Implemented multi-db support plus initial URL structure

Refs #24

Fixes #15

.gitignore

@@ -1,4 +1,9 @@
 build-metadata.json
+datasets.json
+
+# SQLite databases
+*.db
+*.sqlite
 
 # Byte-compiled / optimized / DLL files
 __pycache__/
@@ -102,5 +107,3 @@ ENV/
 # mypy
 .mypy_cache/
 
-# SQLite databases
-*.db

app.py

@@ -1,5 +1,6 @@
 from sanic import Sanic
 from sanic import response
+from sanic.exceptions import NotFound
 from sanic_jinja2 import SanicJinja2
 import sqlite3
 from pathlib import Path
@@ -13,6 +14,19 @@ BUILD_METADATA = 'build-metadata.json'
 DB_GLOBS = ('*.db', '*.sqlite', '*.sqlite3')
 HASH_BLOCK_SIZE = 1024 * 1024
 
+conns = {}
+
+
+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
+    return conns[name]
+
 
 def ensure_build_metadata(regenerate=False):
     build_metadata = app_root / BUILD_METADATA
@@ -55,10 +69,6 @@ def ensure_build_metadata(regenerate=False):
 app = Sanic(__name__)
 jinja = SanicJinja2(app)
 
-#conn = sqlite3.connect('file:flights.db?immutable=1', uri=True)
-conn = sqlite3.connect('file:northwind.db?immutable=1', uri=True)
-conn.row_factory = sqlite3.Row
-
 
 def sqlerrors(fn):
     @wraps(fn)
@@ -76,32 +86,85 @@ def sqlerrors(fn):
 @app.route('/')
 @sqlerrors
 async def index(request, sql=None):
-    sql = sql or request.args.get('sql', '')
-    if not sql:
-        sql = 'select * from sqlite_master'
-    rows = conn.execute(sql)
-    headers = [r[0] for r in rows.description]
-    return jinja.render('index.html', request,
-        headers=headers,
-        rows=list(rows),
-        metadata=json.dumps(ensure_build_metadata(True), indent=2)
+    databases = ensure_build_metadata(True)
+    return jinja.render(
+        'index.html',
+        request,
+        databases=databases,
     )
 
 
-@app.route('/<table:[a-zA-Z0-9].*>.json')
-@sqlerrors
-async def table_json(request, table):
-    sql = 'select * from {} limit 20'.format(table)
-    return response.json([
-        dict(r) for r in conn.execute(sql)
-    ])
+@app.route('/favicon.ico')
+async def favicon(request):
+    return response.text('')
 
 
-@app.route('/<table:[a-zA-Z0-9].*>')
+@app.route('/<db_name:[^/]+$>')
 @sqlerrors
-async def table(request, table):
-    sql = 'select * from {} limit 20'.format(table)
-    return await index(request, sql)
+async def database(request, db_name):
+    name, hash, should_redirect = resolve_db_name(db_name)
+    if should_redirect:
+        return response.redirect(should_redirect)
+    conn = get_conn(name)
+    rows = conn.execute('select * from sqlite_master')
+    headers = [r[0] for r in rows.description]
+    return jinja.render(
+        'database.html',
+        request,
+        database=name,
+        database_hash=hash,
+        headers=headers,
+        rows=rows,
+    )
+
+
+@app.route('/<db_name:[^/]+>/<table:[^/]+$>')
+@sqlerrors
+async def table(request, db_name, table):
+    # The name should have the hash - if it
+    # does not, serve a redirect
+    name, hash, should_redirect = resolve_db_name(db_name)
+    if should_redirect:
+        return response.redirect(should_redirect + '/' + table)
+    conn = get_conn(name)
+    rows = conn.execute('select * from {} limit 20'.format(table))
+    headers = [r[0] for r in rows.description]
+    return jinja.render(
+        'table.html',
+        request,
+        database=name,
+        database_hash=hash,
+        table=table,
+        headers=headers,
+        rows=rows,
+    )
+
+
+def resolve_db_name(db_name):
+    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()
+    expected = info['hash'][:7]
+    if expected != hash:
+        return name, expected, '/{}-{}'.format(
+            name, expected,
+        )
+    return name, expected, None
 
 
 if __name__ == '__main__':

templates/database.html

@@ -0,0 +1,27 @@
+<h1>{{ database }}</h1>
+
+<style>
+td {
+    vertical-align: top;
+    border-top: 1px solid #666;
+    padding: 2px 4px;
+}
+</style>
+<table>
+    <tr>
+        {% for header in headers %}<th scope="col">{{ header }}</th>{% endfor %}
+    </tr>
+    {% for row in rows %}
+        <tr>
+            {% for td in row %}
+                <td>
+                    {% if loop.index == 2 and row.type == "table" %}
+                        <a href="/{{ database }}/{{ td }}">{{ td }}</a>
+                    {% else %}
+                        {{ td }}
+                    {% endif %}
+                </td>
+            {% endfor %}
+        </tr>
+    {% endfor %}
+</table>

templates/index.html

@@ -1,21 +1,4 @@
-<style>
-td {
-    white-space: pre;
-    vertical-align: top;
-    border-top: 1px solid #666;
-    padding: 2px 4px;
-}
-</style>
-<pre>{{ metadata }}</pre>
-<table>
-    <tr>
-        {% for header in headers %}<th scope="col">{{ header }}</th>{% endfor %}
-    </tr>
-    {% for row in rows %}
-        <tr>
-            {% for td in row %}
-                <td>{{ td }}</td>
-            {% endfor %}
-        </tr>
-    {% endfor %}
-</table>
+<h1>Database{% if databases.keys()|length != 1 %}s{% endif %}</h1>
+{% for name, info in databases.items() %}
+    <p><a href="{{ name}}-{{ info.hash|truncate(7, end='') }}">{{ name }}</a></p>
+{% endfor %}

templates/table.html

@@ -0,0 +1,24 @@
+<h1><a href="/{{ database }}-{{ database_hash }}">{{ database }}</a></h1>
+
+<h2>{{ table }}</h2>
+
+<style>
+td {
+    white-space: pre;
+    vertical-align: top;
+    border-top: 1px solid #666;
+    padding: 2px 4px;
+}
+</style>
+<table>
+    <tr>
+        {% for header in headers %}<th scope="col">{{ header }}</th>{% endfor %}
+    </tr>
+    {% for row in rows %}
+        <tr>
+            {% for td in row %}
+                <td>{{ td }}</td>
+            {% endfor %}
+        </tr>
+    {% endfor %}
+</table>