Add named params (#332)

Author: ruslandoga

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- added: Added named params support
 - added: Custom type extensions. See: `Exqlite.TypeExtensions`.
 - changed: Update sqlite to `3.50.1`.
 

c_src/sqlite3_nif.c

@@ -561,6 +561,30 @@ exqlite_bind_parameter_count(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]
     return enif_make_int(env, bind_parameter_count);
 }
 
+///
+/// Get the bind parameter index
+///
+ERL_NIF_TERM
+exqlite_bind_parameter_index(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    statement_t* statement;
+    if (!enif_get_resource(env, argv[0], statement_type, (void**)&statement)) {
+        return raise_badarg(env, argv[0]);
+    }
+
+    ERL_NIF_TERM eos = enif_make_int(env, 0);
+    ErlNifBinary name;
+
+    if (!enif_inspect_iolist_as_binary(env, enif_make_list2(env, argv[1], eos), &name)) {
+        return raise_badarg(env, argv[1]);
+    }
+
+    statement_acquire_lock(statement);
+    int index = sqlite3_bind_parameter_index(statement->statement, (const char*)name.data);
+    statement_release_lock(statement);
+    return enif_make_int(env, index);
+}
+
 ///
 /// Binds a text parameter
 ///
@@ -1423,6 +1447,7 @@ static ErlNifFunc nif_funcs[] = {
   {"prepare", 2, exqlite_prepare, ERL_NIF_DIRTY_JOB_IO_BOUND},
   {"reset", 1, exqlite_reset, ERL_NIF_DIRTY_JOB_CPU_BOUND},
   {"bind_parameter_count", 1, exqlite_bind_parameter_count},
+  {"bind_parameter_index", 2, exqlite_bind_parameter_index},
   {"bind_text", 3, exqlite_bind_text},
   {"bind_blob", 3, exqlite_bind_blob},
   {"bind_integer", 3, exqlite_bind_integer},

lib/exqlite/sqlite3.ex

@@ -158,6 +158,12 @@ defmodule Exqlite.Sqlite3 do
       iex> Sqlite3.step(conn, stmt)
       {:row, [42, 3.14, "Alice", <<0, 0, 0>>, nil]}
 
+      iex> {:ok, conn} = Sqlite3.open(":memory:", [:readonly])
+      iex> {:ok, stmt} = Sqlite3.prepare(conn, "SELECT :42, @pi, $name, @blob, :null")
+      iex> Sqlite3.bind(stmt, %{":42" => 42, "@pi" => 3.14, "$name" => "Alice", :"@blob" => {:blob, <<0, 0, 0>>}, ~c":null" => nil})
+      iex> Sqlite3.step(conn, stmt)
+      {:row, [42, 3.14, "Alice", <<0, 0, 0>>, nil]}
+
       iex> {:ok, conn} = Sqlite3.open(":memory:", [:readonly])
       iex> {:ok, stmt} = Sqlite3.prepare(conn, "SELECT ?")
       iex> Sqlite3.bind(stmt, [42, 3.14, "Alice"])
@@ -174,10 +180,13 @@ defmodule Exqlite.Sqlite3 do
       ** (ArgumentError) unsupported type: #PID<0.0.0>
 
   """
-  @spec bind(statement, [bind_value] | nil) :: :ok
+  @spec bind(
+          statement,
+          [bind_value] | %{optional(String.t()) => bind_value} | nil
+        ) :: :ok
   def bind(stmt, nil), do: bind(stmt, [])
 
-  def bind(stmt, args) do
+  def bind(stmt, args) when is_list(args) do
     params_count = bind_parameter_count(stmt)
     args_count = length(args)
 
@@ -188,8 +197,40 @@ defmodule Exqlite.Sqlite3 do
     end
   end
 
-  # credo:disable-for-next-line Credo.Check.Refactor.CyclomaticComplexity
+  def bind(stmt, args) when is_map(args) do
+    params_count = bind_parameter_count(stmt)
+    args_count = map_size(args)
+
+    if args_count == params_count do
+      bind_all_named(Map.to_list(args), stmt)
+    else
+      raise ArgumentError,
+            "expected #{params_count} named arguments, got #{args_count}: #{inspect(Map.keys(args))}"
+    end
+  end
+
   defp bind_all([param | params], stmt, idx) do
+    do_bind(stmt, idx, param)
+    bind_all(params, stmt, idx + 1)
+  end
+
+  defp bind_all([], _stmt, _idx), do: :ok
+
+  defp bind_all_named([{name, param} | named_params], stmt) do
+    idx = Sqlite3NIF.bind_parameter_index(stmt, to_string(name))
+
+    if idx == 0 do
+      raise ArgumentError, "unknown named parameter: #{inspect(name)}"
+    end
+
+    do_bind(stmt, idx, param)
+    bind_all_named(named_params, stmt)
+  end
+
+  defp bind_all_named([], _stmt), do: :ok
+
+  # credo:disable-for-next-line Credo.Check.Refactor.CyclomaticComplexity
+  defp do_bind(stmt, idx, param) do
     case convert(param) do
       i when is_integer(i) -> bind_integer(stmt, idx, i)
       f when is_float(f) -> bind_float(stmt, idx, f)
@@ -202,12 +243,8 @@ defmodule Exqlite.Sqlite3 do
       {:blob, b} when is_list(b) -> bind_blob(stmt, idx, IO.iodata_to_binary(b))
       _other -> raise ArgumentError, "unsupported type: #{inspect(param)}"
     end
-
-    bind_all(params, stmt, idx + 1)
   end
 
-  defp bind_all([], _stmt, _idx), do: :ok
-
   @spec columns(db(), statement()) :: {:ok, [binary()]} | {:error, reason()}
   def columns(conn, statement), do: Sqlite3NIF.columns(conn, statement)
 

lib/exqlite/sqlite3_nif.ex

@@ -72,6 +72,9 @@ defmodule Exqlite.Sqlite3NIF do
   @spec bind_parameter_count(statement) :: integer
   def bind_parameter_count(_stmt), do: :erlang.nif_error(:not_loaded)
 
+  @spec bind_parameter_index(statement, String.t()) :: integer
+  def bind_parameter_index(_stmt, _name), do: :erlang.nif_error(:not_loaded)
+
   @spec bind_text(statement, non_neg_integer, String.t()) :: integer()
   def bind_text(_stmt, _index, _text), do: :erlang.nif_error(:not_loaded)
 

test/exqlite/query_test.exs

@@ -31,6 +31,16 @@ defmodule Exqlite.QueryTest do
     assert Enum.to_list(columns["y"]) == ["a", "b", "c"]
   end
 
+  test "named params", %{conn: conn} do
+    assert Exqlite.query!(conn, "select :a, @b, $c", %{":a" => 1, "@b" => 2, "$c" => 3}) ==
+             %Exqlite.Result{
+               command: :execute,
+               columns: [":a", "@b", "$c"],
+               rows: [[1, 2, 3]],
+               num_rows: 1
+             }
+  end
+
   defp create_conn!(_) do
     opts = [database: "#{Temp.path!()}.db"]
 

test/exqlite/sqlite3_test.exs

@@ -298,6 +298,55 @@ defmodule Exqlite.Sqlite3Test do
         Sqlite3.bind(statement, [other_tz])
       end
     end
+
+    test "binds named parameters" do
+      {:ok, conn} = Sqlite3.open(":memory:")
+
+      {:ok, statement} =
+        Sqlite3.prepare(conn, "select :42, @pi, :name, $👋, :blob, :null")
+
+      :ok =
+        Sqlite3.bind(statement, %{
+          ":42" => 42,
+          "@pi" => 3.14,
+          :":name" => "Alice",
+          "$👋" => "👋",
+          ":blob" => {:blob, <<0, 1, 2>>},
+          ~c":null" => nil
+        })
+
+      assert {:row, [42, 3.14, "Alice", "👋", <<0, 1, 2>>, nil]} =
+               Sqlite3.step(conn, statement)
+    end
+
+    test "handles repeating named parameters" do
+      {:ok, conn} = Sqlite3.open(":memory:")
+
+      {:ok, statement} =
+        Sqlite3.prepare(conn, "select :name, :name, :name")
+
+      :ok =
+        Sqlite3.bind(statement, %{
+          ":name" => "Alice"
+        })
+
+      assert {:row, ["Alice", "Alice", "Alice"]} = Sqlite3.step(conn, statement)
+    end
+
+    test "raises an error when too few or too many named parameters" do
+      {:ok, conn} = Sqlite3.open(":memory:")
+
+      {:ok, statement} =
+        Sqlite3.prepare(conn, "select :name, :age")
+
+      assert_raise ArgumentError, ~r"expected 2 named arguments, got 1", fn ->
+        Sqlite3.bind(statement, %{":name" => "Alice"})
+      end
+
+      assert_raise ArgumentError, ~r"expected 2 named arguments, got 3", fn ->
+        Sqlite3.bind(statement, %{":name" => "Alice", ":age" => 30, ":extra" => "value"})
+      end
+    end
   end
 
   describe ".bind_text/3" do