Node express save pdf from binary string
<p>I have a problem saving a pdf file from binary data. I get the binary from a web service and my express server (as middleware) should send the file to the client.
The problem is that client and adobe acrobat reader show a blank pdf, so I'm thinking that I done some error saving/encoding the binary data.</p>

<pre><code>exports.downloadReceipt = function(req, res) {
  var idPrenotazione = req.params.idPrenotazione;
  var options = {
    'method': 'GET',
    'uri': api_url + '/ricevute/'+idPrenotazione,
    'headers': {
      'Authorization': req.get('Authorization')
    }
  }

  request(options, function(error, response, body) {
    var date = new Date().getTime();
    var filename = 'ricevuta_'+idPrenotazione+'_'+date+'.pdf';
    var file = folderPath + filename;

  fs.writeFile(file, body, function(err) {
    if(err)
      console.log(err);
    else
      console.log("The file was saved!");
  });      

  // for the moment I only save the file on server file system
  res.end();


  });
}
</code></pre>

<p>I also tried to use createWriteStream instead of writeFile, with and without encoding option</p>

<pre><code>  var options = { encoding: 'binary' };
  var wstream = fs.createWriteStream(file_);
  wstream.write(body);
  wstream.end();
</code></pre>

<p>The string that I get from web service is something like this:</p>

<pre><code>%PDF-1.5
%����
2 0 obj
&lt;&lt;/Length1 17948/Length 9587/Filter/FlateDecode&gt;&gt;stream
x��{y`՝���!ɖ-Y�iɖF�e˖,۲lَ��v�$���s8v��B�$�(4nHiI�RP��@�n�����׶���-P�-Wbi����H��������y��|���^��}3�p9� -[3�~�+���&lt; ��l�E���E7�7��Њ�+�l\�1��?P��rt�
�G��!}ؿj���ɿ~�@�+H߰
o�t�&amp;��u��5m�??ن�5�~���e�����й��޼�3����#��~���ԷX��%����������
k\��\z���d���O�x@�A9(-�A&gt;�@`�B0�  �`+ؠ���Q��\ �&lt;��R�A��*��*A5�@-��"P
�Fh�f�-� 
</code></pre>

<p>[.....]</p>

<pre><code>0000042111 00000 n 
0000042252 00000 n 
0000042393 00000 n 
trailer
&lt;&lt;/Root 7 0 R/ID [&lt;10edca6daaad5a49919bad108ba77f0a&gt;&lt;492e2d9a8ca810421f41667217724e69&gt;]/Info 4 0 R/Size 183&gt;&gt;
%iText-5.5.8
startxref
173008
%%EOF
</code></pre>

<p>What I'm doing wrong? I just have a function that get an image (from the same web service) in base64 and I save it on server file system with writeFile and it works well.</p>

<p>Thanks for help</p>