View part for a PHP application

1
View part for a PHP application

• The last weeks improvement to our PHP
  application was on the model/database part.
• The View part still lacked an architectural
  solution to give it structure
• How to try to separate PHP and HTML?
• In this course, we use a template library called
  Smarty.
• It is a php-based library, which offers the
  possibility to model the output pages using what
  they call templates, which are in a sense
  formatting templates.
• The templates use variables. The program using
  the template instantiates the variables and
  includes the template in the output.

2
Smarty

• http//smarty.php.net
• Documentation
• Downloads
• Installation instructions
• Example application
• The example application has been used as a model
  for implementing an example for the course.
• The example this far is meant for the
  associations public pages.
• Next week we add the maintenance facility.

3
Smarty - principles

• Presentation is separated into template files.
• Template files may be arranged into a
  hierarchical manner
• They may include other template files.
• The application computes all that is required and
  then passes the variables to be displayed to
  smarty
• Smarty includes facilities for various things,
  e.g.
• iteration (like sections)
• formatting (substrings, capitalisation, known
  date and time formats, etc)
• The templates may contain html (and, in fact, may
  only be html, if e.g. for some template there are
  no variables or such).
• The examples will clarify this.

4
Smarty application directories

• Main file (index.php) just calls php programs in
  library directories.
• Other things are put outside of the directories
  from where the web server reads the files (could
  be chosen differently)
• /lib/php/Smarty/ - this is the Smarty library
  installation
• /smarty/association/libs/ - application php
  libraries/functions
• /smarty/association/templates/ Smarty
  templates
• /smarty/association/configs/ - configuration
  files
• /smarty/association/cache/ - internal use
• /smarty/association/templates_c/ - internal use
  (compiled templates)

5
The application html library

• index.php minimal, initiates Smarty and calls
  its services
• association.css the style file
• images subdirectory that contains the image of
  the Finnish flag and the image of the UK flag
• Javascript can be positioned in many ways, e.g.
• In the Smarty templates to be included in the
  html files that are generated
• As separate files, for instance in a subdirectory
  of the application directory

6
The Smarty installation

• The installation just means that the Smarty
  software needs to be downloaded and put in a
  place, where the php programs access it.
• For security, it is a good principle to put all
  that can be put in a place, from where the web
  server does not serve pages.
• In our case, this means installation outside of
  the public_html subdirectory
• I have installed my Smarty in /lib/php/Smarty
• You will need to do the same for the courseworks.
• Therefore, it is advisable to do the same already
  now.

7
/smarty/assocation/libs/

• The libs subdirectory contains PHP code necessary
  for the application.
• setup.php contains code for setting up the
  application in fact it just takes connection to
  the database and initializes the paths for other
  smarty subdirectories than the libs (which has
  already been found, as the setup.php is executed)
• sql.lib.php contains the code for database
  operations. This is more or less the same thing
  as the DBlayer.php last week.
• association.lib.php contains the application php
  functionalities. Notice that I have made a
  separate file of the maintenance functions this
  is not needed this week.

8
association.lib.php

• Initiates the application class, which has a
  database object and a Smarty object.
• Initiation also reads the configuration file,
  another slide on this.
• In the main() function it chooses the action to
  be executed plus its parameters, and calls the
  respective functions.
• As we only display data, a typical action
• Accesses the database.
• Assigns the results (an array) to a Smarty
  variable.
• Calls the Smarty template to generate the output
  page.

9
Configuration files

• These are like the Java property files.
• The lines contain keywords and the respective
  strings.
• When the configuration files are loaded, a
  variable can be specified to load just parts of
  the document.
• This can be used e.g. to load texts for one
  language in an internationalised application. See
  the example
• Respectively, the configuration file has a
  general section, from which everything is read,
  and keyword-separated sections starting
  withkeyword
• Also comments can be used
• See the example file

10
Template files

• The whole templating facility is too large to be
  covered in this lecture.
• We will focus on the key ideas, which are also
  exemplified in our example application
  implementation.
• On the most basic level, the template file can be
  just a html file, which is included in the output
  as such.
• The pages can be constructed in a hierarchical
  manner, using include statements, which, like
  other Smarty commands, are in between and
• E.g. main.tpl contains three include statements
  to include a header, the main content part
  (details on this later) and a footer.

11
Variables

• The variables can be used e.g. for conditionality
  and for output.
• Examples
• header.tpl chooses by language how it forms the
  menu, ie. which of the left side menu items
  contain a link.
• header.tpl also outputs the variables, e.g. when
  forming the links it outputs the current action
  action
• The configuration file contents can be accessed
  with a different notation. The basic notation is
  used e.g. to output the menu item events, etc,
  e.g. events
• Another form, used in main.tpl (the other fails
  here, might have been due to concatenation)
  smarty.config.htmlDir

12
Conditionality and iteration

• The if statements in header.tpl give an idea on
  how conditionality can be managed in an easy
  case.
• Iteration is primarily needed to output sets of
  items.
• These are typically arranged as arrays.
• events.tpl gives an idea on how this can be
  managed.
• The section statement is given an index name
  and it loops over a structure, in this case the
  array of events found from the database.
• It is possible to test for the first and last
  item, and there is also an else for the case that
  the structure is empty.
• Notice that the DBs getAll function retrieves an
  array in format suitable for Smartys section
  structure.

13
Output formatting

• There are various modifiers, with which the
  output variables can be formatted as is needed.
• As example, see how the seconds are removed from
  the SQL time datatype times in events.tpl
• There particular formatters for things like
  dates, see an example of this as well from
  events.tpl