Requirements: PHP4, register_globals are assumed to be off. Ensure you define a path to a datafile in a directory which has write permission.

Most PHP tutorials involving data storage are aimed at databases, usually MySQL. However there are many people who, for one reason or another, want or need to store data in a plain text file.

In this tutorial we will construct a page which allows the user to

• enter new records
• list the records

• edit existing records
• delete records

For data storage I have elected to use an ini-file format, primarily for the ease with which data can be indexed and retrieved with this format. For those not familiar with this format, an ini file is a list of items with values and the file can be divided into sections. The format is like this

	[SECTION_1]
	item1=value1
	item2=value2
	
	[SECTION_2]
	item1=value3
	item2=value4
	item3=value5

For storing records we will adapt this format so that each section is a record with its id as the section name and the field names of the record will be the items. The data in each record will be:-

• username (record id)
• firstName
• lastName
• email

so our text file will be a series of records like this

	[jdoe]
	firstname=John
	lastname=Doe
	email=jd@domain.com

Many of the programming techniques used in this tutorial can also be used with data stored in a database.

The page will display a data form, so the user can enter new records, and a list of the current records in the file. By clicking on the ID field of a record, that record is selected for editing. The data to be changed will be displayed in the same form as that used for new records. When we are editing a record, only the form will be displayed and not the record list.

By clicking on an 'X' at the end of each record, the user can delete a record.

Input form

The data input form has four text boxes, one for each of the fields. These will normally be blank so the user can enter a new record. When the user wants to edit a record, the text boxes will contain the current values. The form looks like this

The form code is

<FORM  method="POST" action="<?php echo $_SERVER['PHP_SELF']?>">
<INPUT TYPE="HIDDEN"  name="userdata" value="1">
<?php
	if (!empty($username))
        		echo "<INPUT TYPE=\"HIDDEN\"  name=\"username\" value=\"$username\">";
?>
<TABLE style="background: #E0E0E0; border: solid 2pt #666666" >
<TR>
    <TD colspan='2' style="border-bottom: solid 1pt #666666; font-weight: bold; text-align: center">
    User data
    </TD>
</TR>
<TR>
    <TD>
    User name
    </TD>
    <TD>
        <INPUT TYPE="TEXT"  name="username" size="10" maxlength="10"
                value='<?php echo $username ?>'
                <?php echo  empty($username) ? '' : ' DISABLED ' ?> >
    </TD>
</TR>
<TR>
    <TD>
    First name
    </TD>
    <TD>
    <INPUT TYPE="TEXT"  name="firstname" size="20" maxlength="20" value='<?php echo $firstname ?>'>
    </TD>
</TR>
<TR>
    <TD>
    Last name
    </TD>
    <TD>
    <INPUT TYPE="TEXT"  name="lastname" size="20" maxlength="20" value='<?php echo $lastname ?>'><br>
    </TD>
    </TR>
<TR>
    <TD>
    Email address
    </TD>
    <TD>
    <INPUT TYPE="TEXT"  name="email" size="30" maxlength="30" value='<?php echo $email ?>'><br>
    </TD>
</TR>
<TR>
     <TD>
      
     </TD>
     <TD>
    <INPUT TYPE="SUBMIT"  value="Send data">
    <?php
    if (!empty($username))
         echo "<INPUT TYPE=\"BUTTON\"  value=\"Cancel\"   onClick=\"history.go(-1);\">";
    ?>
    </TD>
</TR>
</TABLE>
</FORM>

A fairly standard table and form but the highlighted code may warrant further explanation.

<INPUT TYPE="HIDDEN"  name="userdata" value="1">

When we are processing the form, the existence of a 'userdata' item will tell us that data has been posted. Using a hidden field like this works whether the user clicks the submit button or just hits the enter key.

<?php echo  empty($username) ? '' : ' DISABLED ' ?> >

If the user wants to edit a record, the username will contain the id of the record to be edited. The username textbox will be greyed out when editing as we want the user to see but don't want them to be able to change it (because then we wouldn't know which record to update). We do this by disabling the text box

<?php
        if (!empty($username))
             echo "<INPUT TYPE=\"HIDDEN\"  name=\"username\" value=\"$username\">";
        ?>

Because the username textbox is disabled, the username would not be posted, so, if we're editing, we put the username in a hidden field. Similarly, a 'Cancel' button is placed on the form when a record is selected for editing which will take the user back to the record list.

Record List

The record list is produced by the function listData($data). This is a general purpose function that you can use to list in a table any similarly formatted text file by passing your data array to it ($data).

function listData($data) {
     if (count($data) > 0) {
         echo "<TABLE border='0' cellspacing='1' cellpadding='2'>\n";
         # headings
         echo "<tr style='background: #C0C0C0'><th>ID</th>";
         list ( $key, $dataArray) = each($data);
         foreach($dataArray as $k=>$v) {
                 echo "<th>$k</th>";
         }
         echo "<th>Del</th></tr>";

         #data
         $i = 0;
         foreach ($data as $key=>$dataArray) {
                 $bg = ++$i % 2 ? "#FFFFFF" : "#EEEEEE";
                 echo "<tr style='background: $bg'>
                        <td>
                        <a href='$_SERVER['PHP_SELF']?changeid=$key'>$key<a>
                        </td>";
                 foreach ($dataArray as $v) {
                           echo "<td>$v</td>";
                 }
                 echo "<td>[<a href='$_SERVER['PHP_SELF']?delid=$key'>X<a>]</td></tr>";
        }
        echo "</TABLE>";
    }
    else echo "<p>No data</p>";

}

Let's have look at what it does

    if (count($data) > 0) {
         echo "<TABLE border='0' cellspacing='1' cellpadding='2'>\n";
         # headings
         echo "<tr style='background: #C0C0C0'><th>ID</th>";

         list ( $key, $dataArray) = each($data);

         foreach($dataArray as $k=>$v) {
                 echo "<th>$k</th>";
         }

         echo "<th>Del</th></tr>";

         foreach ($data as $key=>$dataArray) {

                 $bg = ++$i % 2 ? "#FFFFFF" : "#EEEEEE";

                 echo "<tr style='background: $bg'>
                        <td>
                        <a href='$_SERVER[PHP_SELF]?
			changeid=$key'>$key<a>
                        </td>";

                 foreach ($dataArray as $v) {
                           echo "<td>$v</td>";
                 }

                 echo "<td>[<a href='$_SERVER[PHP_SELF]
			?delid=$key'>X<a>]</td></tr>";
	}

        echo "</TABLE>";

We want to do all the processing and updating before we display the page again so any changes are immediately displayed. This section is therefore placed above the opening <html> tag.

The first thing we do is initialise our variables and define data file

# initialise variables
$username = $firstname = $lastname = $email = "";
$data = array();
$changed = false;

# define your data file and its path, ensure you have write permission to folder
$myTextFile = 'data/mydata.txt';

Read the data from the current text file, if it exists, storing it i the array '$data'.

    if (file_exists($myTextFile))
        $data = parse_ini_file($myTextFile, true);

Now check if data was submitted using the form. If it is a new record, it will be added to the $data array. If it's and edit, the current values will be updated. The $data array is a two-dimaensional array where the first key is the username and the second key is the data field name. If the userdata item was posted we know form data was sent. Username is our section key and the data items are firstname, lastname and email. Add the items to out $data array (or update if it is already there)

if (isset($_POST['userdata'])) {
  if (!empty($_POST['username']) && !empty($_POST['email']) ) {
        # add new data (or update if exists already)
    $data[$_POST['username']]['firstname'] = $_POST['firstname'];
    $data[$_POST['username']]['lastname'] = $_POST['lastname'];
    $data[$_POST['username']]['email'] = $_POST['email'];

    $changed = true;
  }
else echo "<p>Must have username and email</p>";}

Deletions and edit request come via links in the data table and use query strings to pass the record id's. In these instances we need to look at the $_GET data.

If a deletion has been requested, 'delid' will have a value.

if (isset($_GET['delid'])) {

    # remove deleted item from the array
    unset($data[$_GET['delid']]);
    $changed = true;
}

If the user has requested to edit a record, changeid has a value

This time, all we do is get the data to be displayed in the edit form

if (isset($_GET['changeid'])) {
        # get the items we want to edit so they can appear in the form
        $username = $_GET['changeid'];
        $firstname = $data[$username]['firstname'];
        $lastname = $data[$username]['lastname'];
        $email = $data[$username]['email'];
}

Now check to see if the file needs to be updated, If it does, $changed will be 'true'.

if ($changed) {
    # now create new output file, writing in ini file format
    $fp = fopen('mydata.txt', 'w');

    ksort($data);

    foreach ($data as $key=>$dataArray) {
             fwrite($fp, "[$key]\n");

             foreach ($dataArray as $k => $v) {
                      fwrite($fp, "$k=$v\n");
             }
             fwrite($fp, "\n");
    }
    fclose($fp);
}