RFR: 8328919: Add BodyHandlers / BodySubscribers methods to handle excessive server input [v5]

[Daniel Fuchs]

On Wed, 15 Jan 2025 14:27:09 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Volkan Yazıcı has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove concurrency measures (methods are accessed serially due to the Reactive Streams spec)
>
> src/java.net.http/share/classes/java/net/http/HttpResponse.java line 757:
> 
>> 755:          * and passed to the given downstream {@code BodyHandler}}
>> 756:          * <p>
>> 757:          * If the number of bytes received exceeds the maximum number of bytes
> 
> Although the `BodyHandlers` and `BodySubscribers` already note that they are applicable for reponse bodies, should we be adding any clarification in this new API, stating that the limit applies only to the body after the headers are read (however big those may be in bytes)?

Maybe we could talk of "body bytes".

> src/java.net.http/share/classes/java/net/http/HttpResponse.java line 758:
> 
>> 756:          * <p>
>> 757:          * If the number of bytes received exceeds the maximum number of bytes
>> 758:          * desired as indicated by the given {@code capacity},
> 
> Should we consider simplifying this sentence to "If the number of bytes received exceeds the given {@code capacity}, ..."?

Good suggestion.

> src/java.net.http/share/classes/jdk/internal/net/http/LimitingSubscriber.java line 118:
> 
>> 116:     private boolean allocateLength(List<ByteBuffer> buffers) {
>> 117:         long bufferLength = buffers.stream().mapToLong(Buffer::remaining).sum();
>> 118:         long nextLength = Math.addExact(length, bufferLength);
> 
> `Math.addExact` throws a `ArithmeticException` if there's an overflow during the addition. In its current form, this code can end up propagating the exception from here. Instead we should add a try/catch block to catch it and return false (implying the capacity has exceeded).

Good catch!

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/23096#discussion_r1916810288
PR Review Comment: https://git.openjdk.org/jdk/pull/23096#discussion_r1916804438
PR Review Comment: https://git.openjdk.org/jdk/pull/23096#discussion_r1916807262