# Memona signature plugin

Opens a WebDAV server as a folder inside Memona and signs every Markdown file
saved to it with an ENS name, writing `signer` and `signature` into the file's
frontmatter so anyone can check who wrote it against the name's current ENSv2
records. Signing comes from the
[md-ens-signature](https://github.com/capsulizers/md-ens-signature) library.

The plugin is a WASI component: it speaks no sockets of its own and makes every
request through the host's HTTP interface, under the connection's permissions.
It registers one provider, `signature`, for the `signed-webdav` scheme.

## Connecting

| Field | Meaning |
| --- | --- |
| Server address | The folder's address, for example `https://dav.example.com/files/` |
| Username | Optional account name for HTTP basic authentication |
| Password | Optional password, stored as a secret |
| Signer name | The ENS name that signs, for example `laptop.alice.eth` |
| Signing key | The private key of the address the name resolves to, stored as a secret |
| Sepolia RPC address | The endpoint used to check signers against ENS, by default `https://ethereum-sepolia-rpc.publicnode.com` |

Listing, reading, writing, creating directories, renaming and deleting behave
as in the WebDAV plugin: reads and writes stream in pieces of at most 1 MiB,
conditional writes use `If-Match` and `If-None-Match`, change polling is not
supported, a rename never replaces an existing target, and a folder with
contents is refused rather than removed whole.

## Signing

Saving a `.md` file holds it whole, up to 96 KiB, and writes it once finished,
with `signer` and `signature` set in its frontmatter; every other file streams
straight through. The signature is EIP-191 `personal_sign` over the signer name
and the body's SHA-256, made with the configured key; other frontmatter and the
body stay byte for byte. A key that is not 32 bytes of hex refuses the
connection, and a `.md` file that is not UTF-8 refuses the save.

## Verifying

Reading a `.md` file of up to 40 KiB checks its signature against ENSv2 on
Sepolia through the RPC address and adds an `ens-verification` line to the
frontmatter Memona receives, which Memona shows as a badge; a larger one up to
1 MiB is marked as not checked. Both limits keep hashing and key recovery
inside the instruction budget Memona gives each call. The line never
reaches the server: a save drops it before signing, and one stored on the
server is replaced. Verdicts are reused for 30 seconds per signed body.

## Building

```sh
rustup target add wasm32-wasip2
cargo build --locked --release --target wasm32-wasip2
cargo test --locked --lib
```

The component lands at
`target/wasm32-wasip2/release/memona_plugin_signature.wasm`.

`wit/filesystem.wit` is a copy of the canonical Memona filesystem contract, and
`src/sdk.rs` generates the guest bindings from it, so this repository builds
without a Memona checkout. Refresh the copy from `plugin_system/sdk/wit` in the
[Memona repository](https://git.capsulizers.com/lead/memona) when the contract
moves, and keep `apiVersion` in `manifest.json` in step.

## Packaging for the plugin store

A `.memona-plugin` package is a ZIP archive with the files at its root, never
inside a directory:

```sh
cargo build --locked --release --target wasm32-wasip2
cp target/wasm32-wasip2/release/memona_plugin_signature.wasm plugin.wasm
zip memona-plugin-signature.memona-plugin \
  manifest.json plugin.wasm README.md LICENSE
```

`manifest.json` and `plugin.wasm` are required; `README.md` becomes the guide on
the plugin's public page and `LICENSE` is shown beside it.

## Attribution

The WebDAV code in `src/lib.rs`, `src/dav.rs` and `src/sdk.rs` is copied from
the MIT-licensed
[Memona WebDAV plugin](https://git.capsulizers.com/commons/memona-plugin-webdav)
at commit `3d69750`. That crate keeps its provider, reader and writer private
and exports the component's entry points itself, so it cannot be wrapped as a
dependency without forking it; the copy stays as close to the original as the
signing hook allows, so fixes there carry over with a plain diff.