encode_body: Support %File.Stream{} in :form_multipart

Closes #401

lib/req/steps.ex

@@ -417,6 +417,7 @@ defmodule Req.Steps do
 
         %{request | body: multipart.body}
         |> Req.Request.put_new_header("content-type", multipart.content_type)
+        |> Req.Request.put_new_header("content-length", Integer.to_string(multipart.size))
 
       data = request.options[:json] ->
         %{request | body: Jason.encode_to_iodata!(data)}

lib/req/utils.ex

@@ -326,6 +326,8 @@ defmodule Req.Utils do
     %CollectWithHash{collectable: collectable, type: type}
   end
 
+  @crlf "\r\n"
+
   @doc """
   Encodes fields into "multipart/form-data" format.
   """
@@ -336,40 +338,44 @@ defmodule Req.Utils do
       options[:boundary] ||
         Base.encode16(:crypto.strong_rand_bytes(16), padding: false, case: :lower)
 
-    crlf = "\r\n"
+    footer = [[@crlf, "--", boundary, "--", @crlf]]
 
-    body =
+    {body, size} =
       fields
-      |> Enum.reduce([], &add_form_parts(&2, encode_form_part(&1, boundary)))
-      |> add_form_parts([[crlf, "--", boundary, "--", crlf]])
+      |> Enum.reduce({[], 0}, &add_form_parts(&2, encode_form_part(&1, boundary)))
+      |> add_form_parts({footer, IO.iodata_length(footer)})
 
     %{
+      size: size,
       content_type: "multipart/form-data; boundary=#{boundary}",
       body: body
     }
   end
 
-  defp add_form_parts(parts1, parts2) when is_list(parts1) and is_list(parts2) do
-    [parts1, parts2]
+  defp add_form_parts({parts1, size1}, {parts2, size2})
+       when is_list(parts1) and is_list(parts2) do
+    {[parts1, parts2], size1 + size2}
   end
 
-  defp add_form_parts(parts1, parts2) do
-    Stream.concat(parts1, parts2)
+  defp add_form_parts({parts1, size1}, {parts2, size2}) do
+    {Stream.concat(parts1, parts2), size1 + size2}
   end
 
   defp encode_form_part({name, {value, options}}, boundary) do
     options = Keyword.validate!(options, [:filename, :content_type])
 
-    {parts, options} =
+    {parts, parts_size, options} =
       case value do
         integer when is_integer(integer) ->
-          {[Integer.to_string(integer)], options}
+          part = Integer.to_string(integer)
+          {[part], byte_size(part), options}
 
         value when is_binary(value) or is_list(value) ->
-          {[value], options}
+          {[value], IO.iodata_length(value), options}
 
         stream = %File.Stream{} ->
           filename = Path.basename(stream.path)
+          size = File.stat!(stream.path).size
 
           options =
             options
@@ -378,7 +384,7 @@ defmodule Req.Utils do
               MIME.from_path(filename)
             end)
 
-          {stream, options}
+          {stream, size, options}
       end
 
     params =
@@ -388,17 +394,16 @@ defmodule Req.Utils do
         []
       end
 
-    crlf = "\r\n"
-
     headers =
       if content_type = options[:content_type] do
-        ["content-type: ", content_type, crlf]
+        ["content-type: ", content_type, @crlf]
       else
         []
       end
 
-    headers = ["content-disposition: form-data; name=\"#{name}\"", params, crlf, headers]
-    add_form_parts([[crlf, "--", boundary, crlf, headers, crlf]], parts)
+    headers = ["content-disposition: form-data; name=\"#{name}\"", params, @crlf, headers]
+    header = [[@crlf, "--", boundary, @crlf, headers, @crlf]]
+    add_form_parts({header, IO.iodata_length(header)}, {parts, parts_size})
   end
 
   defp encode_form_part({name, value}, boundary) do

test/req/steps_test.exs

@@ -257,6 +257,7 @@ defmodule Req.StepsTest do
       plug = fn conn ->
         conn = Plug.Parsers.call(conn, Plug.Parsers.init(parsers: [:multipart]))
 
+        assert Plug.Conn.get_req_header(conn, "content-length") == ["393"]
         assert %{"a" => "1", "b" => b, "c" => c} = conn.body_params
 
         assert b.filename == "b.txt"

test/req/utils_test.exs

@@ -72,7 +72,7 @@ defmodule Req.UtilsTest do
 
   describe "encode_form_multipart" do
     test "it works" do
-      %{content_type: content_type, body: body} =
+      %{content_type: content_type, body: body, size: size} =
         Req.Utils.encode_form_multipart(
           [
             field1: 1,
@@ -82,9 +82,11 @@ defmodule Req.UtilsTest do
           boundary: "foo"
         )
 
+      body = IO.iodata_to_binary(body)
+      assert size == byte_size(body)
       assert content_type == "multipart/form-data; boundary=foo"
 
-      assert IO.iodata_to_binary(body) == """
+      assert body == """
              \r\n\
              --foo\r\n\
              content-disposition: form-data; name=\"field1\"\r\n\
@@ -107,7 +109,7 @@ defmodule Req.UtilsTest do
     test "can return stream", %{tmp_dir: tmp_dir} do
       File.write!("#{tmp_dir}/2.txt", "22")
 
-      %{body: body} =
+      %{body: body, size: size} =
         Req.Utils.encode_form_multipart(
           [
             field1: 1,
@@ -117,8 +119,10 @@ defmodule Req.UtilsTest do
         )
 
       assert is_function(body)
+      body = body |> Enum.to_list() |> IO.iodata_to_binary()
+      assert size == byte_size(body)
 
-      assert body |> Enum.to_list() |> IO.iodata_to_binary() == """
+      assert body == """
              \r\n\
              --foo\r\n\
              content-disposition: form-data; name=\"field1\"\r\n\
@@ -132,7 +136,7 @@ defmodule Req.UtilsTest do
              --foo--\r\n\
              """
 
-      %{body: body} =
+      %{body: body, size: size} =
         Req.Utils.encode_form_multipart(
           [
             field2: File.stream!("#{tmp_dir}/2.txt"),
@@ -142,8 +146,10 @@ defmodule Req.UtilsTest do
         )
 
       assert is_function(body)
+      body = body |> Enum.to_list() |> IO.iodata_to_binary()
+      assert size == byte_size(body)
 
-      assert body |> Enum.to_list() |> IO.iodata_to_binary() == """
+      assert body == """
              \r\n\
              --foo\r\n\
              content-disposition: form-data; name=\"field2\"; filename=\"2.txt\"\r\n\