ic-rusqlite

This is a convenience package to create a canister with the Sqlite support.

Prerequisites

It is assumed that you have rust, dfx.

To compile a project with this dependency, you will need to:

• install wasi2ic: cargo install wasi2ic
• install WASI target: rustup target add wasm32-wasip1

Using Precompiled SQLite

If you don't want to install WASI-SDK, you can use the precompiled SQLite version for WASI, just activate the precompiled feature and disable the default features:

cargo add ic-rusqlite --features precompiled

Compiling SQLite

If you intend to compile the SQLite from the source, you will need to install WASI-SDK:

• install WASI-SDK and WASI-oriented clang: WASI-SDK.
• set the WASI_SDK_PATH and PATH variables:

export WASI_SDK_PATH=/opt/wasi-sdk
export PATH=$WASI_SDK_PATH/bin:$PATH

You can automate this by launching the preparation script:

curl -fsSL https://raw.githubusercontent.com/wasm-forge/ic-rusqlite/main/prepare.sh | sh

Finally, to enable rusqlite in your canister, add the helper dependency into your backend canister:

cargo add ic-rusqlite --features compile_sqlite

Developing Canister

You will need to update the dfx.json and specify path to wasm, set type to custom, and specify custom build steps to enforce compilation to the wasm32-wasip1 target. Finally, use wasi2ic to produce wasm executable on the Internet Computer.

Example:

{
  "canisters": {
    "backend": {
      "candid": "can.did",
      "package": "backend",
      "build": [
        "cargo build --release --target wasm32-wasip1",
        "wasi2ic target/wasm32-wasip1/release/backend.wasm target/wasm32-wasip1/release/backend_nowasi.wasm"
      ],
      "wasm": "target/wasm32-wasip1/release/backend_nowasi.wasm",
      "type": "custom",
      "metadata": [
        {
          "name": "candid:service"
        }
      ]
    }
  },
  "version": 1
}

Example

Use the with_connection() function to access your database:

    //...
    
    with_connection(|conn| {
      conn.execute(
          "CREATE TABLE person (
              id    INTEGER PRIMARY KEY,
              name  TEXT NOT NULL,
              data  BLOB
          )",
          (),
      )?;

      let data: Option<Vec<u8>> = None;

      conn.execute(
          "INSERT INTO person (name, data) VALUES (?1, ?2)",
          ("Steven", &data),
      )?;

    })

    //...

Further Examples

• A minimal example is available in the "examples/backend" folder.
• Also see the demo Svelte canister.

For more detailed explanations, see the ic-rusqlite book.