1 files changed, 165 insertions, 0 deletions
diff --git a/apps/files_external/lib/Lib/Storage/SFTPWriteStream.php b/apps/files_external/lib/Lib/Storage/SFTPWriteStream.php
new file mode 100644
index 00000000000..d64e89b5462
--- /dev/null
+++ b/apps/files_external/lib/Lib/Storage/SFTPWriteStream.php
@@ -0,0 +1,165 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Files_External\Lib\Storage;
+
+use Icewind\Streams\File;
+use phpseclib\Net\SSH2;
+
+class SFTPWriteStream implements File {
+	/** @var resource */
+	public $context;
+
+	/** @var \phpseclib\Net\SFTP */
+	private $sftp;
+
+	/** @var string */
+	private $handle;
+
+	/** @var int */
+	private $internalPosition = 0;
+
+	/** @var int */
+	private $writePosition = 0;
+
+	/** @var bool */
+	private $eof = false;
+
+	private $buffer = '';
+
+	public static function register($protocol = 'sftpwrite') {
+		if (in_array($protocol, stream_get_wrappers(), true)) {
+			return false;
+		}
+		return stream_wrapper_register($protocol, get_called_class());
+	}
+
+	/**
+	 * Load the source from the stream context and return the context options
+	 *
+	 * @throws \BadMethodCallException
+	 */
+	protected function loadContext(string $name) {
+		$context = stream_context_get_options($this->context);
+		if (isset($context[$name])) {
+			$context = $context[$name];
+		} else {
+			throw new \BadMethodCallException('Invalid context, "' . $name . '" options not set');
+		}
+		if (isset($context['session']) and $context['session'] instanceof \phpseclib\Net\SFTP) {
+			$this->sftp = $context['session'];
+		} else {
+			throw new \BadMethodCallException('Invalid context, session not set');
+		}
+		return $context;
+	}
+
+	public function stream_open($path, $mode, $options, &$opened_path) {
+		[, $path] = explode('://', $path);
+		$path = '/' . ltrim($path);
+		$path = str_replace('//', '/', $path);
+
+		$this->loadContext('sftp');
+
+		if (!($this->sftp->bitmap & SSH2::MASK_LOGIN)) {
+			return false;
+		}
+
+		$remote_file = $this->sftp->_realpath($path);
+		if ($remote_file === false) {
+			return false;
+		}
+
+		$packet = pack('Na*N2', strlen($remote_file), $remote_file, NET_SFTP_OPEN_WRITE | NET_SFTP_OPEN_CREATE | NET_SFTP_OPEN_TRUNCATE, 0);
+		if (!$this->sftp->_send_sftp_packet(NET_SFTP_OPEN, $packet)) {
+			return false;
+		}
+
+		$response = $this->sftp->_get_sftp_packet();
+		switch ($this->sftp->packet_type) {
+			case NET_SFTP_HANDLE:
+				$this->handle = substr($response, 4);
+				break;
+			case NET_SFTP_STATUS: // presumably SSH_FX_NO_SUCH_FILE or SSH_FX_PERMISSION_DENIED
+				$this->sftp->_logError($response);
+				return false;
+			default:
+				user_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS');
+				return false;
+		}
+
+		return true;
+	}
+
+	public function stream_seek($offset, $whence = SEEK_SET) {
+		return false;
+	}
+
+	public function stream_tell() {
+		return $this->writePosition;
+	}
+
+	public function stream_read($count) {
+		return false;
+	}
+
+	public function stream_write($data) {
+		$written = strlen($data);
+		$this->writePosition += $written;
+
+		$this->buffer .= $data;
+
+		if (strlen($this->buffer) > 64 * 1024) {
+			if (!$this->stream_flush()) {
+				return false;
+			}
+		}
+
+		return $written;
+	}
+
+	public function stream_set_option($option, $arg1, $arg2) {
+		return false;
+	}
+
+	public function stream_truncate($size) {
+		return false;
+	}
+
+	public function stream_stat() {
+		return false;
+	}
+
+	public function stream_lock($operation) {
+		return false;
+	}
+
+	public function stream_flush() {
+		$size = strlen($this->buffer);
+		$packet = pack('Na*N3a*', strlen($this->handle), $this->handle, $this->internalPosition / 4294967296, $this->internalPosition, $size, $this->buffer);
+		if (!$this->sftp->_send_sftp_packet(NET_SFTP_WRITE, $packet)) {
+			return false;
+		}
+		$this->internalPosition += $size;
+		$this->buffer = '';
+
+		return $this->sftp->_read_put_responses(1);
+	}
+
+	public function stream_eof() {
+		return $this->eof;
+	}
+
+	public function stream_close() {
+		$this->stream_flush();
+		if (!$this->sftp->_close_handle($this->handle)) {
+			return false;
+		}
+		return true;
+	}
+}