satellite-provider/_docs/03_implementation/reviews/batch_04_review.md

Code Review Report

Batch: 4 (refactor 02-coupling-refactoring · Phase A) Tasks: AZ-310, AZ-311 Date: 2026-05-10 Verdict: PASS

Scope

Changed files:

• SatelliteProvider.Common/DTO/TileBytes.cs (new)
• SatelliteProvider.Common/Interfaces/ITileService.cs (added 2 methods)
• SatelliteProvider.Services/SatelliteProvider.Services.csproj (added Microsoft.Extensions.Caching.Memory 9.0.10)
• SatelliteProvider.Services/TileService.cs (added IMemoryCache dependency + 2 methods + private BuildTileEntity helper)
• SatelliteProvider.Api/Program.cs (thinned ServeTile and GetTileByLatLon; dropped IMemoryCache/ITileRepository/ISatelliteDownloader injections + redundant using directives)
• SatelliteProvider.Tests/SatelliteProvider.Tests.csproj (added Microsoft.Extensions.Caching.Memory 9.0.10)
• SatelliteProvider.Tests/TileServiceTests.cs (5 new tests; constructor helper takes optional IMemoryCache)
• SatelliteProvider.Tests/InfrastructureTests.cs (constructor signature update)

Phase 1 — Context

Both tasks target architecture-baseline F3 (endpoints bypass ITileService). Phase A of 02-coupling-refactoring consolidates tile-serving logic in TileService.

Phase 2 — Spec Compliance

AC	Status	Evidence
AZ-310 AC-1	Pass	Route preserved (Program.cs:113); response keeps image/jpeg, ETag, Cache-Control: public, max-age=86400
AZ-310 AC-2	Pass	GetOrDownloadTileAsync_CacheHit_ReturnsCachedBytes_AZ310_AC2 (downloader+repo strict-mock asserted untouched)
AZ-310 AC-3	Pass	GetOrDownloadTileAsync_RepoHit_ReadsFromDisk_NoDownloader_AZ310_AC3 (writes a real temp file, asserts no downloader call, no insert)
AZ-310 AC-4	Pass	GetOrDownloadTileAsync_DownloaderFallback_InsertsAndReturnsBytes_AZ310_AC4 (asserts insert + downloader call)
AZ-310 AC-5	Pass	ServeTile(int z, int x, int y, HttpContext, ITileService, ILogger<Program>) — no ISatelliteDownloader/ITileRepository/IMemoryCache
AZ-311 AC-1	Pass	Same route, same query params, same DownloadTileResponse shape; field-by-field projection in Program.cs:155-172
AZ-311 AC-2	Pass	DownloadAndStoreSingleTileAsync_HappyPath_… + …_DownloaderThrows_DoesNotInsert_… cover both branches
AZ-311 AC-3	Pass	GetTileByLatLon(... ITileService, ILogger<Program>) — no ISatelliteDownloader/ITileRepository

Constraints check (AZ-310):

• Cache lifetime: TimeSpan.FromHours(1) absolute + TimeSpan.FromMinutes(30) sliding — preserved verbatim.
• Cache key tile_{z}_{x}_{y}, ETag "{z}_{x}_{y}" — preserved verbatim.
• Cache-Control: public, max-age=86400 — built from TileResponseMaxAge = TimeSpan.FromDays(1) ((long)TotalSeconds = 86400).

Constraints check (AZ-311): query string and JSON shape unchanged.

Phase 3 — Code Quality

• SOLID: TileService now has 5 public methods, all single-responsibility. Private BuildTileEntity removes 3-fold duplication of TileEntity construction.
• Error handling: cancellation token propagates through every async boundary in the new methods. Endpoints still wrap with try/catch + Results.Problem.
• Tests use MockBehavior.Strict where it matters (cache-hit path) and explicit VerifyNoOtherCalls() to assert untouched dependencies.
• Naming: GetOrDownloadTileAsync and DownloadAndStoreSingleTileAsync accurately describe behavior.
• DRY: deduplication of TileEntity construction is a net win. Cache-key + ETag string formats are localized to one method (GetOrDownloadTileAsync); externalizing as constants would not improve readability for two-use values.

Phase 4 — Security Quick-Scan

No new SQL string concatenation, no new external input parsing, no secrets. TileBytes only carries bytes/headers.

Phase 5 — Performance Scan

Identical I/O pattern as pre-refactor — same number of cache lookups, DB queries, downloads, and file reads.

Phase 6 — Cross-Task Consistency

• AZ-310 and AZ-311 share BuildTileEntity — consistent entity construction.
• Both new methods accept CancellationToken cancellationToken = default — consistent signature style.
• Both endpoints follow same flat shape: validate (route binding) → call service → project → return.

Phase 7 — Architecture Compliance

• Layer direction: TileService (Layer 2) imports Microsoft.Extensions.Caching.Memory (system) — fine. ITileService stays in Common (Layer 1).
• Public API: no cross-component internal imports added.
• No new cycles.
• Layer 4 (Program.cs) no longer reaches into Layer 1 (ITileRepository) for tile serving / single-tile flow — the very thing baseline F3 flagged.
• Baseline F3 (Program.cs/ServeTile bypasses ITileService) is resolved by this batch. Documentation update happens in AZ-315.

Findings

None.

Verdict

PASS — no Critical, High, Medium, or Low findings. Build clean (0/0). Unit suite 40/40 green.