php replace $variable in string with the content of $variable

Question

In PHP I have the need to generate HTML pages from a template and insert variables in specific places then save them to disk.

So far this code works well:

<?php 

$client = "John doe";

$template = "

<html>
<body>
<div>
$client
</div>
</body>
</html>

";

$htmlCode = $template;

$fh = fopen("page.html", 'w') or die("can't open file");
fwrite($fh, $htmlCode);
fclose($fh);

?>

ultimately I want to slurp and read in the $template from a file on disk, using something like:

$template = file_get_contents("template.html");

But using this approach I can not get the $client replaced with the "John doe" instead it shows as $client in the HTML code when I save it to disk.

I did read some posts about using regex and printf to replace substings, but i could not see how can I use them in my scenario. I am positive there must be easier and better way.

There will be a need of a lot of variables plopped in many places so I do not want to create a regex for each one. I just want to be able to stick a $variable anywhere in the external html file and PHP should replace it with a variable content (if it exist). Unfortunately file_get_contents() only slurps it into a string exactly as it is without any interpretations. I was wandering if there is another function that I can use for slurping that will actually work as I indented.

Any suggestions are greatly appreciated.

Didn't you read about str_replace() ?

AKS
– AKS

2012-06-22 19:50:04 +00:00
Commented Jun 22, 2012 at 19:50 — AKS
– AKS, Commented Jun 22, 2012 at 19:50
I dont understand your question

Blaster
– Blaster

2012-06-22 19:51:06 +00:00
Commented Jun 22, 2012 at 19:51 — Blaster
– Blaster, Commented Jun 22, 2012 at 19:51

juanrpozo · Accepted Answer · 2012-06-22 20:07:35Z

6

This is very similar to some example code in http://php.net/manual/en/function.ob-start.php and could be useful in your case:

<?php 
function save_callback($buffer) {
    // save buffer to disk
    $fh = fopen("page.html", 'w') or die("can't open file");
    fwrite($fh, $buffer);
    fclose($fh);
    return $buffer; // use it or ignore it
}
$client = "John doe";
ob_start("save_callback");
include("template.php");
ob_end_clean();
?>

answered Jun 22, 2012 at 20:07

juanrpozo

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Comments

Ed Manet · Accepted Answer · 2012-06-22 20:05:36Z

4

I have done the same thing with reading template files. My template looks like this:

<html>
<body>
<div>{client}</div>
</body>
</html>

Then the PHP code will replace "{client}" with $client.

$template = file_get_contents("template.html");
$contents = str_replace("{client}", $client, $template);

Use whatever delimiter you want n the template: %client% [client] ?client? #client#

answered Jun 22, 2012 at 20:05

Ed Manet

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Comments

matt3141 · Accepted Answer · 2012-06-22 20:13:44Z

1

In this case I just matched purely alphanumeric variable names.

echo preg_replace_callback("/[$][a-zA-Z0-9]+/", function($varname) {
    return $GLOBALS[substr($varname[0], 1)];
}, $input);

answered Jun 22, 2012 at 20:13

matt3141

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1 Comment

Zombaya Over a year ago

I dislike this because of the use of $GLOBALS

baikho · Accepted Answer · 2017-01-16 22:15:34Z

1

It is easy, just write the following:

$html = file_get_contents('0.txt');
// or user is:
$html = '&lt;html&gt;&lt;body&gt;$DATA&lt;/body&gt;&lt;/html&gt;'; 
// remember us single quotation (') not double quotation (&quot;) for a string
$DATA = &quot;&lt;h1&gt;Hi&lt;/h1&gt;&quot;;
eval(&quot;\$html = \&quot;$html\&quot;;&quot;);
echo $html;

edited Jan 16, 2017 at 22:15

baikho

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answered Jan 16, 2017 at 20:52

Ramy

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Comments

Niet the Dark Absol · Accepted Answer · 2012-06-22 19:52:29Z

0

You can use a simple regex:

$out = preg_replace_callback("/\$([^\s]+)/",
    function($m) {
        if( isset($GLOBALS[$m[1]]))
            return $GLOBALS[$m[1]];
        else return $m[0];
    },
    $in);

It's not perfect, because it's a very naïve regex, but in most cases it'll do what you want.

Personally, for templating, I'd use something like {%keyword}, that's more easily delimited.

answered Jun 22, 2012 at 19:52

Niet the Dark Absol

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Comments

Asuka165 · Accepted Answer · 2019-03-15 17:27:29Z

If possible, I would use cURL instead. Just like using AJAX in Javascript, you can request a php page with POST variable in cURL.

In your case, you can create something like this...

// Variables
$client = "John doe";
$your_template_url = "http://UseYourURL.com";


// cURL
$ch = curl_init($your_template_url);
curl_setopt($ch, CURLOPT_POSTFIELDS, ["client" => $client ]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$htmlCode = curl_exec($ch);    
curl_close($ch);


// Write into the file
$fh = fopen("page.html", 'w') or die("can't open file");
fwrite($fh, $htmlCode);
fclose($fh);

In your template, you should have something like...

<html>
   <body>
      <div>
         <?php echo $_POST['client']; ?>
      </div>
   </body>
</html>

Make sure your template is php file, not html. Even you want the html code, you still need php to echo your variable into the html file.

Isaac Gonzalez · Accepted Answer · 2012-06-22 19:51:39Z

-1

On php when you are mixing strings and variables if you are using Single quotes:

   $name = "john";
   echo 'The Name is $name';
   // will output: The Name is $name

But if you use double quotes :

    echo "The Name is $name";
    // will output: The Name is john

answered Jun 22, 2012 at 19:51

Isaac Gonzalez

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Comments

Vinas · Accepted Answer · 2012-06-22 19:58:05Z

-3

I believe this happens because you are writting the variable inside double quotes. Everything inside double quotes will be converted literally into string jus the way they are written in the code.

In the example of yousrs, to get the result you want, when you declare the $template variable, you should should concatenated it with the value you want to add to it, like in the following:

$template = "
<html>
<body>
<div>" . $client . "</div>
</body>
</html>
";

Dots concatenate strings in PHP.

That should do the trick! :)

answered Jun 22, 2012 at 19:58

Vinas

15912 bronze badges

2 Comments

user1454661 Over a year ago

That is not what OP asked. When the string is created by file_get_contents, the text $client isn't evaluated as a variable and replaced like "you would expect".

Vinas Over a year ago

Ow, you're right Alex. I think i may have read only the first half of the post. Sorry for that. Anyway, now that i got it, i think the solution'd be to use str_replace(), but I see that was said already! =)

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