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https://github.com/simonw/datasette.git
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6a0c5de615
This will be run at compile time - the goal is to generate a build-
metadata.json file with a bunch of useful facts about the databases that could
be expensive to generate at run-time.
Example metadata:
{
"flights": {
"file": "flights.db",
"tables": {
"airlines": 6048,
"airports": 8107,
"routes": 67663
},
"hash": "07d1283e07786b1235bb7041ea445ae103d1571565580a29eab0203c555725fd"
}
So far we have a sha256 hash of the database file itself, plus a row count for
each table.
Fixes #11
108 lines
3.1 KiB
Python
108 lines
3.1 KiB
Python
from sanic import Sanic
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from sanic import response
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from sanic_jinja2 import SanicJinja2
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import sqlite3
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from pathlib import Path
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from functools import wraps
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import json
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import hashlib
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app_root = Path(__file__).parent
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BUILD_METADATA = 'build-metadata.json'
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DB_GLOBS = ('*.db', '*.sqlite', '*.sqlite3')
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HASH_BLOCK_SIZE = 1024 * 1024
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def ensure_build_metadata(regenerate=False):
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build_metadata = app_root / BUILD_METADATA
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if build_metadata.exists() and not regenerate:
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json.loads(build_metadata.read_text())
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metadata = {}
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for glob in DB_GLOBS:
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for path in app_root.glob(glob):
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name = path.stem
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if name in metadata:
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raise Exception('Multiple files with same stem %s' % name)
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# Calculate hash, efficiently
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m = hashlib.sha256()
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with path.open('rb') as fp:
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while True:
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data = fp.read(HASH_BLOCK_SIZE)
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if not data:
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break
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m.update(data)
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# List tables and their row counts
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tables = {}
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with sqlite3.connect('file:{}?immutable=1'.format(path.name), uri=True) as conn:
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conn.row_factory = sqlite3.Row
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table_names = [
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r['name']
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for r in conn.execute('select * from sqlite_master where type="table"')
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]
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for table in table_names:
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tables[table] = conn.execute('select count(*) from "{}"'.format(table)).fetchone()[0]
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metadata[name] = {
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'hash': m.hexdigest(),
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'file': path.name,
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'tables': tables,
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}
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build_metadata.write_text(json.dumps(metadata, indent=4))
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return metadata
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app = Sanic(__name__)
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jinja = SanicJinja2(app)
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#conn = sqlite3.connect('file:flights.db?immutable=1', uri=True)
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conn = sqlite3.connect('file:northwind.db?immutable=1', uri=True)
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conn.row_factory = sqlite3.Row
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def sqlerrors(fn):
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@wraps(fn)
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async def inner(*args, **kwargs):
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try:
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return await fn(*args, **kwargs)
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except sqlite3.OperationalError as e:
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return response.json({
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'ok': False,
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'error': str(e),
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})
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return inner
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@app.route('/')
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@sqlerrors
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async def index(request, sql=None):
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sql = sql or request.args.get('sql', '')
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if not sql:
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sql = 'select * from sqlite_master'
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rows = conn.execute(sql)
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headers = [r[0] for r in rows.description]
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return jinja.render('index.html', request,
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headers=headers,
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rows=list(rows),
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metadata=json.dumps(ensure_build_metadata(True), indent=2)
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)
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@app.route('/<table:[a-zA-Z0-9].*>.json')
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@sqlerrors
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async def table_json(request, table):
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sql = 'select * from {} limit 20'.format(table)
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return response.json([
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dict(r) for r in conn.execute(sql)
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])
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@app.route('/<table:[a-zA-Z0-9].*>')
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@sqlerrors
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async def table(request, table):
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sql = 'select * from {} limit 20'.format(table)
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return await index(request, sql)
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if __name__ == '__main__':
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app.run(host="0.0.0.0", port=8006)
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