Add cookie chunking support for sessions exceeding 4KB limit - #937
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sefasenturk95 wants to merge 2 commits into
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Add cookie chunking support for sessions exceeding 4KB limit#937sefasenturk95 wants to merge 2 commits into
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This adds optional cookie chunking to handle session data that exceeds
browser cookie size limits (~4KB). When enabled, large cookies are
automatically split into multiple smaller cookies and reconstructed
transparently when reading.
Features:
- Opt-in via chunking config: { enabled: true, chunkSize: 3500 }
- Automatic chunking when session exceeds chunk size
- Transparent reconstruction from chunks on read
- Automatic cleanup of old chunks on save/destroy
- Works with both Node.js req/res and CookieStore patterns
- Backward compatible with existing non-chunked sessions
Chunk naming pattern: {cookieName}.0, {cookieName}.1, etc.
Includes comprehensive test coverage with 6 new test cases.
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@sefasenturk95 is attempting to deploy a commit to the Codeagain Team on Vercel. A member of the Team first needs to authorize it. |
- Add type assertions (as any) to collectAllCookies calls to fix mock type mismatch - Add non-null assertions for array access in test assertions - Fixes prepare script errors during npm install
Author
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@vvo could you take a look at this please? :) Thanks in advance! |
Author
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@vvo hello? Anyone there? 🙈 |
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ThomasGross
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Jun 10, 2026
The Unilogin session (access + refresh + id token) overflows the 4096 byte browser cookie limit, breaking sign-in. Wrap iron-session's exported sealData/unsealData and split the seal across go-session.0, go-session.1, ... when it would otherwise exceed the limit. Mirrors the approach in the unmerged upstream PR vvo/iron-session#937 so we can drop the wrapper once that lands.
xendk
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Jun 10, 2026
The go-session cookie holds two JWTs (access + refresh) plus PKCE and profile fields, and we are hitting the 4 KB per-cookie browser limit for some users. Iron-session 8.0.4 has no built-in workaround and the upstream fix is unreviewed (vvo/iron-session#937). Apply that PR as a patch-package patch against an exact-pinned iron-session@8.0.4 so chunking is available without forking, and enable it in getSessionOptions. With chunking on, iron-session keeps a single go-session cookie when the sealed value fits, and otherwise splits it into go-session.0, go-session.1, ... transparently on read. Letting CI fail on a future Dependabot bump is the intended signal to refresh or drop the patch when upstream merges. To reproduce the patch file (iron-session ships only compiled dist/*, so we cannot patch the source files referenced by PR #937 directly): # 1. Get the iron-session source at v8.0.4 with PR #937 applied. git clone https://github.com/vvo/iron-session.git cd iron-session git fetch origin pull/937/head:pr-937 git diff v8.0.4..pr-937 -- src/core.ts > /tmp/pr-937-core.diff git checkout v8.0.4 git apply /tmp/pr-937-core.diff # 2. Build dist/* with the upstream toolchain. npm install --ignore-scripts npx tsup # 3. Copy the built dist into this project's node_modules and let # patch-package capture the diff against the published 8.0.4. cp dist/* <dpl-web>/go/node_modules/iron-session/dist/ cd <dpl-web>/go npx patch-package iron-session This keeps the committed patch bit-for-bit faithful to what upstream would publish if PR #937 merged, rather than hand-translating TypeScript changes into compiled output. Assisted-by: Claude <noreply@anthropic.com>
xendk
pushed a commit
to danskernesdigitalebibliotek/dpl-web
that referenced
this pull request
Jun 10, 2026
The go-session cookie holds two JWTs (access + refresh) plus PKCE and profile fields, and we are hitting the 4 KB per-cookie browser limit for some users. Iron-session 8.0.4 has no built-in workaround and the upstream fix is unreviewed (vvo/iron-session#937). Apply that PR as a patch-package patch against an exact-pinned iron-session@8.0.4 so chunking is available without forking, and enable it in getSessionOptions. With chunking on, iron-session keeps a single go-session cookie when the sealed value fits, and otherwise splits it into go-session.0, go-session.1, ... transparently on read. Letting CI fail on a future Dependabot bump is the intended signal to refresh or drop the patch when upstream merges. To reproduce the patch file (iron-session ships only compiled dist/*, so we cannot patch the source files referenced by PR #937 directly): # 1. Get the iron-session source at v8.0.4 with PR #937 applied. git clone https://github.com/vvo/iron-session.git cd iron-session git fetch origin pull/937/head:pr-937 git diff v8.0.4..pr-937 -- src/core.ts > /tmp/pr-937-core.diff git checkout v8.0.4 git apply /tmp/pr-937-core.diff # 2. Build dist/* with the upstream toolchain. npm install --ignore-scripts npx tsup # 3. Copy the built dist into this project's node_modules and let # patch-package capture the diff against the published 8.0.4. cp dist/* <dpl-web>/go/node_modules/iron-session/dist/ cd <dpl-web>/go npx patch-package iron-session This keeps the committed patch bit-for-bit faithful to what upstream would publish if PR #937 merged, rather than hand-translating TypeScript changes into compiled output. Assisted-by: Claude <noreply@anthropic.com>
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This PR adds optional cookie chunking to handle session data that exceeds browser cookie size limits (~4KB). When enabled, large cookies are automatically split into multiple smaller cookies and reconstructed transparently when reading.
Multiple users have reported hitting the 4096-byte cookie size limit with iron-session:
Currently, users hitting this limit must either:
This PR provides a third option: automatic cookie chunking for moderate-sized sessions that don't warrant the complexity of external storage.
Changes:
splitCookieIntoChunks()for splitting large cookiesreconstructCookie()andreconstructCookieWithStore()for transparent reassemblysave()method to handle chunking for both Node.js and CookieStore patternsdestroy()method to clean up all chunksDocumentation:
Testing:
Note: This PR addresses a common pain point while maintaining iron-session's stateless, cookie-based architecture. It's a middle-ground solution between "reduce your data" and "switch to Redis."