Help me with a wee bit of coding

Bill_Hoefer

Howdy!

I keep learning and learning. However, I need a little help.

First of all, the server does not support MySQL, therefore, I had to use a flat file system. I managed to make the flat file names random enough to be difficult to guess. So far so good.

This is a simple shopping cart system. I added a submit button next to each item (actually with the Item Number instead of the word “submit.” This allows PHP to add an entry into a flat file. That with a little sessions coding and refreshing the page after each submit, I have it solved and actually creating a flat file for the visitor. So far so good.

I can read the flat file into a “tables” setup – I set-up the data so it uses the delimiter “|” and that allows me to deal with the incoming data as fields with a different line per entry. So far so good.

I have two problems that may or may not be solved by PHP.

Rather then try to sift through the flat file looking for duplicate entries (a visitor can merely press a button several times to accomplish this) - I think that preventing a duplicate entry may be the way to go. Is there a way to set an increment counter (using sessions, of course, so that when the visitor returns to the page from another page, the count is still available) to track an item number (i.e. D1, D2, D3, etc.) and it is equal to one or even if it exists, by-pass the write routine? 😕

Here is basically what I have:

Form Submit Section

Flat File Coding

$D1 = $SESSION['D1'];
$D1 = $POST['D1'];
if ($D1 == "D1")
{
$Full_unique = session_id();
$unique = substr($Full_unique, 0, 6); // $unique = session_id();
$myFile = $unique.".txt";
$fh = fopen($myFile, 'a') or die("can't open file");
$stringData = "D1 | Pink Belt with Silver Buckle | $100\n";
fwrite($fh, $stringData);
fclose($fh);
}

I could work from a short sample code if someone will be so kind.

When the visitor views the flat file results in a tables set-up, is there a way that I can offer him or her the option to delete an item?

Here is what I have so:

<?php
$fp = fopen($myFile, 'r');
if (!$fp) {echo 'ERROR: Unable to open file.</table></body></html>'; exit;}
while (!feof($fp)) {
$line = fgets($fp, 1024); //use 2048 if very long lines
list ($field1, $field2, $field3) = split ('|', $line);
echo '
<tr>
<td align="center" valign="middle">'.$field1.'</td>
<td align="left" valign="middle">'.$field2.'</td>
<td align="center" valign="middle">'.$field3.'</td>
</tr>';
$fp++;
}

fclose($fp);

By the way, my client has agreed to change servers after Christmas. Then I will set-up a MySQL database and redo this right.

Thanks in advance,

Bill 😉

sneakyimp

If I were you, I wouldn't store a delimited flat file, I would use an array() to describe a user's shopping cart contents and then just write the entire array to your flat file using serialize().

http://php.net/serialize

this function will take a '3d' php object or array and turn it into a string that can be saved to a file or stored in a database. It's awesome.

Every time something gets added, you read the contents of your flat file and unserialize() it then you can easily loop through the array to see if the item is already in there. something like

$my_cart = array();

function add_to_cart($item_id, $item_name) {
  global $my_cart;

  foreach($my_cart as $key=>item) {
    if ($item['id'] == $item_id) {
      $my_cart[$key]['quantity']++;
      return;
    }
  } // for each cart item

  // if you reach this point, the item is not in the cart yet so we add it
  $index = sizeof($my_cart);
  $my_cart[$index] = array();
  $my_cart[$index]['id'] = $item_id;
  $my_cart[$index]['name'] = $item_name;
  $my_cart[$index]['quantity'] = 1;

} // add_to_cart()

// to save the cart
function save_cart_to_file($file_name) {
  global $my_cart;

  $output_string = serialize($my_cart);
  // code here to completely replace the contents of your flat file
  // named $file_name with $output_string
  // you may need to specify the path where $file_name is located
}

function read_cart_from_file($file_name) {
  global $my_cart;

  $contents = file_get_contents($file_name); // you may need to add path info to $file_name
  $my_cart = unserialize($contents);
}

Bill_Hoefer

Howdy!

Thanks for the help.

However, I spent the day trying to figure out how to do it.

Basically, I searched the web for a simple script that took and array and serialized it into a flat file. The next script unserialized the flat file’s data and printed on the webpage.

I copied it and it worked perfect – on GoDaddy. I then tried it on Earthlink and it would create a flatfile but not read it back with the other script (yes, I changed the php endings to php4 and none were needed within the script). Earthlink sucks!!!!!

Anyway, it seems that I cannot an array as it seems that Earthlink does not support serializing.

Therefore, is there a way to read back a flat file’s data (one to a line and separated with delimiters like | or || and then scan it before appending it with a new line to prevent a duplicate line of data?

I basically need to have a visitor press a submit button to indicate what they want to add to the cart. Then, by refreshing the page (actually posting to itself), I can get the script to append the request to a flat file. My problem is, I cannot prevent duplicates being posted if a “happy finger” visitor decides to press the submit button for an item a zillion times.

Help,

Bill

sneakyimp

i seriously doubt that earthlink doesn't support serializing. it's more likely that you are having a problem reading the files which will also be a problem for any other flat file approach.

what sort of behavior did you get? what kind of errors?

Bill_Hoefer

Thanks for being so fast getting back to me....

Actually, I got a blank screen - not a think to look at.

However, I did try to isolate the various portions of the code to see what would not work. The buck stopped at the serialize portion.

I figured that if I could get that the simple script to work, I could figure out how to search the unserialzed array and see if it had any duplicates (gulp, maybe I cannot get thsi script to ever work).

Here are th e two simple scripts:

<?php
// My attempt at creating an array
$selection_D1 = array(
'id' => 'D1',

'desc' => 'ugly gold ring',

'price' => '$16,000');

// Serialize the arrays
$serialized_info = serialize($selection_D1);

// Write the serialized array to file

$file = 'info.txt';
$handle = fopen($file, 'a');
fwrite($handle, $serialized_info);
fclose($handle);

// Testing to make sure something shows up on the page
echo "Howdy";

Here is the second half:

<?php

$file = 'info.txt';

$contents = file_get_contents($file);
$info = unserialize($contents);
echo "Catalog Stock Number is ";
echo $info['id'];
echo " ";
echo $info['desc'];
echo " ";
echo $info['price'];
echo " ";
echo "<p>";
?>

and, the flat file looks like this:

a:3:{s:2:"id";s:2:"D1";s:4:"desc";s:14:"ugly gold ring";s:5:"price";s:7:"$16,000";}

Thanks again,

Bill

Bill_Hoefer

An added Note!

I forgot to add that I have been successful if writing a flat file and reading it back into a webpage (actually into a table, no less).

Since Earthlink allowed me to create a flat file with serializing, I am baffled as to why it does not seem to allow unserializing (if that be the problem)?

Regards,

Bill

Bill_Hoefer

Never give up!

I Googled for "earthlink" and "php" and "problems" and found a discussion site where someone explained that Earthlink also uses the extension .php5 (not in their help areas for administrators)!!

Anyway, when I changed the extension from php4 to php5, the scripts worked!

Although that does not solve my over-all problem, it allow sme to continue a wee-bit down the path to success.

Bill

sneakyimp

it's very good that you are finding the problems on your own. i probably would not have guessed that the scripts were not executing on earthlink. generally speaking, you should make sure that a php script is interpreted as PHP by your server before you start worrying about whether not your script works. the script may be fine but if the server doesn't work then it's useless.