docs: restore the HTTP REST API reference (#11454)

* docs: restore the HTTP REST API reference

The REST API documentation was lost in the README refactor, and the wiki
only covers the master server API. Add a complete reference for the three
HTTP surfaces — filer paths, master file-id/topology endpoints, and
volume-server content endpoints — generated from the actual handlers and
query parameters.

* docs: correct REST API details flagged in review

Tagging uses Seaweed- headers not query params, the filer recursive
delete option changes the DELETE default, omitted resize mode does not
mean fit, default file mode is 0660, the master redirect is 308, the
listing flag is -dirListLimit, TUS is enabled by default at /.tus, and
-port.public opens the separate read-only listener.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* docs: match the tagging delete example to canonical header names

Go canonicalizes Seaweed-k1 to Seaweed-K1 on write, and the delete list
is compared case-sensitively, so ?tagging=k1,k2 would not match.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

README.md

@@ -21,6 +21,7 @@ One `weed` binary serves an S3 object store, a POSIX file system, and a lakehous
 
 - [Download Binaries for different platforms](https://github.com/seaweedfs/seaweedfs/releases/latest)
 - [Wiki Documentation](https://github.com/seaweedfs/seaweedfs/wiki)
+- [HTTP REST API](REST_API.md) for the filer, master, and volume servers
 - Community: [Slack](https://join.slack.com/t/seaweedfs/shared_invite/enQtMzI4MTMwMjU2MzA3LTEyYzZmZWYzOGQ3MDJlZWMzYmI0OTE4OTJiZjJjODBmMzUxNmYwODg0YjY3MTNlMjBmZDQ1NzQ5NDJhZWI2ZmY), [Twitter](https://twitter.com/SeaweedFS), [Telegram](https://t.me/Seaweedfs), [Reddit](https://www.reddit.com/r/SeaweedFS/), [Mailing List](https://groups.google.com/d/forum/seaweedfs)
 - [SeaweedFS White Paper](https://github.com/seaweedfs/seaweedfs/wiki/SeaweedFS_Architecture.pdf) and introduction slides: [2025.5](https://docs.google.com/presentation/d/1tdkp45J01oRV68dIm4yoTXKJDof-EhainlA0LMXexQE/edit?usp=sharing), [2021.5](https://docs.google.com/presentation/d/1DcxKWlINc-HNCjhYeERkpGXXm6nTCES8mi2W5G0Z4Ts/edit?usp=sharing), [2019.3](https://www.slideshare.net/chrislusf/seaweedfs-introduction)
 

REST_API.md

@@ -0,0 +1,344 @@
+# SeaweedFS HTTP REST API
+
+SeaweedFS exposes three HTTP surfaces:
+
+| Service | Default port | Addressing |
+|---------|--------------|------------|
+| Filer | 8888 | File system paths (`/dir/name`) |
+| Master | 9333 | File id assignment and cluster topology |
+| Volume server | 8080 | File content by file id (`vid,fid`) |
+
+Most clients only need the filer API (paths) or the S3 API. The master and
+volume APIs are the lower-level blob store interface.
+
+Conventions applying to all three:
+
+- Responses are JSON unless noted otherwise. Append `&pretty=y` to pretty-print.
+- A file id (`fid`) has the form `volumeId,fileKeyCookie`, e.g. `3,01637037d6`.
+  An optional suffix selects a reserved id from a `count` assignment
+  (`3,01637037d6_1`, `_2`, ...), and an optional extension
+  (`3,01637037d6.jpg`) sets the content type on reads.
+- `replication` is a 3-digit replica placement `xyz`: `x` copies in other
+  data centers, `y` on other racks in the same data center, `z` on other
+  volume servers on the same rack. `000` = no replication, `001` = one copy
+  on the same rack, `010` = one copy on a different rack, `100` = one copy in
+  another data center, `200` = two copies in two other data centers, `110` =
+  one copy in another data center plus one on another rack.
+- `ttl` units: `m` minute, `h` hour, `d` day, `w` week, `M` month, `y` year.
+
+## Filer API (port 8888)
+
+The filer presents a POSIX-like namespace over the volume servers.
+
+### Upload a file
+
+```bash
+# PUT the raw body to the target path
+curl -T /home/chris/myphoto.jpg "http://localhost:8888/dir/myphoto.jpg"
+
+# or POST as multipart form (the part filename becomes the entry name)
+curl -F file=@/home/chris/myphoto.jpg "http://localhost:8888/dir/"
+```
+
+Response `201 Created`:
+
+```json
+{"name":"myphoto.jpg","size":43234,"eTag":"0x6c656...","mtime":"...","chunks":[...]}
+```
+
+Query parameters:
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `collection` | collection name | empty |
+| `replication` | replica placement code | filer default |
+| `ttl` | file expiration, e.g. `3d` | never |
+| `disk` | disk type to store on | filer default |
+| `fsync` | `true` fsyncs on the volume server | false |
+| `dataCenter` | preferred data center | empty |
+| `rack` | preferred rack | empty |
+| `dataNode` | preferred volume server | empty |
+| `saveInside` | store small content inside the metadata instead of a volume | false |
+| `maxMB` | split the upload into chunks of this many MB | filer `-maxMB` |
+| `mode` | unix permission bits, e.g. `0644` | `0660` |
+| `op` | `append` appends to an existing file | overwrite |
+| `skipCheckParentDir` | `true` skips the parent-directory existence check | false |
+
+### Create a directory
+
+```bash
+curl -X POST "http://localhost:8888/dir/newdir/"
+```
+
+A POST to a path ending in `/` with no content creates the directory,
+including missing parents.
+
+### Read a file
+
+```bash
+curl "http://localhost:8888/dir/myphoto.jpg"
+```
+
+Supports `Range` requests (`Accept-Ranges: bytes`), `ETag`, and the
+`If-None-Match` / `If-Modified-Since` conditional headers. `HEAD` returns
+headers only. Entry headers stored as extended attributes are echoed back,
+minus internal `Seaweed-` and `xattr-` keys.
+
+Entry metadata instead of content:
+
+```bash
+curl "http://localhost:8888/dir/myphoto.jpg?metadata=true"
+```
+
+`metadata=true&resolveManifest=true` additionally resolves chunked-manifest
+entries into their real chunk list.
+
+### List a directory
+
+```bash
+curl -H "Accept: application/json" "http://localhost:8888/dir/?limit=10&lastFileName=a.jpg"
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `limit` | max entries per page | filer `-dirListLimit` |
+| `lastFileName` | resume listing after this entry name | empty |
+| `namePattern` | include only names matching the wildcard | empty |
+| `namePatternExclude` | exclude names matching the wildcard | empty |
+
+The JSON response carries `Path`, `Entries`, `Limit`, `LastFileName`,
+`ShouldDisplayLoadMore`, and `EmptyFolder`. Without the `Accept` header the
+filer renders its HTML browser.
+
+### Move and copy
+
+```bash
+curl -X POST "http://localhost:8888/dir/newname.jpg?mv.from=/dir/myphoto.jpg"
+curl -X POST "http://localhost:8888/dir/copy.jpg?cp.from=/dir/myphoto.jpg"
+```
+
+`mv.from` renames or moves the source to the request path (`204 No Content`).
+`cp.from` copies it.
+
+### Append
+
+```bash
+curl -T chunk2.bin "http://localhost:8888/dir/file.bin?op=append"
+```
+
+### Delete
+
+```bash
+curl -X DELETE "http://localhost:8888/dir/myphoto.jpg"
+curl -X DELETE "http://localhost:8888/dir/?recursive=true"
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `recursive` | delete a non-empty directory tree | false; when the filer runs with `filer.options.recursive_delete=true`, deletes are recursive unless `recursive=false` |
+| `ignoreRecursiveError` | keep deleting remaining entries after an error | false |
+| `skipChunkDeletion` | remove only the metadata, keep volume data | false |
+
+### Tagging
+
+Tags are carried as `Seaweed-`-prefixed request headers, not query
+parameters; `?tagging` selects the tagging handler and `?tagging=K1,K2`
+lists the keys to remove. Header names are canonicalized on write
+(`Seaweed-k1` is stored as `Seaweed-K1`), and the delete list is matched
+case-sensitively against the stored names.
+
+```bash
+curl -X PUT -H "Seaweed-k1: v1" -H "Seaweed-k2: v2" "http://localhost:8888/dir/file.jpg?tagging"
+curl -X DELETE "http://localhost:8888/dir/file.jpg?tagging=K1,K2"
+```
+
+### Read by file id
+
+```bash
+curl "http://localhost:8888/?proxyChunkId=3,01637037d6"
+```
+
+The filer proxies the chunk read to the right volume server, so only the
+filer port needs to be exposed.
+
+### Resumable uploads
+
+The filer serves the [TUS protocol](https://tus.io/) for resumable uploads
+(`POST`, `PATCH`, `HEAD` on upload URLs). It is enabled by default at
+`/.tus`; `-tusBasePath` changes the endpoint base path.
+
+### Health
+
+`GET /healthz` and `GET /readyz` return `200 OK`.
+
+## Master API (port 9333)
+
+Write-affecting endpoints are automatically proxied to the current leader, so
+any master in the quorum can serve them.
+
+### Assign a file id
+
+```bash
+curl "http://localhost:9333/dir/assign?count=1&replication=001&collection=turbo&dataCenter=dc1&ttl=3d&disk=ssd"
+{"count":1,"fid":"3,01637037d6","url":"127.0.0.1:8080","publicUrl":"localhost:8080"}
+```
+
+Upload the file content to `http://<url>/<fid>` afterwards. With `count>1`,
+use `<fid>_1`, `<fid>_2`, ... for the additional ids.
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `count` | file ids to reserve | 1 |
+| `collection` | collection name | empty |
+| `dataCenter` | preferred data center | empty |
+| `rack` | preferred rack | empty |
+| `dataNode` | preferred volume server | empty |
+| `replication` | replica placement | master `-defaultReplication` |
+| `ttl` | file expiration, e.g. `3d` | never |
+| `disk` | disk type | empty |
+| `dataSize` | expected file size in bytes | 0 |
+| `preallocate` | bytes to preallocate for new volumes | master `-volumePreallocate` |
+| `writableVolumeCount` | grow this many volumes when none are writable | master default |
+| `memoryMapMaxSizeMb` | memory-mapped file size (Windows) | 0 |
+
+### Look up a volume or file id
+
+```bash
+curl "http://localhost:9333/dir/lookup?volumeId=3"
+{"locations":[{"url":"localhost:8080","publicUrl":"localhost:8080"}]}
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `volumeId` | volume id; a full `vid,fid` is accepted too | required |
+| `fileId` | like `volumeId`, but also returns a write JWT when security is on | empty |
+| `collection` | speeds up the lookup | empty |
+| `read` | `yes` generates a read JWT instead of a write JWT | empty |
+
+### Store a file in one call
+
+```bash
+curl -F file=@/home/chris/report.pdf "http://localhost:9333/submit?collection=turbo&replication=001"
+{"fileName":"report.pdf","fid":"3,01637037d6","fileUrl":"localhost:8080/3,01637037d6","size":43234,"eTag":"0x6c656..."}
+```
+
+`POST /submit` accepts multipart file data plus the `dir/assign` placement
+parameters (`count`, `collection`, `dataCenter`, `rack`, `replication`,
+`ttl`, `disk`), assigns a file id, uploads to the volume server, and returns
+the result.
+
+### Redirect to a file
+
+```bash
+curl -v "http://localhost:9333/3,01637037d6"
+```
+
+`GET /{fileId}` answers `308 Permanent Redirect` to a volume server holding
+the file, preserving the query string (e.g. image-resize parameters).
+
+### Cluster status
+
+```bash
+curl "http://localhost:9333/dir/status?pretty=y"   # full topology tree
+curl "http://localhost:9333/vol/status?pretty=y"   # every volume on every node
+curl "http://localhost:9333/collection/info?collection=turbo"
+curl "http://localhost:9333/collection/info?collection=turbo&detail=true"
+```
+
+`collection/info` returns aggregated `TotalSize`, `FileCount`, `UsedSize`,
+`VolumeCount`; `detail=true` splits them per volume layout.
+
+### Grow volumes
+
+```bash
+curl "http://localhost:9333/vol/grow?count=4&replication=001&collection=turbo&ttl=5d&disk=ssd&dataCenter=dc1&rack=rack1"
+{"count":4}
+```
+
+`count` is required; the placement parameters match `dir/assign`. One volume
+serves one write at a time, so pre-allocated volumes raise write concurrency.
+
+### Vacuum deleted space
+
+```bash
+curl "http://localhost:9333/vol/vacuum?garbageThreshold=0.4"
+```
+
+| Parameter | Description | Default |
+|-----------|-------------|---------|
+| `garbageThreshold` | minimum deleted-bytes ratio before a volume is compacted | master `-garbageThreshold` (0.3) |
+
+Vacuuming makes a volume read-only, copies live needles to a new volume, and
+swaps it in.
+
+### Delete a collection
+
+```bash
+curl "http://localhost:9333/col/delete?collection=benchmark"
+```
+
+Deletes all volumes of the collection, including erasure-coded shards.
+`204 No Content` on success.
+
+### Health
+
+```bash
+curl -I "http://localhost:9333/healthz"     # liveness
+curl -I "http://localhost:9333/readyz"      # readiness
+curl "http://localhost:9333/"               # web UI
+```
+
+## Volume server API (port 8080)
+
+The volume server stores file content by file id. Clients normally get the
+volume URL from `dir/assign` or `dir/lookup`.
+
+### Upload
+
+```bash
+curl -F file=@/home/chris/myphoto.jpg "http://127.0.0.1:8080/3,01637037d6"
+{"name":"myphoto.jpg","size":43234,"eTag":"0x6c656...","mime":"image/jpeg","contentMd5":"..."}
+```
+
+PUT or POST the body (or a multipart `file` part) to `/{vid},{fid}`.
+`204 No Content` is returned when the content is unchanged. `?ts=<unix>`
+sets the stored modification time.
+
+### Read
+
+```bash
+curl "http://127.0.0.1:8080/3,01637037d6"
+curl "http://127.0.0.1:8080/3,01637037d6.jpg"        # sets Content-Type from the extension
+```
+
+Supports `Range` and `HEAD`. Image files can be resized server-side:
+
+| Parameter | Description |
+|-----------|-------------|
+| `width`, `height` | resize bounds in pixels |
+| `mode` | `fit` (contain) or `fill` (cover); omitted resizes to `width`/`height` |
+| `crop_x1`, `crop_y1`, `crop_x2`, `crop_y2` | explicit crop rectangle |
+| `cm` | `false` returns the chunk-manifest blob instead of resolving it |
+| `readDeleted` | `true` reads soft-deleted needles |
+| `collection` | passed through redirects for the right volume |
+
+### Delete
+
+```bash
+curl -X DELETE "http://127.0.0.1:8080/3,01637037d6"
+{"size":43234}
+```
+
+`?ts=<unix>` sets the deletion timestamp. Replicated volumes propagate the
+delete to every replica.
+
+### Status
+
+```bash
+curl "http://localhost:8080/status?pretty=y"  # disk and volume inventory
+curl -I "http://localhost:8080/healthz"       # liveness/readiness
+```
+
+`OPTIONS` preflights answer CORS headers. When `-port.public` differs from
+`-port`, the volume server opens a separate read-only public listener on
+that port; `-publicUrl` sets the address it advertises to clients.