PHP - Convert File system path to URL

问题:

I often find that I have files in my projects that need to be accessed from the file system as well as the users browser. One example is uploading photos. I need access to the files on the file system so that I can use GD to alter the images or move them around. But my users also need to be able to access the files from a URL like example.com/uploads/myphoto.jpg.

Because the upload path usually corresponds to the URL I made up a function that seems to work most of the time. Take these paths for example:

File System /var/www/example.com/uploads/myphoto.jpg

URL http://example.com/uploads/myphoto.jpg

If I had a variable set to something like /var/www/example.com/ then I could subtract it from the filesystem path and then use it as the URL to the image.

/**
 * Remove a given file system path from the file/path string.
 * If the file/path does not contain the given path - return FALSE.
 * @param   string  $file
 * @param   string  $path
 * @return  mixed
 */
function remove_path($file, $path = UPLOAD_PATH) {
    if(strpos($file, $path) !== FALSE) {
        return substr($file, strlen($path));
    }
}

$file = /var/www/example.com/uploads/myphoto.jpg;

print remove_path($file, /var/www/site.com/);
//prints "uploads/myphoto.jpg"

Does anyone know of a better way to handle this?

回答1:

Assume the directory is /path/to/root/document_root/user/file and the address is site.com/user/file

The first function I am showing will get the current file's name relative to the World Wide Web Address.

$path = $_SERVER['SERVER_NAME'] . $_SERVER['PHP_SELF'];

and would result in:

site.com/user/file

The second function strips the given path of the document root.

$path = str_replace($_SERVER['DOCUMENT_ROOT'], '', $path)

Given I passed in /path/to/root/document_root/user/file, I would get

/user/file

回答2:

More accurate way (including host port) would be to use this

function path2url($file, $Protocol='http://') {
    return $Protocol.$_SERVER['HTTP_HOST'].str_replace($_SERVER['DOCUMENT_ROOT'], '', $file);
}

回答3:

IMHO such automation is really error prone. You're far better off using some explicit path helpers (eg. one for uploads, one for user pics, etc) or just encapsulate for example an uploaded file with a class.

// Some "pseudo code"
$file = UploadedFile::copy($_FILES['foo']);
$file->getPath(); // /var/www/example.org/uploads/foo.ext
$file->getUri();  // http://example.org/uploads/foo.ext

回答4:

Make it easy on yourself and just define the correct locations for both the filesystem and web folders and prepend the image filename with them.

Somewhere, you'd declare:

define('PATH_IMAGES_FS', '/var/www/example.com/uploads/');
define('PATH_IMAGES_WEB', 'uploads/');

Then you can just swap between paths depending on your need:

$image_file = 'myphoto.jpg';

$file = PATH_IMAGES_FS.$image_file;
//-- stores: /var/www/example.com/uploads/myphoto.jpg

print PATH_IMAGES_WEB.$image_file;
//-- prints: uploads/myphoto.jpg

回答5:

Try this:

$imgUrl = str_replace($_SERVER['DOCUMENT_ROOT'], '', $imgPath)

回答6:

For example, i used this one to convert C:\WAMP\WWW\myfolder\document.txt to http://example.com/myfolder/document.txt use this one:

$file_path=str_replace('\\','/',$file_path);
$file_path=str_replace($_SERVER['DOCUMENT_ROOT'],'',$file_path);
$file_path='http://'.$_SERVER['HTTP_HOST'].$file_path;

回答7:

I've used this and worked with me:

$file_path=str_replace('\\','/',__file__);
$file_path=str_replace($_SERVER['DOCUMENT_ROOT'],'',$file_path);
$path='http://'.$_SERVER['HTTP_HOST'].'/'.$file_path;

And if you need the directory name in url format add this line:

define('URL_DIR',dirname($path));

回答8:

This simple snippet can convert the file path to file's url on the server. Some settings like protocol and port should be kept.

        $filePath = str_replace('\\','/',$filePath);
        $ssl = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') ? true : false;
        $sp = strtolower($_SERVER['SERVER_PROTOCOL']);
        $protocol = substr($sp, 0, strpos($sp, '/')) . (($ssl) ? 's' : '');
        $port = $_SERVER['SERVER_PORT'];
        $stringPort = ((!$ssl && $port == '80') || ($ssl && $port == '443')) ? '' : ':' . $port;
        $host = isset($_SERVER['HTTP_X_FORWARDED_HOST']) ? $_SERVER['HTTP_X_FORWARDED_HOST'] : isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : $_SERVER['SERVER_NAME'];
        $fileUrl = str_replace($_SERVER['DOCUMENT_ROOT'] ,$protocol . '://' . $host . $stringPort, $filePath);

回答9:

The code below is well commented:

function pathToURL($path) {
  //Replace backslashes to slashes if exists, because no URL use backslashes
  $path = str_replace("\\", "/", realpath($path));

  //if the $path does not contain the document root in it, then it is not reachable
  $pos = strpos($path, $_SERVER['DOCUMENT_ROOT']);
  if ($pos === false) return false;

  //just cut the DOCUMENT_ROOT part of the $path
  return substr($path, strlen($_SERVER['DOCUMENT_ROOT']));
  //Note: usually /images is the same with http://somedomain.com/images,
  //      So let's not bother adding domain name here.
}
echo pathToURL('some/path/on/public/html');

回答10:

I always use symlinks in my local development environment and @George's approach fails in this case:

The DOCUMENT_ROOT is set to /Library/WebServer/Documents and there is a symlink /Library/WebServer/Documents/repo1 -> /Users/me/dev/web/repo1

Assume that following codes are in /Users/me/dev/web/repo1/example.php

$_SERVER['DOCUMENT_ROOT'] == "/Library/WebServer/Documents" //default on OS X

while

realpath('./some/relative.file') == "/Users/me/dev/web/repo1/some/relative.file"

Thus, replacing DOCUMENT_ROOT with HTTP_HOST doesn't work.

I come up with this little trick:

function path2url($path) {
    $pos = strrpos(__FILE__, $_SERVER['PHP_SELF']);
    return substr(realpath($path), $pos);
}

// where
__FILE__                         == "/Users/me/dev/web/repo1/example.php"
$_SERVER['PHP_SELF']             ==              "/web/repo1/example.php"
realpath("./some/relative.file") == "/Users/me/dev/web/repo1/some/relative.file"
// If I cut off the pre-fix part from realpath($path), 
// the remainder will be full path relative to virtual host root
path2url("./some/relative.file") ==              "/web/repo1/some/relative.file"

I think it's good practice to fore-prevent the potential bugs even we are not likely to use symlinks in production environment.

回答11:

All answers here promotes str_replace() which replaces all occurences anywhere in the string, not just in the beginning. preg_replace() will make sure we only do an exact match from the beginning of the string:

function remove_path($file, $path = UPLOAD_PATH) {
  return preg_replace("#^($path)#", '', $file);
}

Windows can be a problem where directory separators / and \. Make sure you replace the directory separators first:

function remove_path($file, $path = UPLOAD_PATH) {
  $file = preg_replace("#([\\\\/]+)#", '/', $file);
  $path = preg_replace("#([\\\\/]+)#", '/', $path);
  return preg_replace("#^($path)#", '', $file);
}

I would play with something like the following. Make note of realpath() and rtrim().

function webpath($file) {
  $document_root = rtrim(preg_replace("#([\\\\/]+)#", '/', $_SERVER['DOCUMENT_ROOT']), '/');
  $file = preg_replace("#([\\\\/]+)#", '/', realpath($file));
  return preg_replace("#^($document_root)#", '', $file);
}

echo webpath(__FILE__); // Returns webpath to self
echo webpath('../file.ext'); // Relative paths
echo webpath('/full/path/to/file.ext'); // Full paths