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Diffstat (limited to 'view/tpl/force_image_reload.tpl')
-rw-r--r-- | view/tpl/force_image_reload.tpl | 72 |
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> |