/**
* Decrypt a message and download the files of the message to the $outputFolder
*
* Note: This does not check the MAC before, which you should always do when
* you want to use this in your own application! Use {@link checkMac()} for doing so.
*
* @param string $threemaId The sender ID (= the ID the message came from)
* @param string $messageId
* @param string $box box as binary string
* @param string $nonce nonce as binary string
* @param string|null|false $outputFolder folder for storing the files,
* null=current folder, false=do not download files
* @param \Closure $downloadMessage
* @return ReceiveMessageResult
* @throws Exception
* @throws \Threema\MsgApi\Exceptions\BadMessageException
* @throws \Threema\MsgApi\Exceptions\DecryptionFailedException
* @throws \Threema\MsgApi\Exceptions\UnsupportedMessageTypeException
*/
public final function receiveMessage($threemaId, $messageId, $box, $nonce, $outputFolder = null, \Closure $downloadMessage = null)
{
//fetch the public key
$receiverPublicKey = $this->connection->fetchPublicKey($threemaId);
if (null === $receiverPublicKey || !$receiverPublicKey->isSuccess()) {
throw new Exception('Invalid threema id');
}
$message = $this->cryptTool->decryptMessage($box, $this->privateKey, $this->cryptTool->hex2bin($receiverPublicKey->getPublicKey()), $nonce);
if (null === $message || false === is_object($message)) {
throw new Exception('Could not encrypt box');
}
$receiveResult = new ReceiveMessageResult($messageId, $message);
if ($outputFolder === false) {
return $receiveResult;
}
if ($outputFolder === null || strlen($outputFolder) == 0) {
$outputFolder = '.';
}
if ($message instanceof ImageMessage) {
$result = $this->downloadFile($message, $message->getBlobId(), $downloadMessage);
if (null !== $result && true === $result->isSuccess()) {
$image = $this->cryptTool->decryptImage($result->getData(), $this->cryptTool->hex2bin($receiverPublicKey->getPublicKey()), $this->privateKey, $message->getNonce());
if (null === $image) {
throw new Exception('decryption of image failed');
}
//save file
$filePath = $outputFolder . '/' . $messageId . '.jpg';
$f = fopen($filePath, 'w+');
fwrite($f, $image);
fclose($f);
$receiveResult->addFile('image', $filePath);
}
} else {
if ($message instanceof FileMessage) {
$result = $this->downloadFile($message, $message->getBlobId(), $downloadMessage);
if (null !== $result && true === $result->isSuccess()) {
$file = $this->cryptTool->decryptFile($result->getData(), $this->cryptTool->hex2bin($message->getEncryptionKey()));
if (null === $file) {
throw new Exception('file decryption failed');
}
//save file
$filePath = $outputFolder . '/' . $messageId . '-' . $message->getFilename();
file_put_contents($filePath, $file);
$receiveResult->addFile('file', $filePath);
}
if (null !== $message->getThumbnailBlobId() && strlen($message->getThumbnailBlobId()) > 0) {
$result = $this->downloadFile($message, $message->getThumbnailBlobId(), $downloadMessage);
if (null !== $result && true === $result->isSuccess()) {
$file = $this->cryptTool->decryptFileThumbnail($result->getData(), $this->cryptTool->hex2bin($message->getEncryptionKey()));
if (null === $file) {
throw new Exception('thumbnail decryption failed');
}
//save file
$filePath = $outputFolder . '/' . $messageId . '-thumbnail-' . $message->getFilename();
file_put_contents($filePath, $file);
$receiveResult->addFile('thumbnail', $filePath);
}
}
}
}
return $receiveResult;
}
