Use context in custom filters

README.md

@@ -49,8 +49,8 @@ You can add your own filters and tags/blocks inside your project:
 
 ``` elixir
 defmodule MyFilters do
-  def meaning_of_life(_), do: 42
-  def one(_), do: 1
+  def meaning_of_life(_, _context), do: 42
+  def one(_, _context), do: 1
 end
 
 defmodule ExampleTag do
@@ -90,10 +90,10 @@ It's also possible to apply global filter to all rendered variables setting up t
 ``` elixir
 # config.exs
 config :liquid,
-  global_filter: &MyFilter.counting_sheeps/1
+  global_filter: &MyFilter.counting_sheeps/2
 ```
 or adding a `"global_filter"` value to context for `Liquid.Template.render` function:
-`Liquid.Template.render(tpl, %{global_filter: &MyFilter.counting_sheeps/1})` (you need to define filter function first) 
+`Liquid.Template.render(tpl, %{global_filter: &MyFilter.counting_sheeps/2})` (you need to define filter function first)
 
 ## File systems
 You can also set up the desired default file system for your project using the `config.exs` file 

lib/liquid/filters.ex

@@ -4,7 +4,7 @@ defmodule Liquid.Filters do
   """
   import Kernel, except: [round: 1, abs: 1, floor: 1, ceil: 1]
   import Liquid.Utils, only: [to_number: 1]
-  alias Liquid.HTML
+  alias Liquid.{Context, HTML}
 
   defmodule Functions do
     @moduledoc """
@@ -484,9 +484,9 @@ defmodule Liquid.Filters do
   @doc """
   Recursively pass through all of the input filters applying them
   """
-  def filter([], value), do: value
+  def filter([], value, _context), do: value
 
-  def filter([filter | rest], value) do
+  def filter([filter | rest], value, %Context{} = context) do
     [name, args] = filter
 
     args =
@@ -509,13 +509,13 @@ defmodule Liquid.Filters do
 
         # Fallback to custom if no standard
         {_, nil, _} ->
-          apply_function(custom_filters[name], name, [value | args])
+          apply_function(custom_filters[name], name, [value, context | args])
 
         _ ->
           apply_function(Functions, name, [value | args])
       end
 
-    filter(rest, ret)
+    filter(rest, ret, context)
   end
 
   @doc """

lib/liquid/variable.ex

@@ -31,7 +31,7 @@ defmodule Liquid.Variable do
 
     result =
       try do
-        {:ok, filters |> Filters.filter(ret) |> apply_global_filter(context)}
+        {:ok, filters |> Filters.filter(ret, context) |> apply_global_filter(context)}
       rescue
         e in UndefinedFunctionError -> {e, e.reason}
         e in ArgumentError -> {e, e.message}
@@ -59,8 +59,8 @@ defmodule Liquid.Variable do
 
   defp apply_global_filter(input, %Context{global_filter: nil}), do: input
 
-  defp apply_global_filter(input, %Context{global_filter: global_filter}),
-    do: global_filter.(input)
+  defp apply_global_filter(input, %Context{global_filter: global_filter} = context),
+    do: global_filter.(input, context)
 
   @doc """
   Parses the markup to a list of filters

test/liquid/custom_filter_test.exs

@@ -5,16 +5,22 @@ defmodule Liquid.CustomFilterTest do
   alias Liquid.Template
 
   defmodule MyFilter do
-    def meaning_of_life(_), do: 42
+    def meaning_of_life(_, _), do: 42
   end
 
   defmodule MyFilterTwo do
-    def meaning_of_life(_), do: 40
-    def not_meaning_of_life(_), do: 2
+    def meaning_of_life(_, _), do: 40
+    def not_meaning_of_life(_, _), do: 2
+  end
+
+  defmodule MyFilterThree do
+    def stuff(_, context) do
+      context.assigns.test
+    end
   end
 
   setup_all do
-    Application.put_env(:liquid, :extra_filter_modules, [MyFilter, MyFilterTwo])
+    Application.put_env(:liquid, :extra_filter_modules, [MyFilter, MyFilterTwo, MyFilterThree])
     Liquid.start()
     on_exit(fn -> Liquid.stop() end)
     :ok
@@ -38,6 +44,10 @@ defmodule Liquid.CustomFilterTest do
     )
   end
 
+  test "custom filter can use context" do
+    assert_template_result("100", "{{ 'text' | stuff }}", %{test: 100})
+  end
+
   defp assert_template_result(expected, markup, assigns \\ %{}) do
     assert_result(expected, markup, assigns)
   end

test/liquid/filter_test.exs

@@ -3,7 +3,7 @@ Code.require_file("../../test_helper.exs", __ENV__.file)
 defmodule Liquid.FilterTest do
   use ExUnit.Case
   use Timex
-  alias Liquid.{Filters, Template, Variable}
+  alias Liquid.{Context, Filters, Template, Variable}
   alias Liquid.Filters.Functions
 
   setup_all do
@@ -22,7 +22,7 @@ defmodule Liquid.FilterTest do
   test :filter_parsed do
     name = "'foofoo'"
     filters = [[:replace, ["'foo'", "'bar'"]]]
-    assert "'barbar'" == Filters.filter(filters, name)
+    assert "'barbar'" == Filters.filter(filters, name, %Context{})
   end
 
   test :size do

test/liquid/global_filter_test.exs

@@ -5,12 +5,13 @@ defmodule Liquid.GlobalFilterTest do
   alias Liquid.Template
 
   defmodule MyFilter do
-    def counting_sheeps(input) when is_binary(input), do: input <> " One, two, thr.. z-zz.."
-    def counting_bees(input) when is_binary(input), do: input <> " One, tw.. Ouch!"
+    def counting_sheeps(input, _) when is_binary(input), do: input <> " One, two, thr.. z-zz.."
+    def counting_bees(input, _) when is_binary(input), do: input <> " One, tw.. Ouch!"
+    def context_bees(input, context) when is_binary(input), do: input <> context.assigns.test
   end
 
   setup_all do
-    Application.put_env(:liquid, :global_filter, &MyFilter.counting_sheeps/1)
+    Application.put_env(:liquid, :global_filter, &MyFilter.counting_sheeps/2)
     Liquid.start()
     on_exit(fn -> Liquid.stop(Application.delete_env(:liquid, :global_filter)) end)
     :ok
@@ -22,7 +23,14 @@ defmodule Liquid.GlobalFilterTest do
 
   test "preset filter overrides default applied" do
     assert_template_result("Initial One, tw.. Ouch!", "{{ 'initial' | capitalize }}", %{
-      global_filter: &MyFilter.counting_bees/1
+      global_filter: &MyFilter.counting_bees/2
+    })
+  end
+
+  test "can use context" do
+    assert_template_result("Initial bee", "{{ 'initial' | capitalize }}", %{
+      global_filter: &MyFilter.context_bees/2,
+      test: " bee"
     })
   end