datasette/app.py

386 wiersze
11 KiB
Python

from sanic import Sanic
from sanic import response
from sanic.exceptions import NotFound
from sanic.views import HTTPMethodView
from sanic_jinja2 import SanicJinja2
import sqlite3
from contextlib import contextmanager
from pathlib import Path
from functools import wraps
import urllib.parse
import json
import base64
import hashlib
import sys
import time
app_root = Path(__file__).parent
BUILD_METADATA = 'build-metadata.json'
DB_GLOBS = ('*.db', '*.sqlite', '*.sqlite3')
HASH_BLOCK_SIZE = 1024 * 1024
SQL_TIME_LIMIT_MS = 1000
conns = {}
app = Sanic(__name__)
jinja = SanicJinja2(app)
def get_conn(name):
if name not in conns:
info = ensure_build_metadata()[name]
conns[name] = sqlite3.connect(
'file:{}?immutable=1'.format(info['file']),
uri=True
)
conns[name].row_factory = sqlite3.Row
conns[name].text_factory = lambda x: str(x, 'utf-8', 'replace')
return conns[name]
def ensure_build_metadata(regenerate=False):
build_metadata = app_root / BUILD_METADATA
if build_metadata.exists() and not regenerate:
json.loads(build_metadata.read_text())
metadata = {}
for glob in DB_GLOBS:
for path in app_root.glob(glob):
name = path.stem
if name in metadata:
raise Exception('Multiple files with same stem %s' % name)
# Calculate hash, efficiently
m = hashlib.sha256()
with path.open('rb') as fp:
while True:
data = fp.read(HASH_BLOCK_SIZE)
if not data:
break
m.update(data)
# List tables and their row counts
tables = {}
with sqlite3.connect('file:{}?immutable=1'.format(path.name), uri=True) as conn:
conn.row_factory = sqlite3.Row
table_names = [
r['name']
for r in conn.execute('select * from sqlite_master where type="table"')
]
for table in table_names:
tables[table] = conn.execute('select count(*) from "{}"'.format(table)).fetchone()[0]
metadata[name] = {
'hash': m.hexdigest(),
'file': path.name,
'tables': tables,
}
build_metadata.write_text(json.dumps(metadata, indent=4))
return metadata
class BaseView(HTTPMethodView):
template = None
def redirect(self, request, path):
if request.query_string:
path = '{}?{}'.format(
path, request.query_string
)
r = response.redirect(path)
r.headers['Link'] = '<{}>; rel=preload'.format(path)
return r
async def get(self, request, db_name, **kwargs):
name, hash, should_redirect = resolve_db_name(db_name, **kwargs)
if should_redirect:
return self.redirect(request, should_redirect)
try:
as_json = kwargs.pop('as_json')
except KeyError:
as_json = False
extra_template_data = {}
start = time.time()
try:
data, extra_template_data = self.data(
request, name, hash, **kwargs
)
except sqlite3.OperationalError as e:
data = {
'ok': False,
'error': str(e),
}
end = time.time()
data['took_ms'] = (end - start) * 1000
if as_json:
# Special case for .jsono extension
if as_json == '.jsono':
columns = data.get('columns')
rows = data.get('rows')
if rows and columns:
data['rows'] = [
dict(zip(columns, row))
for row in rows
]
r = response.HTTPResponse(
json.dumps(
data, cls=CustomJSONEncoder
),
content_type='application/json',
headers={
'Access-Control-Allow-Origin': '*'
}
)
else:
context = {**data, **dict(
extra_template_data()
if callable(extra_template_data)
else extra_template_data
)}
r = jinja.render(
self.template,
request,
**context,
)
# Set far-future cache expiry
r.headers['Cache-Control'] = 'max-age={}'.format(
365 * 24 * 60 * 60
)
return r
@app.route('/')
async def index(request, sql=None):
databases = ensure_build_metadata(True)
return jinja.render(
'index.html',
request,
databases=databases,
)
@app.route('/favicon.ico')
async def favicon(request):
return response.text('')
class DatabaseView(BaseView):
template = 'database.html'
def data(self, request, name, hash):
conn = get_conn(name)
sql = request.args.get('sql') or 'select * from sqlite_master'
with sqlite_timelimit(conn, SQL_TIME_LIMIT_MS):
rows = conn.execute(sql)
columns = [r[0] for r in rows.description]
return {
'database': name,
'rows': rows,
'columns': columns,
}, {
'database_hash': hash,
}
class TableView(BaseView):
template = 'table.html'
def data(self, request, name, hash, table):
conn = get_conn(name)
table = urllib.parse.unquote_plus(table)
if request.args:
where_clause, params = build_where_clause(request.args)
sql = 'select * from "{}" where {} limit 50'.format(
table, where_clause
)
else:
sql = 'select * from "{}" limit 50'.format(table)
params = []
with sqlite_timelimit(conn, SQL_TIME_LIMIT_MS):
rows = conn.execute(sql, params)
columns = [r[0] for r in rows.description]
rows = list(rows)
pks = pks_for_table(conn, table)
info = ensure_build_metadata()
total_rows = info[name]['tables'].get(table)
return {
'database': name,
'table': table,
'rows': rows,
'total_rows': total_rows,
'columns': columns,
'primary_keys': pks,
}, lambda: {
'database_hash': hash,
'row_link': lambda row: path_from_row_pks(row, pks),
}
class RowView(BaseView):
template = 'table.html'
def data(self, request, name, hash, table, pk_path):
conn = get_conn(name)
pk_values = compound_pks_from_path(pk_path)
pks = pks_for_table(conn, table)
wheres = [
'"{}"=?'.format(pk)
for pk in pks
]
sql = 'select * from "{}" where {}'.format(
table, ' AND '.join(wheres)
)
rows = conn.execute(sql, pk_values)
columns = [r[0] for r in rows.description]
pks = pks_for_table(conn, table)
rows = list(rows)
if not rows:
raise NotFound('Record not found: {}'.format(pk_values))
return {
'database': name,
'table': table,
'rows': rows,
'columns': columns,
'primary_keys': pks,
}, {
'database_hash': hash,
'row_link': None,
}
app.add_route(DatabaseView.as_view(), '/<db_name:[^/]+?><as_json:(.jsono?)?$>')
app.add_route(TableView.as_view(), '/<db_name:[^/]+>/<table:[^/]+?><as_json:(.jsono?)?$>')
app.add_route(RowView.as_view(), '/<db_name:[^/]+>/<table:[^/]+?>/<pk_path:[^/]+?><as_json:(.jsono?)?$>')
def resolve_db_name(db_name, **kwargs):
databases = ensure_build_metadata()
hash = None
name = None
if '-' in db_name:
# Might be name-and-hash, or might just be
# a name with a hyphen in it
name, hash = db_name.rsplit('-', 1)
if name not in databases:
# Try the whole name
name = db_name
hash = None
else:
name = db_name
# Verify the hash
try:
info = databases[name]
except KeyError:
raise NotFound('Database not found: {}'.format(name))
expected = info['hash'][:7]
if expected != hash:
should_redirect = '/{}-{}'.format(
name, expected,
)
if 'table' in kwargs:
should_redirect += '/' + kwargs['table']
return name, expected, should_redirect
return name, expected, None
def compound_pks_from_path(path):
return [
urllib.parse.unquote_plus(b) for b in path.split(',')
]
def pks_for_table(conn, table):
rows = [
row for row in conn.execute(
'PRAGMA table_info("{}")'.format(table)
).fetchall()
if row[-1]
]
rows.sort(key=lambda row: row[-1])
return [str(r[1]) for r in rows]
def path_from_row_pks(row, pks):
if not pks:
return ''
bits = []
for pk in pks:
bits.append(
urllib.parse.quote_plus(str(row[pk]))
)
return ','.join(bits)
def build_where_clause(args):
sql_bits = []
for key, values in args.items():
if '__' in key:
column, lookup = key.rsplit('__', 1)
else:
column = key
lookup = 'exact'
template = {
'exact': '"{}" = ?',
'contains': '"{}" like ?',
'endswith': '"{}" like ?',
'startswith': '"{}" like ?',
'gt': '"{}" > ?',
'gte': '"{}" >= ?',
'lt': '"{}" < ?',
'lte': '"{}" <= ?',
'glob': '"{}" glob ?',
'like': '"{}" like ?',
}[lookup]
value = values[0]
value_convert = {
'contains': lambda s: '%{}%'.format(s),
'endswith': lambda s: '%{}'.format(s),
'startswith': lambda s: '{}%'.format(s),
}.get(lookup, lambda s: s)
converted = value_convert(value)
sql_bits.append(
(template.format(column), converted)
)
sql_bits.sort(key=lambda p: p[0])
where_clause = ' and '.join(p[0] for p in sql_bits)
params = [p[1] for p in sql_bits]
return where_clause, params
class CustomJSONEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj, sqlite3.Row):
return tuple(obj)
if isinstance(obj, sqlite3.Cursor):
return list(obj)
if isinstance(obj, bytes):
# Does it encode to utf8?
try:
return obj.decode('utf8')
except UnicodeDecodeError:
return {
'$base64': True,
'encoded': base64.b64encode(obj).decode('latin1'),
}
return json.JSONEncoder.default(self, obj)
@contextmanager
def sqlite_timelimit(conn, ms):
deadline = time.time() + (ms / 1000)
def handler():
if time.time() >= deadline:
return 1
conn.set_progress_handler(handler, 10000)
yield
conn.set_progress_handler(None, 10000)
if __name__ == '__main__':
if '--build' in sys.argv:
ensure_build_metadata(True)
else:
app.run(host="0.0.0.0", port=8006)