Demo showing how composer self-update can elevate to

elevate-demo.php

<?php

/**
 * This demo shows a method for elevating to an Admin on Windows and running
 * a command in cmd.exe, from a PHP script. It demonstrates how Composer can
 * self-update to an Admin location.
 *
 * Powershell (available on Windows 7 upwards) is used to invoke the UAC prompt,
 * because it returns a value from the result of the prompt so we can see if the
 * user cancelled. Note that it is impossible to obtain the exit code from the
 * elevated process.
 *
 * Another way of doing this is to run a batch script that calls VBS ShellExecute,
 * but this function does not return an exit code. Also, vbs scripts might not be
 * runnable if the user's PathExt does not contain a .VBS entry.
 *
 * The actual command could have been run in Powershell itself, but this asks
 * the user to authorize Powershell "to make changes to your device" which I
 * felt might be confusing for people running unixy shells, whereas Windows
 * Command Processor looks more native.
 *
 * The Powershell script is saved in the user's temp directory and is deleted
 * (by itself) when it finishes. *
 *
 */


$localFilename = ''; // the location where composer.phar is to be installed
$newFilename = '';   // the location of the downloaded (or rollback) composer.phar
$interactive = true; // assume we are interactive

echo "Upgrading to version '3.0.0' (stable channel).", PHP_EOL;

// Assume rename($newFilename, $localFilename) fails

if (!$interactive) {
    return 1;
}

$cygwin = preg_match('/cygwin/i', php_uname());
if (!$cygwin && !defined('PHP_WINDOWS_VERSION_BUILD')) {
    return 1;
}

// See if we are an admin
exec('cmd.exe /c fltmc.exe filters', $output, $exitCode);
if ($exitCode === 0) {
    return 1;
}

echo 'Unable to write to the "C:\\ProgramData\\ComposerSetup\\bin" directory. Access is denied.', PHP_EOL;
$question = '    Complete this operation with Administrator priviledges [yes]? ';
$answer = readline($question);
$cancelledMsg = 'Operation cancelled. Please re-run the self-update command as an Administrator.'.PHP_EOL;

if (!preg_match('/^y/i', $answer)) {
    echo $cancelledMsg;
    return;
}

$tmpFile = @tempnam(sys_get_temp_dir(), '');
$script = $tmpFile.'.ps1';
rename($tmpFile, $script);


// Format the file names for cmd.exe
if ($cygwin) {
    $localFilename = exec(sprintf("cygpath -w '%s'", $localFilename));
    $newFilename = exec(sprintf("cygpath -w '%s'", $newFilename));
} else {
    // cmd.exe move seems to be fussy about backslashes
    $localFilename = str_replace('/', '\\', $localFilename);
    $newFilename = str_replace('/', '\\', $newFilename);
}

$ps1 = <<<EOT
\$exitCode = 0

try {
    # Use cmd.exe to move new filename to local filename
    #Start-Process -FilePath "\$env:comspec" -ArgumentList "/c move /y `"$newFilename`" `"$localFilename`"" -Verb RunAs -WindowStyle Hidden

    # Demo only: open cmd.exe and keep open for 3 seconds
    Start-Process -FilePath "\$env:comspec" -ArgumentList "/c timeout /t 3" -Verb RunAs -WindowStyle Hidden
} catch {
    \$exitCode = 1
}

Remove-Item -Path \$MyInvocation.MyCommand.Path -Force
exit \$exitCode
EOT;

file_put_contents($script, $ps1);

if ($cygwin) {
    $winPath = exec(sprintf("cygpath -w '%s'", $tmpFile));
    $script = $winPath.'.ps1';
}

$command = sprintf('powershell.exe -File "%s" -WindowStyle Hidden -ExecutionPolicy Bypass', $script);
exec($command, $output, $exitCode);

if ($exitCode === 0) {
    echo 'The result of this operation is unobtainable. Run `composer --version` to check if it succeeded.', PHP_EOL;
    usleep(500);
    return 0;
} else {
    echo $cancelledMsg;
    return 1;
}