Multiget, multiget everywhere!

I spent last days going through sequence of handler functions and understanding at what points I should query for schedule-tag from the server.

There are 3 handlers in the calDavRequestHandlers.js

etags handler
webdavSync Handler
multigetSync Handler

Each handler parses the retrieved xml REST message with nsiSaxParser. At the end of parsing, [when reached to endDocument() function], it calls doMultiget() with a set of items that are identified need fetching.

If an item detected which was deleted, newly created or updated from etags it will be added to the list, itemsNeedFetching{}.

Items will be fetched in doMultiget().

So I decided adding the query, <C: schedule-tag> within multiget would do the thing. (WebDav sync doesn’t return a schdule-tag anyway)

Then the schedule-tag will be added to the list, mItemInfoCache with respected UID with  property name “scheduleTag” (I removed the hyphen in middle of the Local name). This may cause to add a null value for the mItemInfoCache[].scheduleTag and I will manage it in If-Schedule-tag-Match property implementation.

I think this will pretty much cover the retrieval of schedule-tag property.

I found another regression in the code, which spoof the OPTIONS request when dealing with Google calendar.  I found that currently with CalDav v2, Google supports OPTIONS method. So there won’t be any need to spoof the method.  I’ll put this in my todo list as well.

My next step is implementing if-schedule-tag-match property.

New Headers : Schedule-Tag

Schedule-Tag is a new response header defined in RFC 6638 which is somewhat similar to ETag property of resources. The rationa behind the Schedule-Tag, is handing over the responsibility of merging changed object resource properties to the server.
With the current implementation, after every scheduling operation of invited calendar user, (Attendee changes the PARTSTAT value) causes to change the state of the object resource, which simply changes the ETag value and cause to occur inconsequential changes in the calendar user’s data due to some operations which possibly not affects to his/her PARTSTAT value.
Unlike the ETag value, Schedule-Tag only changed after the organizer made a change to the object resource .
Once a client tries a PUT request on an object resource, s/he should specify the last known Schedule-Tag of the object which is being asked with if-schedule-tag-match header which will be implemented in later stages. In case that the object resource has been modified with inconsequential changes, they have to be merged to the attendee object resource within the server and the new value has to be updated. Otherwise server must send a 412 (pre condition violated) status code in the response header.
Bug for the feature is here.
Changes of schedule-tag property in different situations.
I noticed that SOGo server, which I have used to work on has not yet support the schedule-tag property as it doesn’t return a value for schedule-tag value in the request header. Therefore, all current testing is being done with Google calendar.

Mozmill test for IMIP bar

There was a change in the planned routine in last week.  Mohit and I decided to poke into mozmill testing of IMIP bar though it was scheduled to latter stages of the project.

Bug for the test is here.

I had to look into mozmill automated testing API in order to write the test. Mozmill contains with some modules shared between firefox,  thunderbird and specific util modules for lightning. Mozmill thunderbird helper classes provide access to control utilities in thunderbird  while calendar utility classes provide ability to manage with events.

The automated test needed to inject a mail containing an invitation to check whether the IMIP bar is loaded and buttons are displayed. Then accept the event and make sure it is added at the correct location in the calendar view.

Source for the test is here.

In order to attach the invitation (invite.ics) to the email, I had to use thunderbird’s attchment-helpers module along with some other modules from tb as well.

There were few hard cases. First imip bar didn’t showed up and the attachment was showed up in the body. Once going through related RFCs, could find that, it was a some theoretical matter of adding the attachment header as defined in RFC.

Again, it was automatically clicking on “Don’t send email notifications” in the Email notification sending dialog box which appears once it’s clicked on the accept invitation button. gMockPromptService module was pretty much helpful for that. gMockPromptService creates the dialog virtually and returns the value (we can change the return value) to the caller regardless of the context of the caller.

In debugging I found that test functions are not executed unless the function name isn’t starting with the prefix “test”. That was pretty much helpful for debugging.




Deepening in the code

spent last few days exploring the code base and setting up the environment to debug Thunderbird.  Used sogo server to configure the CalDav. As I have installed a 32bit version of ubuntu, had to switch on Intel’s virtuaization feature in order to use sogo’s 64bit zeg image.

A summary on some frequent files would have been a little useful.


This contains utility methods to be used in Lightning operations. ie: cal.LOG(); for logging messages in the error console.  This is loaded in many of the source codes.


Most of the operations related to itip is contained in this file. i.e: determining the latest resource of a event file by examining the sequence number and the datetime stamp.


This contains function implementations for provider services. ie: SendHttprequest to send the queried XML message to the server.


contains all the methods to send the initiate the PROPFIND request to the server to, deleting a calendar resource object from the remote calendar. ie:

Sending the initial PROPFIND request to find  the remote calendar.

sending a PROPFIND request with a “allprop” element is described here.

Initial PROPFIND request:

[xml]<D:propfind xmlns:D=”DAV:” xmlns: CS=”” xmlns:C=”urn:ietf:params:xml:ns:caldav”>

Response from the server:

 <?xml version=”1.0″ encoding=”utf-8″?>
<D:multistatus xmlns:a=”urn:ietf:params:xml:ns:caldav” xmlns:b=”” xmlns:D=”DAV:”>
<D:status>HTTP/1.1 200 OK</D:status>
<D:collection/><calendar xmlns=”urn:ietf:params:xml:ns:caldav”/>
<vevent-collection xmlns=””/>
<vtodo-collection xmlns=””/>
<schedule-outbox xmlns=”urn:ietf:params:xml:ns:caldav”/>
<D:owner xmlns:D=”DAV:”>
<D:current-user-principal xmlns:D=”DAV:”>
<D:supported-report-set xmlns:n2=”urn:inverse:params:xml:ns:inverse-dav” xmlns:n3=”urn:ietf:params:xml:ns:carddav”           xmlns:D=”DAV:” xmlns:n1=”urn:ietf:params:xml:ns:caldav”>
<n1:supported-calendar-component-set xmlns:n1=”urn:ietf:params:xml:ns:caldav” xmlns:D=”DAV:”>
<n1:comp name=”VEVENT”/>
<n1:comp name=”VTODO”/>

I’m trying to send a HTTPrequest to get a property by name. It is done by the “propname” element.

my request:

<D:propfind xmlns:D=”DAV:” xmlns: CS=”” xmlns:C=”urn:ietf:params:xml:ns:caldav”>

As long as the property name is not mentioned, it will be considered as “allprop” request.

As the next step I hope to jump into the implementation of schedule-calendar-transp property.

Entry Points

Automatic scheduling of calendar collections was introduced by CalDav extension which was a protocol built upon WebDav. (There is CardDav protocol introduced parallel to CalDav for transferring of vcard information) CalDav was introduced by the IETF from RFC 6638 but Lightning’s implementation was done before the final version was introduced. Referring to the draft version 4.

I went through both versions to identify changes between them and a list was prepared. I explored the bugzilla and the calendar blog to find bugs related to CalDav properties and  found some of them that can be used to track the implementation.

I started with the bug used to implement the CalDav in Lightning.

Also, hope I will be working the code around this bug to implement proposed schedule-default-calendar-URL Dav property in Lightning.

My next step is to setup the Sogo server for testing features. It seems to be a very much updated and well aligned with the RFC 6638.

Also, I will be using next few days to hack into the code base to get a better understanding about the implementation along with RFCs. New bugs for each feature in the proposal are planned to be posted in the Bugzilla to get feedback and guidance from the community.