Can't get SFTP to work in PHP

Chris_Kloberdanz_28714 0
Viewed 44825

I am writing a simple SFTP client in PHP because we have the need to programatically retrieve files via n remote servers. I am using the PECL SSH2 extension.

I have run up against a road block, though. The documentation on php.net suggests that you can do this:

$stream = fopen("ssh2.sftp://$sftp/path/to/file", 'r');

However, I have an ls method that attempts to something similar

public function ls($dir)
{
    $rd = "ssh2.sftp://{$this->sftp}/$dir";
    $handle = opendir($rd);
    if (!is_resource($handle)) {
        throw new SFTPException("Could not open directory.");
    }

    while (false !== ($file = readdir($handle))) {
        if (substr($file, 0, 1) != '.'){
            print $file . "\n";
        }
    }
    closedir($handle);
}

I get the following error:

PHP Warning:  opendir(): Unable to open ssh2.sftp://Resource id #5/outgoing on remote host

This makes perfect sense because that's what happens when you cast a resource to string. Is the documentation wrong? I tried replacing the resource with host, username, and host and that didn't work either. I know the path is correct because I can run SFTP from the command line and it works fine.

Has anyone else tried to use the SSH2 extenstion with SFTP? Am I missing something obvious here?

UPDATE:

I setup sftp on another machine in-house and it works just fine. So, there must be something about the server I am trying to connect to that isn't working.

wrapper sftp ssh php
10 Answers

This is a bug in the ssh2 package that I found years ago and posted a patch to php.net. It fixes this issue but requires a rebuild of the ssh2 pecl package. You can read more here: https://bugs.php.net/bug.php?id=69981. I included a patch there to the ssh2_fopen_wrappers.c file in the package to fix the issue. Here is a comment I included:

Here is a line of code from ssh2_fopen_wrappers.c that causes this bug: (comment included)

/*
       Find resource->path in the path string, then copy the entire string from the original path.
       This includes ?query#fragment in the path string
*/
    resource->path = estrdup(strstr(path, resource->path));

This line of code -- and therefore this bug -- was introduced as a fix for bug #59794. That line of code is attempting to get a string containing the part, query and fragment from the path variable. Consider this value for the path variable:

ssh2.sftp://Resource id #5/topdir?a=something#heading1

When resource->path is "/topdir", the result is that "/topdir?a=something#heading1" gets assigned to resource->path just like the comment says.

Now consider the case when resource->path is "/". After the line of code is executed, resource->path becomes "//Resource id#5/topdir#heading1". This is clearly not what you want. Here's a line of code that does:

 resource->path = estrdup( strstr( strstr( path, "//" ) + 2, "/" ) );

You may also need to apply the patch for bug # 73597 which removes "Resource id #" from the path string before calling php_url_parse().

user_112331110
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