#921 Allow reading body multiple times

[andriy-dmytruk]

The proposed approach to do the same as in micronaut-projects/micronaut-gcp#1106 did not exactly work. This is because the InputEvent does not allow accessing the InputStream directly. Instead it has a method consumeBody(Function<InputStream>) that should be called with implementation similar to this:

<T> T consumeBody(Function<InputStream, T> function) {
      /* verify that not null and not opened twice ... */
      try {
          return function.call(this.body);
      } finally {
          this.body.close();
      }
      /* ... */
}

Because it closes the stream we cannot read the stream gradually and split it.

The solution is to read the stream as a whole into a byte array and then provide it to all the consumers. This will probably result in the same memory usage as in https://github.com/micronaut-projects/micronaut-gcp/pull/1106/files (since there we split each time and end up with one unused ByteBody caching the whole request). However, it will require reading the whole body before it is consumed (e.g. JSON parser cannot begin parsing the stream before whole body is read into memory).

[andriy-dmytruk]

It seems like with this fix: micronaut-projects/micronaut-servlet#740 we can have an implementation using InputStreamByteBody. Not sure if this is better now.

[yawkat]

@andriy-dmytruk PTAL. My byteBody approach is detailed in this comment: fd99aaa#diff-223b98dc29906194b0c41eeb83d19e55664789c8f55eca639a20b3e9c6ccdf51R114-R132

[andriy-dmytruk]

Cool, this is great!

[andriy-dmytruk]

Rebased on latest 4.1.x branch

[github-actions]

❌ Oracle Cloud CI 17 latest failed: https://ge.micronaut.io/s/cqqo3c6ixfpyi

[yawkat]

@graemerocher please review and merge

[github-actions]

❌ Oracle Cloud CI 17 latest failed: https://ge.micronaut.io/s/52tpddmkuystm

[graemerocher]

There are test failures

[yawkat]

seems there's still an issue with the FnBodyBinder, but that can be fixed in another pr. i've disabled the tck test again

[sonarqubecloud]

Quality Gate failed

Failed conditions
68.8% Coverage on New Code (required ≥ 70%)
1 New Blocker Issues (required ≤ 0)
1 New Critical Issues (required ≤ 0)
1 New Bugs (required ≤ 0)

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[andriy-dmytruk]

@graemerocher Can we merge?