datasette-demo-dbs

Fetch missing demo DBs from URLs when Datasette first starts

Installation

Install this plugin in the same environment as Datasette.

datasette install datasette-demo-dbs

Configuration

Configure the plugin in your Datasette metadata (YAML or JSON). You specify:

• path: directory on disk where downloaded .db files will be stored (defaults to current directory)
• dbs: a mapping of database name to the URL of the SQLite database file

Example metadata.yml:

plugins:
  datasette-demo-dbs:
    path: ./demo-dbs
    dbs:
      demo: https://example.com/path/to/demo.db
      census: https://example.com/path/to/census.db

Equivalent metadata.json:

{
  "plugins": {
    "datasette-demo-dbs": {
      "path": "./demo-dbs",
      "dbs": {
        "demo": "https://example.com/path/to/demo.db",
        "census": "https://example.com/path/to/census.db"
      }
    }
  }
}

How it works

On Datasette startup, for each entry in dbs:

1. If path/<name>.db already exists, it is left as-is and loaded into Datasette.
2. If a marker file path/<name>.deleted exists, the download is skipped.
3. Otherwise, the plugin downloads the content from the URL (following redirects), streams it to path/<name>.db, and registers that database in Datasette under the given name.

Development

To set up this plugin locally, first checkout the code. Then create a new virtual environment:

cd datasette-demo-dbs
python -m venv venv
source venv/bin/activate

Now install the dependencies and test dependencies:

pip install -e '.[test]'

To run the tests:

python -m pytest