From 0299f4af97b2b8a3823c78937b7d86cab19518cb Mon Sep 17 00:00:00 2001
From: Rob Walch <rob@jwplayer.com>
Date: Thu, 25 Mar 2021 11:57:12 -0400
Subject: [PATCH 1/4] Disable CDN Tune-in "age" header check when
 `lowLatencyMode` is set to `false` Resolves #3680

---
 src/loader/playlist-loader.ts | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/loader/playlist-loader.ts b/src/loader/playlist-loader.ts
index 385f8575a79..72d10024ca6 100644
--- a/src/loader/playlist-loader.ts
+++ b/src/loader/playlist-loader.ts
@@ -686,13 +686,17 @@ class PlaylistLoader {
       return;
     }
 
-    // Avoid repeated browser error log `Refused to get unsafe header "age"` when unnecessary or past attempts failed
-    const checkAgeHeader = this.checkAgeHeader && levelDetails.live;
-    const ageHeader: string | null = checkAgeHeader
-      ? loader.getResponseHeader('age')
-      : null;
-    levelDetails.ageHeader = ageHeader ? parseFloat(ageHeader) : 0;
-    this.checkAgeHeader = !!ageHeader;
+    if (
+      this.checkAgeHeader &&
+      levelDetails.live &&
+      this.hls.config.lowLatencyMode
+    ) {
+      const ageHeader = loader.getResponseHeader('age');
+      levelDetails.ageHeader = ageHeader ? parseFloat(ageHeader) : 0;
+      // Avoid repeated browser error log `Refused to get unsafe header "age"` when unnecessary or past attempts failed
+      // Add an "Access-Control-Expose-Headers: age" header to playlist responses to prevent this CORS error
+      this.checkAgeHeader = ageHeader !== null;
+    }
 
     switch (type) {
       case PlaylistContextType.MANIFEST:

From 3a81d94750a56f9d829063a7fc56e1339d1d1f1c Mon Sep 17 00:00:00 2001
From: radiantmediaplayer <arnaud@radiantmediaplayer.com>
Date: Fri, 26 Mar 2021 12:08:33 +0100
Subject: [PATCH 2/4] fix Refused to get unsafe header "age" in Chrome

---
 src/loader/playlist-loader.ts | 3 +--
 src/utils/xhr-loader.ts       | 8 ++------
 2 files changed, 3 insertions(+), 8 deletions(-)

diff --git a/src/loader/playlist-loader.ts b/src/loader/playlist-loader.ts
index 72d10024ca6..ce6fe62fb23 100644
--- a/src/loader/playlist-loader.ts
+++ b/src/loader/playlist-loader.ts
@@ -688,8 +688,7 @@ class PlaylistLoader {
 
     if (
       this.checkAgeHeader &&
-      levelDetails.live &&
-      this.hls.config.lowLatencyMode
+      levelDetails.live
     ) {
       const ageHeader = loader.getResponseHeader('age');
       levelDetails.ageHeader = ageHeader ? parseFloat(ageHeader) : 0;
diff --git a/src/utils/xhr-loader.ts b/src/utils/xhr-loader.ts
index 530b60243dc..ce6f2605d19 100644
--- a/src/utils/xhr-loader.ts
+++ b/src/utils/xhr-loader.ts
@@ -250,12 +250,8 @@ class XhrLoader implements Loader<LoaderContext> {
   }
 
   getResponseHeader(name: string): string | null {
-    if (this.loader) {
-      try {
-        return this.loader.getResponseHeader(name);
-      } catch (error) {
-        /* Could not get headers */
-      }
+    if (this.loader && this.loader.getAllResponseHeaders().indexOf(name) >= 0) {
+      return this.loader.getResponseHeader(name);
     }
     return null;
   }

From 8c4865a34fc4ae1d6b8302cb822378bdd58e40b5 Mon Sep 17 00:00:00 2001
From: radiantmediaplayer <arnaud@radiantmediaplayer.com>
Date: Fri, 26 Mar 2021 15:19:44 +0100
Subject: [PATCH 3/4] Update playlist-loader.ts

---
 src/loader/playlist-loader.ts | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/loader/playlist-loader.ts b/src/loader/playlist-loader.ts
index ce6fe62fb23..ccbdeb607f2 100644
--- a/src/loader/playlist-loader.ts
+++ b/src/loader/playlist-loader.ts
@@ -686,10 +686,7 @@ class PlaylistLoader {
       return;
     }
 
-    if (
-      this.checkAgeHeader &&
-      levelDetails.live
-    ) {
+    if (this.checkAgeHeader && levelDetails.live) {
       const ageHeader = loader.getResponseHeader('age');
       levelDetails.ageHeader = ageHeader ? parseFloat(ageHeader) : 0;
       // Avoid repeated browser error log `Refused to get unsafe header "age"` when unnecessary or past attempts failed

From b9c427c43feee3a3d02443b09f27a636f1288b1a Mon Sep 17 00:00:00 2001
From: Rob Walch <rob@jwplayer.com>
Date: Fri, 26 Mar 2021 15:10:37 -0400
Subject: [PATCH 4/4] Safely read playlist response "age" header

---
 src/loader/playlist-loader.ts | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/loader/playlist-loader.ts b/src/loader/playlist-loader.ts
index ccbdeb607f2..4dfb45daac8 100644
--- a/src/loader/playlist-loader.ts
+++ b/src/loader/playlist-loader.ts
@@ -70,8 +70,6 @@ class PlaylistLoader {
     [key: string]: Loader<LoaderContext>;
   } = Object.create(null);
 
-  private checkAgeHeader: boolean = true;
-
   constructor(hls: Hls) {
     this.hls = hls;
     this.registerListeners();
@@ -148,7 +146,6 @@ class PlaylistLoader {
     data: ManifestLoadingData
   ) {
     const { url } = data;
-    this.checkAgeHeader = true;
     this.load({
       id: null,
       groupId: null,
@@ -686,12 +683,9 @@ class PlaylistLoader {
       return;
     }
 
-    if (this.checkAgeHeader && levelDetails.live) {
+    if (levelDetails.live) {
       const ageHeader = loader.getResponseHeader('age');
       levelDetails.ageHeader = ageHeader ? parseFloat(ageHeader) : 0;
-      // Avoid repeated browser error log `Refused to get unsafe header "age"` when unnecessary or past attempts failed
-      // Add an "Access-Control-Expose-Headers: age" header to playlist responses to prevent this CORS error
-      this.checkAgeHeader = ageHeader !== null;
     }
 
     switch (type) {