DiunDashboard/.planning/phases/01-data-integrity/01-02-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
01-data-integrity	02	api	go http security testing maxbytesreader body-size-limit	phase provides 01-data-integrity plan 01 UPSERT fix and FK enforcement already applied; test file structure established	HTTP 413 response for oversized request bodies (>1MB) on WebhookHandler, TagsHandler POST, TagAssignmentHandler PUT/DELETE maxBodyBytes constant (1 << 20) and MaxBytesReader + errors.As pattern t.Fatalf at all 6 test setup call sites (no more silent test pass-on-setup-failure) 3 new oversized-body tests proving DATA-03 fixed	phase-02 (database refactor — handlers are now correct and hardened, test suite is reliable) any future handler additions that accept a body (pattern established)	added patterns MaxBytesReader + errors.As(*http.MaxBytesError) pattern for request body size limiting in handlers JSON-prefix oversized body test: use valid JSON opening so decoder reads past limit before MaxBytesReader triggers	created modified pkg/diunwebhook/diunwebhook.go pkg/diunwebhook/diunwebhook_test.go	Use MaxBytesReader wrapping r.Body before each JSON decode; distinguish 413 from 400 via errors.As on *http.MaxBytesError Oversized body test bodies must use valid JSON prefix (e.g. {"image":") + padding — all-x bodies trigger JSON parse error before MaxBytesReader limit is reached	MaxBytesReader body guard pattern: r.Body = http.MaxBytesReader(w, r.Body, maxBodyBytes) before decode, errors.As for 413 vs 400 Test setup errors must use t.Fatalf, never silent return	DATA-03 DATA-04	7min	2026-03-23

Phase 01 Plan 02: Body Size Limits and Test Setup Hardening Summary

Request body size limits (1MB cap, HTTP 413) added to four handler paths; six silent test-setup returns replaced with t.Fatalf to surface setup failures in CI

Performance

• Duration: 7 min
• Started: 2026-03-23T20:17:30Z
• Completed: 2026-03-23T20:24:37Z
• Tasks: 2
• Files modified: 2

Accomplishments

• Added maxBodyBytes constant and errors import to diunwebhook.go; applied http.MaxBytesReader + errors.As(*http.MaxBytesError) guard before JSON decode in WebhookHandler, TagsHandler POST, TagAssignmentHandler PUT and DELETE — returns HTTP 413 on body > 1MB
• Replaced 6 silent if err != nil { return } test setup patterns with t.Fatalf(...) so failing setup always fails the test, not silently passes
• Added 3 new oversized-body tests (TestWebhookHandler_OversizedBody, TestTagsHandler_OversizedBody, TestTagAssignmentHandler_OversizedBody); all pass with 413

Task Commits

Each task was committed atomically:

1. RED: add failing 413 tests - 311e91d (test)
2. Task 1: MaxBytesReader in handlers + GREEN test fix - 98dfd76 (feat)
3. Task 2: Replace silent returns with t.Fatalf - 7bdfc5f (fix)

Plan metadata: (docs commit — see below)

Note: TDD task 1 has a RED commit followed by a combined feat commit covering the implementation and the test body correction.

Files Created/Modified

• pkg/diunwebhook/diunwebhook.go — added errors import, maxBodyBytes constant, MaxBytesReader guards in 4 handler paths
• pkg/diunwebhook/diunwebhook_test.go — 3 new oversized-body tests; 6 t.Fatalf replacements

Decisions Made

• http.MaxBytesReader is applied per-handler (not via middleware) to match the existing no-middleware architecture
• Body limit set at 1MB (1 << 20) matching the plan spec
• Oversized body test bodies use a valid JSON prefix ({"image":" + padding) rather than all-x bytes — the JSON decoder reads only 1 byte of invalid content before failing, so all-x never triggers MaxBytesReader; a JSON string value causes the decoder to read the full field before the limit fires

Deviations from Plan

Auto-fixed Issues

1. [Rule 1 - Bug] Oversized body tests used all-x bytes; fixed to use valid JSON prefix

• Found during: Task 1 GREEN phase
• Issue: Test body make([]byte, 1<<20+1) filled with 'x' causes JSON decoder to fail at byte 1 with "invalid character" — MaxBytesReader never triggers because the read count never reaches the limit
• Fix: Changed test bodies to {"image":" (or {"name":") + bytes.Repeat([]byte("x"), 1<<20+1) so the decoder reads past 1MB before encountering an unterminated string
• Files modified: pkg/diunwebhook/diunwebhook_test.go
• Verification: All 3 oversized-body tests now pass with HTTP 413
• Committed in: 98dfd76 (Task 1 feat commit)

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Total deviations: 1 auto-fixed (Rule 1 - test bug) Impact on plan: The fix is necessary for tests to validate what they claim. No scope creep; the handler implementation is exactly as specified.

Issues Encountered

None beyond the test body deviation documented above.

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• DATA-03 and DATA-04 fixed; all Phase 01 plans complete
• Full test suite passes with 0 failures
• Handler hardening pattern (MaxBytesReader + errors.As) established for future handlers
• Ready to transition to Phase 02 (database refactor / PostgreSQL support)

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Phase: 01-data-integrity Completed: 2026-03-23