Pages and Templates

Este tutorial describe el rol de las Páginas y las Plantillas en iHRIS.

Una página es la pieza básica que maneja cada solicitud URL. Es la unidad funcional básica del sistema en una petición de URL que se procesa y se muestra. Si desea añadir una nueva funcionalidad a iHRIS, muy probablemente tendrá que añadir una nueva página. Una página de ejemplo sería "Editar/añadir un documento escaneado."

Una plantilla se utiliza para acceder a los elementos HTML de una página. Se basa en el PHP Document Object Model.

Páginas

Las páginas pueden establecerse para que vivan directamente bajo la base URL de la página, o bajo un módulo y todas las solicitudes se delegan en la clase de página apropiada por el wrangler.

La lógica de una página se maneja por la clase de una página que tiene como sub-clase I2CE_Page por medio del método action() .

Las variables GET y POST variables son (por defecto) pre-procesadas por la clase de la página. Todas las páginas por defecto utilizan un templating que actúa como envoltura para el Document Object Model (DOM). También hay un sistema basado en permisos de task and role incluido.

También hay, por abuso de lenguaje, páginas para el PHP CLI. En este artículo sólo vamos a describir las páginas que URL Pide.

Clases de Páginas

Todas las solicitudes son finalmente delegadas por el wrangler a una subclase de I2CE_Page. Esta clase se encarga de toda la lógica de negocio de la página. Debe determinar la acción apropiada a desarrollar en función de si se trata de una solicitud de POST o GET. Varias páginas se pueden manejar por una clase de página. En la construcción, la página pasa una serie de arreglos de argumentos que se definen por page style y request remainder. Uno puede opcionalmente sobreescribir lo que se envía como el arreglo de las variables POST y GET.

Lógica de la Página

He aquí un resumen de la lógica de la página subyacente por defecto:

• Las variables POST y GOT son (por lo general) pre-processed.
• El conjunto de argumentos son producidos por el wrangler ya que procesa el estilo de la página.
• Los archivos de plantilla raíz o principales, se hay alguno cargado. Esto se especifica como el argumento de 'templates'.
• Los argumentos incluidos en esta página opcionalmente son restricciones de tareas y roles para la página:
  • Los roles que tienen permiso para ver la página se guardan bajo el 'access' clave
  • Las tareas que un user/role debe tener para ver la página se guardan en las 'tasks' clave
• Una vez que el usuario ha pasado las restricciones de acceso de la página, lo siguiente ocurre:
  • El 'pre_page_action' hook se llama
  • Cualquier archivo html por defecto se carga para una página en los template que fueron creados para la página
    El archive html por defecto se guarda bajo el argumento 'defaultHTMLFile'
  • Se llama el método action()
  • Si el método de action() no regreso falso entonces se llama el 'post_page_action' hook
  • Si el método action() regresa falso entonces se genera un mensaje de error de usuario.
  • Si la página solicita una redirección, se realiza y la ejecución se detiene.
  • Si la página no solicito una redirección, entonces:
    • Cualquier declaración echo, print_r, etc. se adjuntan al final del DOM de la plantilla. Estos echo's, etc. solamente deben estar presente para propósitos de debugging y no en el código de producción.
    • A menos que la página solicito suprimir el resultado, la plantilla muestra su resultado(HTML) .
      Este es la única declaración echo que debe utilizarse en un sitio de producción para mostrar html.

El Método de action()

Una sub-clase de I2CE_Page generalmente debe implementar toda su lógica al sobreescribir el método action() .

Conversión de Variables

Las variables POST y GET, a menos que se les solicite específicamente no hacerlo, son pre-procesadas. Además de las variables POST y GET , las variables de SOLICITUD son creadas, que son (generalmente) cualquier variable que existe como POST o GET. Hay algunas cosas que ocurren (generalmente):

• Si la variable GET 'req_query' existe, se adjunta el valor y se guarda como variables de SOLICITUD
• Cualquier nombre de variables con ':' se procesan para definer arreglos de multi-dimensión. Por ejemplo:

$_GET = array(
  'some:thing'] => '5'
  'some:otherthing' => '6'
 )

se convierte en:

$_GET = array(
   'some'=>array(
       'thing'=>'5'
       'otherthing'=>'6'
   )
)

• Si una variable se llama 'i2ce_json' es json_decode() y se fusiona de nuevo con las variables.

Wrangler

El wranger es el componente principal del software que delega las Solicitudes de URL primero a u par de un page name y módulo y luego a la clase de página apropiada. Supongamos para esta sección que nuestro sitio vive en el siguiente URL de base:

http://my.site.org/manage

Converting a URL to a Page

Pages can live directly under the base URL, or under a module. The wrangler processes the URL via the I2CE_Wrangler->processPath() method and returns a page name, the module the page name is registered with, and a request remainder. The module that a page name is registered under is often not the module that provides the page class. Let us outline the logic for the example:

http://my.site.org/manage/some/thing/is/here

• If there is nothing after the base URL, then the module is 'I2CE' and the page name is 'home'.
  There is no request remainder.
  This is not the case in the above example.
• If 'some' is registered as a page name provided by 'I2CE', then the module is 'I2CE' and the page name is 'some'.
  The request remainder is then thing/is/here.
  some is considered to be a page name registered under 'I2CE' if the magic data path /I2CE/page/some exists.
• Otherwise the module is 'some' and the following rules apply:
  • If there is nothing after the 'some', then the module is 'some' and the page name is 'home'
    There is no request remainder
    This is not the case in the above example.
  • If 'thing' is a registered as a page name for 'some' then, the module is 'some' and the page name is 'some.'.
    The request remainder is then is/here

Once the path has been processed, we verify that the returned page exists for the given module. If it does not, we try to handle the request by looking for a default page name for the module. The default page name, if defined exists at the magic data path /modules/$module/default_page.

The registered module, the page name, and the request remainder call all be accessed through I2CE_Pages's API.

Page Styles

Once we have a valid module and page name associated to a URL, we begin processing the page's styles. A page style can consist of three components:

• Another page style which this page style inherits the properties of
• A page class to associate to a page
• A nested array of arguments to pass the the page class constructor. These are merged into any inherited arguments by I2CE_Util::merge_recursive()

Templates

Each page instance is assigned a template which is an instance of I2CE_TemplateMeister, and usually an instance of the sub-class I2CE_Template.

The Template is essentially a wrapper class for a DOMDocument object with some useful convenience methods built in. Although the additional functionality provided by I2CE_TemplateMeister and I2CE_Template is initially very limited, it is greatly augmented by making use of fuzzy methods.

The page will display the DOM contained in the template as html after the page has finished processing.

Template Data

The most significant way the I2CE_Template case is augemented is to provide "Template Data." The module template-data provides the ability to assign arbitrary data to any node in the DOM. The data exists in categories, such as 'FORM' or 'OPTION' and applies to all sub-nodes of the given node. Each piece of data is assigned a name.

If the node is an given by specifying an id (rather than giving an explict instanceof DOMNode) the data will be held in a cache until a node with the given id is added to the template.

When looking for a piece of data assigned to a particular node, we start at the given node and walk up the DOM until the named data is found.

For each category of template data, a default bit of data may be assigned which applies for the whole DOM.

There are several modules which make explicit use of the template data structure.

Warning: The template data mechanism assumes that there is only one template in use per request. Be very careful if you are using multiple templates in one page each making use of template data.

Display Data

Display data are template data in the category 'DISPLAY' which can be set with the setDisplayData() and setDisplayDataImmediate() methods and provide a convenient way of manipulating the template files loaded. The template will look for any DOMElements with the name attribute set and process them according to their tag name and the template data, if any, stored under the name attribute. Here is a list of the commonly used tags that are processed and their rules:

• div, pre, span, textarea: the value of the template data is appended to the next content of the element
• input: If the template data is an array, is is considered to be an array or attribute=>value pairs which are set on the element.
  If it is scalar valued, is is processed according to the value of the attribute type as follows::::
  • input: the attribute value is set to the value of the template data
  • checkbox: if it evaluates to true, then the attribute 'checked' is set. otherwise it is removed
• select: If the value of the template data is an array, <option> tags are added with value attribute set to be the array key and the text content set to the corresponding array value
• a: if the template data is of scalar type then:
  • if the href value is not set, it is set to be the value of the template data.
  • if the href is set the value template date is appended with either a ? or a & as appropriate to the href attribute
• img: If the template data is an array, it is used as a set of attribute=>value pairs. If it is scalar, then the src attribute is set
• form: If the template data is an array, it is used as a set of attribute=>value pairs. If it is scalar, then the action attribute is set
• meta: If the template data is a scalar the content attribute is set
• If the element has the attribute ifset with (case insensitive) value 'true' or 't' or '1' and the template data is not set, then it is removed.
• If the element has the attribute ifset with (case insensitive) value other than 'true' or 't' or '1' and the template data is set, then it not removed.

Options

Closely related to the Display Data module is the Options module which saves template data in the category 'OPTIONS.' It process tags of the form:

<select id='some_id'/>

and if it finds an OPTION template data named 'some_id' it will append a <select> tag for each of these bits of data.

Form Data

A form can be set on any node and can be referenced as

<span type='form' name='form:field'/>

where you would substitute 'form' and 'field' as appropriate. If the 'form' is not specified it uses the default form, if any, set for the page.

Module Attribute

Any DOM Elements with the attribute type set to be 'module' and 'name' attribute are processed according to certain rules. The value of the name attribute is the name of a module. The following attributes are recognized:

• ifenabled: can be t, true, !t or !true. If true and the module is not enabled, or false and the module is enabled the the node is removed.
• if: Tries to call the module's function with the value of the attribute 'if.' If the module returns (something which casts to) false the node is removed. Prepending the value with a ! causes the opposite behavior.
• call: The value is used as the value of a method to call in the module's class.

Suppose we have

someMethod($node,$template,$args)

where $node is the <span> node, $template is the template object and the argument is the array of arguments $args = ($arg1,..,$argN) where [argM] is turned into $argM according to the following rules:

• if [argM] starts with a $ then it refers to template data and the following rules apply:
  • The string has the form $abcd. The value of $argM becomes the template display data with name 'abcd.'
  • The string has the form ${WXYZ}abcd. The value of $argM becomes the template data with category XYZ and with name 'abcd.'
• <NODE> becomes the instance of DOMNode (if any) that the permission string was called on
• <TEMPLATE> becomes the instance of I2CE_Template (if any) that the permission parser was called on
• <USER> becomes the instance of I2CE_User that is this session
• if [argM] starts with a single quote ' then it is a string until the next non-escaped ' is found
• if [argM] starts with a double quote " then is is a string until the next non-escaped " is found.
  In addition the following substitution rules apply:
  • any substring starting with $ and consisting of alpha-numeric characters, - or _ is interpreted as template display data to be substituted
    For example "my name is $name" becomes "my name is Joe" if the template data named 'name' and with type DISPLAY is "Joe"
  • any substring starting with {$ is read until an enclosing } is found. The string between the ${ and } is the name of DISPLAY template data which is then substituted.
  • To prevent the above, { and $ may be escaped with a \
• any string of of alpha-numeric character (and a few permitted punctuation marks) are interpreted as follows:
  • if is is of the form abcd(, then it is interpreted as another method to call on $module as:
    $module->abcd($subargs)
    where sub-args are processed (recursively) according to the same rules and bounded by the next enclosing )
  • otherwise if is is of the form wxyz->abcd(, then it is interpreted as another method to call on $sub_module as:
    $sub_module->abcd($subargs)
    where sub-args are processed (recursively) according to the same rules and bounded by the next enclosing ) and $sub_module is the module class instance associated with wxyz
• otherwise it is interpreted as a string

Arguments are separated by spaces or commas

Tags

As "special cases" of moudle functions, following attributes are scanned for and processed:

• printf attribute: Appends to the node the results of printf substitution of the string with the specified arguments. It also is locale aware and can make use of plural forms.
  printf="'this is something %s',$data'

Scripts

Any scripts tags found in the body of the HTML are moved to the header.

Tasks and Roles

Tasks and roles are used to limit page access and well as the data displayed in the DOM.