From 722e102eab10cf00bd092cba5b0d43cc2b38a657 Mon Sep 17 00:00:00 2001
From: Jinkyou Son <nallwhy@gmail.com>
Date: Fri, 5 Jul 2024 16:08:22 +0900
Subject: [PATCH 1/4] Add quote_boundary opt to content_type/3

---
 lib/multipart.ex | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/lib/multipart.ex b/lib/multipart.ex
index 4433c6c..873fce2 100644
--- a/lib/multipart.ex
+++ b/lib/multipart.ex
@@ -70,9 +70,17 @@ defmodule Multipart do
       iex> Multipart.content_type(multipart, "multipart/mixed")
       "multipart/mixed; boundary=\\"==abc123==\\""
   """
-  @spec content_type(Multipart.t(), String.t()) :: String.t()
-  def content_type(%__MODULE__{boundary: boundary}, mime_type) do
-    [mime_type, "boundary=\"#{boundary}\""]
+  @spec content_type(Multipart.t(), String.t(), Keyword.t()) :: String.t()
+  def content_type(%__MODULE__{boundary: boundary}, mime_type, opts \\ []) do
+    quote_boundary = opts |> Keyword.get(:quote_boundary, true)
+
+    boundary =
+      case quote_boundary do
+        true -> "\"#{boundary}\""
+        false -> boundary
+      end
+
+    [mime_type, "boundary=#{boundary}"]
     |> Enum.join("; ")
   end
 

From 8ffd41d61b0ef9ab88bcb03371d3eb737d0842c6 Mon Sep 17 00:00:00 2001
From: Jinkyou Son <nallwhy@gmail.com>
Date: Tue, 20 Jan 2026 09:11:32 +0900
Subject: [PATCH 2/4] Add unit tests for contet_type/3

---
 test/multipart_test.exs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/test/multipart_test.exs b/test/multipart_test.exs
index c4b5311..f2698cd 100644
--- a/test/multipart_test.exs
+++ b/test/multipart_test.exs
@@ -124,6 +124,20 @@ defmodule MultipartTest do
     assert output == expected_output
   end
 
+  describe "content_type/3" do
+    test "returns Content-Type header with quoted boundary by default" do
+      multipart = Multipart.new("myboundary")
+      content_type = Multipart.content_type(multipart, "multipart/form-data")
+      assert content_type == "multipart/form-data; boundary=\"myboundary\""
+    end
+
+    test "returns Content-Type header with unquoted boundary when specified" do
+      multipart = Multipart.new("myboundary")
+      content_type = Multipart.content_type(multipart, "multipart/form-data", quote_boundary: false)
+      assert content_type == "multipart/form-data; boundary=myboundary"
+    end
+  end
+
   defp file_path(path) do
     Path.join(__DIR__, path)
   end

From b6571c2fc06b164526685f780778c5d1a8451a00 Mon Sep 17 00:00:00 2001
From: Tom Taylor <tom@breakroom.cc>
Date: Tue, 20 Jan 2026 09:24:17 +0000
Subject: [PATCH 3/4] Add docs for disabling boundary quotes

---
 lib/multipart.ex        | 8 ++++++--
 test/multipart_test.exs | 5 ++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/multipart.ex b/lib/multipart.ex
index 873fce2..21ef651 100644
--- a/lib/multipart.ex
+++ b/lib/multipart.ex
@@ -66,9 +66,13 @@ defmodule Multipart do
   @doc """
   Returns the Content-Type header for the `Multipart` message.
 
-      iex> multipart = Multipart.new("==abc123==")
+  Pass in `Keyword` option `:quote_boundary` set `false` to disable quoting the boundary.
+
+      iex> multipart = Multipart.new("abc123")
       iex> Multipart.content_type(multipart, "multipart/mixed")
-      "multipart/mixed; boundary=\\"==abc123==\\""
+      "multipart/mixed; boundary=\\"abc123\\""
+      iex> Multipart.content_type(multipart, "multipart/mixed", quote_boundary: false)
+      "multipart/mixed; boundary=abc123"
   """
   @spec content_type(Multipart.t(), String.t(), Keyword.t()) :: String.t()
   def content_type(%__MODULE__{boundary: boundary}, mime_type, opts \\ []) do
diff --git a/test/multipart_test.exs b/test/multipart_test.exs
index f2698cd..3ec12cf 100644
--- a/test/multipart_test.exs
+++ b/test/multipart_test.exs
@@ -133,7 +133,10 @@ defmodule MultipartTest do
 
     test "returns Content-Type header with unquoted boundary when specified" do
       multipart = Multipart.new("myboundary")
-      content_type = Multipart.content_type(multipart, "multipart/form-data", quote_boundary: false)
+
+      content_type =
+        Multipart.content_type(multipart, "multipart/form-data", quote_boundary: false)
+
       assert content_type == "multipart/form-data; boundary=myboundary"
     end
   end

From fbbbef894e2a8ae3419cefda667d7edd938e3e88 Mon Sep 17 00:00:00 2001
From: Tom Taylor <tom@breakroom.cc>
Date: Tue, 20 Jan 2026 09:27:44 +0000
Subject: [PATCH 4/4] Style tweak

---
 lib/multipart.ex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/multipart.ex b/lib/multipart.ex
index 21ef651..5ad3a97 100644
--- a/lib/multipart.ex
+++ b/lib/multipart.ex
@@ -76,7 +76,7 @@ defmodule Multipart do
   """
   @spec content_type(Multipart.t(), String.t(), Keyword.t()) :: String.t()
   def content_type(%__MODULE__{boundary: boundary}, mime_type, opts \\ []) do
-    quote_boundary = opts |> Keyword.get(:quote_boundary, true)
+    quote_boundary = Keyword.get(opts, :quote_boundary, true)
 
     boundary =
       case quote_boundary do