Webpagetest public instance does not support Early Hints

WebPageTest
1

If you look at the netlog on this page (evanella.org : Chro...irginia USA - EC2 - WebPageTest Result), you will see that there is an early hint (http status code 103) sent in response to the root html page:

netlog shows:

t= 922 [st= 98]          HTTP_TRANSACTION_READ_EARLY_HINTS_RESPONSE_HEADERS
                         --> HTTP/1.1 103
                             link: </style/JUNEBUG.woff2>;

I can then see the object (www.evanella.org/style/JUNEBUG.woff2) being downloaded successfully but when it goes to cache the object, I can see it gets immediately destroyed:

t=924 [st= 0] +SIMPLE_CACHE_ENTRY  [dt=69]
               --> entry_hash = "0x898fe646864da154"
t=924 [st= 0]    SIMPLE_CACHE_ENTRY_SET_KEY
                 --> key = "1/0/_dk_https://evanella.org https://evanella.org https://www.evanella.org/style/JUNEBUG.woff2"
t=924 [st= 0]    SIMPLE_CACHE_ENTRY_OPEN_OR_CREATE_CALL
t=924 [st= 0]    SIMPLE_CACHE_ENTRY_CREATE_OPTIMISTIC
t=924 [st= 0]    SIMPLE_CACHE_ENTRY_OPEN_OR_CREATE_BEGIN
t=928 [st= 4]    SIMPLE_CACHE_ENTRY_OPEN_OR_CREATE_END
t=991 [st=67]    SIMPLE_CACHE_ENTRY_DOOM_CALL
t=991 [st=67]    SIMPLE_CACHE_ENTRY_DOOM_BEGIN
t=991 [st=67]    SIMPLE_CACHE_ENTRY_CLOSE_CALL
t=992 [st=68]    SIMPLE_CACHE_ENTRY_DOOM_END
t=992 [st=68]    SIMPLE_CACHE_ENTRY_CLOSE_BEGIN
t=993 [st=69]    SIMPLE_CACHE_ENTRY_CLOSE_END
t=993 [st=69] -SIMPLE_CACHE_ENTRY

When the page later requests this object, it is not available. It seems to me like WebPageTest public instance doesn’t support 103 Early Hints.

Thoughts?

Peter

2

WebPageTest supports early hints fine. You can see the parsing of the response:

Screenshot 2023-09-06 at 7.19.12 AM
Screenshot 2023-09-06 at 7.19.12 AM1292×750 159 KB

You can also see in the waterfall that the requests are sent long before the HTML comes back. The question is “why is Chrome not using the early hint resources”. It does look like it uses some of them (the js, the image). The ones that it doesn’t use are all cache-control: no-store (which is likely why you see the cache entry being closed right away).

3

You are absolutely right. The object I was looking at had “no-store” set. Thank you!

Peter