Question

I have a requirement. I need to access a user’s email that is on company specific domain. I need to get the calendar of that user and publish it to web application. I am exhausted finding any API that can help me to do that. The email client used by company is Thunder Bird, So , in specific, I need to access calender’s from Thunder Bird for that particular user. Can any one tell me some suggestions for this.

Answer 1

Kumar

Your question is very unprecise (what kind of is the server providing the emails/calendars? Is there a LDAP Domain? And so on). I suppose you are talking about an old Exchange Server because of some Domain and WebDAV and problems while searching? But I maybe can give you at least a bit of help, that may lead you to already trodden paths of other coders, so that you may find a simple and fast solution.

Today I finished a M$ Exchange 2003 Connector as a proof-of-concept. And I tell you, that it was really hard for me as a student while an Internship. Nonetheless, I researched and searched and queried and annoyed other to get hints for a useful API, but none fulfilled my purposes.

One small framework I found which is nice to use is called Sardine WebDAV Client for Java. The project is very light-weighted, though it was helpful to get an idea how WebDAV works, even due to sources you can always look at.

All other solutions aimed at a lot of different MAPI CC++ Libs for Linux. That was no option for me.

So, what options did I have? No direct access to the customers Exchange 2k3 Server, but one email account. So you all may forgive me, but I found it much easier to make a POST request to the E2k3 Server via OWA, because it was activated than trying some heavy lib supported ways of accessing.

Maybe this comes to your avail- Get the form-field information from the OWA form and build a connection string you Post to the server. Perhaps this is a string that might give you an idea. So you need to call a DLL like this:

HttpPost httpPost = new HttpPost("https://" + getUrl()
        + "/exchweb/bin/auth/owaauth.dll");

httpPost.setEntity(new StringEntity("destination=https%3A%2F%2F"
    + getUrl() + "%2Fexchange%2F&flags=0&username=" + getUser()
    + "&password=" + getPassword()
    + "&SubmitCreds=Log+On&trusted=4&flags=4", "UTF-8"));

The information how to make a form based authentication came from here: Exchange 2003 Forms-Based Authentication. As you can see I grabbed from the browser the Link, which is used to communicate with the E2k. The next step is simple – send the request and wait for…

HttpResponse response = httpclient.execute(httpPost);

If you get a good response in return, then you can filter out the Session ID. The next step after a successful login is to search for appointments. Therefore you should find a appropriate method to work with on an established WebDAV connection by asking M$ for some Information: SEARCH Method

Then, you read what it can do. I went on with a well-known Find-Machine and queried for Searching Calendar Folders with WebDAV.

After that you can create a POST request like this:

HttpPost hp = new HttpPost(
    "https://owa.SERVER.de/exchange/USER/Calendar") {
     @Override
     public String getMethod() {
         return "SEARCH";
     }
    };

Now you can make use of the SEARCH method. That is good, because your program is ready to send the request.

hp.setEntity(new StringEntity(QUERY, ContentType.TEXT_XML));
HttpResponse response = httpclient2.execute(hp);

I know it is no perfect solution. Because there were two circumstances which made me wonder. Firstly: I retrieved a Session ID, but I wasn’t in need to re-use it anywhere, as long as I kept it in a field. And secondly: I needed to call for another HttpClient. I cannot explain right now. If I used the same HttpClient I used for logon, then all request were in vain. That is why I had to call another HttpClient.

The last and most difficult step was to get behind the query, because the only debugging help I had were HTTP Error Numbers and the bad descriptions in the MSDN. Sorry for that. Well, this is what really worked fine. I got behind it with Trial and Error.

private final static String QUERY = "<?xml version=\"1.0\"?><g:searchrequest   
    xmlns:g=\"DAV:\"><g:sql> Select \"DAV:href\", \"urn:schemas:calendar:dtstart\",   
    \"urn:schemas:calendar:dtend\", \"urn:schemas:mailheader:subject\", 
    \"urn:schemas:calendar:duration\" FROM Scope('SHALLOW TRAVERSAL OF 
    \"/exchange/USER/Calendar\"')</g:sql></g:searchrequest>";

This is no particular query. I just alternated it from another Document and removed all stuff I didnt’t need.

I hope this helps you a bit. About providing Thunderbird Appointment/Calendar dates I can’t tell anything because this is yet beyond my knowledge.

Best regards and good night,

Semo