence of a front controller that defines an environment. The environment is defined in the `SF_ENVIRONMENT` constant. 63 64 To change the environment in which you're browsing your application, just choose another front controller. The default front controllers available when you create a new application with the `symfony init-app` task are `index.php` for the production environment and `myapp_dev.php` for the development environment (provided that your application is called `myapp`). The default `mod_rewrite` configuration will use `index.php` when the URL doesn't contain a front controller script name. So both of these URLs display the same page (`mymodule/index`) in the production environment: 65 66 http://localhost/index.php/mymodule/index 67 http://localhost/mymodule/index 68 69 and this URL displays that same page in the development environment: 70 71 http://localhost/myapp_dev.php/mymodule/index 72 73 Creating a new environment is as easy as creating a new front controller. For instance, you may need a staging environment to allow your customers to test the application before going to production. To create this staging environment, just copy `web/myapp_dev.php` into `web/myapp_staging.php`, and change the value of the `SF_ENVIRONMENT` constant to `staging`. Now, in all the configuration files, you can add a new `staging:` section to set specific values for this environment, as shown in Listing 6-2. 74 75 Listing 6-2 - Sample `app.yml` with Specific Settings for the Staging Environment 76 77 staging: 78 mail: 79 webmaster: dummy@mysite.com 80 contact: dummy@mysite.com 81 all: 82 mail: 83 webmaster: webmaster@mysite.com 84 contact: contact@mysite.com 85 86 If you want to see how the application reacts in this new environment, call the related front controller: 87 88 http://localhost/myapp_staging.php/mymodule/index 89 90 ### Batch Files 91 92 You may want to execute a script from the command line (or via a cron table) with access to all the symfony classes and features, for instance to launch batch e-mail jobs or to periodically update your model through a process-intensive calculation. For such a script, you need to include the same lines as in a front controller at the beginning. Listing 6-3 shows an example of the beginning of a batch script. 93 94 Listing 6-3 - Sample Batch Script 95 96 [php] 97 <?php 98 99 define('SF_ROOT_DIR', realpath(dirname(__FILE__).'/..')); 100 define('SF_APP', 'myapp'); 101 define('SF_ENVIRONMENT', 'prod'); 102 define('SF_DEBUG', false); 103 104 require_once(SF_ROOT_DIR.DIRECTORY_SEPARATOR.'apps'.DIRECTORY_SEPARATOR.SF_APP.DIRECTORY_SEPARATOR.'config'.DIRECTORY_SEPARATOR.'config.php'); 105 106 // add code here 107 108 You can see that the only missing line is the call to the `dispatch()` method of the sfController object, which can be used only with a web server, not in a batch process. Defining an application and an environment gives you access to a specific configuration. Including the application `config.php` initiates the context and the autoloading. 109 110 >**TIP** 111 >The symfony CLI offers an `init-batch` task, which automatically creates a skeleton similar to the one in Listing 6-3 in the `batch/` directory. Just pass it an application name, an environment name, and a batch name as arguments. 112 113 Actions 114 ------- 115 116 The actions are the heart of an application, because they contain all the application's logic. They use the model and define variables for the view. When you make a web request in a symfony application, the URL defines an action and the request parameters. 117 118 ### The Action Class 119 120 Actions are methods named `executeActionName` of a class named `moduleNameActions` inheriting from the `sfActions` class, and grouped by modules. The action class of a module is stored in an `actions.class.php` file, in the module's `actions/` directory. 121 122 Listing 6-4 shows an example of an `actions.class.php` file with only an `index` action for the whole `mymodule` module. 123 124 Listing 6-4 - Sample Action Class, in `apps/myapp/modules/mymodule/actions/actions.class.php` 125 126 [php] 127 class mymoduleActions extends sfActions 128 { 129 public function executeIndex() 130 { 131 132 } 133 } 134 135 >**CAUTION** 136 >Even if method names are not case-sensitive in PHP, they are in symfony. So don't forget that the action methods must start with a lowercase `execute`, followed by the exact action name with the first letter capitalized. 137 138 In order to request an action, you need to call the front controller script with the module name and action name as parameters. By default, this is done by appending the couple `module_name`/`acti`on_name to the script. This means that the action defined in Listing 6-4 can be called by this URL: 139 140 http://localhost/index.php/mymodule/index 141 142 Adding more actions just means adding more `execute` methods to the `sfActions` object, as shown in Listing 6-5. 143 144 Listing 6-5 - Action Class with Two Actions, in myapp/modules/mymodule/actions/actions.cla`ss.php` 145 146 [php] 147 class mymoduleActions extends sfActions 148 { 149 public function executeIndex() 150 { 151 ... 152 } 153 154 public function executeList() 155 { 156 ... 157 } 158 } 159 160 If the size of an action class grows too much, you probably need to do some refactoring and move some code to the model layer. Actions should often be kept short (not more than a few lines), and all the business logic should usually be in the model. 161 162 Still, the number of actions in a module can be important enough to lead you to split it in two modules. 163 164 >**SIDEBAR** 165 >Symfony coding standards 166 > 167 >In the code examples given in this book, you probably noticed that the opening and closing curly braces (`{` and `}`) occupy one line each. This standard makes the code easier to read. 168 > 169 >Among the other coding standards of the framework, indentation is always done by two blank spaces; tabs are not used. This is because tabs have a different space value according to the text editor you use, and because code with mixed tab and blank indentation is impossible to read. 170 > 171 >Core and generated symfony PHP files do not end with the usual `?>` closing tag. This is because it is not really needed, and because it can create problems in the output if you ever have blanks after this tag. 172 > 173 >And if you really pay attention, you will see that a line never ends with a blank space in symfony. The reason, this time, is more prosaic: lines ending with blanks look ugly in Fabien's text editor. 174 175 ### Alternative Action Class Syntax 176 177 An alternative action syntax is available to dispatch the actions in separate files, one file per action. In this case, each action class extends `sfAction` (instead of `sfActions`) and is named `actionNameAction`. The actual action method is simply named `execute`. The file name is the same as the class name. This means that the equivalent of Listing 6-5 can be written with the two files shown in Listings 6-6 and 6-7. 178 179 Listing 6-6 - Single Action File, in `myapp/modules/mymodule/actions/indexAction.class.php` 180 181 [php] 182 class indexAction extends sfAction 183 { 184 public function execute() 185 { 186 ... 187 } 188 } 189 190 Listing 6-7 - Single Action File, in `myapp/modules/mymodule/actions/listAction.class.php` 191 192 [php] 193 class listAction extends sfAction 194 { 195 public function execute() 196 { 197 ... 198 } 199 } 200 201 ### Retrieving Information in the Action 202 203 The action class offers a way to access controller-related information and the core symfony objects. Listing 6-8 demonstrates how to use them. 204 205 Listing 6-8 - `sfActions` Common Methods 206 207 [php] 208 class mymoduleActions extends sfActions 209 { 210 public function executeIndex() 211 { 212 // Retrieving request parameters 213 $password = $this->getRequestParameter('password'); 214 215 // Retrieving controller information 216 $moduleName = $this->getModuleName(); 217 $actionName = $this->getActionName(); 218 219 // Retrieving framework core objects 220 $request = $this->getRequest(); 221 $userSession = $this->getUser(); 222 $response = $this->getResponse(); 223 $controller = $this->getController(); 224 $context = $this->getContext(); 225 226 // Setting action variables to pass information to the template 227 $this->setVar('foo', 'bar'); 228 $this->foo = 'bar'; // Shorter version 229 230 } 231 } 232 233 >**SIDEBAR** 234 >The context singleton 235 > 236 >You already saw, in the front controller, a call to sfContext::getInstance(). In an action, the getContext() method returns the same singleton. It is a very useful object that stores a reference to all the symfony core objects related to a given request, and offers an accessor for each of them: 237 > 238 >`sfController`: The controller object (`->getController()`) `sfRequest`: The request object (`->getRequest()`) `sfResponse`: The response object (`->getResponse()`) `sfUser`: The user session object (`->getUser()`) `sfDatabaseConnection`: The database connection (`->getDatabaseConnection()`) `sfLogger`: The logger object (`->getLogger()`) `sfI18N`: The internationalization object (`->getI18N()`) 239 > 240 >You can call the `sfContext::getInstance()` singleton from any part of the code. 241 242 ### Action Termination 243 244 Various behaviors are possible at the conclusion of an action's execution. The value returned by the action method determines how the view will be rendered. Constants of the `sfView` class are used to specify which template is to be used to display the result of the action. 245 246 If there is a default view to call (this is the most common case), the action should end as follows: 247 248 [php] 249 return sfView::SUCCESS; 250 251 Symfony will then look for a template called `actionNameSuccess.php`. This is defined as the default action behavior, so if you omit the `return` statement in an action method, symfony will also look for an `actionNameSuccess.php` template. Empty actions will also trigger that behavior. See Listing 6-9 for examples of successful action termination. 252 253 Listing 6-9 - Actions That Will Call the `indexSuccess.php` and `listSuccess.php` Templates 254 255 [php] 256 public function executeIndex() 257 { 258 return sfView::SUCCESS; 259 } 260 261 public function executeList() 262 { 263 } 264 265 If there is an error view to call, the action should end like this: 266 267 [php] 268 return sfView::ERROR; 269 270 Symfony will then look for a template called `actionNameError.php`. 271 272 To call a custom view, use this ending: 273 274 [php] 275 return 'MyResult'; 276 277 Symfony will then look for a template called `actionNameMyResult.php`. 278 279 If there is no view to call--for instance, in the case of an action executed in a batch process--the action should end as follows: 280 281 [php] 282 return sfView::NONE; 283 284 No template will be executed in that case. It means that you can bypass completely the view layer and output HTML code directly from an action. As shown in Listing 6-10, symfony provides a specific renderText() method for this case. This can be useful when you need extreme responsiveness of the action, such as for Ajax interactions, which will be discussed in Chapter 11. 285 286 Listing 6-10 - Bypassing the View by Echoing the Response and Returning `sfView::NONE` 287 288 [php] 289 public function executeIndex() 290 { 291 echo "<html><body>Hello, World!</body></html>"; 292 293 return sfView::NONE; 294 } 295 296 // Is equivalent to 297 public function executeIndex() 298 { 299 return $this->renderText("<html><body>Hello, World!</body></html>"); 300 } 301 302 In some cases, you need to send an empty response but with some headers defined in it (especially the `X-JSON` header). Define the headers via the `sfResponse` object, discussed in the next chapter, and return the `sfView::HEADER_ONLY` constant, as shown in Listing 6-11. 303 304 Listing 6-11 - Escaping View Rendering and Sending Only Headers 305 306 [php] 307 public function executeRefresh() 308 { 309 $output = '<"title","My basic letter"],["name","Mr Brown">'; 310 $this->getResponse()->setHttpHeader("X-JSON", '('.$output.')'); 311 312 return sfView::HEADER_ONLY; 313 } 314 315 If the action must be rendered by a specific template, ignore the `return` statement and use the `setTemplate()` method instead. 316 317 [php] 318 $this->setTemplate('myCustomTemplate'); 319 320 ### Skipping to Another Action 321 322 In some cases, the action execution ends by requesting a new action execution. For instance, an action handling a form submission in a POST request usually redirects to another action after updating the database. Another example is an action alias: the `index` action is often a way to display a list, and actually forwards to a `list` action. 323 324 The action class provides two methods to execute another action: 325 326 * If the action forwards the call to another action: 327 328 [php] 329 $this->forward('otherModule', 'index'); 330 331 * If the action results in a web redirection: 332 333 [php] 334 $this->redirect('otherModule/index'); 335 $this->redirect('http://www.google.com/'); 336 337 >**NOTE** 338 >The code located after a forward or a redirect in an action is never executed. You can consider that these calls are equivalent to a `return` statement. They throw an `sfStopException` to stop the execution of the action; this exception is later caught by symfony and simply ignored. 339 340 The choice between a redirect or a forward is sometimes tricky. To choose the best solution, keep in mind that a forward is internal to the application and transparent to the user. As far as the user is concerned, the displayed URL is the same as the one requested. In contrast, a redirect is a message to the user's browser, involving a new request from it and a change in the final resulting URL. 341 342 If the action is called from a submitted form with `method="post"`, you should always do a redirect. The main advantage is that if the user refreshes the resulting page, the form will not be submitted again; in addition, the back button works as expected by displaying the form and not an alert asking the user if he wants to resubmit a POST request. 343 344 There is a special kind of forward that is used very commonly. The `forward404()` method forwards to a "page not found" action. This method is often called when a parameter necessary to the action execution is not present in the request (thus detecting a wrongly typed URL). Listing 6-12 shows an example of a `show` action expecting an `id` parameter. 345 346 Listing 6-12 - Use of the `forward404()` Method 347 348 [php] 349 public function executeShow() 350 { 351 $article = ArticlePeer::retrieveByPK($this->getRequestParameter('id')); 352 if (!$article) 353 { 354 $this->forward404(); 355 } 356 } 357 358 >**TIP** 359 >If you are looking for the error 404 action and template, you will find them in the `$sf_symfony_ data_dir/modules/default/` directory. You can customize this page by adding a new `default` module to your application, overriding the one located in the framework, and by defining an `error404` action and an error404Success template inside. Alternatively, you can set the error_404_module and error_404_ action constants in the `settings.yml` file to use an existing action. 360 361 Experience shows that, most of the time, an action makes a redirect or a forward after testing something, such as in Listing 6-12. That's why the sfActions class has a few more methods, named `forwardIf()`, `forwardUnless()`, `forward404If()`, `forward404Unless()`, `redirectIf()`, and `redirectUnless()`. These methods simply take an additional parameter representing a condition that triggers the execution if tested true (for the `xxxIf()` methods) or false (for the `xxxUnless()` methods), as illustrated in Listing 6-13. 362 363 Listing 6-13 - Use of the `forward404If()` Method 364 365 [php] 366 // This action is equivalent to the one shown in Listing 6-12 367 public function executeShow() 368 { 369 $article = ArticlePeer::retrieveByPK($this->getRequestParameter('id')); 370 $this->forward404If(!$article); 371 } 372 373 // So is this one 374 public function executeShow() 375 { 376 $article = ArticlePeer::retrieveByPK($this->getRequestParameter('id')); 377 $this->forward404Unless($article); 378 } 379 380 Using these methods will not only keep your code short, but it will also make it more readable. 381 382 >**TIP** 383 >When the action calls forward404() or its fellow methods, symfony throws an sfError404Exception that manages the 404 response. This means that if you need to display a 404 message from somewhere where you don't want to access the controller, you can just throw a similar exception. 384 385 ### Repeating Code for Several Actions of a Module 386 387 The convention to name actions `executeActionName()` (in the case of an `sfActions` class) or execute() (in the case of an sfAction class) guarantees that symfony will find the action method. It gives you the ability to add other methods of your own that will not be considered as actions, as long as they don't start with `execute`. 388 389 There is another useful convention for when you need to repeat several statements in each action before the actual action execution. You can then extract them into the `preExecute()` method of your action class. You can probably guess how to repeat statements after every action is executed: wrap them in a `postExecute()` method. The syntax of these methods is shown in Listing 6-14. 390 391 Listing 6-14 - Using `preExecute`, `postExecute`, and Custom Methods in an Action Class 392 393 [php] 394 class mymoduleActions extends sfActions 395 { 396 public function preExecute() 397 { 398 // The code inserted here is executed at the beginning of each action call 399 ... 400 } 401 402 public function executeIndex() 403 { 404 ... 405 } 406 407 public function executeList() 408 { 409 ... 410 $this->myCustomMethod(); // Methods of the action class are accessible 411 } 412 413 public function postExecute() 414 { 415 // The code inserted here is executed at the end of each action call 416 ... 417 } 418 419 protected function myCustomMethod() 420 { 421 // You can also add your own methods, as long as they don't start with "execute" 422 // In that case, it's better to declare them as protected or private 423 ... 424 } 425 } 426 427 Accessing the Request 428 --------------------- 429 430 You're familiar with the `getRequestParameter('myparam')` method, used to retrieve the value of a request parameter by its name. As a matter of fact, this method is a proxy for a chain of calls to the request's parameter holder `getRequest()->getParameter('myparam')`. The action class has access to the request object, called `sfWebRequest` in symfony, and to all its methods, via the `getRequest()` method. Table 6-1 lists the most useful `sfWebRequest` methods. 431 432 Table 6-1 - Methods of the `sfWebRequest` Object 433 434 Name | Function | Sample Output 435 -------------------------------- | -------------------------------------- | ----------------------------------------------------------------------- 436 **Request Information** | | 437 `getMethod()` | Request method | Returns `sfRequest::GET` or `sfRequest::POST` constants 438 `getMethodName()` | Request method name | `'POST'` 439 `getHttpHeader('Server')` | Value of a given HTTP header | `'Apache/2.0.59 (Unix) DAV/2 PHP/5.1.6'` 440 `getCookie('foo')` | Value of a named cookie | `'bar'` 441 `isXmlHttpRequest()`* | Is it an Ajax request? | `true` 442 `isSecure()` | Is it an SSL request? | `true` 443 **Request Parameters** | | 444 `hasParameter('foo')` | Is a parameter present in the request? | `true` 445 `getParameter('foo')` | Value of a named parameter | `'bar'` 446 `getParameterHolder()->getAll()` | Array of all request parameters | 447 **URI-Related Information** | | 448 `getUri()` | Full URI | `'http://localhost/myapp_dev.php/mymodule/myaction'` 449 `getPathInfo()` | Path info | `'/mymodule/myaction'` 450 `getReferer()`** | Referrer | `'http://localhost/myapp_dev.php/'` 451 `getHost()` | Host name | `'localhost'` 452 `getScriptName()` | Front controller path and name | `'myapp_dev.php'` 453 **Client Browser Information** | | 454 `getLanguages()` | Array of accepted languages | `Array( ` ` [0] => fr ` ` [1] => fr_FR ` ` [2] => en_US ` ` [3] => en )` 455 `getCharsets()` | Array of accepted charsets | `Array( ` ` [0] => ISO-8859-1 ` ` [1] => UTF-8 ` ` [2] => * )` 456 getAcceptableContentType() | Array of accepted content types | `Array( [0] => text/xml [1] => text/html` 457 458 * *Works only with prototype* 459 460 ** *Sometimes blocked by proxies* 461 462 The `sfActions` class offers a few proxies to access the request methods more quickly, as shown in Listing 6-15. 463 464 Listing 6-15 - Accessing the `sfRequest` Object Methods from an Action 465 466 [php] 467 class mymoduleActions extends sfActions 468 { 469 public function executeIndex() 470 { 471 $hasFoo = $this->getRequest()->hasParameter('foo'); 472 $hasFoo = $this->hasRequestParameter('foo'); // Shorter version 473 $foo = $this->getRequest()->getParameter('foo'); 474 $foo = $this->getRequestParameter('foo'); // Shorter version 475 } 476 } 477 478 For multipart requests to which users attach files, the `sfWebRequest` object provides a means to access and move these files, as shown in Listing 6-16. 479 480 Listing 6-16 - The `sfWebRequest` Object Knows How to Handle Attached Files 481 482 [php] 483 class mymoduleActions extends sfActions 484 { 485 public function executeUpload() 486 { 487 if ($this->getRequest()->hasFiles()) 488 { 489 foreach ($this->getRequest()->getFileNames() as $fileName) 490 { 491 $fileSize = $this->getRequest()->getFileSize($fileName); 492 $fileType = $this->getRequest()->getFileType($fileName); 493 $fileError = $this->getRequest()->hasFileError($fileName); 494 $uploadDir = sfConfig::get('sf_upload_dir'); 495 $this->getRequest()->moveFile('file', $uploadDir.'/'.$fileName); 496 } 497 } 498 } 499 } 500 501 You don't have to worry about whether your server supports the `$_SERVER` or the `$_ENV` variables, or about default values or server-compatibility issues--the `sfWebRequest` methods do it all for you. Besides, their names are so evident that you will no longer need to browse the PHP documentation to find out how to get information from the request. 502 503 User Session 504 ------------ 505 506 Symfony automatically manages user sessions and is able to keep persistent data between requests for users. It uses the built-in PHP session-handling mechanisms and enhances them to make them more configurable and easier to use. 507 508 ### Accessing the User Session 509 510 The session object for the current user is accessed in the action with the `getUser()` method and is an instance of the `sfUser` class. This class contains a parameter holder that allows you to store any user attribute in it. This data will be available to other requests until the end of the user session, as shown in Listing 6-17. User attributes can store any type of data (strings, arrays, and associative arrays). They can be set for every individual user, even if that user is not identified. 511 512 Listing 6-17 - The `sfUser` Object Can Hold Custom User Attributes Existing Across Requests 513 514 [php] 515 class mymoduleActions extends sfActions 516 { 517 public function executeFirstPage() 518 { 519 $nickname = $this->getRequestParameter('nickname'); 520 521 // Store data in the user session 522 $this->getUser()->setAttribute('nickname', $nickname); 523 } 524 525 public function executeSecondPage() 526 { 527 // Retrieve data from the user session with a default value 528 $nickname = $this->getUser()->getAttribute('nickname', 'Anonymous Coward'); 529 } 530 } 531 532 >**CAUTION** 533 >You can store objects in the user session, but it is strongly discouraged. This is because the session object is serialized between requests and stored in a file. When the session is deserialized, the class of the stored objects must already be loaded, and that's not always the case. In addition, there can be "stalled" objects if you store Propel objects. 534 535 Like many getters in symfony, the `getAttribute()` method accepts a second argument, specifying the default value to be used when the attribute is not defined. To check whether an attribute has been defined for a user, use the `hasAttribute()` method. The attributes are stored in a parameter holder that can be accessed by the `getAttributeHolder()` method. It allows for easy cleanup of the user attributes with the usual parameter holder methods, as shown in Listing 6-18. 536 537 Listing 6-18 - Removing Data from the User Session 538 539 [php] 540 class mymoduleActions extends sfActions 541 { 542 public function executeRemoveNickname() 543 { 544 $this->getUser()->getAttributeHolder()->remove('nickname'); 545 } 546 547 public function executeCleanup() 548 { 549 $this->getUser()->getAttributeHolder()->clear(); 550 } 551 } 552 553 The user session attributes are also available in the templates by default via the `$sf_user` variable, which stores the current `sfUser` object, as shown in Listing 6-19. 554 555 Listing 6-19 - Templates Also Have Access to the User Session Attributes 556 557 [php] 558 <p> 559 Hello, <?php echo $sf_user->getAttribute('nickname') ?> 560 </p> 561 562 >**NOTE** 563 >If you need to store information just for the duration of the current request--for instance, to pass information through a chain of action calls--you may prefer the `sfRequest` class, which also has `getAttribute()` and `setAttribute()` methods. Only the attributes of the `sfUser` object are persistent between requests. 564 565 ### Flash Attributes 566 567 A recurrent problem with user attributes is the cleaning of the user session once the attribute is not needed anymore. For instance, you may want to display a confirmation after updating data via a form. As the form-handling action makes a redirect, the only way to pass information from this action to the action it redirects to is to store the information in the user session. But once the confirmation message is displayed, you need to clear the attribute; otherwise, it will remain in the session until it expires. 568 569 The flash attribute is an ephemeral attribute that you can define and forget, knowing that it will disappear after the very next request and leave the user session clean for the future. In your action, define the flash attribute like this: 570 571 [php] 572 $this->setFlash('attrib', $value); 573 574 The template will be rendered and delivered to the user, who will then make a new request to another action. In this second action, just get the value of the flash attribute like this: 575 576 [php] 577 $value = $this->getFlash('attrib'); 578 579 Then forget about it. After delivering this second page, the `attrib` flash attribute will be flushed. And even if you don't require it during this second action, the flash will disappear from the session anyway. 580 581 If you need to access a flash attribute from a template, use the `$sf_flash` object: 582 583 [php] 584 <?php if ($sf_flash->has('attrib')): ?> 585 <?php echo $sf_flash->get('attrib') ?> 586 <?php endif; ?> 587 588 or just: 589 590 [php] 591 <?php echo $sf_flash->get('attrib') ?> 592 593 Flash attributes are a clean way of passing information to the very next request. 594 595 ### Session Management 596 597 Symfony's session-handling feature completely masks the client and server storage of the session IDs to the developer. However, if you want to modify the default behaviors of the session-management mechanisms, it is still possible. This is mostly for advanced users. 598 599 On the client side, sessions are handled by cookies. The symfony session cookie is called `symfony`, but you can change its name by editing the `factories.yml` configuration file, as shown in Listing 6-20. 600 601 Listing 6-20 - Changing the Session Cookie Name, in `apps/myapp/config/factories.yml` 602 603 all: 604 storage: 605 class: sfSessionStorage 606 param: 607 session_name: my_cookie_name 608 609 >**TIP** 610 >The session is started (with the PHP function `session_start()`) only if the `auto_start` parameter is set to true in factories.yml (which is the case by default). If you want to start the user session manually, disable this setting of the storage factory. 611 612 Symfony's session handling is based on PHP sessions. This means that if you want the client-side management of sessions to be handled by URL parameters instead of cookies, you just need to change the use_trans_sid setting in your php.ini. Be aware that this is not recommended. 613 614 session.use_trans_sid = 1 615 616 On the server side, symfony stores user sessions in files by default. You can store them in your database by changing the value of the `class` parameter in `factories.yml`, as shown in Listing 6-21. 617 618 Listing 6-21 - Changing the Server Session Storage, in `apps/myapp/config/factories.yml` 619 620 all: 621 storage: 622 class: sfMySQLSessionStorage 623 param: 624 db_table: SESSION_TABLE_NAME # Name of the table storing the sessions 625 database: DATABASE_CONNECTION # Name of the database connection to use 626 627 The available session storage classes are `sfMySQLSessionStorage`, `sfPostgreSQLSessionStorage`, and `sfPDOSessionStorage`; the latter is preferred. The optional `database` setting defines the database connection to be used; symfony will then use `databases.yml` (see Chapter 8) to determine the connection settings (host, database name, user, and password) for this connection. 628 629 Session expiration occurs automatically after sf_timeout seconds. This constant is 30 minutes by default and can be modified for each environment in the `settings.yml` configuration file, as shown in Listing 6-22. 630 631 Listing 6-22 - Changing Session Lifetime, in `apps/myapp/config/settings.yml` 632 633 default: 634 .settings: 635 timeout: 1800 # Session lifetime in seconds 636 637 Action Security 638 --------------- 639 640 The ability to execute an action can be restricted to users with certain privileges. The tools provided by symfony for this purpose allow the creation of secure applications, where users need to be authenticated before accessing some features or parts of the application. Securing an application requires two steps: declaring the security requirements for each action and logging in users with privileges so that they can access these secure actions. 641 642 ### Access Restriction 643 644 Before being executed, every action passes by a special filter that checks if the current user has the privileges to access the requested action. In symfony, privileges are composed of two parts: 645 646 * Secure actions require users to be authenticated. 647 * Credentials are named security privileges that allow organizing security by group. 648 649 Restricting access to an action is simply made by creating and editing a YAML configuration file called `security.yml` in the module `config/` directory. In this file, you can specify the security requirements that users must fulfill for each action or for `all` actions. Listing 6-23 shows a sample `security.yml`. 650 651 Listing 6-23 - Setting Access Restrictions, in `apps/myapp/modules/mymodule/config/security.yml` 652 653 read: 654 is_secure: off # All users can request the read action 655 656 update: 657 is_secure: on # The update action is only for authenticated users 658 659 delete: 660 is_secure: on # Only for authenticated users 661 credentials: admin # With the admin credential 662 663 all: 664 is_secure: off # off is the default value anyway 665 666 Actions are not secure by default, so when there is no `security.yml` or no mention of an action in it, actions are accessible by everyone. If there is a `security.yml`, symfony looks for the name of the requested action and, if it exists, checks the fulfillment of the security requirements. What happens when a user tries to access a restricted action depends on his credentials: 667 668 * If the user is authenticated and has the proper credentials, the action is executed. 669 * If the user is not identified, he will be redirected to the default login action. 670 * If the user is identified but doesn't have the proper credentials, he will be redirected to the default secure action, shown in Figure 6-1. 671 672 The default login and secure pages are pretty simple, and you will probably want to customize them. You can configure which actions are to be called in case of insufficient privileges in the application `settings.yml` by changing the value of the properties shown in Listing 6-24. 673 674 Figure 6-1 - The default secure action page 675 676  677 678 Listing 6-24 - Default Security Actions Are Defined in `apps/myapp/config/settings.yml` 679 680 all: 681 .actions: 682 login_module: default 683 login_action: login 684 685 secure_module: default 686 secure_action: secure 687 688 ### Granting Access 689 690 To get access to restricted actions, users need to be authenticated and/or to have certain credentials. You can extend a user's privileges by calling methods of the `sfUser` object. The authenticated status of the user is set by the `setAuthenticated()` method. Listing 6-25 shows a simple example of user authentication. 691 692 Listing 6-25 - Setting the Authenticated Status of a User 693 694 [php] 695 class myAccountActions extends sfActions 696 { 697 public function executeLogin() 698 { 699 if ($this->getRequestParameter('login') == 'foobar') 700 { 701 $this->getUser()->setAuthenticated(true); 702 } 703 } 704 705 public function executeLogout() 706 { 707 $this->getUser()->setAuthenticated(false); 708 } 709 } 710 711 Credentials are a bit more complex to deal with, since you can check, add, remove, and clear credentials. Listing 6-26 describes the credential methods of the `sfUser` class. 712 713 Listing 6-26 - Dealing with User Credentials in an Action 714 715 [php] 716 class myAccountActions extends sfActions 717 { 718 public function executeDoThingsWithCredentials() 719 { 720 $user = $this->getUser(); 721 722 // Add one or more credentials 723 $user->addCredential('foo'); 724 $user->addCredentials('foo', 'bar'); 725 726 // Check if the user has a credential 727 echo $user->hasCredential('foo'); => true 728 729 // Check if the user has one of the credentials 730 echo $user->hasCredential(array('foo', 'bar')); => true 731 732 // Check if the user has both credentials 733 echo $user->hasCredential(array('foo', 'bar'), true); => true 734 735 // Remove a credential 736 $user->removeCredential('foo'); 737 echo $user->hasCredential('foo'); => false 738 739 // Remove all credentials (useful in the logout process) 740 $user->clearCredentials(); 741 echo $user->hasCredential('bar'); => false 742 } 743 } 744 745 If a user has the `'foo'` credential, that user will be able to access the actions for which the `security.yml` requires that credential. Credentials can also be used to display only authorized content in a template, as shown in Listing 6-27. 746 747 Listing 6-27 - Dealing with User Credentials in a Template 748 749 [php] 750 <ul> 751 <li><?php echo link_to('section1', 'content/section1') ?></li> 752 <li><?php echo link_to('section2', 'content/section2') ?></li> 753 <?php if ($sf_user->hasCredential('section3')): ?> 754 <li><?php echo link_to('section3', 'content/section3') ?></li> 755 <?php endif; ?> 756 </ul> 757 758 As for the authenticated status, credentials are often given to users during the login process. This is why the `sfUser` object is often extended to add login and logout methods, in order to set the security status of users in a central place. 759 760 >**TIP** 761 >Among the symfony plug-ins, the `sfGuardPlugin` extends the session class to make login and logout easy. Refer to Chapter 17 for more information. 762 763 ### Complex Credentials 764 765 The YAML syntax used in the security.yml file allows you to restrict access to users having a combination of credentials, using either AND-type or OR-type associations. With such a combination, you can build a complex workflow and user privilege management system--for instance, a content management system (CMS) back-office accessible only to users with the admin credential, where articles can be edited only by users with the `editor` credential and published only by the ones with the `publisher` credential. Listing 6-28 shows this example. 766 767 Listing 6-28 - Credentials Combination Syntax 768 769 editArticle: 770 credentials: [ admin, editor ] # admin AND editor 771 772 publishArticle: 773 credentials: [ admin, publisher ] # admin AND publisher 774 775 userManagement: 776 credentials: [[ admin, superuser ]] # admin OR superuser 777 778 Each time you add a new level of square brackets, the logic swaps between AND and OR. So you can create very complex credential combinations, such as this: 779 780 credentials: [[root, [supplier, [owner, quasiowner]], accounts]] 781 # root OR (supplier AND (owner OR quasiowner)) OR accounts 782 783 Validation and Error-Handling Methods 784 ------------------------------------- 785 786 Validating the action input--mostly request parameters--is a repetitive and tedious task. Symfony offers a built-in request validation system, using methods of the action class. 787 788 Let's start with an example. When a user makes a request for `myAction`, symfony always looks for a method called `validateMyAction()` first. If it is found, then symfony executes it. The return value of this validation method determines the next method to be executed: if it returns `true`, then `executeMyAction()` is executed; otherwise, `handleErrorMyAction()` is executed. And, if in the latter case, handleErrorMyAction() doesn't exist, symfony looks for a generic handleError() method. If that doesn't exist either, it simply returns `sfView::ERROR` to render the `myActionError. php` template. Figure 6-2 depicts this process. 789 790 Figure 6-2 - The validation process 791 792  793 794 So the key to validation is to respect the naming conventions for the action methods: 795 796 * `validateActionName` is the validation method, returning `true` or `false`. It is the first method looked for when the action `ActionName` is requested. If it doesn't exist, the action method is executed directly. 797 * `hand`leErrorActionName is the method called when the validation method fails. If it doesn't exist, the `Error` template is displayed. 798 * `executeActionName` is the action method. It must exist for all actions. 799 800 Listing 6-29 shows an example of an action class with validation methods. Whether the validation passes or fails in this example, the `myActionSuccess.php` template will be executed, but not with the same parameters. 801 802 Listing 6-29 - Sample Validation Methods 803 804 [php] 805 class mymoduleActions extends sfActions 806 { 807 public function validateMyAction() 808 { 809 return ($this->getRequestParameter('id') > 0); 810 } 811 812 public function handleErrorMyAction() 813 { 814 $this->message = "Invalid parameters"; 815 816 return sfView::SUCCESS; 817 } 818 819 public function executeMyAction() 820 { 821 $this->message = "The parameters are correct"; 822 } 823 } 824 825 You can put any code you want in the `validate()` methods. Just make sure they return either `true` or `false`. As it is a method of the `sfActions` class, it has access to the `sfRequest` and `sfUser` objects as well, which can be really useful for input and context validation. 826 827 You could use this mechanism to implement form validation (that is, control the values entered by the user in a form before processing it), but this is the type of repetitive task for which symfony provides automated tools, as described in Chapter 10. 828 829 Filters 830 ------- 831 832 The security process can be understood as a filter by which all requests must pass before executing the action. According to some tests executed in the filter, the processing of the request is modified--for instance, by changing the action executed (default/secure instead of the requested action in the case of the security filter). Symfony extends this idea to filter classes. You can specify any number of filter classes to be executed before the action execution or before the response rendering, and do this for every request. You can see filters as a way to package some code, similar to `preExecute()` and `postExecute()`, but at a higher level (for a whole application instead of for a whole module). 833 834 ### The Filter Chain 835 836 Symfony actually sees the processing of a request as a chain of filters. When a request is received by the framework, the first filter (which is always the `sfRenderingFilter`) is executed. At some point, it calls the next filter in the chain, then the next, and so on. When the last filter (which is always `sfExecutionFilter`) is executed, the previous filter can finish, and so on back to the rendering filter. Figure 6-3 illustrates this idea with a sequence diagram, using an artificially small filter chain (the real one contains more filters). 837 838 Figure 6-3 - Sample filter chain 839 840  841 842 This process justifies the structure of the filter classes. They all extend the `sfFilter` class, and contain one `execute()` method, expecting a `$filterChain` object as parameter. Somewhere in this method, the filter passes to the next filter in the chain by calling `$filterChain->execute()`. See Listing 6-30 for an example. So basically, filters are divided into two parts: 843 844 * The code before the call to `$filterChain->execute()` executes before the action execution. 845 * The code after the call to `$filterChain->execute()` executes after the action execution and before the rendering. 846 847 Listing 6-30 - Filter Class Struture 848 849 [php] 850 class myFilter extends sfFilter 851 { 852 public function execute ($filterChain) 853 { 854 // Code to execute before the action execution 855 ... 856 857 // Execute next filter in the chain 858 $filterChain->execute(); 859 860 // Code to execute after the action execution, before the rendering 861 ... 862 } 863 } 864 865 The default filter chain is defined in an application configuration file called `filters.yml`, and is shown in Listing 6-31. This file lists the filters that are to be executed for every request. 866 867 Listing 6-31 - Default Filter Chain, in `myapp/config/filters.yml` 868 869 rendering: ~ 870 web_debug: ~ 871 security: ~ 872 873 # Generally, you will want to insert your own filters here 874 875 cache: ~ 876 common: ~ 877 flash: ~ 878 execution: ~ 879 880 These declarations have no parameter (the tilde character, `~`, means "null" in YAML), because they inherit the parameters defined in the symfony core. In the core, symfony defines `class` and `param` settings for each of these filters. For instance, Listing 6-32 shows the default parameters for the `rendering` filter. 881 882 Listing 6-32 - Default Parameters of the rendering Filter, in $sf_symfony_data_dir/config/filters.yml 883 884 rendering: 885 class: sfRenderingFilter # Filter class 886 param: # Filter parameters 887 type: rendering 888 889 By leaving the empty value (`~`) in the application `filters.yml`, you tell symfony to apply the filter with the default settings defined in the core. 890 891 You can customize the filter chain in various ways: 892 893 * Disable some filters from the chain by adding an `enabled: off` parameter. For instance, to disable the web debug filter, write: 894 895 web_debug: 896 enabled: off 897 898 * Do not remove an entry from the `filters.yml` to disable a filter; symfony would throw an exception in this case. 899 * Add your own declarations somewhere in the chain (usually after the `security` filter) to add a custom filter (as discussed in the next section). Be aware that the `rendering` filter must be the first entry, and the `execution` filter must be the last entry of the filter chain. 900 * Override the default class and parameters of the default filters (notably to modify the security system and use your own security filter). 901 902 >**TIP** 903 >The `enabled: off` parameter works well to disable your own filters, but you can deactivate the default filters via the `settings.yml` file, by modifying the values of the `web_debug`, `use_security`, `cache`, and `use_flash` settings. This is because each of the default filters has a `condition` parameter that tests the value of these settings. 904 905 ### Building Your Own Filter 906 907 It is pretty simple to build a filter. Create a class definition similar to the one shown in Listing 6-30, and place it in one of the project's lib/ folders to take advantage of the autoloading feature. 908 909 As an action can forward or redirect to another action and consequently relaunch the full chain of filters, you might want to restrict the execution of your own filters to the first action call of the request. The `isFirstCall()` method of the `sfFilter` class returns a Boolean for this purpose. This call only makes sense before the action execution. 910 911 These concepts are clearer with an example. Listing 6-33 shows a filter used to auto-log users with a specific `MyWebSite` cookie, which is supposedly created by the login action. It is a rudimentary but working way to implement the "remember me" feature offered in login forms. 912 913 Listing 6-33 - Sample Filter Class File, Saved in `apps/myapp/lib/rememberFilter.class.php` 914 915 [php] 916 class rememberFilter extends sfFilter 917 { 918 public function execute($filterChain) 919 { 920 // Execute this filter only once 921 if ($this->isFirstCall()) 922 { 923 // Filters don't have direct access to the request and user objects. 924 // You will need to use the context object to get them 925 $request = $this->getContext()->getRequest(); 926 $user = $this->getContext()->getUser(); 927 928 if ($request->getCookie('MyWebSite')) 929 { 930 // sign in 931 $user->setAuthenticated(true); 932 } 933 } 934 935 // Execute next filter 936 $filterChain->execute(); 937 } 938 } 939 940 In some cases, instead of continuing the filter chain execution, you will need to forward to a specific action at the end of a filter. `sfFilter` doesn't have a `forward()` method, but `sfController` does, so you can simply do that by calling the following: 941 942 [php] 943 return $this->getController()->forward('mymodule', 'myAction'); 944 945 >**NOTE** 946 >The `sfFilter` class has an `initialize()` method, executed when the filter object is created. You can override it in your custom filter if you need to deal with filter parameters (defined in `filters.yml`, as described next) in your own way. 947 948 ### Filter Activation and Parameters 949 950 Creating a filter file is not enough to activate it. You need to add your filter to the filter chain, and for that, you must declare the filter class in the `filters.yml`, located in the application or in the module `config/` directory, as shown in Listing 6-34. 951 952 Listing 6-34 - Sample Filter Activation File, Saved in `apps/myapp/config/filters.yml` 953 954 rendering: ~ 955 web_debug: ~ 956 security: ~ 957 958 remember: # Filters need a unique name 959 class: rememberFilter 960 param: 961 cookie_name: MyWebSite 962 condition: %APP_ENABLE_REMEMBER_ME% 963 964 cache: ~ 965 common: ~ 966 flash: ~ 967 execution: ~ 968 969 When activated, the filter is executed for each request. The filter configuration file can contain one or more parameter definitions under the `param` key. The filter class has the ability to get the value of these parameters with the getParameter() method. Listing 6-35 demonstrates how to get a filter parameter value. 970 971 Listing 6-35 - Getting the Parameter Value, in `apps/myapp/lib/rememberFilter.class.php` 972 973 [php] 974 class rememberFilter extends sfFilter 975 { 976 public function execute ($filterChain) 977 { 978 ... 979 if ($request->getCookie($this->getParameter('cookie_name'))) 980 ... 981 } 982 } 983 984 The `condition` parameter is tested by the filter chain to see if the filter must be executed. So your filter declarations can rely on an application configuration, just like the one in Listing 6-34. The remember filter will be executed only if your application `app.yml` shows this: 985 986 all: 987 enable_remember_me: on 988 989 ### Sample Filters 990 991 The filter feature is useful to repeat code for every action. For instance, if you use a distant analytics system, you probably need to put a code snippet calling a distant tracker script in every page. You could put this code in the global layout, but then it would be active for all of the application. Alternatively, you could place it in a filter, such as the one shown in Listing 6-36, and activate it on a per-module basis. 992 993 Listing 6-36 - Google Analytics Filter 994 995 [php] 996 class sfGoogleAnalyticsFilter extends sfFilter 997 { 998 public function execute($filterChain) 999 { 1000 // Nothing to do before the action 1001 $filterChain->execute(); 1002 1003 // Decorate the response with the tracker code 1004 $googleCode = ' 1005 <script src="http://www.google-analytics.com/urchin.js" type="text/javascript"> 1006 </script> 1007 <script type="text/javascript"> 1008 _uacct="UA-'.$this->getParameter('google_id').'";urchinTracker(); 1009 </script>'; 1010 $response = $this->getContext()->getResponse(); 1011 $response->setContent(str_ireplace('</body>', $googleCode.'</body>',$response->getContent())); 1012 } 1013 } 1014 1015 Be aware that this filter is not perfect, as it should not add the tracker on responses that are not HTML. 1016 1017 Another example would be a filter that switches the request to SSL if it is not already, to secure the communication, as shown in Listing 6-37. 1018 1019 Listing 6-37 - Secure Communication Filter 1020 1021 [php] 1022 class sfSecureFilter extends sfFilter 1023 { 1024 public function execute($filterChain) 1025 { 1026 $context = $this->getContext(); 1027 $request = $context->getRequest(); 1028 if (!$request->isSecure()) 1029 { 1030 $secure_url = str_replace('http', 'https', $request->getUri()); 1031 return $context->getController()->redirect($secure_url); 1032 // We don't continue the filter chain 1033 } 1034 else 1035 { 1036 // The request is already secure, so we can continue 1037 $filterChain->execute(); 1038 } 1039 } 1040 } 1041 1042 Filters are used extensively in plug-ins, as they allow you to extend the features of an application globally. Refer to Chapter 17 to learn more about plug-ins, and see the online wiki ([http://www.symfony-project.com/trac/wiki](http://www.symfony-project.com/trac/wiki)) for more filter examples. 1043 1044 Module Configuration 1045 -------------------- 1046 1047 A few module behaviors rely on configuration. To modify them, you must create a `module.yml` file in the module's `config/` directory and define settings on a per-environment basis (or under the `all:` header for all environments). Listing 6-38 shows an example of a `module.yml` file for the `mymodule` module. 1048 1049 Listing 6-38 - Module Configuration, in `apps/myapp/modules/mymodule/config/module.yml` 1050 1051 all: # For all environments 1052 enabled: true 1053 is_internal: false 1054 view_name: sfPhpView 1055 1056 The enabled parameter allows you to disable all actions of a module. All actions are redirected to the `module_disabled_module`/`module_disabled_action` action (as defined in `settings.yml`). 1057 1058 The is_internal parameter allows you to restrict the execution of all actions of a module to internal calls. For example, this is useful for mail actions that you must be able to call from another action, to send an e-mail message, but not from the outside. 1059 1060 The view_name parameter defines the view class. It must inherit from `sfView`. Overriding this value allows you to use other view systems, with other templating engines, such as Smarty. 1061 1062 Summary 1063 ------- 1064 1065 In symfony, the controller layer is split into two parts: the front controller, which is the unique entry point to the application for a given environment, and the actions, which contain the page logic. An action has the ability to determine how its view will be executed, by returning one of the `sfView` constants. Inside an action, you can manipulate the different elements of the context, including the request object (`sfRequest`) and the current user session object (`sfUser`). 1066 1067 Combining the power of the session object, the action object, and the security configuration provides a complete security system, with access restriction and credentials. Special `validate()` and `handleError()` methods in actions allow handling of request validation. And if the `preExecute()` and `postExecute()` methods are made for reusability of code inside a module, the filters authorize the same reusability for all the applications by making controller code executed for every request.
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| Généré le : Fri Mar 16 22:42:14 2007 | par Balluche grâce à PHPXref 0.7 |