fix: add silent=True and validation to /epoch/enroll JSON parsing

[BossChaos]

Security Fix

The /epoch/enroll endpoint used request.get_json() without silent=True, causing a 400 BadRequest on non-JSON Content-Type headers.
Additionally, there was no isinstance check to validate the parsed data is a dict before calling .get() on it.

Impact

• Sending Content-Type: text/plain with POST /epoch/enroll causes 400
• Sending a JSON array [] crashes with AttributeError on .get()

Fix

• Added silent=True to request.get_json()
• Added isinstance(data, dict) check with proper 400 response

Testing

Verified that the endpoint now returns a proper 400 error for invalid Content-Types and JSON arrays instead of raising unhandled exceptions.

---

RTC Wallet: RTC6d1f27d28961279f1034d9561c2403697eb55602

[saim256]

Approved current head 7206822.

This is a narrow, correct hardening for /epoch/enroll: the route now uses request.get_json(silent=True) and rejects non-dict payloads before calling .get(), so malformed/non-object JSON no longer reaches the field-access path.

Validation performed locally:

• git diff --check origin/main...HEAD -- node/rustchain_v2_integrated_v2.2.1_rip200.py
• python -m py_compile node\rustchain_v2_integrated_v2.2.1_rip200.py
• python tools\bcos_spdx_check.py --base-ref origin/main
• manual line/diff review around /epoch/enroll

Caveats:

• This overlaps with open PR #4808, which applies the same pattern to /epoch/enroll plus several other JSON parsing routes, so maintainers should merge only one compatible version of this change.
• python -m ruff check node\rustchain_v2_integrated_v2.2.1_rip200.py --select E9,F821,F811 --output-format=concise still reports pre-existing issues already present on origin/main in this large integrated file (json/send_file redefinitions plus undefined log, miners, and status). This PR does not introduce those findings.

No production node or external endpoint was exercised.

[strongkeep-debug]

Approved current head 7206822.

I checked the changed /epoch/enroll path with a Flask test client. The new silent=True plus dict guard returns the intended 400 {"error": "Invalid JSON body"} for wrong content type, JSON arrays, and malformed JSON before the later enrollment, signature, or attestation-gate logic runs. The touched hunk is narrow and leaves valid dict payload handling on the existing path.

Validation run locally:

• python -m py_compile node\rustchain_v2_integrated_v2.2.1_rip200.py
• git diff --check origin/main...HEAD -- node\rustchain_v2_integrated_v2.2.1_rip200.py
• python tools\bcos_spdx_check.py --base-ref origin/main
• Flask test-client smoke for text/plain, JSON array [], and malformed JSON bodies; all returned the same 400 JSON body.
• uv run --no-project --with ruff python -m ruff check node\rustchain_v2_integrated_v2.2.1_rip200.py --select E9,F821,F811 --output-format=concise still reports the pre-existing large-file issues outside this diff (json/send_file redefinitions and undefined log/miners/status).

Caveat: this overlaps with #4808, so maintainers should merge only one compatible JSON-hardening version. No live node or external endpoint was exercised.

[godd-ctrl]

Approved current head 7206822 after reviewing the /epoch/enroll JSON parsing hardening. The route now calls request.get_json(silent=True) and rejects non-dict payloads before any .get() calls, so malformed JSON, wrong content types, and JSON arrays stay on a controlled 400 Invalid JSON body path instead of reaching enrollment logic. Validation: python -m py_compile node\rustchain_v2_integrated_v2.2.1_rip200.py -> passed; git diff --check origin/main...HEAD -- node\rustchain_v2_integrated_v2.2.1_rip200.py -> passed; python tools\bcos_spdx_check.py --base-ref origin/main -> OK. Targeted Ruff E9/F821/F811 still reports the same pre-existing integrated-file findings outside this one-line route change. Caveat: this overlaps with #4808, so maintainers should merge only one compatible JSON-hardening version. No live node, wallet, or production endpoint was exercised.

[loganoe]

Approved. The endpoint now uses request.get_json(silent=True) and rejects non-dict parsed bodies before calling .get(), so both invalid content types and JSON arrays return controlled 400 responses instead of Flask/parser exceptions or AttributeError.

Validation performed: git diff --check origin/main...HEAD, python3 -m py_compile node/rustchain_v2_integrated_v2.2.1_rip200.py, python3 tools/bcos_spdx_check.py --base-ref origin/main, and a Flask test-client smoke test for text/plain, JSON array, and empty-object /epoch/enroll requests.

[508704820]

Code Review: Add silent=True and Validation to /epoch/enroll JSON Parsing

Adds silent=True to prevent HTTP 500 on malformed JSON, and isinstance(data, dict) validation to reject non-object payloads.

Approve — consistent with #4871 pattern.

[shuibui]

Code Review: Approve

Good fix.

**Verdict: Approve.

[TJCurnutte]

Approved. The endpoint now handles malformed or non-object JSON explicitly instead of relying on Flask's default parse exception or crashing on .get().

Validation performed:

• Reviewed the focused change in /epoch/enroll.
• Confirmed request.get_json(silent=True) is used and a non-dict body now returns 400 {"error": "Invalid JSON body"} before any .get() calls.
• Ran git diff --check origin/main...HEAD on the PR branch: passed.
• Ran python3 -m py_compile node/rustchain_v2_integrated_v2.2.1_rip200.py: passed.

This is a reasonable fail-closed input-validation fix for the enroll route.