Add url arg to the CLI (#947)

lib/livebook_app.ex

@@ -84,10 +84,7 @@ if Mix.target() == :app do
     end
 
     defp import_livebook(url) do
-      LivebookWeb.Endpoint.access_struct_url()
-      |> Map.replace!(:path, "/import")
-      |> append_query("url=#{URI.encode_www_form(url)}")
-      |> URI.to_string()
+      LivebookWeb.Helpers.notebook_import_url(url)
       |> Livebook.Utils.browser_open()
     end
 
@@ -111,14 +108,5 @@ if Mix.target() == :app do
     defp macos?() do
       :os.type() == {:unix, :darwin}
     end
-
-    # TODO: On Elixir v1.14, use URI.append_query/2
-    defp append_query(%URI{query: query} = uri, query_to_add) when query in [nil, ""] do
-      %{uri | query: query_to_add}
-    end
-
-    defp append_query(%URI{} = uri, query) do
-      %{uri | query: uri.query <> "&" <> query}
-    end
   end
 end

lib/livebook_cli/server.ex

@@ -15,9 +15,14 @@ defmodule LivebookCLI.Server do
   @impl true
   def usage() do
     """
-    Usage: livebook server [options]
+    Usage: livebook server [url] [options]
 
-    Available options:
+    An optional url can be given as argument. If one is given,
+    a browser window will open importing the given url as a notebook:
+
+        livebook server https://example.com/my-notebook.livemd
+
+    ## Available options
 
       --autosave-path      The directory where notebooks with no file are persisted.
                            Defaults to livebook/notebooks/ under the default user cache
@@ -52,7 +57,7 @@ defmodule LivebookCLI.Server do
 
   @impl true
   def call(args) do
-    opts = args_to_options(args)
+    {opts, extra_args} = args_to_options(args)
     config_entries = opts_to_config(opts, [])
     put_config_entries(config_entries)
 
@@ -62,7 +67,7 @@ defmodule LivebookCLI.Server do
     case check_endpoint_availability(base_url) do
       :livebook_running ->
         IO.puts("Livebook already running on #{base_url}")
-        open_from_options(base_url, opts)
+        open_from_options(base_url, opts, extra_args)
 
       :taken ->
         print_error(
@@ -75,7 +80,7 @@ defmodule LivebookCLI.Server do
         # so it's gonna start listening
         case Application.ensure_all_started(:livebook) do
           {:ok, _} ->
-            open_from_options(LivebookWeb.Endpoint.access_url(), opts)
+            open_from_options(LivebookWeb.Endpoint.access_url(), opts, extra_args)
             Process.sleep(:infinity)
 
           {:error, error} ->
@@ -116,7 +121,7 @@ defmodule LivebookCLI.Server do
     end
   end
 
-  defp open_from_options(base_url, opts) do
+  defp open_from_options(base_url, opts, []) do
     if opts[:open] do
       Livebook.Utils.browser_open(base_url)
     end
@@ -128,6 +133,18 @@ defmodule LivebookCLI.Server do
     end
   end
 
+  defp open_from_options(base_url, _opts, [url]) do
+    base_url
+    |> LivebookWeb.Helpers.notebook_import_url(url)
+    |> Livebook.Utils.browser_open()
+  end
+
+  defp open_from_options(_base_url, _opts, _extra_args) do
+    print_error(
+      "Too many arguments entered. Ensure only one argument is used to specify the file path and all other arguments are preceded by the relevant switch"
+    )
+  end
+
   @switches [
     autosave_path: :string,
     cookie: :string,
@@ -147,9 +164,9 @@ defmodule LivebookCLI.Server do
   ]
 
   defp args_to_options(args) do
-    {opts, _} = OptionParser.parse!(args, strict: @switches, aliases: @aliases)
+    {opts, extra_args} = OptionParser.parse!(args, strict: @switches, aliases: @aliases)
     validate_options!(opts)
-    opts
+    {opts, extra_args}
   end
 
   defp validate_options!(opts) do

lib/livebook_web/helpers.ex

@@ -376,6 +376,26 @@ defmodule LivebookWeb.Helpers do
   def file_system_label(%FileSystem.Local{}), do: "Local disk"
   def file_system_label(%FileSystem.S3{} = fs), do: fs.bucket_url
 
+  @doc """
+  Returns a URL (including localhost) to import the given `url` as a notebook.
+  """
+  def notebook_import_url(base_url \\ LivebookWeb.Endpoint.access_struct_url(), url) do
+    base_url
+    |> URI.parse()
+    |> Map.replace!(:path, "/import")
+    |> append_query("url=#{URI.encode_www_form(url)}")
+    |> URI.to_string()
+  end
+
+  # TODO: On Elixir v1.14, use URI.append_query/2
+  defp append_query(%URI{query: query} = uri, query_to_add) when query in [nil, ""] do
+    %{uri | query: query_to_add}
+  end
+
+  defp append_query(%URI{} = uri, query) do
+    %{uri | query: uri.query <> "&" <> query}
+  end
+
   @doc """
   Returns the text in singular or plural depending on the quantity