Issue with HTTP/2 communicating with GCP servers with TE: Trailers

[Jaikiran Pai]

On 15/05/21 5:32 pm, Jaikiran Pai wrote:
>
> On 15/05/21 5:13 pm, Jaikiran Pai wrote:
>> Hello Krzysztof,
>>
>> On 15/05/21 1:07 am, Krzysztof K. wrote:
>>> Hi,
>>> I have an issue using http client communicating with servers that 
>>> most probably are on GCP (I see header: "via: 1.1 google").
>>>
>>> I get "java.io.IOException: Received RST_STREAM: Protocol error".
>>> ...
>>>
>>> But I'm on JDK 16 (build 16+35-2229) and I get this error when 
>>> connecting to a website when I use the header "TE: Trailers" (needs 
>>> first letter capitalized).
>>>
>>> When I remove this header everything works, if I switch to HTTP 1.1 
>>> (with that header) it also works.
>>>
>>> Here is a minimal reproducible example:
>>>
>>> HttpClient.newBuilder()
>>>   .build()
>>>   .send(
>>>     HttpRequest.newBuilder()
>>>     .header("TE", "Trailers")
>>
>> IMO, this is more of an application issue than the JDK. In HTTP/2 the 
>> TE header[1] is expected to only have the value "trailers" (case 
>> sensitive) as noted here[2]. If you change your code to use 
>> "trailers" instead of "Trailers" it works (as you seem to have 
>> noticed). As for why it works in Firefox or curl, I'm not sure - 
>> perhaps they have special handling of this specific header to lower 
>> case its value if it's "Trailers"?
>
> A quick check of the curl source code[1] suggests that it does indeed 
> do special handling of this TE request param[2].

I meant request header.

-Jaikiran