Sample Application: Guestbook

We have two templates for our guestbook, one for viewing and one for adding a new entry.

{* Smarty *}

<table border="0" width="300">
    <tr>
        <th colspan="2" bgcolor="#d1d1d1">Guestbook Entries (<a href="{$SCRIPT_NAME}?action=add">add</a>)</th>
    </tr>
    {foreach from=$data item="entry"}
        <tr bgcolor="{cycle values="#dedede,#eeeeee" advance=false}">
            <td>{$entry.Name|escape}</td>        
            <td align="right">{$entry.EntryDate|date_format:"%e %b, %Y %H:%M:%S"}</td>        
        </tr>
        <tr>
            <td colspan="2" bgcolor="{cycle values="#dedede,#eeeeee"}">{$entry.Comment|escape}</td>
        </tr>
    {foreachelse}
        <tr>
            <td colspan="2">No records</td>
        </tr>
    {/foreach}
</table>

guestbook.tpl is the template for viewing the guestbook. It loops over the guestbook data (which was assigned from displayBook()) in a foreach loop and displays the Name, Date and Comment from each entry. The date is formatted with the date_format modifier. The Name and Comment are HTML-escaped using the escape modifier to avoid any HTML tag clashes or scripting attacks. The {cycle} function is used to cycle through background colors every two table rows.

{* Smarty *}

<form action="{$SCRIPT_NAME}?action=submit" method="post">

<table border="1">

    {if $error ne ""}
        <tr>
            <td bgcolor="yellow" colspan="2">
                {if $error eq "name_empty"}You must supply a name.
                {elseif $error eq "comment_empty"} You must supply a comment.
                {/if}
            </td>
        </tr>
    {/if}
    <tr>
        <td>Name:</td>
        <td><input type="text" name="Name" value="{$post.Name|escape}" size="40"></td>
    </tr>
    <tr>
        <td valign="top">Comment:</td>
        <td><textarea name="Comment" cols="40" rows="10">{$post.Comment|escape}</textarea></td>
    </tr>
    <tr>
        <td colspan="2" align="center"><input type="submit" value="Submit"></td>
    </tr>

</table>


</form>

guestbook_form.tpl is the template for adding an entry to the guestbook. If the form is being redisplayed due to a validation error, the form values are repopulated and the appropriate error message is displayed. The form values are HTML-escaped so there are no HTML tag or quote character clashes (very important!)

With this sample application we have accomplished several key aspects of a Smarty driven application.

* All presentation elements are contained in the template. We don't assign HTML tags or other presentation elements from outside the template. The only thing we assign is the page content, in this case the guestbook entries.

* Error messages are also maintained from the template. We don't assign error messages themselves, but error codes which are used to determine which error message to display. An alternative way to maintain error messages are from within Smarty config files, where you can have error_code = Error Message in the config file, then displayed with {$smarty.config.$error_code}

* PHP objects are used extensively to show their usefulness for easily passing information around (such as sql/template objects and error codes) avoiding procedural functions and clunky parameter passing.

Hopefully this gives you an idea how to setup your applications to work with Smarty in a way that cleanly separates the application from its presentation.