How do i store variables in URL?

[Trainor91]

Hi, 

 

I am building a website that will contain listings, there will be a categories page which will bring the user to the subcategories for that category then the user can see all listings linked to that subcategory. At the minute I am just linking each page using basic href tags to go to the page name.php and all my pages end up being homepage.com/clickedlink.php. 

 

How do I change my URL's so that if i click on a certain category the url changes to page name.php?category=chosen category?

 

Thanks

[Strider64]

<a href="index.php?category=pizza">Mmm Pizza</a>

Then at the top or another page:

<?php
if (isset($_GET['category']) {
  $my_favorite_food = $_GET['category'];
}
?>

Edited January 19, 2015 by Strider64

[QuickOldCar]

If you need to use or retain a multiple get query value use http_build_query

[Trainor91]

Hi,

 

I am currently displaying the results of a query in table format using the code below: 

 

echo '<td class="categorydata"><a href="computing.php?subcategory='.strtolower($row['subcategory']).'"><img class="catimg" src="'.$row['subcategory_img_path'].'" border="0" /></br>'.$row['subcategory'].'</a></td>';

When i click on a cell the URL is changing but im not being redirected to another page. Does anyone know why this is and what I need to do?

 

At the minute, if i click on audio for instance the URL changes to:

http://c2share.com/computing.php?subcategory=audio

as expected but the page does not change :S

 

I have researched this a bit but still not 100% on how it works.

 

Any help would be appreciated.

 

Thanks

Edited January 20, 2015 by Trainor91

[QuickOldCar]

Show the entire code for computing.php

[Trainor91]

Show the entire code for computing.php

<?php
include 'core/init.php';
include 'includes/overall/header.php';
?>


<h1> Computing </h1>


<?php
$sql = "SELECT * FROM categories WHERE Category ='Computing' ORDER BY subcategory ASC";
$result = mysql_query($sql) or die(mysql_error()."<br>".$sql);
$catNo = 1;


echo "<table class='categorytable'> <tr class='categoryrow'>";


while($row = mysql_fetch_array($result)){
   echo '<td class="categorydata"><a href="computing.php?subcategory='.strtolower($row['subcategory']).'"><img class="catimg" src="'.$row['subcategory_img_path'].'" border="0" /></br>'.$row['subcategory'].'</a></td>';
    if ($catNo % 3 == 0) {
    echo "</tr><tr>";
    }
    $catNo++;
 }


echo "</tr> </table>";?>
</br>


<?php
include 'includes/overall/footer.php';


?>

[QuickOldCar]

As strider mentioned the other post you have to pull the GET value if it exists.

if(isset($_GET['subcategory']) && trim($_GET['subcategory']) !=''){
$subcategory = trim($_GET['subcategory']) !='');
}

if(isset($subcategory)){
$sql2 = "SELECT * FROM categories WHERE subcategory='".mysql_real_escape_string($subcategory)."'";
$result2 = mysql_query($sql2) or die(mysql_error()."<br>".$sql2);
    while($row2 = mysql_fetch_assoc($result2)){
        //whatever your values are
        echo $row2['id']."<br />";
        echo $row2['name']."<br />";
    }
}

If you want to retain your href loop to navigate, need to do an additional query and display the results

 

mysql_* functions are deprecated and should be using mysqli or pdo

should escape anything being inserted to a database

mysql_real_escape_string

[Trainor91]

As strider mentioned the other post you have to pull the GET value if it exists.

if(isset($_GET['subcategory']) && trim($_GET['subcategory']) !=''){
$subcategory = trim($_GET['subcategory']) !='');
}

if(isset($subcategory)){
$sql2 = "SELECT * FROM categories WHERE subcategory='".mysql_real_escape_string($subcategory)."'";
$result2 = mysql_query($sql2) or die(mysql_error()."<br>".$sql2);
    while($row2 = mysql_fetch_assoc($result2)){
        //whatever your values are
        echo $row2['id']."<br />";
        echo $row2['name']."<br />";
    }
}

If you want to retain your href loop to navigate, need to do an additional query and display the results

 

mysql_* functions are deprecated and should be using mysqli or pdo

should escape anything being inserted to a database

mysql_real_escape_string

Ok thanks, would this go inside the computing.php file or a new file? Had already started with mysql functions before i realised it was deprecated, im going to change it all to mysqli at the end though but thanks

[QuickOldCar]

It's up to you how you want to set this all up.

You could make an included menu just hrefs

Optionally can just do a form and a select dropdown in a loop, when selected would set the GET value instead of all those href links

 

could do if/else or build dynamic sql queries based upon what is set

an example would be if no subcategories is set to just display all, if a subcategory is set only display that

$sql2 = "SELECT * FROM categories";

if(isset($subcategory)){
$sql2 .= " WHERE subcategory='".mysql_real_escape_string($subcategory)."'";
}

[Trainor91]

I am displaying query results in a table on computing.php page. The code for this page is below:

<?php
include 'core/init.php';
include 'includes/overall/header.php';
?>


<h1> Computing </h1>


<?php
$sql = "SELECT * FROM categories WHERE Category = 'Computing' ORDER BY subcategory ASC";
$result = mysql_query($sql) or die(mysql_error()."<br>".$sql);
$catNo = 1;


echo "<table class='categorytable'> <tr class='categoryrow'>";


while($row = mysql_fetch_array($result)){
   echo '<td class="categorydata"><a href="computing.php?subcategory='.strtolower($row['subcategory']).'"><img class="catimg" src="'.$row['subcategory_img_path'].'" border="0" /></br>'.$row['subcategory'].'</a></td>';
    if ($catNo % 3 == 0) { 
    
    echo "</tr><tr>";
    }
    $catNo++;
 }


echo "</tr> </table>";?>
</br>


<?php
include 'includes/overall/footer.php';
?>

The URL for the computing.php page is http://c2share.com/computing.php then when i click on a subcategory the URL changes to http://c2share.com/computing.php?subcategory=projectors but the page is the exact same. 

 

How would I be able to be directed to a blank page where the page is relevant to the ?subcategory=projectors part of the URL?

 

Really struggling with this, have researched POST and GET variables but still not sure how to get it to do what i want :S

 

I'm aware that mysql_ functions are deprecated but I'm going to worry about that when I get all the functionality working the way i want it to.

Edited January 20, 2015 by Trainor91

[CroNiX]

Try this just before your query:

//set a default value for the subcategory. This will be used if no subcategory exists in the URL
$subcategory = 'Computing';

//Check if the subcategory exists in $_GET, and it contains a value. If it does, use that value for the subcategory.
if (isset($_GET['subcategory'] && trim($_GET['subcategory']) != '')
{
  $subcategory = trim($_GET['subcategory']);
}

//Perform the query using the subcategory. Either the default, or the one passed via the URL.
$sql = "SELECT * FROM categories WHERE Category = '$subcategory' ORDER BY subcategory ASC";

Edited January 20, 2015 by CroNiX

[Trainor91]

 

Try this just before your query:

//set a default value for the subcategory. This will be used if no subcategory exists in the URL
$subcategory = 'Computing';

//Check if the subcategory exists in $_GET, and it contains a value. If it does, use that value for the subcategory.
if (isset($_GET['subcategory'] && trim($_GET['subcategory']) != '')
{
  $subcategory = trim($_GET['subcategory']);
}

//Perform the query using the subcategory. Either the default, or the one passed via the URL.
$sql = "SELECT * FROM categories WHERE Category = '$subcategory' ORDER BY subcategory ASC";

I think I kind of got it but when echoing the variable it is always returning '1' instead of what the value in the subcategory is?

[QuickOldCar]

Don't you have a category and also subcategory column in database?

Seems the below code is trying to return a subcategory name within the category column

 

$sql = "SELECT * FROM categories WHERE Category = '$subcategory' ORDER BY subcategory ASC";

[Trainor91]

Don't you have a category and also subcategory column in database?

Seems the below code is trying to return a subcategory name within the category column

 

$sql = "SELECT * FROM categories WHERE Category = '$subcategory' ORDER BY subcategory ASC";

Yes, within the categories table there is categoryid, category, subcategory, I know what you mean but if i change it to subcategory = '$subcategory' now it doesn't work quite as well. In saying that - It still isn't working how I want it

[QuickOldCar]

You should make a dynamic query depending what is set.

 

Btw, I saw all you past queries you had Category as uppercased

if (isset($_GET['category'] && trim($_GET['category']) != ''){
  $category = trim($_GET['category']);
}

if (isset($_GET['subcategory'] && trim($_GET['subcategory']) != ''){
  $subcategory = trim($_GET['subcategory']);
}

$sql_array = array();
if ($category) {
    $sql_array[] = " category = '$category' ";
}
if ($subcategory) {
    $sql_array[] = " subcategory = '$subcategory' ";
}

$sql = "SELECT * FROM categories";

if (!empty($sql_array)) {
    $sql .= ' WHERE ' . implode(' AND ', $sql_array);
}