Cannot play cached audio from service worker
<p><strong>Summary:</strong> Unable to cache <strong>and use</strong> the cached audio via a Service Worker.</p>

<hr>

<p><strong>Trying to:</strong> cache relatively small audio files (2-3mb) using service worker and cache API. These are loaded/played via a HTML Audio element, which usually sets a 'range' header.</p>

<p><strong>Problem:</strong> Service worker responds with the whole content, ignoring the range header, and the Audio element ignores the content and does not play.</p>

<p><strong>Without service worker:</strong> server obeys the range header, sends partial content, Audio element is happy and plays the audio.</p>

<p>I am using Google Chrome 52.</p>

<p><em>Note:</em> Solution appears to have been noted by <a href="https://github.com/whatwg/fetch/issues/144#issuecomment-151385725" rel="noreferrer">mnot "Serve range requests from a complete cache entry"</a> but has any browser implemented this? Or, is there any workaround??</p>

<hr>

<p><strong>Technical info</strong></p>

<p>Chrome terminal stderr: <code>[1:1:0603/164806:ERROR:render_media_log.cc(23)] MediaEvent: PIPELINE_ERROR demuxer: could not open</code></p>

<p>Chrome console error: <code>Uncaught (in promise) DOMException: The element has no supported sources.</code></p>

<p>Chrome headers (with SW, 2 parts):</p>

<pre><code>PART#1

GENERAL
Request URL:http://localhost:3333/audio.m4a
Request Method:GET
Status Code:200 OK (from ServiceWorker)
Remote Address:127.0.0.1:3333

RESPONSE
accept-ranges:bytes
connection:keep-alive
content-length:2449048
content-type:audio/x-m4a
date:Fri, 03 Jun 2016 10:14:02 GMT
etag:"56f8f953-255e98"
last-modified:Mon, 28 Mar 2016 09:28:51 GMT
server:nginx
x-content-type-options:nosniff
x-frame-options:SAMEORIGIN
x-xss-protection:1; mode=block

REQUEST
Provisional headers are shown
Accept-Encoding:identity;q=1, *;q=0
Range:bytes=0-
Referer:http://localhost:3333/
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.10 Safari/537.36

PART #2

GENERAL
Request URL:http://localhost:3333/audio.m4a
Request Method:GET
Status Code:200 OK (from ServiceWorker)
Remote Address:127.0.0.1:3333

RESPONSE
accept-ranges:bytes
connection:keep-alive
content-length:2449048
content-type:audio/x-m4a
date:Fri, 03 Jun 2016 10:14:02 GMT
etag:"56f8f953-255e98"
last-modified:Mon, 28 Mar 2016 09:28:51 GMT
server:nginx
x-content-type-options:nosniff
x-frame-options:SAMEORIGIN
x-xss-protection:1; mode=block

REQUEST
Provisional headers are shown
Accept-Encoding:identity;q=1, *;q=0
Range:bytes=2392064-
Referer:http://localhost:3333/
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.10 Safari/537.36
</code></pre>

<p>Chrome headers (without SW, 3 parts!):</p>

<pre><code>PART #1

GENERAL
Request URL:http://localhost:3333/audio.m4a
Request Method:GET
Status Code:206 Partial Content
Remote Address:127.0.0.1:3333

RESPONSE
Connection:keep-alive
Content-Length:2449048
Content-Range:bytes 0-2449047/2449048
Content-Type:audio/x-m4a
Date:Fri, 03 Jun 2016 10:24:32 GMT
ETag:"56f8f953-255e98"
Last-Modified:Mon, 28 Mar 2016 09:28:51 GMT
Server:nginx
X-Content-Type-Options:nosniff
X-Frame-Options:SAMEORIGIN
X-XSS-Protection:1; mode=block

REQUEST
Accept:*/*
Accept-Encoding:identity;q=1, *;q=0
Accept-Language:en-GB,en-US;q=0.8,en;q=0.6
Connection:keep-alive
Host:localhost:3333
Range:bytes=0-
Referer:http://localhost:3333/
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.10 Safari/537.36

PART #2

GENERAL
Request URL:http://localhost:3333/audio.m4a
Request Method:GET
Status Code:206 Partial Content
Remote Address:127.0.0.1:3333

RESPONSE
Connection:keep-alive
Content-Length:56984
Content-Range:bytes 2392064-2449047/2449048
Content-Type:audio/x-m4a
Date:Fri, 03 Jun 2016 10:24:32 GMT
ETag:"56f8f953-255e98"
Last-Modified:Mon, 28 Mar 2016 09:28:51 GMT
Server:nginx
X-Content-Type-Options:nosniff
X-Frame-Options:SAMEORIGIN
X-XSS-Protection:1; mode=block

REQUEST
Accept:*/*
Accept-Encoding:identity;q=1, *;q=0
Accept-Language:en-GB,en-US;q=0.8,en;q=0.6
Connection:keep-alive
Host:localhost:3333
If-Range:"56f8f953-255e98"
Range:bytes=2392064-2449047
Referer:http://localhost:3333/
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.10 Safari/537.36


PART #3

GENERAL
Request URL:http://localhost:3333/audio.m4a
Request Method:GET
Status Code:206 Partial Content
Remote Address:127.0.0.1:3333

RESPONSE
Content-Length:2121368
Content-Range:bytes 327680-2449047/2449048
Content-Type:audio/x-m4a
Date:Fri, 03 Jun 2016 10:24:32 GMT
ETag:"56f8f953-255e98"
Last-Modified:Mon, 28 Mar 2016 09:28:51 GMT
Server:nginx
X-Content-Type-Options:nosniff
X-Frame-Options:SAMEORIGIN
X-XSS-Protection:1; mode=block

REQUEST
Provisional headers are shown
Accept-Encoding:identity;q=1, *;q=0
Range:bytes=327680-
Referer:http://localhost:3333/
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.10 Safari/537.36
</code></pre>