feat: add helpers function to deal and merge headers and query

Author: zoedsoupe

lib/supabase/fetcher.ex

@@ -108,7 +108,7 @@ defmodule Supabase.Fetcher do
           url: Finch.Request.url(),
           options: Finch.request_opts(),
           service: Supabase.service(),
-          query: map,
+          query: list({String.t(), String.t()}),
           body_decoder: module,
           error_parser: module
         }
@@ -119,9 +119,9 @@ defmodule Supabase.Fetcher do
     :client,
     :body,
     method: :get,
-    query: %{},
+    query: [],
     options: [],
-    headers: %{},
+    headers: [],
     body_decoder: Supabase.Fetcher.JSONDecoder,
     error_parser: Supabase.ErrorParser
   ]
@@ -505,6 +505,51 @@ defmodule Supabase.Fetcher do
     get_header(resp, header) || default
   end
 
+  @doc """
+  Tries to find and return the value for a query param, given it name, if it doesn't
+  existis, it returns the default value informed or `nil`.
+  """
+  @spec get_query_param(t, param :: String.t(), default :: String.t() | nil) :: String.t() | nil
+  def get_query_param(%__MODULE__{} = builder, key, default \\ nil)
+      when is_binary(key) and (is_binary(default) or is_nil(default)) do
+    case List.keyfind(builder.query, key, 0) do
+      nil -> default
+      {^key, value} -> value
+    end
+  end
+
+  @doc """
+  Tries to find and return the value for a request headers, given it name, if it doesn't
+  existis, it returns the default value informed or `nil`.
+
+  Do not confuse with `get_header/2`.
+  """
+  @spec get_req_header(t, name :: String.t(), default :: String.t() | nil) :: String.t() | nil
+  def get_req_header(%__MODULE__{} = builder, key, default \\ nil)
+      when is_binary(key) and (is_binary(default) or is_nil(default)) do
+    case List.keyfind(builder.headers, key, 0) do
+      nil -> default
+      {^key, value} -> value
+    end
+  end
+
+  @doc """
+  Merges an existing query param value with a new one, prepending the new value
+  with the existing one. If no current value exists for the param, this function
+  will behave the same as `with_query/2`.
+  """
+  @spec merge_query_param(t, param :: String.t(), value :: String.t(),
+          with: joinner :: String.t()
+        ) :: t
+  def merge_query_param(%__MODULE__{} = builder, key, value, [with: w] \\ [with: ","])
+      when is_binary(key) and is_binary(value) and is_binary(w) do
+    if curr = get_query_param(builder, key) do
+      with_query(builder, %{key => "#{curr}#{w}#{value}"})
+    else
+      with_query(builder, %{key => value})
+    end
+  end
+
   defimpl Inspect, for: Supabase.Fetcher do
     import Inspect.Algebra
 

test/supabase/fetcher_test.exs

@@ -165,7 +165,88 @@ defmodule Supabase.FetcherTest do
     end
   end
 
-  # VCR and "integration" tests
+  describe "get_query_param/3" do
+    setup ctx do
+      fetcher = ctx.client |> Fetcher.new() |> Fetcher.with_query(%{"key1" => "value1", "key2" => "value2"})
+      {:ok, Map.put(ctx, :fetcher, fetcher)}
+    end
+
+    test "retrieves an existing query parameter", %{fetcher: fetcher} do
+      assert Fetcher.get_query_param(fetcher, "key1") == "value1"
+    end
+
+    test "returns nil for a missing query parameter", %{fetcher: fetcher} do
+      assert Fetcher.get_query_param(fetcher, "key3") == nil
+    end
+
+    test "returns the default value for a missing query parameter", %{fetcher: fetcher} do
+      assert Fetcher.get_query_param(fetcher, "key3", "default_value") == "default_value"
+    end
+
+    test "handles empty query parameters gracefully", %{client: client} do
+      fetcher = Fetcher.new(client)
+      assert Fetcher.get_query_param(fetcher, "key") == nil
+    end
+  end
+
+  describe "get_req_header/3" do
+    setup ctx do
+      fetcher =
+        Fetcher.new(ctx.client)
+        |> Fetcher.with_headers(%{
+          "Authorization" => "Bearer token",
+          "Content-Type" => "application/json"
+        })
+
+      {:ok, fetcher: fetcher}
+    end
+
+    test "retrieves an existing header", %{fetcher: fetcher} do
+      assert Fetcher.get_req_header(fetcher, "Authorization") == "Bearer token"
+    end
+
+    test "returns nil for a missing header", %{fetcher: fetcher} do
+      assert Fetcher.get_req_header(fetcher, "Accept") == nil
+    end
+
+    test "returns the default value for a missing header", %{fetcher: fetcher} do
+      assert Fetcher.get_req_header(fetcher, "Accept", "application/xml") == "application/xml"
+    end
+
+    test "handles empty headers gracefully", %{client: client} do
+      fetcher = Fetcher.new(client)
+      assert Fetcher.get_req_header(fetcher, "Authorization") == nil
+    end
+  end
+
+  describe "merge_query_param/4" do
+    setup ctx do
+      fetcher = Fetcher.new(ctx.client) |> Fetcher.with_query(%{"key1" => "value1"})
+      {:ok, fetcher: fetcher}
+    end
+
+    test "merges a new query parameter when key does not exist", %{fetcher: fetcher} do
+      updated_fetcher = Fetcher.merge_query_param(fetcher, "key2", "value2")
+      assert Fetcher.get_query_param(updated_fetcher, "key2") == "value2"
+    end
+
+    test "merges with default separator when key exists", %{fetcher: fetcher} do
+      updated_fetcher = Fetcher.merge_query_param(fetcher, "key1", "value2")
+      assert Fetcher.get_query_param(updated_fetcher, "key1") == "value1,value2"
+    end
+
+    test "merges with custom separator when specified", %{fetcher: fetcher} do
+      updated_fetcher = Fetcher.merge_query_param(fetcher, "key1", "value2", [with: "|"])
+      assert Fetcher.get_query_param(updated_fetcher, "key1") == "value1|value2"
+    end
+
+    test "handles merging into an empty query", %{client: client} do
+      fetcher = Fetcher.new(client)
+      updated_fetcher = Fetcher.merge_query_param(fetcher, "key1", "value1")
+      assert Fetcher.get_query_param(updated_fetcher, "key1") == "value1"
+    end
+  end
+
   defp have_header?(headers, name) do
     Enum.any?(headers, fn {k, _} ->
       String.downcase(k) == String.downcase(name)