Add OPML importing

lib/frenzy/opml/importer.ex

@@ -0,0 +1,66 @@
+defmodule Frenzy.OPML.Importer do
+  import Record
+
+  @typedoc """
+  The data created from an OPML import.
+  A list of groups. Each group has a name (String) or :default (if the OPML specified no group) and a list of feed URLs.
+  """
+  @type import_data() :: %{optional(String.t() | :default) => [String.t()]}
+
+  defrecord :xmlElement, extract(:xmlElement, from_lib: "xmerl/include/xmerl.hrl")
+  defrecord :xmlAttribute, extract(:xmlAttribute, from_lib: "xmerl/include/xmerl.hrl")
+
+  @spec parse_opml(String.t()) :: import_data()
+  def parse_opml(text) do
+    {doc, _} =
+      text
+      |> String.trim()
+      |> :binary.bin_to_list()
+      |> :xmerl_scan.string()
+
+    outline_elements = :xmerl_xpath.string('/opml/body/outline', doc)
+
+    outline_elements
+    |> Enum.flat_map(&get_feeds/1)
+    |> Enum.reduce(%{}, fn {group, feed_url}, acc ->
+      Map.update(acc, group, [], fn feeds -> [feed_url | feeds] end)
+    end)
+  end
+
+  defp get_feeds(outline_el) do
+    attributes = xmlElement(outline_el, :attributes)
+
+    # if the <outline> contains a xmlUrl attribute, it is a top level feed (uses the :default group)
+    # otherwise, it is a group of feeds
+
+    if Enum.any?(attributes, fn attr -> xmlAttribute(attr, :name) == :xmlUrl end) do
+      [{:default, get_feed_from_outline(outline_el)}]
+    else
+      get_feeds_from_group(outline_el)
+    end
+  end
+
+  defp get_feed_from_outline(feed_el) do
+    [attr] = :xmerl_xpath.string('//@xmlUrl', feed_el)
+
+    xmlAttribute(attr, :value)
+    |> List.to_string()
+  end
+
+  defp get_feeds_from_group(group_el) do
+    [title_attr] = :xmerl_xpath.string('/outline/@title', group_el)
+
+    group_title =
+      xmlAttribute(title_attr, :value)
+      |> List.to_string()
+
+    :xmerl_xpath.string('/outline/outline/@xmlUrl', group_el)
+    |> Enum.map(fn attr ->
+      feed_url =
+        xmlAttribute(attr, :value)
+        |> List.to_string()
+
+      {group_title, feed_url}
+    end)
+  end
+end

lib/frenzy_web/controllers/account_controller.ex

@@ -1,6 +1,6 @@
 defmodule FrenzyWeb.AccountController do
   use FrenzyWeb, :controller
-  alias Frenzy.{Repo, User, FervorClient}
+  alias Frenzy.{Repo, User, FervorClient, Filter}
   alias FrenzyWeb.Router.Helpers, as: Routes
   alias FrenzyWeb.Endpoint
 
@@ -102,4 +102,48 @@ defmodule FrenzyWeb.AccountController do
 
     redirect(conn, to: Routes.account_path(Endpoint, :show))
   end
+
+  def import(conn, %{"file" => %Plug.Upload{} = file}) do
+    user = conn.assigns[:user]
+
+    {:ok, content} = File.read(file.path)
+
+    parsed = Frenzy.OPML.Importer.parse_opml(content)
+
+    total_imported_feeds =
+      Enum.map(parsed, fn {group_id, feeds} ->
+        group_title =
+          case group_id do
+            :default -> "Default"
+            _ when is_binary(group_id) -> group_id
+          end
+
+        group_changeset = Ecto.build_assoc(user, :groups, %{title: group_title})
+
+        {:ok, group} = Repo.insert(group_changeset)
+
+        Enum.each(feeds, fn feed_url ->
+          feed_changeset =
+            Ecto.build_assoc(group, :feeds, %{
+              feed_url: feed_url,
+              filter: %Filter{
+                mode: "reject",
+                score: 0
+              }
+            })
+
+          {:ok, _feed} = Repo.insert(feed_changeset)
+        end)
+
+        Enum.count(feeds)
+      end)
+      |> Enum.sum()
+
+    conn
+    |> put_flash(
+      :info,
+      "Imported #{Enum.count(parsed)} groups and #{total_imported_feeds} feeds."
+    )
+    |> redirect(to: Routes.group_path(Endpoint, :index))
+  end
 end

lib/frenzy_web/router.ex

@@ -43,6 +43,7 @@ defmodule FrenzyWeb.Router do
     get "/account/change_fever_password", AccountController, :change_fever_password
     post "/account/change_fever_password", AccountController, :do_change_fever_password
     post "/account/remove_client", AccountController, :remove_client
+    post "/account/import", AccountController, :import
 
     get "/", GroupController, :index
     resources "/groups", GroupController, except: [:edit, :update]

lib/frenzy_web/templates/account/show.html.eex

@@ -5,32 +5,42 @@
 
 <a href="<%= Routes.account_path(@conn, :change_fever_password) %>" class="btn btn-secondary">Change Fever Password</a>
 
-<h2 class="mt-4">Approved Clients</h2>
+<section class="mt-4">
+  <h2>Import/Export Data</h2>
+  <%= form_for @conn, Routes.account_path(@conn, :import), [method: :post, multipart: true], fn f -> %>
+    <%= file_input f, :file %>
+    <%= submit "Import OPML", class: "btn btn-primary" %>
+  <% end %>
+</section>
 
-<table class="table table-striped">
-  <thead>
-    <tr>
-      <th>Client</th>
-      <th>Revoke Access</th>
-    </tr>
-  </thead>
-  <tbody>
-    <%= for {approved, fervor} <- @clients do %>
+<section class="mt-4">
+  <h2>Approved Clients</h2>
+
+  <table class="table table-striped">
+    <thead>
       <tr>
-        <td>
-          <%= if fervor.website do %>
-            <a href="<%= fervor.website %>"><%= fervor.client_name %></a>
-          <% else %>
-            <%= fervor.client_name %>
-          <% end %>
-        </td>
-        <td>
-          <%= form_tag Routes.account_path(@conn, :remove_client), method: :post do %>
-            <input type="hidden" name="client_id" value="<%= approved.client_id %>">
-            <%= submit "Revoke", class: "btn btn-danger" %>
-          <% end %>
-        </td>
+        <th>Client</th>
+        <th>Revoke Access</th>
       </tr>
-    <% end %>
-  </tbody>
-</table>
+    </thead>
+    <tbody>
+      <%= for {approved, fervor} <- @clients do %>
+        <tr>
+          <td>
+            <%= if fervor.website do %>
+              <a href="<%= fervor.website %>"><%= fervor.client_name %></a>
+            <% else %>
+              <%= fervor.client_name %>
+            <% end %>
+          </td>
+          <td>
+            <%= form_tag Routes.account_path(@conn, :remove_client), method: :post do %>
+              <input type="hidden" name="client_id" value="<%= approved.client_id %>">
+              <%= submit "Revoke", class: "btn btn-danger" %>
+            <% end %>
+          </td>
+        </tr>
+      <% end %>
+    </tbody>
+  </table>
+</section>