From 81943cc16c9a498bc1185a836f1325e23db963e1 Mon Sep 17 00:00:00 2001
From: pmeinhardt <mnhrdt@gmail.com>
Date: Thu, 17 Dec 2020 08:35:19 +0100
Subject: [PATCH] Prototype new upload implementation using SFTP

---
 examples/upload.exs  |   5 +++
 lib/sshkit.ex        |  11 +++--
 lib/sshkit/upload.ex | 105 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 118 insertions(+), 3 deletions(-)
 create mode 100644 examples/upload.exs
 create mode 100644 lib/sshkit/upload.ex

diff --git a/examples/upload.exs b/examples/upload.exs
new file mode 100644
index 00000000..ed12658c
--- /dev/null
+++ b/examples/upload.exs
@@ -0,0 +1,5 @@
+{:ok, conn} = SSHKit.connect("127.0.0.1", port: 2222, user: "deploy", password: "deploy", silently_accept_hosts: true)
+
+:ok = SSHKit.upload(conn, "test/fixtures", "/tmp/fixtures", recursive: true)
+
+:ok = SSHKit.close(conn)
diff --git a/lib/sshkit.ex b/lib/sshkit.ex
index 1d1ed835..5719aa6e 100644
--- a/lib/sshkit.ex
+++ b/lib/sshkit.ex
@@ -22,6 +22,7 @@ defmodule SSHKit do
 
   alias SSHKit.Context
   alias SSHKit.Host
+  alias SSHKit.Upload
 
   @doc """
   TODO
@@ -245,8 +246,12 @@ defmodule SSHKit do
     |> SSHKit.upload("local.txt", as: "remote.txt")
   ```
   """
-  def upload(context, source, options \\ []) do
-    # TODO
+  def upload(conn, source, target, options \\ []) do
+    upload = Upload.init(source, target, options)
+
+    with {:ok, upload} <- Upload.start(upload, conn) do
+      Upload.loop(upload)
+    end
   end
 
   @doc ~S"""
@@ -280,7 +285,7 @@ defmodule SSHKit do
     |> SSHKit.download("remote.txt", as: "local.txt")
   ```
   """
-  def download(context, source, options \\ []) do
+  def download(conn, source, options \\ []) do
     # TODO
   end
 end
diff --git a/lib/sshkit/upload.ex b/lib/sshkit/upload.ex
new file mode 100644
index 00000000..f6e78953
--- /dev/null
+++ b/lib/sshkit/upload.ex
@@ -0,0 +1,105 @@
+defmodule SSHKit.Upload do
+  @moduledoc """
+  TODO
+  """
+
+  defstruct [:source, :target, :options, :cwd, :stack, :channel]
+
+  def init(source, target, options \\ []) do
+    %__MODULE__{source: Path.expand(source), target: target, options: options}
+  end
+
+  def start(%__MODULE__{} = upload, connection) do
+    with {:ok, upload} <- prepare(upload) do
+      {:ok, channel} = :ssh_sftp.start_channel(connection.ref) # accepts options like timeout… http://erlang.org/doc/man/ssh_sftp.html#start_channel-1
+      {:ok, %{upload | channel: channel}}
+    end
+  end
+
+  defp prepare(%__MODULE__{source: source, options: options} = upload) do
+    # TODO: Support globs, https://hexdocs.pm/elixir/Path.html#wildcard/2
+    if !Keyword.get(options, :recursive, false) && File.dir?(source) do
+      {:error, "Option :recursive not specified, but local file is a directory (#{source})"} # TODO: Better error
+    else
+      {:ok, %{upload | cwd: Path.dirname(source), stack: [[Path.basename(source)]]}}
+    end
+  end
+
+  def stop(%__MODULE__{channel: nil} = upload), do: {:ok, upload}
+  def stop(%__MODULE__{channel: channel} = upload) do
+    with :ok <- :ssh_sftp.stop_channel(channel) do
+      {:ok, %{upload | channel: nil}}
+    end
+  end
+
+  # TODO: Handle unstarted uploads w/o channel, cwd, stack… and provide helpful error?
+
+  def continue(%__MODULE__{stack: []} = upload) do
+    {:ok, upload}
+  end
+
+  def continue(%__MODULE__{stack: [[] | paths]} = upload) do
+    {:ok, %{upload | cwd: Path.dirname(upload.cwd), stack: paths}}
+  end
+
+  def continue(%__MODULE__{stack: [[name | rest] | paths]} = upload) do
+    path = Path.join(upload.cwd, name)
+    relpath = Path.relative_to(path, Path.expand(upload.source))
+    relpath = if relpath == path, do: ".", else: relpath
+
+    remote =
+      upload.target
+      |> Path.join(relpath)
+      |> Path.expand()
+
+    with {:ok, stat} <- File.stat(path, time: :posix) do
+      # TODO: Set timestamps… if :preserve option is true, http://erlang.org/doc/man/ssh_sftp.html#write_file_info-3
+
+      channel = upload.channel
+
+      case stat.type do
+        :directory ->
+          # TODO: Timeouts
+          :ok = :ssh_sftp.make_dir(channel, remote)
+          {:ok, names} = File.ls(path)
+          {:ok, %{upload | cwd: path, stack: [names | [rest | paths]]}}
+
+        :regular ->
+          # TODO: Timeouts
+          {:ok, handle} = :ssh_sftp.open(channel, remote, [:write, :binary])
+
+          path
+          |> File.stream!([], 16_384)
+          |> Stream.each(fn data -> :ok = :ssh_sftp.write(channel, handle, data) end)
+          |> Stream.run()
+
+          :ok = :ssh_sftp.close(channel, handle)
+          {:ok, %{upload | stack: [rest | paths]}}
+
+        :symlink ->
+          nil
+
+        _ ->
+          {:error, {:unkown_file_type, path}}
+      end
+    end
+  end
+
+  # TODO: Make `loop` return a stream? Possibly rename to "stream" then
+  def loop(%__MODULE__{stack: []}) do
+    :ok
+  end
+
+  def loop(%__MODULE__{} = upload) do
+    case continue(upload) do
+      {:ok, upload} ->
+        loop(upload)
+
+      error ->
+        error
+    end
+  end
+
+  def done?(%__MODULE__{stack: []}), do: true
+  def done?(%__MODULE__{}), do: false
+end