feat(etag): add getBody option

[yusukebe]

Fixes #4031

This PR introduces a new option getBody for ETag middleware.

This will help customize the function to get the content to generate a hash in such a way on the AWS Lambda, which can't use c.res.clone().

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.32%. Comparing base (4a1dd5f) to head (27bead1).

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #4201    +/-   ##
========================================
  Coverage   91.31%   91.32%            
========================================
  Files         168      168            
  Lines       10791    10796     +5     
  Branches     3186     3070   -116     
========================================
+ Hits         9854     9859     +5     
  Misses        936      936            
  Partials        1        1            

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[github-actions]

Bundle size check

	main (4a1dd5f)	#4201 (6baa461)	+/-
Bundle Size (B)	19,027B	19,027B	0B
Bundle Size (KB)	18.58K	18.58K	0K

Compiler Diagnostics (typescript-go)

	main (4a1dd5f)	#4201 (6baa461)	+/-
Files	231	231	0
Lines	106,340	106,340	0
Identifiers	106,183	106,183	0
Symbols	371,551	371,551	0
Types	293,004	293,004	0
Instantiations	3,568,489	3,568,489	0
Memory used	229,864K	229,718K	-146K
Memory allocs	10,003,691	10,003,595	-96
Parse time	0.066s	0.071s	0.005s
Bind time	0.014s	0.041s	0.027s
Check time	1.343s	1.392s	0.049s
Emit time	0s	0s	0s
Total time	1.425s	1.508s	0.083s

---

Reported by octocov

[github-actions]

Bundle size check

	main (4a1dd5f)	#4201 (6baa461)	+/-
Bundle Size (B)	19,027B	19,027B	0B
Bundle Size (KB)	18.58K	18.58K	0K

Compiler Diagnostics (tsc)

	main (4a1dd5f)	#4201 (6baa461)	+/-
Files	261	261	0
Lines	116,441	116,441	0
Identifiers	114,443	114,443	0
Symbols	259,900	259,900	0
Types	162,567	162,567	0
Instantiations	3,039,293	3,039,293	0
Memory used	272,070K	272,866K	796K
I/O read	0.02s	0.02s	0s
I/O write	0s	0s	0s
Parse time	0.65s	0.65s	0s
Bind time	0.27s	0.27s	0s
Check time	3.74s	3.8s	0.06s
Emit time	0s	0s	0s
Total time	4.66s	4.72s	0.06s

---

Reported by octocov

[yusukebe]

@cjnoname Can you review this?

[cjnoname]

@cjnoname Can you review this?

Hey mate,

It doesn't work because once you consume the ArrayBuffer, the stream is no longer available—you'll need to recreate the request at that point.

This will work:

      let body: ArrayBuffer | ReadableStream<Uint8Array<ArrayBufferLike>> | null;
      if (options?.arrayBuffer) {
        body = await res.arrayBuffer();
        c.res = new Response(body, {
          status: res.status,
          statusText: res.statusText,
          headers: new Headers(res.headers)
        });
      } else {
        body = res.clone().body;
      }