php run write function only if input words don't match unwanted words from a text file

Question

1) How to run php function to write input text to a file(text.txt) only if, not a single input word match from another text file(unwanted-words.txt)

<?php
$para = $_POST['para'];

if ($_POST)
    {
    $handle = fopen("text.txt", "a");
    fwrite($handle, $para . ":<br/>" );
    fclose($handle);
    }

?>

<form method="post">
Para:<input type="text" name="para"><br/>
<input type="submit" name="submit" value="Post">
</form>

2) Also, Which format should i use for unwanted words in file unwanted-words.txt :

badword,bad word,bad-word,bad_word,bad.word

OR

badword
bad word
bad-word
bad_word
bad.word

OR some other format

Thanks in advance

Answer 1

You can try this :

Class Text in Text.php

<?php

/**
 * Text Class
 */

class Text
{
    //text string
    private $text;

    public function __construct($text)
    {
        //set value for $this->text for each objects/instances
        $this->text = $text;
    }

    //filter with a "filter file"
    public function filterFile($filter)
    {
        //get unwanted words file content :D
        $filter = file_get_contents($filter);
        //explode string every end of line for getting an array
        $filter = explode(PHP_EOL, $filter);
        foreach ($filter as $v) {
            if(preg_match("/$v/i", $this->text)){
                $this->text = "";
            }
        }
        //return object for succesive methods (ex: $ex->a()->b()->c() )
        return $this;
    }

    //save modified string in file
    //first param => file name
    public function save($filename)
    {
        //set handle
        $handle = fopen($filename, 'a');
        //if true
        if($handle)
        {
            //write file
            fwrite($handle, $this->text.PHP_EOL);
        } else {
            return false;
        }
        //close handle
        fclose($handle);
    }
}

Unwanted words in txt file : unwanted-words.txt for example

badword
bad word
bad-word
bad_word
bad.word

I your page...

<?php

require "Text.php";
if($_POST["para"])
{
    //new instance of Text Class
    $text = new Text($_POST["para"]);
    $text->filterFile('unwanted-words.txt')->save("test.txt");
}

?>

<form method="post">
Para:<input type="text" name="para"><br/>
<input type="submit" name="submit" value="Post">
</form>

When submitting, text is append to file only if unanted word are not matched