Is there a way to access a string as a filehandle in php?

Question

I'm on a server where I'm limited to PHP 5.2.6 which means str_getcsv is not available to me. I'm using, instead fgetcsv which requires "A valid file pointer to a file successfully opened by fopen(), popen(), or fsockopen()." to operate on.

My question is this: is there a way to access a string as a file handle?

My other option is to write the string out to a text file and then access it via fopen() and then use fgetcsv, but I'm hoping there's a way to do this directly, like in perl.

Answer 1

Unfortunately, that is not possible. You cannot treat a string as if it's a stream from a file. You would indeed have to first write the string to a file, and then open said file using fopen.

And now for the obvious part, have you considered upgrading?

Answer 2

If you take a look in the user notes on the manual page for str_getcsv, you'll find this note from daniel, which proposes this function (quoting) :

<?php
if (!function_exists('str_getcsv')) {
    function str_getcsv($input, $delimiter = ",", $enclosure = '"', $escape = "\\") {
        $fiveMBs = 5 * 1024 * 1024;
        $fp = fopen("php://temp/maxmemory:$fiveMBs", 'r+');
        fputs($fp, $input);
        rewind($fp);

        $data = fgetcsv($fp, 1000, $delimiter, $enclosure); //  $escape only got added in 5.3.0

        fclose($fp);
        return $data;
    }
}
?>

It seems to be doing exactly what you asked for : it uses a stream, which points to a temporary filehandle in memory, to use fgetcsv on it.

See PHP input/output streams for the documentation about, amongst others, the php://temp stream wrapper.

Of course, you should test that it works OK for you -- but, at least, this should give you an idea of how to achieve this ;-)

Answer 3

You can use stream handles such as php://memory to achieve what you're after. Just open, fwrite, rewind, and you should be able to use fgetcsv.

Answer 4

To answer your general question, yes you can treat a variable as a file stream.

http://www.php.net/manual/en/function.stream-context-create.php

The following is a copy and paste from a few different comments on the PHP manual (so I cannot vouch for how production ready it is):

<?php
class VariableStream {
    private $position;
    private $varname;
    public function stream_open($path, $mode, $options, &$opened_path) {
        $url = parse_url($path);
        $this->varname = $url["host"];
        $this->position = 0;
        return true;
    }
    public function stream_read($count) {
        $p=&$this->position;
        $ret = substr($GLOBALS[$this->varname], $p, $count);
        $p += strlen($ret);
        return $ret;
    }
    public function stream_write($data){
        $v=&$GLOBALS[$this->varname];
        $l=strlen($data);
        $p=&$this->position;
        $v = substr($v, 0, $p) . $data . substr($v, $p += $l);
        return $l;
    }
    public function stream_tell() {
        return $this->position;
    }
    public function stream_eof() {
        return $this->position >= strlen($GLOBALS[$this->varname]);
    }
    public function stream_seek($offset, $whence) {
        $l=strlen(&$GLOBALS[$this->varname]);
        $p=&$this->position;
        switch ($whence) {
            case SEEK_SET: $newPos = $offset; break;
            case SEEK_CUR: $newPos = $p + $offset; break;
            case SEEK_END: $newPos = $l + $offset; break;
            default: return false;
        }
        $ret = ($newPos >=0 && $newPos <=$l);
        if ($ret) $p=$newPos;
        return $ret;
    }
}

stream_wrapper_register("var", "VariableStream");
$csv = "foo,bar\ntest,1,2,3\n";

$row = 1;
if (($handle = fopen("var://csv", "r")) !== FALSE) {
    while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
        $num = count($data);
        echo "<p> $num fields in line $row: <br /></p>\n";
        $row++;
        for ($c=0; $c < $num; $c++) {
            echo $data[$c] . "<br />\n";
        }
    }
    fclose($handle);
}
?>

Of course, for your particular example, there are simpler stream methods that can be used.