Query Strings In URL

[Wolphie]

I'm not really sure how i'd go about writing a script with dynamic query strings in the URL.

 

e.g.

 

articles.php?cat=php&id=23

 

That will display the "PHP" category and the article inside that with the id "23"

 

So examples of how to do this would be appreciated.

 

Also, are clean URL's the way to go?

 

If so, how would i go about using them?

[papaface]

I would encode the parameters in the URL and make sure the variables are escaped.

[CMC]

are you using a database?

[Wolphie]

Ok, i'm pretty experienced with SQL strings etc....along with PHP itself.

The thing i do not understand is how people use query strings within the URL itself dynamically.

Yes i do use a database, and i would most likely encode them....depending on the kind of website i plan on developing. (My understanding is that encoded URL's are not particulary search engine friendly)

[trq]

A simple example.

 

articles.php (lists all articles as links)

<?php

 // connect to db.

 $sql = "SELECT id,title FROM articles";
 if ($result = mysql_query($sql)) {
   if (mysql_num_rows($result)) {
     while ($row = mysql_fetch_assoc($result)) {
       echo "<a href=\"article.php?id={$row['id']}\">{$row['title']}</a><br />";
     }
   }
 }

?>

 

article.php (displays article as requested via $_GET)

<?php

 // connect to db.

 if (isset($_GET['id'])) {
   $id = mysql_real_escape_string($_GET['id']);
   $sql = "SELECT data,title FROM articles WHERE id = '$id' LIMIT 1";
   if ($result = mysql_query($sql)) {
     if (mysql_num_rows($result)) {
       $row = mysql_fetch_assoc($result);
       echo "<span class=\"title\">{$row['title']}</span>";
       echo "<span class=\"data\">{$row['data']}</span>";
     }
   }
 }

?>

 

Theres no error handling or defaults, but should give you a good start.

[Wolphie]

I know that, i know the basics. But what i mean is, how would you write a complex URL query string.

For example, include categories in the URL too.

 

articles.php?cat=php&id=12

 

Rather than just the single parameter

[CMC]

Just name another $_GET variable.

ex: articles.php?cat=cars&id=67

<?php
$cat = $_GET['cat']; //pulls data from cat=
$id = $_GET['id']; //pulls data from id=
?>

Can use as many parameters as you want, you've just got to name them all.

 

ex: pets.php?cat=dogs&type=poodle&color=black&id=8

<?php
$cat = $_GET['cat'];
$type = $_GET['type'];
$color = $_GET['color'];
$id = $_GET['id'];
?>

 

And your right about non-friendly URL's. A good way around this is to use Apache's mod_rewrite feature.

Following is a tutorial I found very helpful: http://www.workingwith.me.uk/articles/scripting/mod_rewrite

[Wolphie]

Does this require a different method of coding? (For clean URLs)

[teng84]

Does this require a different method of coding? (For clean URLs)

regex !

[trq]

I know that, i know the basics. But what i mean is, how would you write a complex URL query string. For example, include categories in the URL too.

 

Im not sure what you mean by complex, the principle is exactly the same.

 

<?php

  // connect to db.

  $sql = "SELECT id,cat,title FROM articles";
  if ($result = mysql_query($sql)) {
    if (mysql_num_rows($result)) {
      while ($row = mysql_fetch_assoc($result)) {
        echo "<a href=\"article.php?cat={$row['cat']}&id={$row['id']}\">{$row['title']}</a><br />";
      }
    }
  }

?>

 

As for clean urls. I think your talking about mod_rewrite, this is handled via apache, not php.