Merge pull request #448 from Treer/avatars

Force local cache update when user changes their profile picture

1 files changed, 72 insertions, 0 deletions

diff --git a/view/tpl/force_image_reload.tpl b/view/tpl/force_image_reload.tpl
new file mode 100644
index 000000000..839bd22b5
--- /dev/null
+++ b/view/tpl/force_image_reload.tpl
@@ -0,0 +1,72 @@
+{{* 
+Force the browser to reload an image from the server instead of the cache.
+based on an answer from http://stackoverflow.com/a/22429796/3343347
+
+Usage: Set $imgUrl to the src url you want to be re-fetched from the server
+
+*}}
+
+<script>
+  $(document).ready(
+    function() {
+      forceImgReload("{{$imgUrl}}");
+    }
+  );
+
+  {{* 
+    * find and return any existing img tags with a matching src url, and set them to an intermediate 
+    * src url so they can later be reverted back once the cached version has been updated.
+    *}}
+  function prepareImagesForReload(srcUrl) {
+
+    var result = $("img[src='" + srcUrl + "']").get();
+
+    for (i = 0; i < result.length; i++) {
+      {{* 
+        * Set the image to a reloading image, in this case an animated "reloading" svg 
+        * Ideally this wont be displayed long enough to matter.
+        *}}
+      result[i].src = "data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100' preserveAspectRatio='xMidYMid' class='uil-reload'%3E%3Cpath fill='none' class='bk' d='M0 0h100v100H0z'/%3E%3Cg%3E%3Cpath d='M50 15a35 35 0 1 0 24.787 10.213' fill='none' stroke='%23777' stroke-width='12'/%3E%3Cpath d='M50 0v30l16-15L50 0' fill='%23777'/%3E%3CanimateTransform attributeName='transform' type='rotate' from='0 50 50' to='360 50 50' dur='1s' repeatCount='indefinite'/%3E%3C/g%3E%3C/svg%3E";
+    }
+
+    return result;
+  }
+
+  function restoreImages(srcUrl, imgList) {
+
+    for (i = 0; i < imgList.length; i++) {
+      imgList[i].src = srcUrl;
+    }
+  }
+
+  function forceImgReload(srcUrl) {
+    var imgList;
+    var step = 0; 
+    var iframe = window.document.createElement("iframe");   // Hidden iframe, in which to perform the load+reload.
+  
+    {{* Callback function, called after iframe load+reload completes (or fails).
+        Will be called TWICE unless twostage-mode process is cancelled. (Once after load, once after reload). *}}
+    var iframeLoadCallback = function(e) { 
+
+      if (step === 0) { 
+        // initial load just completed.  Note that it doesn't actually matter if this load succeeded or not.
+      
+        step = 1; 
+        imgList = prepareImagesForReload(srcUrl); 
+        iframe.contentWindow.location.reload(true); // initiate forced-reload!
+      
+      } else if (step === 1) {
+        // forced re-load is done 
+
+        restoreImages(srcUrl, imgList);
+        if (iframe.parentNode) iframe.parentNode.removeChild(iframe);
+      }
+    }
+
+    iframe.style.display = "none";
+    window.parent.document.body.appendChild(iframe); {{* NOTE: if this is done AFTER setting src, Firefox MAY fail to fire the load event! *}}
+    iframe.addEventListener("load",  iframeLoadCallback, false);
+    iframe.addEventListener("error", iframeLoadCallback, false);
+    iframe.src = srcUrl;  
+  }
+</script>