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Chapter 20. Using remote files

As long as support for the "URL fopen wrapper" is enabled when you configure PHP (which it is unless you explicitly pass the --disable-url-fopen-wrapper flag to configure (for versions up to 4.0.3) or set allow_url_fopen to off in php.ini (for newer versions)), you can use HTTP and FTP URLs with most functions that take a filename as a parameter, including the require() and include() statements.

Note: You can't use remote files in include() and require() statements on Windows.

For example, you can use this to open a file on a remote web server, parse the output for the data you want, and then use that data in a database query, or simply to output it in a style matching the rest of your website.

Example 20-1. Getting the title of a remote page

<?php
$file = fopen ("http://www.php.net/", "r");
if (!$file) {
    echo "<p>Unable to open remote file.\n";
    exit;
}
while (!feof ($file)) {
    $line = fgets ($file, 1024);
    /* This only works if the title and its tags are on one line */
    if (eregi (" php Manual>(.*)</title>", $line, $out)) {
        $title = $out[1];
        break;
    }
}
fclose($file);
?></PRE
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><P
>
   You can also write to files on an FTP as long you connect as a user
   with the correct access rights, and the file doesn't exist already.
   To connect as a user other than 'anonymous', you need to specify
   the username (and possibly password) within the URL, such as
   'ftp://user:password@ftp.example.com/path/to/file'. (You can use the
   same sort of syntax to access files via HTTP when they require Basic
   authentication.)
  </P
><P
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   <TABLE
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CLASS="EXAMPLE"
><TR
><TD
><DIV
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><A
NAME="AEN6063"
></A
><P
><B
>Example 20-2. Storing data on a remote server</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="php"
><?php
$file = fopen ("ftp://ftp.php.net/incoming/outputfile", "w");
if (!$file) {
    echo "<p>Unable to open remote file for writing.\n";
    exit;
}
/* Write the data here. */
fputs ($file, "$HTTP_USER_AGENT\n");
fclose ($file);
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   <DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>Note: </B
>
     You might get the idea from the example above to use this
     technique to write to a remote log, but as mentioned above, you
     can only write to a new file using the URL fopen() wrappers. To
     do distributed logging like that, you should take a look at
     <A
HREF="function.syslog.html"
><B
CLASS="function"
>syslog()</B
></A
>.
    </P
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