many modifications to improve the support of (at least) lightning

- changed default uid handling to UID2UID (means keep them unchanged), as the other modes created doublicates on client and server, as the client did not understand that the server changes his uid's (against the RFC specs).
- ability to delete events (not yet InfoLogs!), by tracking the id's of the GET request of the client and deleting the ones NOT send back to the server in PUT requests
- added etag handling to allow to reject put requests if the calendar is not up to date (HTTP_IF header with etag in client PUT requests) and to report unmodified calendars to the client (HTTP_IF_NONE_MATCH header with etag gets 304 Not modified response)
- returning 501 Not implemented response, for WebDAV/CalDAV request (eg. PROPFIND), to let the client know we dont support it
- ability to use contacts identified by their mail address as participants (mail addresses which are no contacts still get written to the description!)
- support uid for InfoLog (requires InfoLog version >= 1.5)

icalsrv.php

@@ -10,6 +10,21 @@
    * @note <b> THIS IS STILL EXPERIMENTAL CODE </b> do not use in production.
    * @note this script is supposed to be at:  egw-root/icalsrv.php
    * 
+   * NEW RalfBecker Aug 2007
+   * many modifications to improve the support of (at least) lightning
+   * - changed default uid handling to UID2UID (means keep them unchanged), as the other
+   *   modes created doublicates on client and server, as the client did not understand
+   *   that the server changes his uid's (against the RFC specs).
+   * - ability to delete events (not yet InfoLogs!), by tracking the id's of the GET request 
+   *   of the client and deleting the ones NOT send back to the server in PUT requests
+   * - added etag handling to allow to reject put requests if the calendar is not up to date
+   *   (HTTP_IF header with etag in client PUT requests) and to report unmodified calendars
+   *   to the client (HTTP_IF_NONE_MATCH header with etag gets 304 Not modified response)
+   * - returning 501 Not implemented response, for WebDAV/CalDAV request (eg. PROPFIND), to 
+   *   let the client know we dont support it
+   * - ability to use contacts identified by their mail address as participants (mail addresses
+   *   which are no contacts still get written to the description!)
+   * - support uid for InfoLog (requires InfoLog version >= 1.5)
    * @version 0.9.37-ng-a2 added a todo plan for v0.9.40
    * @date 20060510
    * @since 0.9.37-ng-a1 removed fixed default domain authentication
@@ -133,7 +148,12 @@
 	* the related Egroupware element.
 	* See further in @ref secuidmapping in the icalsrv_resourcehandler documentation.
 	*/
-	$uid_export_mode = UMM_ID2UID;
+	// New RalfBecker Aug 2007
+	// NOT using UID2UID creates doublicates on the iCal client, as it does NOT understand,
+	// that posted events get their uid changed by the server.
+	// I think uid's should be handled as specified in the RFC: the first clients assigns them
+	// AND noone is supposted to change them after that!
+	$uid_export_mode = UMM_UID2UID;
 
 	/** uid  mapping import  configuration switch
 	* @var int
@@ -142,7 +162,9 @@
 	* elements, that are then updated with the ical info.
 	* See further in @ref secuidmapping in the icalsrv_resourcehandler documentation.
 	*/
-	$uid_import_mode = UMM_UID2ID;
+	// New RalfBecker Aug 2007
+	// NOT using UID2UID creates doublicates on the iCal client, see above
+	$uid_import_mode = UMM_UID2UID;
 
 	/** 
 	* @section secisuidmapping Basic Possible settings of UID to ID mapping.
@@ -326,13 +348,13 @@
 
 	// build a virtual calendar with ical facilities from the found vircal
 	// array_storage data
-	$icalvc =& CreateObject('icalsrv.icalvircal');
+	require_once(EGW_INCLUDE_ROOT.'/icalsrv/inc/class.icalvircal.inc.php');
+	$icalvc =& new icalvircal;
 	if(!$icalvc->fromArray($vircal_arstore))
 	{
 		error_log('icalsrv.php: ' . $cnmsg . ' couldnot restore from repository.' );
 		fail_exit($cnmsg . ' internal problem ' , '403');
 	}
-
 	// YES: $icalvc created ok! acces rights needs to be checked though!
 
 	// HACK: ATM basic auth is always needed!! (JVL) ,so we force icalvc into it
@@ -409,11 +431,14 @@
 	$icalvc->reimport_missing_elements = $reimport_missing_elements;
 	$logmsg = "";
 
-	// oke now process the actual import or export to/from icalvc..
+	
-	if($_SERVER['REQUEST_METHOD'] == 'PUT')
+	// NEW RalfBecker Aug 2007
+	// We have to handle the request methods different, specially the WebDAV ones we dont support
+	switch($_SERVER['REQUEST_METHOD'])
 	{
+	case 'PUT':
 		// *** PUT Request so do an Import *************
-
+		
 		if($isdebug)
 		{
 			error_log('icalsrv.php: importing, by user:' .$GLOBALS['egw_info']['user']['account_id']
@@ -435,6 +460,21 @@
 			fail_exit('importing in groupcalendars is not allowed', '403');
 		}
 
+		// NEW RalfBecker Aug 2007
+		// for a PUT we have to check if the currently loaded calendar is still up to date
+		// (not changed eg. by someone else or via the webfrontend).
+		// This is done by comparing the ETAG given as HTTP_IF with the current ETAG (last modification date)
+		// of the calendar --> on failure we return 412 Precondition failed, to not overwrite the modifications 
+		if (isset($_SERVER['HTTP_IF']) && preg_match('/\(\[([0-9]+)\]\)/',$_SERVER['HTTP_IF'],$matches))
+		{
+			$etag = $icalvc->get_etag();
+			//error_log("PUT: current etag=$etag, HTTP_IF=$_SERVER[HTTP_IF]");
+			if ($matches[1] != $etag)
+			{
+				fail_exit('Precondition Failed',412);
+			}
+		}
+	
 		// I0 read the payload
 		$logmsg = 'IMPORTING in '. $importMode . ' mode';
 		$fpput = fopen("php://input", "r");
@@ -469,16 +509,31 @@
 			log_ical($logmsg,"import",$vcalstr);
 		}
 
+		// NEW RalfBecker Aug 2007
+		// we have to send a new etag header, as otherwise the client (at least lightning) has a wrong etag,
+		// if it's not requesting the calendar again via GET
+		header("ETag: ". $icalvc->get_etag());
+
 		// handle response ...
 		$GLOBALS['egw']->common->egw_exit();
-	}
+	
-	else
+	case 'GET':
-	{
+		// *** GET Request so do an export
-		// *** GET (or POST?) Request so do an export
 		$logmsg = 'EXPORTING';
 		// derive a ProductType from our http Agent and set it in icalvc
 		$icalvc->deviceType = icalsrv_resourcehandler::httpUserAgent2deviceType($reqagent);
 
+		// NEW RalfBecker Aug 2007
+		// if an IF_NONE_MATCH is given, check if we need to send a new export, or the current one is still up-to-date
+		if (isset($_SERVER['HTTP_IF_NONE_MATCH']))
+		{
+			$etag = $icalvc->get_etag();
+			error_log("GET: current etag=$etag, HTTP_IF_NONE_MATCH=$_SERVER[HTTP_IF_NONE_MATCH]");
+			if ($_SERVER['HTTP_IF_NONE_MATCH'] == $etag)
+			{
+				fail_exit('Not Modified',304);
+			}
+		}
 		// export the data from the virtual calendar
 		$vcalstr = $icalvc->export_vcal();
 
@@ -493,6 +548,10 @@
 			$logmsg .= "\n exported " . $cnmsg ." : OK ";
 		} 
 		// DONE exporting
+		
+		// NEW RalfBecker Aug 2007
+		// returnung max modification date of events as etag header
+		header("ETag: ". $icalvc->export_etag);
 
 		if($logdir) log_ical($logmsg,"export",$vcalstr);
 		// handle response ...
@@ -503,6 +562,11 @@
 		}
 		echo $vcalstr;
 		$GLOBALS['egw']->common->egw_exit();
+
+	default:
+	case 'PROPFIND':
+		// tell the client we do NOT support full WebDAV/CalDAV
+		fail_exit('Not Implemented',501);
 	}
 
 	// // --- SOME UTILITY FUNCTIONS -------