From 6fdf81f26676a712966044a3bc7ced2fcdfc0a8f Mon Sep 17 00:00:00 2001
From: Sean Nichols <seannichols94@gmail.com>
Date: Mon, 19 Dec 2016 00:39:32 -0500
Subject: [PATCH] Ignore falsy header values and improve ajaxHeaders
 documentation

---
 src/openseadragon.js         | 5 ++++-
 src/tiledimage.js            | 1 -
 src/tilesource.js            | 3 +++
 src/viewer.js                | 1 +
 test/demo/customheaders.html | 4 ++--
 5 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/openseadragon.js b/src/openseadragon.js
index a5116963..d2c52174 100644
--- a/src/openseadragon.js
+++ b/src/openseadragon.js
@@ -2189,7 +2189,10 @@ function OpenSeadragon( options ){
 
                 if (headers) {
                     Object.keys(headers).forEach(function (headerName) {
-                        request.setRequestHeader(headerName, headers[headerName]);
+                        // Falsy header values will be ignored
+                        if (headers[headerName]) {
+                            request.setRequestHeader(headerName, headers[headerName]);
+                        }
                     });
                 }
 
diff --git a/src/tiledimage.js b/src/tiledimage.js
index f9b311cc..16ef99b5 100644
--- a/src/tiledimage.js
+++ b/src/tiledimage.js
@@ -81,7 +81,6 @@
  *      Defaults to the setting in {@link OpenSeadragon.Options}.
  * @param {Object} [options.ajaxHeaders={}]
  *      A set of headers to include when making tile AJAX requests.
- *      Note that these headers will be merged over any headers specified in {@link OpenSeadragon.Options}.
  */
 $.TiledImage = function( options ) {
     var _this = this;
diff --git a/src/tilesource.js b/src/tilesource.js
index 66bb10ac..d8c16803 100644
--- a/src/tilesource.js
+++ b/src/tilesource.js
@@ -582,6 +582,9 @@ $.TileSource.prototype = {
      * Responsible for retrieving the headers which will be attached to the image request for the
      * region specified by the given x, y, and level components.
      * This option is only relevant if {@link OpenSeadragon.Options}.loadTilesWithAjax is set to true.
+     * The headers returned here will override headers specified at the Viewer or TiledImage level.
+     * Specifying a falsy value for a header will clear its existing value set at the Viewer or
+     * TiledImage level (if any).
      * @function
      * @param {Number} level
      * @param {Number} x
diff --git a/src/viewer.js b/src/viewer.js
index a5b3104f..a3a09828 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -1239,6 +1239,7 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
      * @param {Object} [options.ajaxHeaders]
      *      A set of headers to include when making tile AJAX requests.
      *      Note that these headers will be merged over any headers specified in {@link OpenSeadragon.Options}.
+     *      Specifying a falsy value for a header will clear its existing value set at the Viewer level (if any).
      * requests.
      * @param {Function} [options.success] A function that gets called when the image is
      * successfully added. It's passed the event object which contains a single property:
diff --git a/test/demo/customheaders.html b/test/demo/customheaders.html
index 4937b231..cdd98401 100644
--- a/test/demo/customheaders.html
+++ b/test/demo/customheaders.html
@@ -58,14 +58,14 @@
             ajaxHeaders: {
                 // Example of using the viewer-level ajaxHeaders option
                 // for providing an authentication token.
-                'Authentication': 'Bearer MY_AUTH_TOKEN'
+                "Authentication": "Bearer MY_AUTH_TOKEN"
             }
         });
 
         viewer.addTiledImage({
             // The headers specified here will be combined with those in the Viewer object (if any)
             ajaxHeaders: {
-                "X-My-TileSource-Header": "Something"
+                "X-My-TiledImage-Header": "Something"
             },
             tileSource: myCustomTileSource
         });