Range requests: Make status/range verification optional

Verifying media responses performs 3 verifications: * The response should also be a range response * The response's range should match the request's range * There should not be mixed origins with opaque response While the last verification is mandatory for same-origin policy, the first two are optional, and may be skipped if the user-agent decides to be lenient towards servers who don't handle range requests properly. See #7655 (comment)
whatwg · Apr 11, 2022 · 9accf7d · 9accf7d
1 parent 64d4e4d
commit 9accf7d
Showing 1 changed file with 30 additions and 14 deletions.
diff --git a/source b/source
@@ -34690,16 +34690,22 @@ interface <dfn interface>MediaError</dfn> {
   (number, number or "<code data-x="">until end</code>") tuple <var>byteRange</var>:</p>
 
   <ol>
-   <li><p>If <var>response</var> is a <span>network error</span>, then return false.</p></li>
-
-   <li><p>If <var>byteRange</var> is "<code data-x="">entire resource</code>", then return
-   true.</p></li>
+   <li><p>If <var>response</var> is a <span>network error</span>, then return
+   "<code data-x="">failure</code>".</p></li>
 
    <li><p>Let <var>internalResponse</var> be <var>response</var>'s
    <span>unsafe response</span>.</p></li>
 
    <li><p>If <var>internalResponse</var>'s <span data-x="concept-response-status">status</span> is
-   not 206, then return false.</p></li>
+   neither 200 or 206, then return "<code data-x="">failure</code>".</p></li>
+
+   <li><p>If <var>internalResponse</var>'s <span data-x="concept-response-status">status</span> is
+   200, then: If <var>byteRange</var> is "<code data-x="">entire resource</code>" then return
+   "<code data-x="">success</code>". Otherwise return
+   "<code data-x="">range not supported</code>".</p></li>
+
+   <li><p>If <var>byteRange</var> is "<code data-x="">entire resource</code>" then set
+   <var>byteRange</var> to (0, "<code data-x="">until end</code>").</p></li>
 
    <li><p>Let <var>origin</var> be "<code data-x="">rewritten</code>" if
    <var>internalResponse</var>'s <span data-x="concept-response-url">URL</span> is null; otherwise
@@ -34724,7 +34730,8 @@ interface <dfn interface>MediaError</dfn> {
     <p>then set <var>resource</var>'s <span data-x="media-resource-origin">origin</span> to
     <var>origin</var>.</p>
 
-    <p>Otherwise, if <var>response</var> is <span>CORS-cross-origin</span>, then return false.</p>
+    <p>Otherwise, if <var>response</var> is <span>CORS-cross-origin</span>, then return
+    "<code data-x="">failure</code>".</p>
 
     <p>Otherwise, set <var>resource</var>'s <span data-x="media-resource-origin">origin</span> to
     "<code data-x="">multiple</code>".</p>
@@ -34739,9 +34746,9 @@ interface <dfn interface>MediaError</dfn> {
 
    <li><p>If <var>start</var> is not <var>byteRange</var>[0], or if
    <var>byteRange</var>[1] is neither "<code data-x="">until end</code>" or <var>end</var>,
-   return false.</p></li>
+   return "<code data-x="">range mismatch</code>".</p></li>
 
-   <li><p>Return true.</p></li>
+   <li><p>Return "<code data-x="">success</code>".</p></li>
   </ol>
 
   <p>The <dfn data-x="concept-media-load-resource" export>resource fetch algorithm</dfn> for a
@@ -34878,12 +34885,21 @@ interface <dfn interface>MediaError</dfn> {
           </ol>
          </li>
 
-         <li><p>If the result of <span data-x="verify a media response">verifying</span>
-         <var>response</var> given the <var>current media resource</var> and
-         <var>byteRange</var> is false, then call <var>finalize</var>. Otherwise,
-         <span data-x="body-incrementally-read">incrementally read</span> <var>response</var>'s
-         <span data-x="concept-response-body">body</span> given <var>updateMedia</var>,
-         <var>processEndOfMedia</var>, <var>finalize</var>, and <var>global</var>.</p></li>
+         <li>
+          <p>If the result of
+          <span data-x="verify a media response">verifying</span> <var>response</var> given the
+          <var>current media resource</var> and <var>byteRange</var> is
+          "<code data-x="">failure</code>", then call <var>finalize</var>. Otherwise,
+          <span data-x="body-incrementally-read">incrementally read</span>
+          <var>response</var>'s <span data-x="concept-response-body">body</span> given
+          <var>updateMedia</var>, <var>processEndOfMedia</var>, <var>finalize</var>, and
+          <var>global</var>.</p>
+
+          <p>User-agents may also treat "<code data-x="">range mismatch</code>" and
+          "<code data-x="">range not supported</code>" as failures. Supporting media loading from
+          servers without proper support for HTTP range requests requires buffering on the client
+          side, which might have implications on performance and memory use.</p>
+         </li>
 
          <li><p>Update the <span>media data</span> with the contents of <var>response</var>'s
          <span>unsafe response</span> obtained in this fashion. <var>response</var> can be