# `Slap.KV.HTTP.Router`
[🔗](https://github.com/mjrusso/slap/blob/slap_kv-v0.4.0/slap_kv/lib/slap/kv/http/router.ex#L1)

`Slap.KV` over HTTP, as a Plug. Under `:prefix` (default `/v1/kv`, relative
to a `Plug.forward/4` mount):

  * `GET /v1/kv/{partition}/{key}` - the value (200, with the version as
    the `ETag`), or 404. `HEAD` is the same without the body.
  * `PUT /v1/kv/{partition}/{key}` - writes the request body. 204 with the
    new version as the `ETag`.
  * `DELETE /v1/kv/{partition}/{key}` - 204.
  * `GET /v1/kv/{partition}?prefix=&gte=&lt=&limit=&cursor=` - a page of
    the partition's rows in key order (see `Slap.KV.scan/2`), as JSON:
    `{"rows": [{"key": k, "value": v}], "cursor": c}`, with keys, values
    and the cursor in unpadded base64url, and `cursor` `null` after the
    last page.

The partition and key are path segments and the scan's bounds query
parameters, all percent-encoded (a key may contain `/` as `%2F`, and a
`+` in a query parameter must be sent as `%2B`).

`PUT` and `DELETE` take `If-Match: "version"`, and `PUT` takes
`If-None-Match: *` (the row must not exist); a failed condition is 412,
with the current version as the `ETag` when there is a row. 503 (with
`Retry-After`) means the shard is unavailable or the request timed out:
a write may still have been applied.

It does not authenticate: put that in front of it.

Options:

  * `:prefix` - default `"/v1/kv"`.
  * `:max_value` - the largest value, in bytes (default 8 MiB; 413 above
    it).
  * `:cluster` - KV cluster serving these requests (default
    `Slap.KV.Cluster`).

Each response sends a `[:slap, :kv, :http, :request]` telemetry event.

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*Consult [api-reference.md](api-reference.md) for complete listing*