diff --git a/htdocs/comm/action/class/ical.class.php b/htdocs/comm/action/class/ical.class.php
index badd5db5c98..26db2cd5e6e 100644
--- a/htdocs/comm/action/class/ical.class.php
+++ b/htdocs/comm/action/class/ical.class.php
@@ -54,8 +54,8 @@ class ICal
 	/**
 	 *  Read text file, icalender text file
 	 *
-	 *  @param  string  $file       File
-	 *  @return string
+	 *  @param  string  		$file       File
+	 *  @return string|null					Content of remote file read or null if error
 	 */
 	public function read_file($file)
 	{
@@ -65,7 +65,7 @@ class ICal
 
 		$tmpresult = getURLContent($file, 'GET');
 		if ($tmpresult['http_code'] != 200) {
-			$file_text = '';
+			$file_text = null;
 			$this->error = 'Error: '.$tmpresult['http_code'].' '.$tmpresult['content'];
 		} else {
 			$file_text = preg_replace("/[\r\n]{1,} /", "", $tmpresult['content']);
@@ -102,17 +102,40 @@ class ICal
 	/**
 	 * Translate Calendar
 	 *
-	 * @param	string 	$uri	Url
+	 * @param	string	 	$uri			Url
+	 * @param	string		$usecachefile	Full path of a cache file to use a cache file
+	 * @param	string		$delaycache		Delay in seconds for cache (by default 3600 secondes)
 	 * @return	array|string
 	 */
-	public function parse($uri)
+	public function parse($uri, $usecachefile = '', $delaycache = 3600)
 	{
 		$this->cal = array(); // new empty array
 
 		$this->event_count = -1;
+		$this->file_text = null;
+
+		// Save file into a cache
+		if ($usecachefile) {
+			include_once DOL_DOCUMENT_ROOT.'/core/lib/files.lib.php';
+			$datefile = dol_filemtime($usecachefile);
+			$now = dol_now('gmt');
+			//print $datefile.' '.$now.' ...';
+			if ($datefile && $datefile > ($now - $delaycache)) {
+				// We reuse the cache file
+				$this->file_text = file_get_contents($usecachefile);
+			}
+		}
 
 		// read FILE text
-		$this->file_text = $this->read_file($uri);
+		if (is_null($this->file_text)) {
+			$this->file_text = $this->read_file($uri);
+
+			if ($usecachefile && !is_null($this->file_text)) {
+				// Save the file content into cache file
+				file_put_contents($usecachefile, $this->file_text, LOCK_EX);
+				dolChmod($usecachefile);
+			}
+		}
 
 		$this->file_text = preg_split("[\n]", $this->file_text);
 
diff --git a/htdocs/comm/action/index.php b/htdocs/comm/action/index.php
index 3460355a803..b4e11125aee 100644
--- a/htdocs/comm/action/index.php
+++ b/htdocs/comm/action/index.php
@@ -49,6 +49,7 @@ if (empty($conf->global->AGENDA_EXT_NB)) {
 	$conf->global->AGENDA_EXT_NB = 5;
 }
 $MAXAGENDA = $conf->global->AGENDA_EXT_NB;
+$DELAYFORCACHE = 300;	// 300 seconds
 
 $disabledefaultvalues = GETPOST('disabledefaultvalues', 'int');
 
@@ -615,7 +616,7 @@ if (!empty($conf->use_javascript_ajax)) {	// If javascript on
 				$default = '';
 			}
 
-			$s .= '<div class="nowrap inline-block minheight30"><input type="checkbox" id="check_ext'.$htmlname.'" name="check_ext'.$htmlname.'" value="1" '.$default.'> <label for="check_ext'.$htmlname.'">'.dol_escape_htmltag($val['name']).'</label> &nbsp; </div>';
+			$s .= '<div class="nowrap inline-block minheight30"><input type="checkbox" id="check_ext'.$htmlname.'" name="check_ext'.$htmlname.'" value="1" '.$default.'> <label for="check_ext'.$htmlname.'" title="'.dol_escape_htmltag($langs->trans("Cache").' '.round($DELAYFORCACHE / 60).'mn').'">'.dol_escape_htmltag($val['name']).'</label> &nbsp; </div>';
 		}
 	}
 
@@ -1010,9 +1011,13 @@ if ($mode == 'show_day') {
 	// Request only leaves for the current selected day
 	$sql .= " AND '".$db->escape($year)."-".$db->escape($month)."-".$db->escape($day)."' BETWEEN x.date_debut AND x.date_fin";	// date_debut and date_fin are date without time
 } elseif ($mode == 'show_week') {
-	// TODO: Add filter to reduce database request
+	// Restrict on current month (we get more, but we will filter later)
+	$sql .= " AND date_debut < '".dol_get_last_day($year, $month)."'";
+	$sql .= " AND date_fin >= '".dol_get_first_day($year, $month)."'";
 } elseif ($mode == 'show_month') {
-	// TODO: Add filter to reduce database request
+	// Restrict on current month
+	$sql .= " AND date_debut <= '".dol_get_last_day($year, $month)."'";
+	$sql .= " AND date_fin >= '".dol_get_first_day($year, $month)."'";
 }
 
 $resql = $db->query($sql);
@@ -1083,8 +1088,11 @@ if (count($listofextcals)) {
 		$colorcal = $extcal['color'];
 		$buggedfile = $extcal['buggedfile'];
 
+		$pathforcachefile = dol_sanitizePathName($conf->user->dir_temp).'/'.dol_sanitizeFileName('extcal_'.$namecal.'_user'.$user->id).'.cache';
+		//var_dump($pathforcachefile);exit;
+
 		$ical = new ICal();
-		$ical->parse($url);
+		$ical->parse($url, $pathforcachefile, $DELAYFORCACHE);
 
 		// After this $ical->cal['VEVENT'] contains array of events, $ical->cal['DAYLIGHT'] contains daylight info, $ical->cal['STANDARD'] contains non daylight info, ...
 		//var_dump($ical->cal); exit;
diff --git a/htdocs/core/lib/date.lib.php b/htdocs/core/lib/date.lib.php
index 03223a7b65a..773cb6a1a97 100644
--- a/htdocs/core/lib/date.lib.php
+++ b/htdocs/core/lib/date.lib.php
@@ -117,6 +117,7 @@ function getServerTimeZoneInt($refgmtdate = 'now')
  *  @param      int			$duration_unit      Unit of added delay (d, m, y, w, h, i)
  *  @param      int         $ruleforendofmonth  Change the behavior of PHP over data-interval, 0 or 1
  *  @return     int      			        	New timestamp
+ *  @see convertSecondToTime(), convertTimeToSeconds()
  */
 function dol_time_plus_duree($time, $duration_value, $duration_unit, $ruleforendofmonth = 0)
 {
diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index ab96f650b6f..278f70507bb 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -6844,6 +6844,22 @@ function dol_mkdir($dir, $dataroot = '', $newmask = '')
 }
 
 
+/**
+ *	Change mod of a file
+ *
+ *  @param	string		$filepath		Full file path
+ *	@return void
+ */
+function dolChmod($filepath)
+{
+	global $conf;
+
+	if (!empty($conf->global->MAIN_UMASK)) {
+		@chmod($filepath, octdec($conf->global->MAIN_UMASK));
+	}
+}
+
+
 /**
  *	Return picto saying a field is required
  *