feat(analytics): gzip event batch body to bypass adblockers#1407
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feat(analytics): gzip event batch body to bypass adblockers#1407
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Adblockers were dropping /analytics/events/batch requests because the JSON body contains the substring "$click". The client now gzips the payload and sends it as application/octet-stream; the server's body schema gunzips via a yup .transform() before validation, and still accepts plain JSON for older SDK clients.
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📝 WalkthroughWalkthroughAccept gzipped JSON analytics batches as binary ( ChangesAnalytics Compression Support
Sequence Diagram(s)sequenceDiagram
participant Client as Client
participant Network as Network
participant Server as Server
participant Decompressor as Decompressor
participant DB as DB
Client->>Client: encodeAnalyticsBody(json) (optional gzip)
Client->>Network: POST /api/.../events/batch (body + Content-Type)
Network->>Server: deliver request
Server->>Decompressor: maybeDecodeBinaryBody(originalBody)
Decompressor-->>Server: parsed JSON or error
Server->>DB: insert events (on success)
DB-->>Server: insert result
Server-->>Network: HTTP 200 or 400
Network-->>Client: response
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~25 minutes
🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
✏️ Tip: You can configure your own custom pre-merge checks in the settings. ✨ Finishing Touches📝 Generate docstrings
🧪 Generate unit tests (beta)
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Greptile SummaryThis PR gzips the analytics event batch body before sending it to the server, preventing keyword-matching adblockers from silently dropping requests that contain tokens like
Confidence Score: 5/5Safe to merge — the gzip encoding path is well-guarded, the JSON back-compat path is untouched, and all error branches are covered by new tests. The server-side transform correctly propagates StatusError through yup's cast chain (non-ValidationError errors are re-thrown as-is in both yupValidate and validateSmartRequest), so the custom 400 messages reach the client intact. Size limits are enforced at the C++ layer via maxOutputLength. The client-side fallback for keepalive requests is intentional and well-documented. No logic errors, security gaps, or missing guards were found in the changed paths. No files require special attention. Important Files Changed
Reviews (2): Last reviewed commit: "Merge origin/dev into gzip-analytics-bat..." | Re-trigger Greptile |
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🧹 Nitpick comments (2)
packages/stack-shared/src/interface/client-interface.ts (1)
139-145: ⚡ Quick winSilent
catch {}violates the "NEVER try-catch-all" guidelineThe bare
catchswallows anyCompressionStreamruntime error without logging or surfacing it. The feature-unavailability case is already handled by the guard at line 136 (returns plain JSON whenCompressionStreamCtoris absent). Actual compression errors (e.g., mid-stream failure) should propagate; the outertry/catchinsendAnalyticsEventBatchalready converts them toResult.error, which is the correct silent-fail path for analytics.As per coding guidelines: "NEVER try-catch-all … Use
runAsynchronouslyorrunAsynchronouslyWithAlertinstead."♻️ Proposed fix — remove the internal catch and rely on the outer error boundary
- try { - const stream = new Blob([jsonBody]).stream().pipeThrough(new CompressionStreamCtor("gzip")); - const buffer = await new Response(stream).arrayBuffer(); - return { body: new Uint8Array(buffer), contentType: "application/octet-stream" }; - } catch { - return { body: jsonBody, contentType: "application/json" }; - } + const stream = new Blob([jsonBody]).stream().pipeThrough(new CompressionStreamCtor("gzip")); + const buffer = await new Response(stream).arrayBuffer(); + return { body: new Uint8Array(buffer), contentType: "application/octet-stream" };
sendAnalyticsEventBatchalready wraps the call intry { … } catch (e) { return Result.error(e) }, so a propagated compression error will be swallowed there rather than here — maintaining the silent-failure semantic for analytics without hiding the error path from the type system.🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@packages/stack-shared/src/interface/client-interface.ts` around lines 139 - 145, Remove the bare catch that swallows compression errors inside the blob-compression block and let exceptions propagate to the outer error boundary in sendAnalyticsEventBatch; specifically, in the block that uses CompressionStreamCtor to gzip the Blob (the try that creates `stream = new Blob([jsonBody]).stream().pipeThrough(new CompressionStreamCtor("gzip"))` and builds the Uint8Array), delete the internal catch so runtime compression failures surface to the existing try/catch in sendAnalyticsEventBatch (which converts them to Result.error), while keeping the earlier guard that handles missing CompressionStreamCtor and the fallback JSON return when that guard triggers.apps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.ts (1)
206-218: 💤 Low valueConsider using
toMatchInlineSnapshotfor consistency once the error body shape is confirmedThe other error-path tests all use
toMatchInlineSnapshot. This one asserts onlyres.status. Once you've run the test and seen the actual400body, locking it with an inline snapshot would align with the guideline ("prefer.toMatchInlineSnapshotover other selectors, if possible").🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@apps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.ts` around lines 206 - 218, The test "rejects a binary body that isn't valid gzip" only asserts res.status but other error-path tests use toMatchInlineSnapshot; update this test (the it block named "rejects a binary body that isn't valid gzip") to assert the full response body using expect(await res.json()).toMatchInlineSnapshot(...) (or expect(await res.text()...) if the body is text) after running the test once to capture the actual 400 response shape, and replace the current expect(res.status).toBe(400) with the inline snapshot assertion to keep consistency with the other error-path tests.
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@apps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.ts`:
- Around line 206-218: The test "rejects a binary body that isn't valid gzip"
only asserts res.status but other error-path tests use toMatchInlineSnapshot;
update this test (the it block named "rejects a binary body that isn't valid
gzip") to assert the full response body using expect(await
res.json()).toMatchInlineSnapshot(...) (or expect(await res.text()...) if the
body is text) after running the test once to capture the actual 400 response
shape, and replace the current expect(res.status).toBe(400) with the inline
snapshot assertion to keep consistency with the other error-path tests.
In `@packages/stack-shared/src/interface/client-interface.ts`:
- Around line 139-145: Remove the bare catch that swallows compression errors
inside the blob-compression block and let exceptions propagate to the outer
error boundary in sendAnalyticsEventBatch; specifically, in the block that uses
CompressionStreamCtor to gzip the Blob (the try that creates `stream = new
Blob([jsonBody]).stream().pipeThrough(new CompressionStreamCtor("gzip"))` and
builds the Uint8Array), delete the internal catch so runtime compression
failures surface to the existing try/catch in sendAnalyticsEventBatch (which
converts them to Result.error), while keeping the earlier guard that handles
missing CompressionStreamCtor and the fallback JSON return when that guard
triggers.
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: 0abc892c-5217-4f5c-a2b3-32a49009cc75
📒 Files selected for processing (4)
apps/backend/src/app/api/latest/analytics/events/batch/route.tsxapps/e2e/tests/backend/backend-helpers.tsapps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.tspackages/stack-shared/src/interface/client-interface.ts
- Remove inner try/catch in encodeAnalyticsBody; runtime compression errors now propagate to the existing Result.error in sendAnalyticsEventBatch instead of being swallowed silently. - Convert the invalid-gzip test to toMatchInlineSnapshot for parity with other error-path tests. - Add a regression test that gzips a 9 MB zero buffer to exercise the MAX_DECOMPRESSED_BYTES guard.
Unintentional drift from a mid-task file rewrite — the literal U+FFFD character was written into the source instead of the original � escape. Functionally identical, but restores the original bytes.
mantrakp04
requested changes
May 5, 2026
- Skip gzip when keepalive=true: pagehide/visibilitychange flushes must dispatch fetch synchronously before page tear-down; awaiting async compression first lets the browser cancel the request. - Re-add a runtime fallback in encodeAnalyticsBody so partial/broken CompressionStream support falls back to plain JSON instead of dropping the batch via Result.error. - Add e2e regression test for the MAX_COMPRESSED_BYTES (1 MB) cap. - Add unit tests in client-interface.test.ts covering gzip happy path, missing CompressionStream, keepalive skip, and runtime compression error. - Throw in niceBackendFetch when rawContentType is provided without rawBody, mirroring the body/rawBody guard.
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Actionable comments posted: 1
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@apps/e2e/tests/backend/backend-helpers.ts`:
- Line 158: Remove the unnecessary type cast on rawBody in the request options
object: rawBody is already a Uint8Array (an ArrayBufferView) and is assignable
to BodyInit, so drop the "as BodyInit" cast and return the object with body:
rawBody when rawBody !== undefined; update the expression that currently reads
"...rawBody !== undefined ? { body: rawBody as BodyInit } : {}" to use rawBody
directly to satisfy the no-cast guideline and preserve typing.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: a2e48ceb-9b48-430b-bd0d-ed0c98292047
📒 Files selected for processing (4)
apps/e2e/tests/backend/backend-helpers.tsapps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.tspackages/stack-shared/src/interface/client-interface.test.tspackages/stack-shared/src/interface/client-interface.ts
🚧 Files skipped from review as they are similar to previous changes (1)
- packages/stack-shared/src/interface/client-interface.ts
Contributor
There was a problem hiding this comment.
Actionable comments posted: 1
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@packages/stack-shared/src/interface/client-interface.ts`:
- Around line 148-156: The catch is too broad and hides unexpected errors;
change the bare catch to catch (err) and only swallow expected
compression-support failures (e.g., err instanceof TypeError or (typeof
DOMException !== "undefined" && err instanceof DOMException) or err.name ===
"NotSupportedError"/"TypeError"), then return the JSON fallback (body: jsonBody,
contentType: "application/json"); for any other error rethrow it so failures in
stream creation or response handling are not silently ignored. Reference the
CompressionStreamCtor/stream/new Response(jsonBody) block and
EventTracker._flush() fallback behavior when applying this check.
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
ℹ️ Review info
⚙️ Run configuration
Configuration used: defaults
Review profile: CHILL
Plan: Pro
Run ID: e6bd7ae7-9da5-426e-8aff-5e14b8daa352
📒 Files selected for processing (4)
apps/backend/src/app/api/latest/analytics/events/batch/route.tsxapps/e2e/tests/backend/backend-helpers.tsapps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.tspackages/stack-shared/src/interface/client-interface.ts
🚧 Files skipped from review as they are similar to previous changes (2)
- apps/backend/src/app/api/latest/analytics/events/batch/route.tsx
- apps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.ts
mantrakp04
approved these changes
May 5, 2026
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Summary
The
POST /api/latest/analytics/events/batchendpoint was being dropped by content-blocking browser extensions (adblockers) because the JSON request body literally contains the substring$click. Many filter lists pattern-match on tokens like that and silently kill the request — analytics events from anyone with an adblocker enabled never reached our backend.This PR encodes the request body so keyword-matching filters can't see those tokens, while keeping the URL path unchanged (only the body was being matched here) and keeping older SDK clients working.
Approach
CompressionStream("gzip")API and POST it asapplication/octet-stream. Falls back to plain JSON ifCompressionStreamisn't available (very old browsers / non-browser runtimes)..transform()on the body schema detects anArrayBuffer/Uint8Arrayinput, gunzips it, andJSON.parses before normal schema validation runs. The existing JSON path is untouched, so requests from older SDK versions in the wild continue to work without changes — and all existing schema-error snapshot tests still pass verbatim.node:zlib'smaxOutputLengthenforces the latter at the C++ layer.Bonus: gzip also gives a meaningful bandwidth win — click/page-view events compress very well — and keepalive bodies (which have a 64 KB cap in browsers) get more headroom.
Files
apps/backend/src/app/api/latest/analytics/events/batch/route.tsx— body schema gains.transform()that gunzips binary inputs; size limits added; everything else unchanged.packages/stack-shared/src/interface/client-interface.ts—sendAnalyticsEventBatchnow routes through a new module-levelencodeAnalyticsBodyhelper that gzips and switches Content-Type. Same outer signature; encoding is internal.apps/e2e/tests/backend/backend-helpers.ts—niceBackendFetchgains optionalrawBody/rawContentTypeparams so tests can send non-JSON payloads. Existing JSON callers unaffected.apps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.ts— adds two tests:inserted: 1Out of scope (intentional)
/analytics/, but some do. We're shipping the body fix first and will revisit if requests still get blocked after deployment.client-interface.ts(instack-shared) was touched;event-tracker.ts(the caller) is unchanged because it already passes a JSON string. Nopnpm -w run generate-sdksneeded.Test plan
pnpm typecheck— greenpnpm lint— greenanalytics_internal.eventsshows the expected rowspnpm test run apps/e2e/tests/backend/endpoints/api/v1/analytics-events-batch.test.ts) and confirm both new cases plus all preexisting snapshots passSummary by CodeRabbit
New Features
Bug Fixes
Tests