Chapter 19 - Mastering Symfony's Configuration Files
Now that you know symfony very well, you are already able to dig into its code to understand its core design and discover new hidden abilities. But before extending the symfony classes to match your own requirements, you should take a closer look at some of the configuration files. Many features are already built into symfony and can be activated by just changing configuration settings. This means that you can tweak the symfony core behavior without overriding its classes. This chapter takes you deep into the configuration files and their powerful capabilities.
Symfony Settings
The frontend/config/settings.yml
file contains the main symfony configuration for the frontend
application. You have already seen the function of many settings from this file in the previous chapters, but let's revisit them.
As explained in Chapter 5, this file is environment-dependent, which means that each setting can take a different value for each environment. Remember that each parameter defined in this file is accessible from inside the PHP code via the sfConfig
class. The parameter name is the setting name prefixed with sf_
. For instance, if you want to get the value of the cache
parameter, you just need to call sfConfig::get('sf_cache')
.
Default Modules and Actions
Symfony provides default pages for special situations. In the case of a routing error, symfony executes an action of the default
module, which is stored in the $sf_symfony_lib_dir/controller/default/
directory. The settings.yml
file defines which action is executed depending on the error:
error_404_module
anderror_404_action
: Action called when the URL entered by the user doesn't match any route or when ansfError404Exception
occurs. The default value isdefault/error404
.login_module
andlogin_action
: Action called when a nonauthenticated user tries to access a page defined assecure
insecurity.yml
(see Chapter 6 for details). The default value isdefault/login
.secure_module
andsecure_action
: Action called when a user doesn't have the credentials required for an action. The default value isdefault/secure
.module_disabled_module
andmodule_disabled_action
: Action called when a user requests a module declared as disabled inmodule.yml
. The default value isdefault/disabled
.
Before deploying an application to production, you should customize these actions, because the default
module templates include the symfony logo on the page. See Figure 19-1 for a screenshot of one of these pages, the error 404 page.
Figure 19-1 - Default 404 error page
You can override the default pages in two ways:
- You can create your own default module in the application's
modules/
directory, override all the actions defined in thesettings.yml
file (index
,error404
,login
,secure
,disabled
) and all the related templates (indexSuccess.php
,error404Success.php
,loginSuccess.php
,secureSuccess.php
,disabledSuccess.php
). - You can change the default module and action settings of the
settings.yml
file to use pages of your application.
Two other pages bear a symfony look and feel, and they also need to be customized before deployment to production. These pages are not in the default
module, because they are called when symfony cannot run properly. Instead, you will find these default pages in the $sf_symfony_lib_dir/exception/data/
directory:
error500.php
: Page called when an internal server error occurs in the production environment. In other environments (where debug is set totrue
), when an error occurs, symfony displays the full execution stack and an explicit error message (see Chapter 16 for details).unavailable.php
: Page called when a user requests a page while the application is disabled (with thedisable
task). It is also called while the cache is being cleared (that is, between a call to thephp symfony cache:clear
task and the end of this task execution). On systems with a very large cache, the cache-clearing process can take several seconds. Symfony cannot execute a request with a partially cleared cache, so requests received before the end of the process are redirected to this page.
To customize these pages, simply create error500.php
and unavailable.php
pages in your project or application's web/errors/
directory. Symfony will use these instead of its own.
note
To have requests redirected to the unavailable.php
page when needed, you need to set the check_lock
setting to on
in the application settings.yml
. The check is deactivated by default, because it adds a very slight overhead for every request.
Optional Feature Activation
Some parameters of the settings.yml
file control optional framework features that can be enabled or disabled. Deactivating unused features boosts performances a bit, so make sure to review the settings listed in Table 19-1 before deploying your application.
Table 19-1 - Optional Features Set Through settings.yml
Parameter | Description | Default Value |
---|---|---|
use_database |
Enables the database manager. Set it to off if you don't use a database. |
on |
i18n |
Enables interface translation (see Chapter 13). Set it to on for multilingual applications. |
off |
logging_enabled |
Enables logging of symfony events. Set it to off when you want to turn symfony logging off completely. | on |
escaping_strategy |
Enables the output escaping feature (see Chapter 7). Set it to on if you want data passed to your templates to be escaped. |
off |
cache |
Enables template caching (see Chapter 12). Set it to on if one of your modules includes cache.yml file. The cache filter (sfCacheFilter ) is enabled only if it is on. |
off in development, on in production |
web_debug |
Enables the web debug toolbar for easy debugging (see Chapter 16). Set it to on to display the toolbar on every page. |
on in development, off in production |
check_symfony_version |
Enables the check of the symfony version for every request. Set it to on for automatic cache clearing after a framework upgrade. Leave it set to off if you always clear the cache after an upgrade. | off |
check_lock |
Enables the application lock system, triggered by the cache:clear and project:disable tasks (see the previous section). Set it to on to have all requests to disabled applications redirected to the $sf_symfony_lib_dir/exception/data/unavailable.php page. |
off |
compressed |
Enables PHP response compression. Set it to on to compress the outgoing HTML via the PHP compression handler. |
off |
Feature Configuration
Symfony uses some parameters of settings.yml
to alter the behavior of built-in features such as form validation, cache, and third-party modules.
Output Escaping Settings
Output escaping settings control the way the variables are accessible in the template (see Chapter 7). The settings.yml
file includes two settings for this feature:
- The
escaping_strategy
setting can take the valueon
, oroff
. - The
escaping_method
setting can be set toESC_RAW
,ESC_SPECIALCHARS
,ESC_ENTITIES
,ESC_JS
, orESC_JS_NO_ENTITIES
.
Routing Settings
The routing settings (see Chapter 9) are defined in factories.yml
, under the routing
key. Listing 19-1 show the default routing configuration.
Listing 19-1 - Routing Configuration Settings, in frontend/config/factories.yml
routing: class: sfPatternRouting param: load_configuration: true suffix: . default_module: default default_action: index variable_prefixes: [':'] segment_separators: ['/', '.'] variable_regex: '[\w\d_]+' debug: %SF_DEBUG% logging: %SF_LOGGING_ENABLED% cache: class: sfFileCache param: automatic_cleaning_factor: 0 cache_dir: %SF_CONFIG_CACHE_DIR%/routing lifetime: 31556926 prefix: %SF_APP_DIR%
- The
suffix
parameter sets the default suffix for generated URLs. The default value is a period (.
), and it corresponds to no suffix. Set it to.html
, for instance, to have all generated URLs look like static pages. - When a routing rule doesn't define the
module
or theaction
parameter, values from thefactories.yml
are used instead:default_module
: Defaultmodule
request parameter. Defaults to thedefault
module.default_action
: Defaultaction
request parameter. Defaults to theindex
action.
- By default, route patterns identify named wildcards by a colon (
:
) prefix. But if you want to write your rules in a more PHP-friendly syntax, you can add the dollar ($
) sign in thevariable_prefixes
array. That way, you can write a pattern like '/article/$year/$month/$day/$title' instead of '/article/:year/:month/:day/:title'. - The pattern routing will identify named wildcards between separators. The default separators are the slash and the dot, but you can add more if you want in the
segment_separators
parameter. For instance, if you add the dash (-
), you can write a pattern like '/article/:year-:month-:day/:title'. - The pattern routing uses its own cache, in production mode, to speed up conversions between external URLs and internal URIs. By default, this cache uses the filesystem, but you can use any cache class, provided that you declare the class and its settings in the
cache
parameter. See Chapter 15 for the list of available cache storage classes. To deactivate the routing cache in production, set thedebug
parameter toon
.
These are only the settings for the sfPatternRouting
class. You can use another class for your application routing, either your own or one of symfony's routing factories (sfNoRouting
and sfPathInfoRouting
). With either of these two factories, all external URLs look like 'module/action?key1=param1'. No customization possible--but it's fast. The difference is that the first uses PHP's GET
, and the second uses PATH_INFO
. Use them mainly for backend interfaces.
There is one additional parameter related to routing, but this one is stored in settings.yml
:
no_script_name
enables the front controller name in generated URLs. Theno_script_name
setting can be on only for a single application in a project, unless you store the front controllers in various directories and alter the default URL rewriting rules. It is usually on for the production environment of your main application and off for the others.
Form Validation Settings
note
The features described in this section are deprecated in symfony 1.1 and only work if you enable the sfCompat10
plugin.
Form validation settings control the way error messages output by the Validation
helpers look (see Chapter 10). These errors are included in <div>
tags, and they use the validation_error_ class
setting as a class
attribute and the validation_error_id_prefix
setting to build up the id
attribute. The default values are form_error
and error_for_
, so the attributes output by a call to the form_error()
helper for an input named foobar
will be class="form_error" id="error_for_foobar"
.
Two settings determine which characters precede and follow each error message: validation_error_prefix
and validation_error_suffix
. You can change them to customize all error messages at once.
Cache Settings
Cache settings are defined in cache.yml
for the most part, except for two in settings.yml
: cache
enables the template cache mechanism, and etag
enables ETag handling on the server side (see Chapter 15). You can also specify which storage to use for two all cache systems (the view cache, the routing cache, and the i18n cache) in factories.yml
. Listing 19-2 show the default view cache factory configuration.
Listing 19-2 - View Cache Configuration Settings, in frontend/config/factories.yml
view_cache: class: sfFileCache param: automatic_cleaning_factor: 0 cache_dir: %SF_TEMPLATE_CACHE_DIR% lifetime: 86400 prefix: %SF_APP_DIR%/template
The class
can be any of sfFileCache
, sfAPCCache
, sfEAcceleratorCache
, sfXCacheCache
, sfMemcacheCache
, and sfSQLiteCache
. It can also be your own custom class, provided it extends sfCache
and provides the same generic methods for setting, retrieving and deleting a key in the cache. The factory parameters depend on the class you choose, but there are constants:
lifetime
defines the number of seconds after which a cache part is removedprefix
is a prefix added to every cache key (use the environment in the prefix to use different cache depending on the environment). Use the same prefix for two applications if you want their cache to be shared.
Then, for each particular factory, you have to define the location of the cache storage.
- for
sfFileCache
, thecache_dir
parameter locates the absolute path to the cache directory sfAPCCache
,sfEAcceleratorCache
, andsfXCacheCache
don't take any location parameter, since they use PHP native functions for communicating with APC, EAccelerator or the XCache cache systems- for
sfMemcacheCache
, enter the hostname of the Memcached server in thehost
parameter, or an array of hosts in theservers
parameter - for
sfSQLiteCache
, the absolute path to the SQLite database file should be entered in thedatabase
parameter
For additional parameters, check the API documentation of each cache class.
The view is not the only component to be able to use a cache. Both the routing
and the I18N
factories offer a cache
parameter in which you can set any cache factory, just like the view cache. For instance, Listing 19-1 shows of the routing uses the file cache for its speedup tactics by default, but you can change it to whatever you want.
Logging Settings
Two logging settings (see Chapter 16) are stored in settings.yml
:
error_reporting
specifies which events are logged in the PHP logs. By default, it is set toE_PARSE | E_COMPILE_ERROR | E_ERROR | E_CORE_ERROR | E_USER_ERROR
for the production environment (so the logged events areE_PARSE
,E_COMPILE_ERROR
,E_ERROR
,E_CORE_ERROR
, andE_USER_ERROR
) and toE_ALL | E_STRICT
for the development environment.- The
web_debug
setting activates the web debug toolbar. Set it toon
only in the development and test environments.
Paths to Assets
The settings.yml
file also stores paths to assets. If you want to use another version of the asset than the one bundled with symfony, you can change these path settings:
- Rich text editor JavaScript files stored in
rich_text_js_dir
(by default,js/tiny_mce
) - Prototype libraries stored in
prototype_web_dir
(by default,/sf/prototype
) - Files needed by the administration generator stored in
admin_web_dir
- Files needed by the web debug toolbar stored in
web_debug_web_dir
- Files needed by the javascript calendar stored in
calendar_web_dir
Default Helpers
Default helpers, loaded for every template, are declared in the standard_helpers
setting (see Chapter 7). By default, these are the Partial
, Cache
, and Form
helper groups. If you use a helper group in all templates of an application, adding its name to the standard_helpers
setting saves you the hassle of declaring it with use_helper()
on each template.
Activated Modules
Activated modules from plug-ins or from the symfony core are declared in the enabled_modules
parameter. Even if a plug-in bundles a module, users can't request this module unless it is declared in enabled_modules
. The default
module, which provides the default symfony pages (congratulations, page not found, and so on), is the only enabled module by default.
Character Set
The character set of the responses is a general setting of the application, because it is used by many components of the framework (templates, output escaper, helpers, and so on). Defined in the charset
setting, its default (and advised) value is utf-8
.
Miscellaneous Configuration
The settings.yml
file contains a few more parameters, used internally by symfony for core behaviors. Listing 19-3 lists them as they appear in the configuration file.
Listing 19-3 - Miscellaneous Configuration Settings, in frontend/config/settings.yml
# Remove comments in core framework classes as defined in the core_compile.yml strip_comments: on # Maximum number of forwards followed by the action before raising an exception max_forwards: 5 # Global constants path_info_array: SERVER path_info_key: PATH_INFO url_format: PATH
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Adding Your application settings
The settings.yml
file defines symfony settings for an application. As discussed in Chapter 5, when you want to add new parameters, the best place to do so is in the frontend/config/app.yml
file. This file is also environment-dependent, and the settings it defines are available through the sfConfig class with the app_
prefix.
all: creditcards: fake: off # app_creditcards_fake visa: on # app_creditcards_visa americanexpress: on # app_creditcards_americanexpress
You can also write an app.yml
file in the project configuration directory, and this provides a way to define custom project settings. The configuration cascade also applies to this file, so the settings defined in the application app.yml
file override the ones defined at the project level.
Extending the Autoloading Feature
The autoloading feature, briefly explained in Chapter 2, exempts you from requiring classes in your code if they are located in specific directories. This means that you can just let the framework do the job for you, allowing it to load only the necessary classes at the appropriate time, and only when needed.
The autoload.yml
file lists the paths in which autoloaded classes are stored. The first time this configuration file is processed, symfony parses all the directories referenced in the file. Each time a file ending with .php
is found in one of these directories, the file path and the class names found in this file are added to an internal list of autoloading classes. This list is saved in the cache, in a file called config/config_autoload.yml.php
. Then, at runtime, when a class is used, symfony looks in this list for the class path and includes the .php
file automatically.
Autoloading works for all .php
files containing classes and/or interfaces.
By default, classes stored in the following directories in your projects benefit from the autoloading automatically:
myproject/lib/
myproject/lib/model
myproject/apps/frontend/lib/
myproject/apps/frontend/modules/mymodule/lib
There is no autoload.yml
file in the default application configuration directory. If you want to modify the framework settings--for instance, to autoload classes stored somewhere else in your file structure--create an empty autoload.yml file and override the settings of $sf_symfony_lib_dir/config/config/autoload.yml
or add your own.
The autoload.yml file must start with an autoload: key and list the locations where symfony should look for classes. Each location requires a label; this gives you the ability to override symfony's entries. For each location, provide a name
(it will appear as a comment in config_autoload.yml.php
) and an absolute path
. Then define if the search must be recursive
, which directs symfony to look in all the subdirectories for .php
files, and exclude
the subdirectories you want. Listing 19-4 shows the locations used by default and the file syntax.
Listing 19-4 - Default Autoloading Configuration, in $sf_symfony_lib_dir/config/config/autoload.yml
autoload: # plugins plugins_lib: name: plugins lib path: %SF_PLUGINS_DIR%/*/lib recursive: on plugins_module_lib: name: plugins module lib path: %SF_PLUGINS_DIR%/*/modules/*/lib prefix: 2 recursive: on # project project: name: project path: %SF_LIB_DIR% recursive: on exclude: [model, symfony] project_model: name: project model path: %SF_LIB_DIR%/model recursive: on # application application: name: application path: %SF_APP_LIB_DIR% recursive: on modules: name: module path: %SF_APP_DIR%/modules/*/lib prefix: 1 recursive: on
A rule path can contain wildcards and use the file path parameters defined in the configuration classes (see the next section). If you use these parameters in the configuration file, they must appear in uppercase and begin and end with %
.
Editing your own autoload.yml
will add new locations to symfony's autoloading, but you may want to extend this mechanism and add your own autoloading handler to symfony's handler. As symfony uses the standard spl_autoload_register()
function to manage class autoloading, you can register more callbacks in the application configuration class:
class frontendConfiguration extends sfApplicationConfiguration { public function initialize() { parent::initialize(); // load symfony autoloading first // insert your own autoloading callables here spl_autoload_register(array('myToolkit', 'autoload')); } }
When the PHP autoloading system encounters a new class, it will first try the symfony autoloading method (and use the locations defined in autoload.yml
). If it doesn't find a class definition, all the other callables registered with spl_autoload_register()
will be called, until the class is found. So you can add as many autoloading mechanisms as you want--for instance, to provide a bridge to other framework components (see Chapter 17).
Custom File Structure
Each time the framework uses a path to look for something (from core classes to templates, plug-ins, configurations, and so on), it uses a path variable instead of an actual path. By changing these variables, you can completely alter the directory structure of a symfony project, and adapt to the file organization requirements of any client.
caution
Customizing the directory structure of a symfony project is possible but not necessarily a good idea. One of the strengths of a framework like symfony is that any web developer can look at a project built with it and feel at home, because of the respect for conventions. Make sure you consider this issue before deciding to use your own directory structure.
The Basic File Structure
The path variables are defined in the sfProjectConfiguration
and sfApplicationConfiguration
classes and stored in the sfConfig
object. Listing 19-5 shows a listing of the path variables and the directory they reference.
Listing 19-5 - Default File Structure Variables, defined in sfProjectConfiguration
and sfApplicationConfiguration
sf_root_dir # myproject/ sf_apps_dir # apps/ sf_app_dir # frontend/ sf_app_config_dir # config/ sf_app_i18n_dir # i18n/ sf_app_lib_dir # lib/ sf_app_module_dir # modules/ sf_app_template_dir # templates/ sf_cache_dir # cache/ sf_app_base_cache_dir # frontend/ sf_app_cache_dir # prod/ sf_template_cache_dir # templates/ sf_i18n_cache_dir # i18n/ sf_config_cache_dir # config/ sf_test_cache_dir # test/ sf_module_cache_dir # modules/ sf_config_dir # config/ sf_data_dir # data/ sf_doc_dir # doc/ sf_lib_dir # lib/ sf_log_dir # log/ sf_test_dir # test/ sf_plugins_dir # plugins/ sf_web_dir # web/ sf_upload_dir # uploads/
Every path to a key directory is determined by a parameter ending with _dir
. Always use the path variables instead of real (relative or absolute) file paths, so that you will be able to change them later, if necessary. For instance, when you want to move a file to the uploads/
directory in an application, you should use sfConfig::get('sf_upload_dir')
for the path instead of sfConfig::get('sf_root_dir').'/web/uploads/'
.
Customizing the File Structure
You will probably need to modify the default project file structure if you develop an application for a client who already has a defined directory structure and who is not willing to change it to comply with the symfony logic. By overriding the sf_XXX_dir
variables with sfConfig
, you can make symfony work for a totally different directory structure than the default structure. The best place to do this is in the application ProjectConfiguration
class for project directories, or XXXConfiguration
class for applications directories.
For instance, if you want all applications to share a common directory for the template layouts, add this line to the configure()
method of the ProjectConfiguration
class to override the sf_app_template_dir
settings:
sfConfig::set('sf_app_template_dir', sfConfig::get('sf_root_dir').DIRECTORY_SEPARATOR.'templates');
note
Even if you can change your project directory structure by calling sfConfig::set()
, it's better to use the dedicated methods defined by the project and application configuration classes if possible as they take care of changing all the related paths. For example, the setCacheDir()
method changes the following constants: sf_cache_dir
, sf_app_base_cache_dir
, sf_app_cache_dir
, sf_template_cache_dir
, sf_i18n_cache_dir
, sf_config_cache_dir
, sf_test_cache_dir
, and sf_module_cache_dir
.
Modifying the Project Web Root
All the paths built in the configuration classes rely on the project root directory, which is determined by the ProjectConfiguration
file included in the front controller. Usually, the root directory is one level above the web/
directory, but you can use a different structure. Suppose that your main directory structure is made of two directories, one public and one private, as shown in Listing 19-7. This typically happens when hosting a project on a shared host.
Listing 19-7 - Example of Custom Directory Structure for a Shared Host
symfony/ # Private area apps/ config/ ... www/ # Public area images/ css/ js/ index.php
In this case, the root directory is the symfony/
directory. So the index.php
front controller simply needs to include the config/ProjectConfiguration.class.php
file as follows for the application to work:
require_once(dirname(__FILE__).'/../symfony/config/ProjectConfiguration.class.php');
In addition, use the setWebDir()
method to change the public area from the usual web/
to www/
, as follows:
class ProjectConfiguration extends sfProjectConfiguration { public function setup() { // ... $this->setWebDir($this->getRootDir().'/../www'); } }
Linking to Symfony Libraries
The path to the framework files is defined in the ProjectConfiguration
class, located in the config/
directory, as you can see in Listing 19-8.
Listing 19-8 - The Path to the Framework Files, in myproject/config/ProjectConfiguration.class.php
<?php require_once '/path/to/symfony/lib/autoload/sfCoreAutoload.class.php'; sfCoreAutoload::register(); class ProjectConfiguration extends sfProjectConfiguration { public function setup() { } }
The path is initialized when you call a php symfony generate:project
from the command line, and refer to the symfony installation used to build the project. It is used both by the command line and by the MVC architecture.
This means that you can switch to another installation of symfony by changing the path to the framework files.
The path should be absolute, but by using dirname(__FILE__)
, you can refer to files inside the project structure and preserve independence of the chosen directory for the project installation. For instance, many projects choose to have the symfony lib/
directory appear as a symbolic link in the project lib/vendor/symfony/
directory, as follows:
myproject/ lib/ vendor/ symfony/ => /path/to/symfony/
In this case, the ProjectConfiguration
class just needs to define the symfony lib directory as follows:
<?php require_once dirname(__FILE__).'/../lib/vendor/symfony/lib/autoload/sfCoreAutoload.class.php'; sfCoreAutoload::register(); class ProjectConfiguration extends sfProjectConfiguration { public function setup() { } }
The same principle also applies if you choose to include the symfony files as a svn:externals
in the project lib/vendor/
directory:
myproject/ lib/ vendor/ svn:externals symfony http://svn.symfony-project.com/branches/1.1
tip
Sometimes, the different servers running an application don't have the same path to the symfony libraries. One way to enable that is to exclude the ProjectConfiguration.class.php
file from the synchronization (by adding it to rsync_exclude.txt
). Another method is to keep the same paths in the development and production versions of ProjectConfiguration.class.php
, but to have these paths point to symbolic links that can vary according to the server.
Understanding Configuration Handlers
Each configuration file has a handler. The job of configuration handlers is to manage the configuration cascade, and to do the translation between the configuration files and the optimized PHP code executable at runtime.
Default Configuration Handlers
The default handler configuration is stored in $sf_symfony_lib_dir/config/config/config_handlers.yml
. This file links the handlers to the configuration files according to a file path. Listing 19-9 shows an extract of this file.
Listing 19-9 - Extract of $sf_symfony_lib_dir/config/config/config_handlers.yml
config/settings.yml: class: sfDefineEnvironmentConfigHandler param: prefix: sf_ config/app.yml: class: sfDefineEnvironmentConfigHandler param: prefix: app_ config/filters.yml: class: sfFilterConfigHandler modules/*/config/module.yml: class: sfDefineEnvironmentConfigHandler param: prefix: mod_ module: yes
For each configuration file (config_handlers.yml
identifies each file by a file path with wildcards), the handler class is specified under the class
key.
The settings of configuration files handled by sfDefineEnvironmentConfigHandler
can be made available directly in the code via the sfConfig
class, and the param key contains a prefix value.
You can add or modify the handlers used to process each configuration file--for instance, to use INI or XML files instead of YAML files.
note
The configuration handler for the config_handlers.yml
file is sfRootConfigHandler
and, obviously, it cannot be changed.
If you ever need to modify the way the configuration is parsed, create an empty config_handlers.yml
file in your application's config/
folder and override the class
lines with the classes you wrote.
Adding Your Own Handler
Using a handler to deal with a configuration file provides two important benefits:
- The configuration file is transformed into executable PHP code, and this code is stored in the cache. This means that the configuration is parsed only once in production, and the performance is optimal.
- The configuration file can be defined at different levels (project and application) and the final parameter values will result from a cascade. So you can define parameters at a project level and override them on a per-application basis.
If you feel like writing your own configuration handler, follow the example of the structure used by the framework in the $sf_symfony_lib_dir/config/
directory.
Let's suppose that your application contains a myMapAPI
class, which provides an interface to a third-party web service delivering maps. This class needs to be initialized with a URL and a user name, as shown in Listing 19-10.
Listing 19-10 - Example of Initialization of the myMapAPI
Class
$mapApi = new myMapAPI(); $mapApi->setUrl($url); $mapApi->setUser($user);
You may want to store these two parameters in a custom configuration file called map.yml
, located in the application config/ directory. This configuration file might contain the following:
api: url: map.api.example.com user: foobar
In order to transform these settings into code equivalent to Listing 19-9, you must build a configuration handler. Each configuration handler must extend sfConfigHandler
and provide an execute()
method, which expects an array of file paths to configuration files as a parameter, and must return data to be written in a cache file. Handlers for YAML files should extend the sfYamlConfigHandler
class, which provides additional facilities for YAML parsing. For the map.yml
file, a typical configuration handler could be written as shown in Listing 19-11.
Listing 19-11 - A Custom Configuration Handler, in frontend/lib/myMapConfigHandler.class.php
<?php class myMapConfigHandler extends sfYamlConfigHandler { public function execute($configFiles) { // Parse the yaml $config = $this->parseYamls($configFiles); $data = "<?php\n"; $data. = "\$mapApi = new myMapAPI();\n"; if (isset($config['api']['url']) { $data. = sprintf("\$mapApi->setUrl('%s');\n", $config['api']['url']); } if (isset($config['api']['user']) { $data. = sprintf("\$mapApi->setUser('%s');\n", $config['api']['user']); } return $data; } }
The $configFiles
array that symfony passes to the execute()
method will contain a path to all the map.yml
files found in the config/
folders. The parseYamls()
method will handle the configuration cascade.
In order to associate this new handler with the map.yml
file, you must create a config_handlers.yml
configuration file with the following content:
config/map.yml: class: myMapConfigHandler
note
The class
must either be autoloaded (that's the case here) or defined in the file whose path is written in a file
parameter under the param
key.
As with many other symfony configuration files, you can also register a configuration handler directly in your PHP code:
sfContext::getInstance()->getConfigCache()->registerConfigHandler('config/map.yml', 'myMapConfigHandler', array());
When you need the code based on the map.yml
file and generated by the myMapConfigHandler
handler in your application, call the following line:
include(sfContext::getInstance()->getConfigCache()->checkConfig('config/map.yml'));
When calling the checkConfig()
method, symfony looks for existing map.yml
files in the configuration directories and processes them with the handler specified in the config_handlers.yml
file, if a map.yml.php
does not already exist in the cache or if the map.yml
file is more recent than the cache.
tip
If you want to handle environments in a YAML configuration file, the handler can extend the sfDefineEnvironmentConfigHandler
class instead of sfYamlConfigHandler
. Instead of calling the parseYaml()
method to retrieve the configuration, you should call the getConfiguration()
method: $config = $this->getConfiguration($configFiles)
.
sidebar
Using Existing configuration handlers
If you just need to allow users to retrieve values from the code via sfConfig
, you can use the sfDefineEnvironmentConfigHandler
configuration handler class. For instance, to have the url
and user
parameters available as sfConfig::get('map_url')
and sfConfig::get('map_user')
, define your handler as follows:
config/map.yml: class: sfDefineEnvironmentConfigHandler param: prefix: map_
Be careful not to choose a prefix already used by another handler. Existing prefixes are sf_
, app_
, and mod_
.
Summary
The configuration files can heavily modify the way the framework works. Because symfony relies on configuration even for its core features and file loading, it can adapt to many more environments than just the standard dedicated host. This great configurability is one of the main strengths of symfony. Even if it sometimes frightens newcomers, who see in configuration files a lot of conventions to learn, it allows symfony applications to be compatible with a very large number of platforms and environments. Once you become a master of symfony's configuration, no server will ever refuse to run your applications!
This work is licensed under the GFDL license.