?_searchmode=raw option (#686)

datasette/views/table.py

@@ -356,13 +356,18 @@ class TableView(RowTableShared):
             pair for pair in special_args.items() if pair[0].startswith("_search")
         )
         search = ""
+        search_mode_raw = special_args.get("_searchmode") == "raw"
         if fts_table and search_args:
             if "_search" in search_args:
                 # Simple ?_search=xxx
                 search = search_args["_search"]
                 where_clauses.append(
-                    "{fts_pk} in (select rowid from {fts_table} where {fts_table} match escape_fts(:search))".format(
-                        fts_table=escape_sqlite(fts_table), fts_pk=escape_sqlite(fts_pk)
+                    "{fts_pk} in (select rowid from {fts_table} where {fts_table} match {match_clause})".format(
+                        fts_table=escape_sqlite(fts_table),
+                        fts_pk=escape_sqlite(fts_pk),
+                        match_clause=":search"
+                        if search_mode_raw
+                        else "escape_fts(:search)",
                     )
                 )
                 extra_human_descriptions.append('search matches "{}"'.format(search))
@@ -375,10 +380,12 @@ class TableView(RowTableShared):
                         raise DatasetteError("Cannot search by that column", status=400)
 
                     where_clauses.append(
-                        "rowid in (select rowid from {fts_table} where {search_col} match escape_fts(:search_{i}))".format(
+                        "rowid in (select rowid from {fts_table} where {search_col} match {match_clause})".format(
                             fts_table=escape_sqlite(fts_table),
                             search_col=escape_sqlite(search_col),
-                            i=i,
+                            match_clause=":search_{}".format(i)
+                            if search_mode_raw
+                            else "escape_fts(:search_{})".format(i),
                         )
                     )
                     extra_human_descriptions.append(

docs/json_api.rst

@@ -281,6 +281,12 @@ Special table arguments
     Like ``_search=`` but allows you to specify the column to be searched, as
     opposed to searching all columns that have been indexed by FTS.
 
+``?_searchmode=raw``
+    With this option, queries passed to ``?_search=`` or ``?_search_COLUMN=`` will
+    not have special characters escaped. This means you can make use of the full
+    set of `advanced SQLite FTS syntax <https://www.sqlite.org/fts5.html#full_text_query_syntax>`__,
+    though this could potentially result in errors if the wrong syntax is used.
+
 ``?_where=SQL-fragment``
     If the :ref:`config_allow_sql` config option is enabled, this parameter
     can be used to pass one or more additional SQL fragments to be used in the

tests/test_api.py

@@ -952,6 +952,19 @@ def test_sortable_columns_metadata(app_client):
             "/fixtures/searchable.json?_search=AND",
             [],
         ),
+        (
+            # Without _searchmode=raw this should return no results
+            "/fixtures/searchable.json?_search=te*+AND+do*",
+            [],
+        ),
+        (
+            # _searchmode=raw
+            "/fixtures/searchable.json?_search=te*+AND+do*&_searchmode=raw",
+            [
+                [1, "barry cat", "terry dog", "panther"],
+                [2, "terry dog", "sara weasel", "puma"],
+            ],
+        ),
         (
             "/fixtures/searchable.json?_search=weasel",
             [[2, "terry dog", "sara weasel", "puma"]],