From f872e0dc9bb77c7e513bad5e31b805b1dbd2e68a Mon Sep 17 00:00:00 2001
From: hqweay <hqweay@gmail.com>
Date: Mon, 27 Jun 2022 21:33:31 +0800
Subject: [PATCH] caching link content for link preview

---
 _includes/link-previews.html | 24 ++++++++++++++++++------
 _notes/your-first-note.md    |  2 ++
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/_includes/link-previews.html b/_includes/link-previews.html
index 49801cc..b9eb370 100644
--- a/_includes/link-previews.html
+++ b/_includes/link-previews.html
@@ -50,6 +50,8 @@
   var tooltipWrapper = document.getElementById('tooltip-wrapper')
   var tooltipContent = document.getElementById('tooltip-content')
 
+  var linkHistories = {};
+
   function hideTooltip() {
     opacityTimeout = setTimeout(function() {
       tooltipWrapper.style.opacity = 0;
@@ -66,20 +68,30 @@
     var top = window.pageYOffset || document.documentElement.scrollTop
 
     if (event.target.host === window.location.host) {
-      iframe.src = event.target.href
-      iframe.onload = function() {
-        tooltipContentHtml = ''
-        tooltipContentHtml += '<div style="font-weight: bold;">' + iframe.contentWindow.document.querySelector('h1').innerHTML + '</div>'
-        tooltipContentHtml += iframe.contentWindow.document.querySelector('content').innerHTML
+      if (!linkHistories[event.target.href]) {
+        iframe.src = event.target.href
+        iframe.onload = function() {
+          tooltipContentHtml = ''
+          tooltipContentHtml += '<div style="font-weight: bold;">' + iframe.contentWindow.document.querySelector('h1').innerHTML + '</div>'
+          tooltipContentHtml += iframe.contentWindow.document.querySelector('content').innerHTML
 
-        tooltipContent.innerHTML = tooltipContentHtml
+          tooltipContent.innerHTML = tooltipContentHtml
+          linkHistories[event.target.href] = tooltipContentHtml
 
+          tooltipWrapper.style.display = 'block';
+          setTimeout(function() {
+            tooltipWrapper.style.opacity = 1;
+          }, 1)
+        } 
+      } else {
+        tooltipContent.innerHTML = linkHistories[event.target.href]
         tooltipWrapper.style.display = 'block';
         setTimeout(function() {
           tooltipWrapper.style.opacity = 1;
         }, 1)
       }
 
+
       tooltipWrapper.style.left = elem_props.left - (tooltipWrapper.offsetWidth / 2) + (elem_props.width / 2) + "px";
       if ((window.innerHeight - elem_props.top) < (tooltipWrapper.offsetHeight)) {
           tooltipWrapper.style.top = elem_props.top + top - tooltipWrapper.offsetHeight - 10 + "px";
diff --git a/_notes/your-first-note.md b/_notes/your-first-note.md
index e7ca5cb..44d89aa 100644
--- a/_notes/your-first-note.md
+++ b/_notes/your-first-note.md
@@ -58,6 +58,8 @@ Notice in the "Notes mentioning this note" section that there is another note li
 
 If you're on a device with mouse support, try hovering your mouse on internal links to preview the notes: [[a note about cats]].
 
+Links that have been previewed will be cached to avoid redundant requests.
+
 ### Images and other Markdown goodies
 
 Finally, because you have the full power of Markdown in this template, you can use regular Markdown syntax for various formatting options.