eTemplate - Templates and Dialog-Editor for eGroupWare

by Ralf Becker RalfBecker AT outdoor-training DOT de

Updated by Raphael Alla raphael AT olineopensolutions DOT com

A developers tutorial how to write an application with the new eTemplates.
It is also an introduction how to write a eGW- and setup(3)-compatible app.

Introduction - The concept of the eTemplates

The eTemplates

consist out of rows and cols with input-fields of several types
there is a dialog-editor (one part of the etemplate-app) to create the eTemplate
eTemplates can be (and are usually) nested, eg. a template-field can contain an other eTemplate
each field / cell of the template can have a label which is automatically run through lang() (the content of the field can be run through lang() too)
the dialog editor can write all labels in a lang-file (merging it with the existing ones)
eTemplates have a name of the form app.function[.subtemplate] which is used to call them up
they can have further keys, on loading the class picks the most appropriate one for a user:
1. group: the id of a group if the template is just for that group (that allows admin to show different views to each group)
2. lang: the 2 or 5 letter language code (or empty for a non-language specific template)
3. template set: they belong too (if the template-set key is empty it is an default-template)
4. version: version number like: '1.3.001'
they are stored in an array and in serialized form in the db-table 'egw_etemplate'
the dialog editor can dump all templates of an app for distribution (so they can be in the CVS too)
they encapsulate different UI (User Interface) types from the app: at the moment only a HTML one is ready, but a GTK one (using php-gtk, running as native app under Linux and win32) and XUL is under development.
Here is a first screenshot of the DB-Tools as native Linux Application:

Tutorial / Example: a simple media database

As an example we will run now through the necessary steps to create a simple media database using eTemplates and other tools and classes from the eTemplate app: db-tools and class.so_sql.inc.php.

Out media database should have the usual fields: name, author, description, type: BOOK, CD, VIDEO and should be able to edit records and search for them.

As a pre-acquistion you need to get / checkout the etemplate app, install the app via setup/manage applications and enable your account for using the app (Admin/User account: check eTemplates).

1. Creating a new eGW app directory

Each app need a name, eg. 'et_media'. We now need to create the following directory structure above the eGroupWare dir:

et_media                           that has to be identical to our app-name
        + setup                         files necessary for the setup program, give the webserver write-permission to that dir
        + inc                           class-files
        + templates                     templates, still needed to store the images and get around a lot of complains from the API
                + default
                        + images        here goes our images / icons

2. Creating et_media/setup/setup.inc.php

That files contains the necessary information for setup to install the app.

<?php
        $setup_info['et_media']['name']      = 'et_media';
        $setup_info['et_media']['title']     = 'eT-Media';
        $setup_info['et_media']['version']   = '1.2';
        $setup_info['et_media']['app_order'] = 100;             // at the end
        $setup_info['et_media']['tables']    = array('egw_et_media');
        $setup_info['et_media']['enable']    = 1;

        /* Dependencies for this app to work */
        $setup_info['et_media']['depends'][] = array(
                 'appname' => 'phpgwapi',
                 'versions' => Array('1.2','1.3','1.4')
        );
        $setup_info['et_media']['depends'][] = array(
                 'appname' => 'etemplate',
                 'versions' => Array('1.2','1.3','1.4')
        );

3. Setting up the db-table with the db_tools and setup

To enable setup to create a db-table for us and to supply the so_sql-class with the necessary information, we need to define the type and size of the fields / columns in our db-table.

We can use the db-Tools from the etemplate application to create the file for us:

start the etemplate app and click on the button up, right which says db-Tools
select Application: eT-Media
type 'egw_et_media' in the field in front of the [Add Table] button and click on the button
now use [Add Column] to create the necessary fields as shown on the screenshot
Click on [Write Table] (you need to give the webserver write-permission to the setup-dir of et_media or you will get an error message, leave the write-permission as it is necessary later on too, click on write again)
log out and log into setup and start manage applications
eT-Media is shown as not installed and only install is offered, check it and submit
you can now log out from setup, the db-table is now created
In order to be able to use your eT-Media application, do not forget to give yourself access to it (Admin/User account: check eT-Media)

4. Creating an eTemplates for the edit-dialog

Now we need a nice edit dialog and use the eTemplate editor to set it up:

start the etemplate app and type 'et_media.edit' in the name field. Save the template in order to create it
an empty template is displayed. An eTemplate can be thought off as a "grid". The first cell may be a bit tricky to find, but will be highlighted when moving the mouse over it. On my computer this cell appears in pink as illustrated below:
Double click on the pink spot will bring the following dialog:
The top row allows you to add column and rows to the template. We will need 2 columns and 6 rows
Create the following label in the first top left cell:

In the top right cell, we will create a user entry and call it "name": this is the same name as thee column in our egw_et_media table. This is important as those fields will be populated automatically for us by eGroupWare:
Complete the template as follows. The widget used for "type" is a Selectbox, the one used for "description" is a textarea. Note that the name of the input is "descr" and not description, as this is the name of the column in the table. Finally on the last row we have two widgets of type "Submitbutton" of names "read" and "save" and of corresponding label.

Then before moving to the next stage save the template as an XML file by clicking on "Export XML". Once again the server must have write permissions on the directory.

5. Setting up the index page

The index page is only used if someone clicks on the navbar icon (or on the black cross as we haven't supplied one so far).
Create the file /et_media/index.php with the following content:

<?php
        $GLOBALS['phpgw_info']['flags'] = array(
                'currentapp'    => 'et_media',
                'noheader'      => True,
                'nonavbar'      => True
        );
        include('../header.inc.php');
        $GLOBALS['egw']->redirect_link('/index.php', 'menuaction=et_media.ui_et_media.edit');

6. The code for our Application

An eGroupWare application is organized around 3 application layers:

the storage layer, managed by a "Storage Object" (so). This object is responsible for handling all access to the storage engine. We use the "stock" so_sql class for this, so we need no extra so-object for the moment.
the business layer, managed by a "Business Object" (bo). This object is responsible for all the business logic. The business object can extend the storage object, to avoid passing the so-methods as stubs to the ui layer.
the user interface layer, managed by a "User Interface" (ui) object. This object is responsible for all interaction with the user, including displaying and gathering data to and from the user. The ui object can extend the bo-object.

For this, we create 2 files in the "inc" directory, called class.bo_et_media.inc.php and class.ui_et_media.inc.php. In this simple application, the bo layer will be fairly minimal, this said it is a good idea to create the application using the right standards from the start.

Here is the file /et_media/inc/class.bo_et_media.inc.php:

<?php
/**
 * eGroupWare editable Templates - Example media database (et_media)
 *
 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
 * @package etemplate
 * @subpackage et_media
 * @link http://www.egroupware.org
 * @author Ralf Becker <RalfBecker@outdoor-training.de>
 */

include_once(EGW_INCLUDE_ROOT . '/etemplate/inc/class.so_sql.inc.php');

/**
 * Business object for et_media
 */
class bo_et_media extends so_sql
{
	/**
	 * Available media types
	 *
	 * @var array
	 */
	var $types = array(
		''      => 'Select one ...',
		'cd'    => 'Compact Disc',
		'dvd'   => 'DVD',
		'book'  => 'Book',
		'video' => 'Video Tape'
	);
	/**
	 * Constructor initializing so_sql
	 *
	 * @return so_et_media
	 */
	function bo_et_media()
	{
		$this->so_sql('et_media','egw_et_media');		// calling the constructor of the extended bo object
		$this->empty_on_write = "''";
	}
}

And finally the start of the /et_media/inc/class.ui_et_media.inc.php:

<?php
/**
 * eGroupWare editable Templates - Example media database (et_media)
 *
 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
 * @package etemplate
 * @subpackage et_media
 * @link http://www.egroupware.org
 * @author Ralf Becker <RalfBecker@outdoor-training.de>
 */

include_once(EGW_INCLUDE_ROOT . '/et_media/inc/class.bo_et_media.inc.php');

class ui_et_media extends bo_et_media
{
	/**
	 * Public functions callable via menuaction
	 *
	 * @var array
	 */
	var $public_functions = array(
		'edit' => True,
	);

	/**
	 * Constructor
	 *
	 * @return ui_et_media
	 */
	function ui_et_media()
	{
		$this->bo_et_media();		// calling the constructor of the extended bo object

		$this->tmpl =& CreateObject('etemplate.etemplate','et_media.edit');
	}

	/**
	 * Edit a media database entry
	 *
	 * @param array $content=null
	 * @param string $msg=''
	 */
	function edit($content=null,$msg = '')
	{
		if (is_array($content))		// not first call from index
		{
			if ($content['id'] > 0)
			{
				$this->read($content);
			}
			//echo "<p>edit: content ="; _debug_array($content);
			$this->data_merge($content);
			//echo "<p>edit: data ="; _debug_array($this->data);

			if (isset($content['save']))
			{
				$msg .= !$this->save() ? lang('Entry saved') : lang('Error: while saving !!!');
			}
		}

		// now we fill in the content array for the next call to etemplate.exec

		$content = $this->data + array(
			'msg' => $msg
		);
		$sel_options = array(
			'type' => $this->types
		);
		$this->tmpl->exec('et_media.ui_et_media.edit',$content,$sel_options,$no_button,array(
			'id' => $this->data['id']
		));
	}

The edit function is called from our index.php file or as callback for this form / dialog. In that case $content is an array with the content the user put into the fields of the dialog.

Let first have a look what happened if we called the first time (or what we do to show the dialog again with the changed data):

the $content array is set up with our internal data-array (which is empty on the first call) and the message
$sel_options has the options for our selectbox: the options are an array where the keys are the values returned by the selectbox and the values are what the selectbox shows to the user. As we can have more than one selectbox in a dialog, the key in $sel_options need to be the same as the name of the selectbox.
$readonlys: if a field name is set in $readonlys to True, its content is showed readonly (for regular fields like type Text) or left out for buttons (we use this later to show the delete-button only when an entry is loaded)
the array $preserv is preserved, which means its stored in the app's session-data and is delivered back like the content of the fields to the callback-function. We use it here to store the id of the entry. This is similar to use a hidden input-field in a form, but it does not need to be serialized by the app and is NOT transmitted to the user and back.
at last we call etemplate::exec to show the template with the content from $content and set the function itself as callback for the dialog / form.

Now let's have a look what happens if the user submits the form and our callback is called:

the callback (this function) is not the submit-address of the form, the form get's always submitted to the function process_exec of the etemplate class. This function changes for some field-types the content (eg. a date-field consists of 3 single fields, process_exec takes care that it is delivered back as timestamp, as we set it in content before). It can even submit the form back to the user if for a address-selection a search for a pattern has to be performed and the matches are shown to the user. In this case the callback is NOT called. The same is true if an int field contains letters or is not within the minimum or maximum set. Not all of the is already working, it will follow in the next days/weeks.
For the specialist process_exec uses $_POST and ignores $_GET set as query in the url.
the so_sql function data_merge, copies all values from $content, which are columns in the db-table, in our internal data array. Values which are not real data, like buttons pressed are not copied (!).
if $content['save'] is set, the [Save] button has been pressed ('save' is the name NOT the label of the save button), in that case we use so_sql's save function to save the content of our internal data-array to the db.
the same check is used for the [Read]: we uses the content of all fields to search db for matching entries. The user can use wildcards to perform a search on all field. The wildcards are '*' and '?', so_sql translates them into sql-wildcards.
if the search return False we just set our message var.
if something is found we use so_sql's init-function to set the data of the first match. Later on we will show a list if more than one entry is found.
after that the content array is filled again as described above.

Now we are able to store entries in the db and retrieve them by searching the database for patterns in the different fields. You can try your new application now. You can create new records and save them. By just entering the name or author, the database will find the corresponding match and populate the form for you.

We are only lacking some way to show if we get more than one match on a search, that's what we are going to implement next:

7. Adding a list-dialog for the search-function

First we need to create an other eTemplate to show the list: 'et_media.show' as follows. This is made of a label of name "msg" (to display messages), an HorizontalRule widget, and a Template widget: we will use a "sub template" called et_media.show.rows to display the rows of the search function. I have set the option of the template widget to "entry" as this is the name we will use to access to the data in the sub-template.

The 'et_media.show.rows' template is created as a 3x2 table. On the header row, two labels "Name" and "Author" and one empty cell.

ond row, two labels of name ${row}[name] and ${row}[author]. In the last cell a submitButton of label "Edit" and of name "edit[$row_cont[id]]"

The class of the header row is "th" and the class of the content row is "row". eTemplate will automatically vary the colors of the "row" class to provide a nice visual effect.

Here is a view of the et_media.show template once the two templates have been created:

We need some code / a function in the class to call the template and fill the content:

	/**
	 * Showing entries from the media database
	 *
	 * @param array $found
	 */
	function show($found=null)
	{
		if (!is_array($found) || !count($found))
		{
			$this->edit();
			return;
		}
		array_unshift($found,false);	// change the array to start with index 1
		$content = array(
			'msg' => lang('%1 matches on search criteria',count($found)-1),
			'entry' => $found,
		);
		$this->tmpl->read('et_media.show');

		$this->tmpl->exec('et_media.ui_et_media.edit',$content);
	}
}

This function is called by edit with the matches of a search:

We build an array with all the matches, the index in that array is the row-number starting with 1(!) ($entry = array('empty') + $found; would do the same).
The names in the data-row (last row) of 'et_media.show.rows' are like '${row}[name]'. Variable expansion is performed on each name and expands that for the first row to '1[name]' which addresses the name in the first match.
$content contains again 'msg' which we set to the number of entries found and the above array with the data of all rows under the key 'entry', as we put that in Options for the field loading the sub-template 'et_media.show.rows'. It not necessary to put something in Options-field / use a sub-array for a sub-template, but it can be very helpful to organize a complex content-array. (As an exercise you can remove 'entry' from the Options-field and change the function accordingly).
we now explicitly read the template 'et_media.show' (the constructor reed 'et_media.edit') and execute it again with the edit function as callback (because of that, show does NOT need to be listed in public_functions)
as 'et_media.show.rows' contains only one data-row, but field names with variables to expand, that row is auto-repeated for as many data we put into the content array (or the sub-array if we used the Options-field).

To call the show function, we need to make some changes to the edit-function too:

			elseif (isset($content['read']))
			{
				unset($content['id']);					// not set by user, so don't use for search
				unset($content['read']);
				$found = $this->search($content,False,'name,author');	// searches by using the no-empty fields

				if (!$found)
				{
					$msg .= lang('Nothing matched search criteria !!!');
				}
				elseif (count($found) == 1)
				{
					$this->init($found[0]);				// only one match --> show it in the editor
				}
				else
				{
					$this->show($found);				// multiple matches --> use the show function/template
					return;
				}
			}
			elseif (isset($content['entry']['edit']))			// the callback from for the show function/template
			{								// the id is set via the button name of '$row_cont[id]'
				list($id) = each($content['entry']['edit']);		// note its not only ['edit'] !!!
				if ($id > 0)
				{
					$this->read(array('id' => $id));
				}
			}

the first part should be self-explaining, we call show with $found if it contain more than one entry.
The show function uses edit as callback, the [Edit] buttons in each row has 'edit[$row_cont[id]]' as name. If an [Edit] button is pressed $content['entry']['edit'] is set to the id of the entry of that row. We use that id to read the whole entry.

This is what the new "show" template looks like:

While making these changes we can add a [Cancel] and [Delete] button too:

			elseif (isset($content['cancel']))
			{
				$content = array(); 										// clear the contents
			}
			elseif (isset($content['delete']))
			{
				$this->bo->so->delete($r_id);
				$content = array(); 										// clear the content
			}
			
            $no_button = array(     										// no delete button if id == 0 --> entry not saved
                    'delete' => !$this->content['id']; 
            );

on cancel we just clear the internal data-array with so_sql's init function.
on delete we have to call so_sql's delete before (it deletes the db-row corresponding with our internal data-array)
the last block checks if the id field is set (it can only be set by a read or save) and disables the [Delete] button if not ($this->db_key_cols[$this->autoinc_id] == 'id').

Of course we have to add this buttons to the template 'et_media.edit'. I trust you can add 2 submit buttons with the names 'cancel' and 'delete', a Label and a nice help messages by now without looking at a screenshot ;-).

The eTemplate is saved in the eGroupware database. If changes done to the eTemplate should be reverted, a eTemplate setup file is required, see section Dumping the eTemplate to a File for Distribution. Note that reverting only works if a valid version has previously been dumped to a distribution file or if a new revision identifier of the template has been used to save the changes.

8. Creating the English lang-file

To get rid of the stars '*' behind each Label and to be able to translate the app in other languages we need to create a lang-file
There are 2 possibilities to create it automatically:

Use the [Write Langfile] button in the eTemplate editor (put the app-name 'et_media' in the name-field first)
That will NOT write the messages in the classes!!!
We can use the TranslationTools to scans our sources for lang('...') calls ([search new phrases] button).
Other phrases like the media types can be added manually via [Add] button in the Translation Tools.

9. Dumping the eTemplate to a File for Distribution

To be able to put the eTemplates in CVS and to ship them with your app, you need to dump them in a file first.

This is done in the eTemplate editor by putting the app-name or an template-name in the Name field and clicking on the button [Dump4Setup]. This creates the file et_media/setup/etemplates.inc.php. The eTemplate-class loads this file whenever it finds a new version automatically.

To recover a changed eTemplate to the state saved in the distribution file, the following steps need to be performed:

Remove the modified template (or the modified version of the template) in the eTemplate application
Touch the setup/etemplates.inc.php file in the application directory (update it's timestamp).

In case the modification was done in a sub-template, e.g. the definition of the rows in a list view, the correct (sub-) template name and version needs to be chosen for deletion. It is visible in the edit window of the elements modified.

10. Further information

Please note: All files of the et_media example can be found in the et_media sub-directory of etemplate's doc directory. Symlinking or coping to the eGroupWare install directory, allows to immediately install it via setup.

the reference-documentation of the eTemplates
for all functions and parameters of the etemplate-class(es) look in the phpDocumentor docu of etemplate created from comments (yes there are comments) in the sources:
- class.uietemplate.inc.php for the exec function
- class.boetemplate.inc.php for the variable replacement in names and about the autorepeat rows and columns
- class.soetemplate.inc.php for writeLangFile and all functions to read, store and dump an eTemplate
for all functions and parameters of the so_sql-class look in the comments of the file class.so_sql.inc.php
for setup, the necessary files of an app or the format of tables_current.inc.php look at the excellent docu of setup3 in the doc-dir of the setup app.