PHP Search for a string in remote webpage - php

Question

I am trying to write a script with PHP where it'll open up a text file ./urls.txt and check each domain for a specific word. I am really new to PHP.
Example:
Look for the word "Hello" in the following domains.
List:
Domain1.LTD
Domain2.LTD
Domain3.LTD
and just simply print out domain name + valid/invalid.
<?PHP
$link = "http://yahoo.com"; //not sure how to loop to read each line from a file.
$linkcontents = file_get_contents($link);
$needle = "Hello";
if (strpos($linkcontents, $needle) == false) {
echo "Valid";
} else {
echo "Invalid";
}
?>

Answer 1

$arrayOfLinks = array(
"http://example.com/file.txt",
"https://www.example-site-2.com/files/file.txt"
);
$needle = "Hello";
foreach($arrayOfLinks as $link){ // loop through the array
$linkcontents = file_get_contents($link);
if (stripos($linkcontents , $needle) !== false) { // stripos is case-insensitive search
// the needle exists in $linkcontents
// !== false instead of != false since stripos can return 0 meaning the needle is the first word of the contents
echo "Valid";
} else {
// the word does not exist in the given text
echo "Invalid";
}
}

Answer 2

First of all use CURL in favor of file_get_contents() because of security.
This would be a correct strpos example:
//your previous code
if (strpos($linkcontents, $needle) !== false) { // see the !==
echo "Valid"; //Needle found
} else {
echo "Invalid"; //Needle not found
}
For more complex crawling you could use some regexp instead of strpos.