From 018af454f286120452e33d2568dd40908474a8a8 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Thu, 7 Jun 2018 08:26:05 -0700
Subject: [PATCH] Initial sketch of custom URL routing, refs #306

---
 datasette/routes.py  | 78 ++++++++++++++++++++++++++++++++++++++++++++
 tests/test_routes.py | 65 ++++++++++++++++++++++++++++++++++++
 2 files changed, 143 insertions(+)
 create mode 100644 datasette/routes.py
 create mode 100644 tests/test_routes.py

diff --git a/datasette/routes.py b/datasette/routes.py
new file mode 100644
index 00000000..a404a3c0
--- /dev/null
+++ b/datasette/routes.py
@@ -0,0 +1,78 @@
+from collections import namedtuple
+from datasette.views.database import DatabaseView
+from datasette.views.special import JsonDataView
+from datasette.views.table import TableView
+
+RouteResult = namedtuple('RouteResult', ('view', 'kwargs', 'redirect'))
+
+
+def redirect(path):
+    return RouteResult(None, None, path)
+
+
+def resolve(path, database_exists, table_exists, database_hash):
+    bits = path.split('/')
+    # Kill the leading /:
+    del bits[0]
+    # /-/...
+    if bits[0] == '-':
+        return resolve_special(bits[1:])
+    # /databasename
+    bit = bits[0]
+    rest = ''
+    if bits[1:]:
+        rest = '/'.join([''] + bits[1:])
+    # Might be database-databasehash
+    if '-' in bit:
+        database, databasehash = bit.rsplit('-', 1)
+        if database_exists(database):
+            # Is the hash correct?
+            expected_hash = database_hash(database)
+            if expected_hash == databasehash:
+                if not rest:
+                    return RouteResult(
+                        DatabaseView, {'database': database}, None
+                    )
+                else:
+                    # Pass on to table logic
+                    return resolve_table(rest, database, table_exists)
+            else:
+                # Bad hash, redirect
+                return redirect('/{}-{}{}'.format(
+                    database, expected_hash, rest)
+                )
+    # If we get here, maybe the full string is a DB name?
+    if database_exists(bit):
+        database = bit
+        databasehash = database_hash(bit)
+        return redirect('/{}-{}{}'.format(database, databasehash, rest))
+    return None
+
+
+def resolve_table(rest, database, table_exists):
+    # TODO: Rows, views, canned queries
+    table = rest.lstrip('/')
+    if not table_exists(database, table):
+        return None
+    return RouteResult(TableView, {'database': database, 'table': table}, None)
+
+
+specials = {'inspect', 'metadata', 'versions', 'plugins', 'config'}
+
+
+def resolve_special(path_bits):
+    if len(path_bits) != 1:
+        return None
+    filename = path_bits[0]
+    as_json = False
+    if filename.endswith('.json'):
+        as_json = True
+        filename = filename.replace('.json', '')
+    if filename not in specials:
+        return None
+    kwargs = {
+        'filename': filename,
+    }
+    if as_json:
+        kwargs['format'] = 'json'
+    return RouteResult(JsonDataView, kwargs, None)
diff --git a/tests/test_routes.py b/tests/test_routes.py
new file mode 100644
index 00000000..de682cbc
--- /dev/null
+++ b/tests/test_routes.py
@@ -0,0 +1,65 @@
+from datasette import routes
+from datasette.views.database import DatabaseView
+from datasette.views.special import JsonDataView
+from datasette.views.table import TableView
+import pytest
+
+MOCK_DATABASES = {
+    # database: set-of-tables
+    'foo': {'bar'},
+    'foo-bar': {'baz'}
+}
+MOCK_DATABASE_HASHES = {
+    'foo': 'foohash',
+    'foo-bar': 'foobarhash',
+}
+
+
+def database_exists(database):
+    return database in MOCK_DATABASES
+
+
+def table_exists(database, table):
+    print('table_exists: ', database, table)
+    return table in MOCK_DATABASES.get(database, set())
+
+
+def database_hash(database):
+    return MOCK_DATABASE_HASHES[database]
+
+
+@pytest.mark.parametrize('path,expected', [
+    ('/does-not-exist', None),
+    # This should redirect
+    ('/foo', routes.RouteResult(
+        None, None, '/foo-foohash'
+    )),
+    ('/foo-bar-badhash', routes.RouteResult(
+        None, None, '/foo-bar-foobarhash'
+    )),
+    ('/foo-foohash', routes.RouteResult(
+        DatabaseView, {'database': 'foo'}, None
+    )),
+    # Table views
+    ('/foo/bar', routes.RouteResult(
+        None, None, '/foo-foohash/bar'
+    )),
+    ('/foo/bad', routes.RouteResult(
+        None, None, '/foo-foohash/bad'
+    )),
+    ('/foo-foohash/bad', None),
+    ('/foo-foohash/bar', routes.RouteResult(
+        TableView, {'database': 'foo', 'table': 'bar'}, None
+    )),
+] + [
+    ('/-/{}'.format(filename), routes.RouteResult(
+        JsonDataView, {'filename': filename}, None
+    )) for filename in ('inspect', 'metadata', 'versions', 'plugins', 'config')
+] + [
+    ('/-/{}.json'.format(filename), routes.RouteResult(
+        JsonDataView, {'filename': filename, 'format': 'json'}, None
+    )) for filename in ('inspect', 'metadata', 'versions', 'plugins', 'config')
+])
+def test_routes(path, expected):
+    actual = routes.resolve(path, database_exists, table_exists, database_hash)
+    assert actual == expected