This was actually an assignment given to me as part of an interview process some time back. The brief was simple: to have an upload utility that allowed a search term to be specified and a text file to be uploaded, with the contents of the uploaded file then displayed in the browser with the search term highlighted.
My first pass is a pure PHP solution. Please note this is not production code and I would never push code like this!
<?php
/*
* - check the Execute Permissions of the upload directory
*
* - checking file extensions in code using MIME type, which has some drawbacks as it is browser dependant
* - added optional ability to restrict file type by extension (.txt) which is easy to extend to other file types - this is more restrictive & therefore more secure
* - check size of uploaded file
* - would normally move successfully uploaded file to another location (outside the web directory)
*
*/
// max file upload size to be used in script
define('FILE_SIZE_LIMIT', 20480);
if (isset($_POST['submit']))
{
// initialise an empty array to hold errors
$errArr = array();
// check to see if the user wants the search to be case sensitive or not
$caseSensitive = (isset($_POST['casesensitive']) && $_POST['casesensitive'] == 'on')?'on':'off';
// check to see if the user wants to allow only .txt files, or other text files as well
$txtOnly = (isset($_POST['txtonly'])&&$_POST['txtonly']=='on')?'on':'off';
// check for and get the search term
if(isset($_POST['searchterm']) && $_POST['searchterm'] != '')
{
$searchTerm = $_POST['searchterm'];
}
else
{
$errArr[] = 'You did not enter a search term';
}
// checks for errors and checks that file is uploaded
if ($_FILES['uploadedfile']['error'] == UPLOAD_ERR_OK && is_uploaded_file($_FILES['uploadedfile']['tmp_name']))
{
// check the file type - this gets the MIME type - not neccessarily the best way to check, esp. for image files!!
$fileType = $_FILES['uploadedfile']['type'];
// array will make it easier to add other files types later if we want to (csv,htm,html,xml,css,rtf etc)
$allowedExtensions = array("txt");
// get the file extension
$fileext = strtolower(substr(strrchr($_FILES['uploadedfile']['name'],'.'),1));
// checking the MIME type
if ($fileType == "text/plain")
{
// explicitely checking file extensions and creating a list of "allowed" extensions offers most control / security
if($txtOnly == 'on' && !in_array($fileext, $allowedExtensions))
{
$errArr[] = "Files with that extension ($fileext) are not allowed!";
}
// get the file size
$fileSize = $_FILES['uploadedfile']['size'];
// check file size
if($fileSize > 0)
{
if($fileSize <= FILE_SIZE_LIMIT)
{
// read the contents of the file
$content = file_get_contents($_FILES['uploadedfile']['tmp_name']);
// allow for line-breaks
$content = str_replace("\n", "<br />", $content);
// we need to have some checks in place on this uploaded content - this would be a start
$content = htmlentities($content, ENT_QUOTES);
// count number of times search term occurs in content
// check to see if the user selected case-sensitive or not
if($caseSensitive == 'on')
{
$searchCount = substr_count($content, $searchTerm);
// output the contents of the file with the search term highlighted
// below line is "first-pass" which obviously doesn't work with case-sensitive
// would naturally replace it later with the final solution - leaving it in place for now...
$output = str_replace($searchTerm, '<span class="highlighted-result">'.$searchTerm.'</span>', $content);
}
else
{
$searchCount = substr_count(strtolower($content), strtolower($searchTerm));
// below is final solution to case sensitive problem when replacing / highlighting text
// output the contents of the file with the search term highlighted
$output = preg_replace("|($searchTerm)|Ui", "<span class=\"highlighted-result\">$1</span>", $content);
}
$output = html_entity_decode($output);
}
else
{
$errArr[] = 'That file is too big!';
}
}
else
{
$errArr[] = 'That file is empty!';
}
$fileName = $_FILES['uploadedfile']['name'];
}
else
{
$errArr[] = 'That is not a text file!';
}
}
else
{
$errArr[] = 'No file selected or there was an error uploading you file!';
}
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Text file upload and Highlight utility</title>
<link rel="stylesheet" href="stylee.css" type="text/css" />
</head>
<body>
<h1>Text file upload and Highlight utility</h1>
<?php
if(isset($errArr)) // the array is set
{
if(empty($errArr)) // the array is empty - there were no errors - output the search results
{
// give info about the search term
echo '<h2>Your search term <span class="highlighted-result">'.$searchTerm.'</span> occurred '.$searchCount.' times</h2>';
echo '<p>Search info:</p>';
echo '<ul><li>Name: '.$fileName.'</li><li>Size: '.$fileSize.'</li><li>Case sensitive:'.$caseSensitive.'</li></ul>';
echo '<div id="output">'.$output.'</div>';
}
else
{
foreach($errArr as $msg) // there were errors - output them
{
echo '<p class="error">'.$msg.'</p>';
}
}
}
?>
<ol>
<li>Select a text file</li>
<li>Enter a search term</li>
<li>Submit to see results</li>
</ol>
<form enctype="multipart/form-data" action="index.php" method="post">
<fieldset>
<legend>Upload text file:</legend>
<p><label for="uploadedfile">File:</label><input type="file" name="uploadedfile" /> (limit <?php echo FILE_SIZE_LIMIT; ?>)</p>
<p><label for="searchterm">Search term:</label><input type="text" name="searchterm" id="searchterm" /></p>
<p><input type="checkbox" name="casesensitive" /> Case sensitive</p>
<p><input type="checkbox" name="txtonly" /> .txt extension only</p>
<p><input name="submit" type="submit" value="submit" /></p>
</fieldset>
</form>
</body>
</html>
See the demo here…