New WIP writable canned queries

Refs #698. Replaces #703

datasette/templates/query.html

@@ -27,11 +27,12 @@
 {% endblock %}
 
 {% block content %}
+
 <h1 style="padding-left: 10px; border-left: 10px solid #{{ database_color(database) }}">{{ metadata.title or database }}</h1>
 
 {% block description_source_license %}{% include "_description_source_license.html" %}{% endblock %}
 
-<form class="sql" action="{{ database_url(database) }}{% if canned_query %}/{{ canned_query }}{% endif %}" method="get">
+<form class="sql" action="{{ database_url(database) }}{% if canned_query %}/{{ canned_query }}{% endif %}" method="{% if canned_write %}post{% else %}get{% endif %}">
     <h3>Custom SQL query{% if display_rows %} returning {% if truncated %}more than {% endif %}{{ "{:,}".format(display_rows|length) }} row{% if display_rows|length == 1 %}{% else %}s{% endif %}{% endif %} <span class="show-hide-sql">{% if hide_sql %}(<a href="{{ path_with_removed_args(request, {'_hide_sql': '1'}) }}">show</a>){% else %}(<a href="{{ path_with_added_args(request, {'_hide_sql': '1'}) }}">hide</a>){% endif %}</span></h3>
     {% if not hide_sql %}
         {% if editable and config.allow_sql %}
@@ -74,7 +75,9 @@ <h3>Query parameters</h3>
     </tbody>
 </table>
 {% else %}
-    <p class="zero-results">0 results</p>
+    {% if not canned_write %}
+        <p class="zero-results">0 results</p>
+    {% endif %}
 {% endif %}
 
 {% include "_codemirror_foot.html" %}

datasette/views/database.py

@@ -106,14 +106,16 @@ async def data(
         canned_query=None,
         metadata=None,
         _size=None,
+        named_parameters=None,
+        write=False,
     ):
         params = {key: request.args.get(key) for key in request.args}
         if "sql" in params:
             params.pop("sql")
         if "_shape" in params:
             params.pop("_shape")
         # Extract any :named parameters
-        named_parameters = self.re_named_parameter.findall(sql)
+        named_parameters = named_parameters or self.re_named_parameter.findall(sql)
         named_parameter_values = {
             named_parameter: params.get(named_parameter) or ""
             for named_parameter in named_parameters
@@ -129,12 +131,48 @@ async def data(
             extra_args["custom_time_limit"] = int(params["_timelimit"])
         if _size:
             extra_args["page_size"] = _size
-        results = await self.ds.execute(
-            database, sql, params, truncate=True, **extra_args
-        )
-        columns = [r[0] for r in results.description]
 
         templates = ["query-{}.html".format(to_css_class(database)), "query.html"]
+
+        # Execute query - as write or as read
+        if write:
+            if request.method == "POST":
+                params = await request.post_vars()
+                write_ok = await self.ds.databases[database].execute_write(
+                    sql, params, block=True
+                )
+                self.ds.add_message(request, "Query executed")
+                return self.redirect(
+                    request, request.path
+                )
+            else:
+                async def extra_template():
+                    return {
+                        "request": request,
+                        "path_with_added_args": path_with_added_args,
+                        "path_with_removed_args": path_with_removed_args,
+                        "named_parameter_values": named_parameter_values,
+                        "canned_query": canned_query,
+                        "success_message": request.args.get("_success") or "",
+                        "canned_write": True,
+                    }
+                return (
+                    {
+                        "database": database,
+                        "rows": [],
+                        "truncated": False,
+                        "columns": [],
+                        "query": {"sql": sql, "params": params},
+                    },
+                    extra_template,
+                    templates,
+                )
+        else:  # Not a write
+            results = await self.ds.execute(
+                database, sql, params, truncate=True, **extra_args
+            )
+            columns = [r[0] for r in results.description]
+
         if canned_query:
             templates.insert(
                 0,

datasette/views/table.py

@@ -221,6 +221,22 @@ async def display_columns_and_rows(
 class TableView(RowTableShared):
     name = "table"
 
+    async def post(self, request, db_name, table_and_format):
+        # Handle POST to a canned query
+        canned_query = self.ds.get_canned_query(db_name, table_and_format)
+        assert canned_query, "You may only POST to a canned query"
+        return await QueryView(self.ds).data(
+            request,
+            db_name,
+            None,
+            canned_query["sql"],
+            metadata=canned_query,
+            editable=False,
+            canned_query=table_and_format,
+            named_parameters=canned_query.get("params"),
+            write=bool(canned_query.get("write")),
+        )
+
     async def data(
         self,
         request,
@@ -241,6 +257,8 @@ async def data(
                 metadata=canned_query,
                 editable=False,
                 canned_query=table,
+                named_parameters=canned_query.get("params"),
+                write=bool(canned_query.get("write")),
             )
 
         db = self.ds.databases[database]