GET /api/v3/cards?ids= accepts at most 20 ids. Above that the request
fails with 400 "each value in ids must be a mongodb id" — which blames
the ids when the real problem is how many there are. Express/NestJS
parse the query string with qs, whose default arrayLimit is 20; past it
the repeated params stop being an array and become an object keyed "0",
"1", …, and @IsMongoId({ each: true }) then rejects every value.
I had chunked at 40, having read the controller and its DTO and found no
documented ceiling. The limit is not there — it is in the query parser
underneath them, which I did not think to check. Verified live: 20 ids
return 200, 21 return 400 with identical ids.
The worse half of this was mine alone. The crawler caught assembleBoard
failures and dropped them, so every board over 20 cards vanished from
the index while the crawl reported "failures: none". Board errors now go
into Snapshot.failures and are surfaced by refresh_index.
Impact of both fixes on a full re-crawl: 205 files -> 255, and the
reported board (27 cards, 18 files) reads fully. The two failures that
remain are genuine 403s — boards this account cannot see — and are now
visible rather than silent.
Thanks to the bug report, which had the root cause exactly right.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
7.9 KiB
The Schulcloud API, as verified against this instance
Everything here was confirmed against https://schulcloud-thueringen.de with a
real student account on 2026-09-11, not inferred from source. Where upstream
source and live behaviour disagreed, live behaviour won.
Two services, one origin
| Service | Source repo | Base path | Self-documenting at |
|---|---|---|---|
| Main server (NestJS) | schulcloud-server |
/api/v3/ |
/api/v3/docs, /api/v3/docs-json |
| Files storage | file-storage |
/api/v3/file/ |
/api/v3/file/docs, /api/v3/file/docs-json |
Both accept the same bearer token. The files service was split out of
schulcloud-server into its own repository, which is why no file paths
appear in the main docs-json — a detail that will send you in circles if you
only read the main spec. Fetch both:
curl -s "$TSC_URL/api/v3/docs-json" -o docs-v3.json # 212 paths
curl -s "$TSC_URL/api/v3/file/docs-json" -o docs-file.json # 26 paths
These are the authoritative reference for this instance's deployed version.
Prefer them over the GitHub sources, which track main and may be ahead.
Which repositories matter
The hpi-schul-cloud org has ~100 repos, most archived or superseded. The live
ones relevant here:
schulcloud-server— the API. Readapps/server/src/modules/<module>/api/for controllers and DTOs.file-storage— the files service, extracted from the above.src/modules/files-storage/api/controller/files-storage.controller.tsis the whole surface.nuxt-client— the current web front end. Useful for seeing which API calls the real UI makes in which order.schulcloud-client— the legacy Handlebars front end. Still receives commits, but it is not where new features land.
Superseded/archived and worth ignoring: authorization-service,
schulcloud-editor, nexboard-api-js, end-to-end-tests, docker-compose,
H5P-Nodejs-library, shd-client.
Note the naming: /api/v1 is the old Feathers surface. On this instance
/api/v1/docs 404s, and the v3 NestJS API covers everything this server needs.
Content model
Course ─┬─ column board ─── column ─── card ─── element ─┬─ richText
│ ├─ file ──── fileRecord(s)
│ ├─ link
│ └─ …
├─ lesson (Thema) ─── contents[] + materials[]
└─ task (Aufgabe) ─── description + fileRecord(s)
On the account this was built against: 26 courses holding 30 column boards, 18 lessons, 42 tasks and 175 files. Column boards hold the great majority of current material; lessons are the older format.
Endpoints this server uses
| Purpose | Call |
|---|---|
| Identity, school id, permissions | GET /api/v3/me |
| Courses | GET /api/v3/courses?skip&limit |
| One course's contents | GET /api/v3/course-rooms/{courseId}/board |
| Dashboard tiles | GET /api/v3/dashboard |
| Tasks | GET /api/v3/tasks, GET /api/v3/tasks/finished |
| Lesson body | GET /api/v3/lessons/{lessonId} |
| Lesson's tasks | GET /api/v3/lessons/{lessonId}/tasks |
| Board structure | GET /api/v3/boards/{boardId} |
| What a board belongs to | GET /api/v3/boards/{boardId}/context |
| Card bodies | GET /api/v3/cards?ids=<id>&ids=<id> |
| Files of an entity | GET /api/v3/file/list/{storageLocation}/{storageLocationId}/{parentType}/{parentId} |
| One file's metadata | GET /api/v3/file/{fileRecordId} |
| File bytes | GET /api/v3/file/download/{fileRecordId}/{fileName} |
| News | GET /api/v3/news |
| Instance settings (no auth) | GET /api/v3/config/public |
| Remaining idle budget | POST /api/v3/authentication/refresh-session → {expiresInSeconds} |
Gotchas that cost real time
course-rooms, not courses, for course contents. GET /api/v3/courses/{id}
does not exist. The route that returns a course's lessons/tasks/boards is
GET /api/v3/course-rooms/{roomId}/board, and its :roomId is the course id.
Nothing in the naming suggests this.
/api/v3/rooms is a different feature. "Rooms" are the newer standalone
collaboration spaces, unrelated to courses. On this instance the account has
none, so GET /api/v3/rooms returns {"data":[]} — which reads like a broken
endpoint but is simply an empty feature.
limit maxima are enforced and mis-documented. The OpenAPI schema says
maximum: 99; the runtime validator rejects anything > 100. Page at 99 to
satisfy both. Asking for 200 returns a 400 API_VALIDATION_ERROR, not a
truncated list.
There is no GET /tasks/{id}. Single-task detail has to be assembled: the
list endpoints give metadata but omit description, which appears only on the
course page's task element. get_task does this join.
Board files need three calls. A file element's content carries only
{caption, alternativeText} — no file id. The bytes are found by listing
files-storage with parentType: 'boardnodes' and the element id as
parentId. This is the single least discoverable part of the API, and applies
equally to fileFolder and drawing elements.
GET /cards?ids= accepts at most 20 ids. Above that the request fails with
400 "each value in ids must be a mongodb id" — blaming the ids when the real
problem is how many there are. Express/NestJS parse the query string with qs,
whose default arrayLimit is 20; past it, repeated params become an object
keyed "0", "1", … and @IsMongoId({ each: true }) then rejects every value.
Nothing in the controller or its DTO says so: the limit lives in the query
parser underneath them. Verified live — 20 ids return 200, 21 return 400 with
identical ids. A board with more than 20 cards is therefore unreadable in one
request; getCards chunks at 20.
storageLocationId is the school id (from /me), with
storageLocation: 'school', for every parent type in normal use.
Lesson ids come back as buffers. GET /api/v3/lessons/{id} returns nested
ids as {buffer:{type:'Buffer',data:[...]}} rather than hex strings — a leak
from the legacy Mongo serialisation. normalizeObjectId in src/render.ts
converts them.
The JWT's exp is not the session lifetime, and the source misleads here.
Both the current and legacy whitelist implementations re-set a Valkey TTL on
every authenticated request, which reads as a sliding window. The live instance
does not behave that way: a session ends ~2 h after login, and successful
reads in between do not extend it (measured — see docs/AUTH.md). This is the
clearest case in this API of live behaviour diverging from upstream source.
GET /api/v3/config/public is unauthenticated and useful. 78 keys of
instance configuration, including the session timeouts and feature flags. Handy
for checking deployed settings without a token.
Content-Disposition on downloads is malformed. It comes back as
attachment;; filename="…" — note the doubled semicolon — and the filename is
percent-encoded inside the quotes. Parse defensively.
Content element types
From ContentElementType in schulcloud-server, all seen live except where
noted: richText, file, fileFolder, link, drawing,
collaborativeTextEditor, externalTool, videoConference, h5p, deleted.
Collaborative text editor contents are not retrievable through the API —
GET /api/v3/collaborative-text-editor/{parentType}/{parentId} returns a URL to
the Etherpad-style editor, not the document text.
Re-verifying after an upstream release
npm run probe re-checks every assumption above against the live instance and
prints what it finds — both token clocks included: days until hard expiry, and
seconds of idle budget remaining.