Incompatibility with Cyrus / Fastmail

jtagcat commented 1 month ago

https://github.com/jtagcat/calredact/blob/6c12f21a34d440c4633859c171da24d62495eed3/main.go#L106-L115 Tested faulty with fastmail.com (Cyrus). Same generated request works (207) on OX App Suite and Nextcloud.

Code in question: https://github.com/jtagcat/calredact/blob/6c12f21a34d440c4633859c171da24d62495eed3/main.go#L106-L115

Response for go-webdav on fastmail.com:

HTTP/1.1 400 Bad Request
Server: nginx
Date: Mon, 08 Jul 2024 18:25:32 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 491
Connection: keep-alive
Vary: Accept-Encoding
X-Frontend: frontend1
X-Trace-Id: ti_72b00284f07bc0d6f468732a01304fd4

<!DOCTYPE html>
<html style='color-scheme:dark light'>
  <head>
    <title>400 Bad Request</title>
  </head>
  <body>
    <h1>Bad Request</h1>
    <p>The request was not understood by this server.</p>
    <hr>
    <address>Cyrus-HTTP/3.11.0-alpha0-568-g843fbadbe-fm-20240701.003-g843fbadb Cyrus-SASL/2.1.27 Lib/XML2.9.10 Jansson/2.14 OpenSSL/1.1.1w Wslay/1.1.1 Zlib/1.2.11 Xapian/1.5.0 LibiCal/3.1 ICU4C/74.2 SQLite/3.34.1 Server at caldav.fastmail.com Port 2275</address>
  </body>
</html>

Response for patched request:

HTTP/1.1 207 Multi-Status
Server: nginx
Date: Mon, 08 Jul 2024 18:19:52 GMT
Content-Type: application/xml; charset=utf-8
Connection: keep-alive
Vary: Accept-Encoding, Brief, Prefer
X-Frontend: frontend1
X-Trace-Id: ti_cc0dac5f325d8344d7401cd5217ce56d
Content-Length: 648

<?xml version="1.0" encoding="utf-8"?>
<d:multistatus xmlns:c="urn:ietf:params:xml:ns:caldav" xmlns:d="DAV:">
  <d:response>
    <d:href>/dav/calendars/user/calretest@fastmail.com/5B895624-3D36-11EF-B5BC-83625697A2A5/e5213f54-a17a-403f-90b5-83919b5ef783.ics</d:href>
    <d:propstat>
      <d:prop>
        <c:calendar-data><![CDATA[BEGIN:VCALENDAR
END:VCALENDAR
]]></c:calendar-data>
        <d:getlastmodified>Mon, 08 Jul 2024 16:33:15 GMT</d:getlastmodified>
        <d:getetag>"70e4896a60aabe57ad32610e9b090bf7b5257208"</d:getetag>
      </d:prop>
      <d:status>HTTP/1.1 200 OK</d:status>
    </d:propstat>
  </d:response>
</d:multistatus>

Requests (left: generated, right: patched):

It appears that the primary incompatibility is the d: and c:/:c syntax. I'm a mere consumer, not familiar with the RFCs. Is this an issue with go-webdav or Cyrus?

I based the patch on Cyrus source + proxying Thunderbird traffic as well.

emersion commented 1 month ago

Hm. In theory the xmlns things should be equivalent.

There are other differences, e.g. name attributes. Does it work if you leave the xmlns attrs as-is, but use the fixed up name attrs?

jtagcat commented 1 month ago

Hm. In theory the xmlns things should be equivalent.

There are other differences, e.g. name attributes. Does it work if you leave the xmlns attrs as-is, but use the fixed up name attrs?

No. I'll note, that in Cyrus source, the xmlns was treated to be inherited — duplicating it in children seems not necessary.

emersion commented 1 month ago

Yeah, but given the design of the encoding/xml package, this is what we end up with.

dilyanpalauzov commented 3 weeks ago

You can upload the faulty request as text towards Cyrus IMAP — https://github.com/cyrusimap/cyrus-imapd/issues/ (more or less this is Fastmail). Typing the request from the image, in order to reproduce the problem, is cumbersome and error prone. Apart from namespaces, left and right requests have other differences - in the first comp-filter one request has VEVENT, the other VCALENDAR; one comp-element has empty name=, the other has name=VCALENDAR.

It is not clear from the screenshot with the requests provided here, whether the namespaces are the problem, or the other differences cause the failure.

emersion / go-webdav

Incompatibility with Cyrus / Fastmail #166