From 7f82f53d49ffff6468b0aacdc6e96b8e7a1e8332 Mon Sep 17 00:00:00 2001
From: Brandon Casey <2381475+brandonocasey@users.noreply.github.com>
Date: Wed, 20 Jan 2021 10:31:06 -0500
Subject: [PATCH] feat: add support for #EXT-X-SERVER-CONTROL (#121)

https://developer.apple.com/documentation/http_live_streaming/enabling_low-latency_hls#3281374
https://tools.ietf.org/html/draft-pantos-hls-rfc8216bis-08#section-4.4.3.8
---
 src/parse-stream.js                | 22 ++++++++++++++++++++++
 src/parser.js                      |  3 +++
 test/fixtures/m3u8/llhls.json      |  7 +++++++
 test/fixtures/m3u8/llhlsDelta.json |  7 +++++++
 4 files changed, 39 insertions(+)

diff --git a/src/parse-stream.js b/src/parse-stream.js
index 6633d12..47c7dc7 100644
--- a/src/parse-stream.js
+++ b/src/parse-stream.js
@@ -498,6 +498,28 @@ export default class ParseStream extends Stream {
         this.trigger('data', event);
         return;
       }
+      match = (/^#EXT-X-SERVER-CONTROL:(.*)$/).exec(newLine);
+      if (match && match[1]) {
+        event = {
+          type: 'tag',
+          tagType: 'server-control'
+        };
+        event.attributes = parseAttributes(match[1]);
+        ['CAN-SKIP-UNTIL', 'PART-HOLD-BACK', 'HOLD-BACK'].forEach(function(key) {
+          if (event.attributes.hasOwnProperty(key)) {
+            event.attributes[key] = parseFloat(event.attributes[key]);
+          }
+        });
+
+        ['CAN-SKIP-DATERANGES', 'CAN-BLOCK-RELOAD'].forEach(function(key) {
+          if (event.attributes.hasOwnProperty(key)) {
+            event.attributes[key] = (/YES/).test(event.attributes[key]);
+          }
+        });
+
+        this.trigger('data', event);
+        return;
+      }
 
       match = (/^#EXT-X-PRELOAD-HINT:(.*)$/).exec(newLine);
       if (match && match[1]) {
diff --git a/src/parser.js b/src/parser.js
index f0c542f..bdf3538 100644
--- a/src/parser.js
+++ b/src/parser.js
@@ -391,6 +391,9 @@ export default class Parser extends Stream {
               this.manifest.parts = this.manifest.parts || [];
               this.manifest.parts.push(entry.attributes);
             },
+            'server-control'() {
+              this.manifest.serverControl = entry.attributes;
+            },
             'preload-hint'() {
               this.manifest.preloadHints = this.manifest.preloadHints || [];
               this.manifest.preloadHints.push(entry.attributes);
diff --git a/test/fixtures/m3u8/llhls.json b/test/fixtures/m3u8/llhls.json
index a034553..378ba6c 100644
--- a/test/fixtures/m3u8/llhls.json
+++ b/test/fixtures/m3u8/llhls.json
@@ -187,5 +187,12 @@
       "uri": "fileSequence272.mp4"
     }
   ],
+  "serverControl": {
+    "CAN-SKIP-DATERANGES": true,
+    "CAN-BLOCK-RELOAD": true,
+    "CAN-SKIP-UNTIL": 12,
+    "PART-HOLD-BACK": 1,
+    "HOLD-BACK": 2
+  },
   "targetDuration": 4
 }
diff --git a/test/fixtures/m3u8/llhlsDelta.json b/test/fixtures/m3u8/llhlsDelta.json
index 9272e3c..0caee88 100644
--- a/test/fixtures/m3u8/llhlsDelta.json
+++ b/test/fixtures/m3u8/llhlsDelta.json
@@ -160,5 +160,12 @@
       "bar"
     ]
   },
+  "serverControl": {
+    "CAN-SKIP-DATERANGES": true,
+    "CAN-BLOCK-RELOAD": true,
+    "CAN-SKIP-UNTIL": 12,
+    "PART-HOLD-BACK": 1,
+    "HOLD-BACK": 2
+  },
   "targetDuration": 4
 }