I'm working on a project where I'm keeping all HTML content separate from the rest of the PHP code. Each instance where any HTML needs to be parsed for PHP variables is sent through a function call. Most these deal with dynamic data from the database.
A simple example of a template file:
<div id='{$data['id']}'>{$data['text']}</div>
The variables in the $data array are passed through a function call where the HTML snippet needs to be added to the output buffer:
$output .= $html->load_template('template_id', array('id' => 123, 'text' => 'Testing'));
The html::load_template() function simply locates the correct text file, and is supposed to load the variables and return the string as HTML. This is where I'm having issues:
public static function load($template, $data=array()) {
ob_start();
include ( TEMPLATE . $template .'.tpl' );
ob_flush();
}
I've tried using include() and file_get_contents(), but to no avail - I'm looking for a simple solution where I can use the {$data['var']} syntax, preferably retaining the template HTML as a simple variable, so it can then be added to the output.
I'm trying to avoid using eval().
Can someone give me some guidance?
I've done the same thing in the past, you can modify your below code like this:
public static function load($template, $data=array()) {
ob_start();
include ( TEMPLATE . $template .'.tpl' );
$getData = ob_get_clean();
preg_match_all("|{([^>].*)}|U", $getData, $getDataArr, PREG_SET_ORDER);
if (is_array($getDataArr) && count($getDataArr) > 0) {
foreach ($getDataArr as $php) {
if (strpos($php[1],'$') !== false) {
$getData= str_replace($php[0], (eval('return $'.str_replace('$', '', $php[1]).';')), $getData);
}
}
}
echo $getData;
}
Related
I'm designing a simple templating system for a CMS in PHP which internally currently uses something like:
require_once 'templates/template1.php`;
to import the desired template.
I would like every content {{field123}} in this PHP file to be automatically converted into <?php echo $row['field123']; ?> before being passed into require_once and executed by PHP.
Is there a way to activate a preprocessor (I know that PHP is already named after preprocessor) that does this replacement {{anything}} -> <?php echo $row['anything']; ?> before executing the PHP code template1.php? If not, what's the usual way to do this?
Having PHP code in templates - especially code with potential side-effects - can get dirty real quick. I would recommend using static templates, treating them as strings instead of executing them, then parsing them for tokens, with your main application compiling them and handling output.
Here is a rudimentary implementation that parses variables into tokens, and also handles mapped function calls in your templates. First, "fetching" our template (for a simple example):
$tpl = 'This is a sample template file.
It can have values like {{foo}} and {{bar}}.
It can also invoke mapped functions:
{{func:hello}} or {{func:world}}.
Hello user {{username}}. Have a good day!';
Then, the template parser:
function parse_template(string $tpl, array $vars): string {
// Catch function tokens, handle if handler exists:
$tpl = preg_replace_callback('~{{func:([a-z_]+)}}~', function($match) {
$func = 'handler_' . $match[1];
if(function_exists($func)) {
return $func();
}
return "!!!What is: {$match[1]}!!!";
}, $tpl);
// Generate tokens for your variable keys;
$keys = array_map(fn($key) => '{{' . $key . '}}', array_keys($vars));
// Substitute tokens:
$tpl = str_replace($keys, $vars, $tpl);
return $tpl;
}
These are our handler functions, with handler_X matching {{func:X}}.
function handler_hello() {
return 'HELLO THERE';
}
function handler_world() {
return '#Current World Population: ' . mt_rand();
}
Then, here are the variables you'd like to parse in:
$vars = [
'foo' => 'Food',
'bar' => 'Barnacle',
'username' => 'Herbert'
];
Now let's parse our template:
$parsed = parse_template($tpl, $vars);
echo $parsed;
This results in:
This is a sample template file.
It can have values like Food and Barnacle.
It can also invoke mapped functions:
HELLO THERE or #Current World Population: 1477098027.
Hello user Herbert. Have a good day!
Job done. You really don't need a complicated templating engine for something like this. You could easily extend this to allow the handlers to receive arguments defined in the template tokens -- however I'll leave that for your homework part. This should do to demonstrate the concept.
As mentioned in a comment and in How do I capture PHP output into a variable?, the use of output buffering can work:
<?php
ob_start();
?>
Hello
{{field123}} and {{field4}}
World
<?php // or require_once 'template1.php'; ?>
<?php
$s = ob_get_clean();
$a = array('field123' => 'test', 'field4' => 'test2');
$s = preg_replace_callback('/{{(.*?)}}/', function ($m) use ($a) { return isset($a[$m[1]]) ? $a[$m[1]] : $m[0]; }, $s);
echo $s;
?>
// Output:
// Hello
// test and test2
// World
Here we also used a method similar to Replace with dynamic variable in preg_replace to do the replacement.
I was wandering if it were possible to store a html schema page with special strings to replace with variable and how to do it.
In an external file, I would like to put the html structure of a product, let's call it schema.php:
<span id="{% id %}">{%= name %}</span>
<span>{%= imageURL() %}</span>
The example above is just a simpler example. In the external file, the html would be more complex. I know that if there were just few lines I could just echo them with a simple function but this is not the case.
In another file I have a class that handle products, let's call it class.php:
class Product {
//logic that is useless to post here.
public function imageURL() {
return "/some/url".$this->id."jpg";
}
}
In this class I would like to add a function that take the content from schema.php and then echo it in the public file for users.
I tried with file_get_contents() and file_put_contents() but it just doesn't work:
$path_to_file = 'data/prodotti/scheda.inc';
$file_contents = file_get_contents($path_to_file);
$file_contents = str_replace(
"{%= ",
"<?php echo $this->",
$file_contents
);
$file_contents = str_replace(
" }",
"; ?>",
$file_contents
);
file_put_contents($path_to_file, $file_contents);
is it possible to call schema.php page and print it with custom variables?
By "schema page" I think you mean "template" and yes, but the best way to do it is to use an existing templating engine such as Smarty or a Mustache implementation like https://github.com/bobthecow/mustache.php instead of implementing it yourself because of the risks of XSS, HTML-injection, and how you'll eventually want features like looping and conditionals.
you can do it normaly with php require func. without any strings to replace, if you just want to use that file as "template" then:
in schema.php:
<?php
echo'<span id="'.$id.'">'.$name.'</span>
<span>'.$imageURL.'</span>';
?>
in class.php:
<?php
class Product {
//logic that is useless to post here.
public function imageURL() {
return "/some/url".$this->id."jpg";
}
}
$imageURL = imageURL(); ?>
Index.php or whatever the main page that handles class.php and temp.php(schema)
<?php
//avoid undefined variables on errors
//in case that you don't check for values submitted
$id = 0;
$name = 0;
$imageURL = '';
//set vars values
$id = /*something*/;
$name = /*something 2*/;
$imageURL = /*something3*/;
//all date will be replaced is ready, oky nothing to wait for
require('path/to/schema.php');
Note: If you gets these data from user, then you should validate with if(isset()).
hope that helps,
So I have a case were I need to interpret a PHP file and then put it in a variable as a string.
I have this some what common helper function to do this:
function ob ($path) {
ob_start();
include($path);
$string = ob_get_contents();
ob_end_clean();
return $string;
}
Just give it the path and it will give you the string after it has been interpreted. Works great.
However I also need to send it a variable. I tried just appending a GET request string to the path, but it appeared not to work. The function prototype would look like this:
// how would I implement this?
function ob ($path, $variable_to_send) {
}
How should I do this?
Simply use a global variable.
Set it in one file like this:
$GLOBALS['arg'] = 'test';
Access it in another file similarly:
$arg_passed = $GLOBALS['arg'];
If you wanted to architect this a bit more use the registry pattern.
Note this assumes that this is the same HTTP request. If you need persistence across HTTP requests use session variables.
Let the external script is external.php:
<?php
echo $argument;
?>
and the caller scrip is caller.php (on the same folder of external.php):
<?php
function ob ($path, $argument) {
ob_start();
include($path);
$string = ob_get_contents();
ob_end_clean();
return $string;
}
$out = ob("external.php","Ciao");
echo "$out Cade";
?>
The result will be:
Ciao Cade
I am working with a Drupal theme, and I see a lot of variables which look like were created with extract(). Is it possible to track back, and see where that array is?
I take you are referring to the variables passed to a template file, which effectively are extracted from an array.
The code that does that in Drupal 7 is in theme_render_template().
function theme_render_template($template_file, $variables) {
extract($variables, EXTR_SKIP); // Extract the variables to a local namespace
ob_start(); // Start output buffering
include DRUPAL_ROOT . '/' . $template_file; // Include the template file
return ob_get_clean(); // End buffering and return its contents
}
The function is called from theme(), which executes the following code.
// Render the output using the template file.
$template_file = $info['template'] . $extension;
if (isset($info['path'])) {
$template_file = $info['path'] . '/' . $template_file;
}
$output = $render_function($template_file, $variables);
$render_function by default is set to 'theme_render_template', but its value is set with the following code (in theme()).
// The theme engine may use a different extension and a different renderer.
global $theme_engine;
if (isset($theme_engine)) {
if ($info['type'] != 'module') {
if (function_exists($theme_engine . '_render_template')) {
$render_function = $theme_engine . '_render_template';
}
$extension_function = $theme_engine . '_extension';
if (function_exists($extension_function)) {
$extension = $extension_function();
}
}
}
Just echo the $GLOBALS variable and you might find where it came from if the array was not unset.
Im not familiar with Drupal so this is just a suggestion, but if drupal has a templating structure or if an array is passed from a controller or such then possible that extract is used,
You could use get_defined_vars within your view to get all vars and its possible that there is an array there that you can cross reference with variables you know of that are in the same array or such.
<?php
$vars = get_defined_vars();
print_r($vars);
//or maybe
print_r($this);
?>
I have two files like below
SomeClass.php
class SomeClass {
public function display() {
$content = file_get_contents("helloworld.php");
eval($content);
}
public function helloWorld() {
echo "hello World!";
}
}
helloworld.php
<?php
$this->helloWorld() ;
?>
<p>It's html expression</p>
As you can see, I tried to execute helloworld.php in the display function.
Of course, It occur an error because the html tag is placed in the display function.
Is there any good way to execute helloworld.php text in the display function preserving helloworld.php code?
If you're trying to execute a specific file in the context of the current code, why not use include or require?
Remember, if eval is the answer, the question is wrong.
If you really want to use eval here,
eval('?>' . $content);
should work. Yes, you can close and reopen the PHP tag inside. This is how certain template engines work.
You can capture it with output buffering.
ob_start();
include "helloworld.php";
$content = ob_get_contents();
ob_end_clean();
There is no way to do this, unless you want to do string concatination.
I tested this with a few minor changes to the helloworld.php file as such it works:
$this->helloWorld() ;
?><p>It's html expression</p>
This shows that the text is run raw as if it were hard included.
Now if you DONT or CANT change the open <?php tag, you can go one of two ways.
The easy way (String Concatenation):
public function display() {
$content = file_get_contents("helloworld.php");
eval('?>' . $content); //append a php close tag, so the file looks like "?><?php"
}
The harder way (String Replace):
public function display() {
$content = file_get_contents("helloworld.php");
//safely check the beginning of the file, if its an open php tag, remove it.
if('<?php' == substr($content, 0, 5)) {
$content = substr($content, 5);
}
eval($content);
}
you can use include or require for this purpose.