Feature: Share private bookmarks using a URL containing a private key

  - Add a share link next to « Permalink » in linklist (using share icon
from fork awesome)
  - This link generates a private key associated to the bookmark
  - Accessing the bookmark while logged out with the proper key will
display it

Fixes #475

4 files changed, 37 insertions, 5 deletions

diff --git a/application/bookmark/BookmarkFileService.php b/application/bookmark/BookmarkFileService.php
index eb7899bf..14b3d620 100644
--- a/application/bookmark/BookmarkFileService.php
+++ b/application/bookmark/BookmarkFileService.php
@@ -97,12 +97,15 @@ class BookmarkFileService implements BookmarkServiceInterface
     /**
      * @inheritDoc
      */
-    public function findByHash(string $hash): Bookmark
+    public function findByHash(string $hash, string $privateKey = null): Bookmark
     {
         $bookmark = $this->bookmarkFilter->filter(BookmarkFilter::$FILTER_HASH, $hash);
         // PHP 7.3 introduced array_key_first() to avoid this hack
         $first = reset($bookmark);
-        if (! $this->isLoggedIn && $first->isPrivate()) {
+        if (!$this->isLoggedIn
+            && $first->isPrivate()
+            && (empty($privateKey) || $privateKey !== $first->getAdditionalContentEntry('private_key'))
+        ) {
             throw new Exception('Not authorized');
         }
 
diff --git a/application/bookmark/BookmarkServiceInterface.php b/application/bookmark/BookmarkServiceInterface.php
index 37a54d03..9fa61533 100644
--- a/application/bookmark/BookmarkServiceInterface.php
+++ b/application/bookmark/BookmarkServiceInterface.php
@@ -20,13 +20,14 @@ interface BookmarkServiceInterface
     /**
      * Find a bookmark by hash
      *
-     * @param string $hash
+     * @param string      $hash       Bookmark's hash
+     * @param string|null $privateKey Optional key used to access private links while logged out
      *
      * @return Bookmark
      *
      * @throws \Exception
      */
-    public function findByHash(string $hash): Bookmark;
+    public function findByHash(string $hash, string $privateKey = null);
 
     /**
      * @param $url
diff --git a/application/front/controller/admin/ManageShaareController.php b/application/front/controller/admin/ManageShaareController.php
index 908ebae3..e490f85a 100644
--- a/application/front/controller/admin/ManageShaareController.php
+++ b/application/front/controller/admin/ManageShaareController.php
@@ -321,6 +321,32 @@ class ManageShaareController extends ShaarliAdminController
     }
 
     /**
+     * GET /admin/shaare/private/{hash} - Attach a private key to given bookmark, then redirect to the sharing URL.
+     */
+    public function sharePrivate(Request $request, Response $response, array $args): Response
+    {
+        $this->checkToken($request);
+
+        $hash = $args['hash'] ?? '';
+        $bookmark = $this->container->bookmarkService->findByHash($hash);
+
+        if ($bookmark->isPrivate() !== true) {
+            return $this->redirect($response, '/shaare/' . $hash);
+        }
+
+        if (empty($bookmark->getAdditionalContentEntry('private_key'))) {
+            $privateKey = bin2hex(random_bytes(16));
+            $bookmark->addAdditionalContentEntry('private_key', $privateKey);
+            $this->container->bookmarkService->set($bookmark);
+        }
+
+        return $this->redirect(
+            $response,
+            '/shaare/' . $hash . '?key=' . $bookmark->getAdditionalContentEntry('private_key')
+        );
+    }
+
+    /**
      * Helper function used to display the shaare form whether it's a new or existing bookmark.
      *
      * @param array $link data used in template, either from parameters or from the data store
diff --git a/application/front/controller/visitor/BookmarkListController.php b/application/front/controller/visitor/BookmarkListController.php
index 5267c8f5..78c474c9 100644
--- a/application/front/controller/visitor/BookmarkListController.php
+++ b/application/front/controller/visitor/BookmarkListController.php
@@ -137,8 +137,10 @@ class BookmarkListController extends ShaarliVisitorController
      */
     public function permalink(Request $request, Response $response, array $args): Response
     {
+        $privateKey = $request->getParam('key');
+
         try {
-            $bookmark = $this->container->bookmarkService->findByHash($args['hash']);
+            $bookmark = $this->container->bookmarkService->findByHash($args['hash'], $privateKey);
         } catch (BookmarkNotFoundException $e) {
             $this->assignView('error_message', $e->getMessage());