Add revision diff endpoint and progressive enhancement export/wiki UI.

Diff: GET /api/v1/revisions/{id}/diff/{other_id} — unified diff between two revisions.
UI: <details>-based export menus on thread and node views (works without JS).
UI: Revision history link for wiki-mode namespaces.

docs/api.md

@@ -527,6 +527,32 @@ Response `200`:
 
 ---
 
+### Diff Revisions
+
+```
+GET /api/v1/revisions/{revision_id}/diff/{other_id}
+```
+
+Compares two revisions of the same node. Returns a unified diff.
+
+Response `200`:
+```json
+{
+  "from_revision": "...",
+  "to_revision": "...",
+  "from_number": 1,
+  "to_number": 2,
+  "node_id": "...",
+  "diff": "--- revision 1\n+++ revision 2\n@@ ... @@\n..."
+}
+```
+
+Errors:
+- `400` if the two revisions belong to different nodes
+- `404` if either revision is not found
+
+---
+
 ### Theme CSS
 
 ```

docs/testing.md

@@ -191,6 +191,12 @@ curl -s "$REMARKBOX/api/v1/nodes/$NODE_ID/revisions" | python3 -m json.tool
 curl -s "$REMARKBOX/api/v1/revisions/$REVISION_ID" | python3 -m json.tool
 ```
 
+### Diff Revisions
+
+```bash
+curl -s "$REMARKBOX/api/v1/revisions/$REVISION_ID/diff/$OTHER_REVISION_ID" | python3 -m json.tool
+```
+
 ## Themes
 
 ### Get Namespace Theme CSS

remarkbox/api/__init__.py

@@ -9,6 +9,7 @@ def includeme(config):
     config.add_route("api-node-wiki-edit", "/api/v1/nodes/{node_id}/wiki-edit")
     config.add_route("api-node-detail", "/api/v1/nodes/{node_id}")
     config.add_route("api-revision-detail", "/api/v1/revisions/{revision_id}")
+    config.add_route("api-revision-diff", "/api/v1/revisions/{revision_id}/diff/{other_id}")
     config.add_route("api-auth-login", "/api/v1/auth/login")
     config.add_route("api-auth-verify", "/api/v1/auth/verify")
     config.add_route("api-user-profile", "/api/v1/user/profile")

remarkbox/api/remarkbox_client.py

@@ -553,6 +553,21 @@ class RemarkboxClient:
         """
         return self._request("GET", "/api/v1/revisions/{}".format(revision_id))
 
+    def diff_revisions(self, revision_id, other_id):
+        """Compare two revisions of the same node via unified diff.
+
+        Args:
+            revision_id: UUID of the first (from) revision
+            other_id: UUID of the second (to) revision
+
+        Returns:
+            dict with keys: from_revision, to_revision, from_number,
+            to_number, node_id, diff
+        """
+        return self._request(
+            "GET", "/api/v1/revisions/{}/diff/{}".format(revision_id, other_id)
+        )
+
     # ----- Themes -----
 
     def get_theme_css(self, namespace):

remarkbox/api/wiki.py

@@ -1,5 +1,7 @@
 """Wiki mode and revision history API endpoints."""
 
+import difflib
+
 from pyramid.view import view_config
 
 from remarkbox.models.node import get_node_by_id, Node
@@ -132,3 +134,54 @@ def api_get_revision(request):
             return denied
 
     return {"revision": serialize_revision(revision)}
+
+
+@view_config(
+    route_name="api-revision-diff",
+    request_method="GET",
+    renderer="json",
+    require_csrf=False,
+)
+def api_revision_diff(request):
+    """Compare two revisions of the same node via unified diff."""
+    revision_id = request.matchdict["revision_id"]
+    other_id = request.matchdict["other_id"]
+
+    revision = get_object_by_id(request.dbsession, revision_id, Revision)
+    if revision is None:
+        request.response.status_code = 404
+        return {"error": "Revision not found: {}".format(revision_id)}
+
+    other = get_object_by_id(request.dbsession, other_id, Revision)
+    if other is None:
+        request.response.status_code = 404
+        return {"error": "Revision not found: {}".format(other_id)}
+
+    if revision.node_id != other.node_id:
+        request.response.status_code = 400
+        return {"error": "Revisions belong to different nodes"}
+
+    node = get_node_by_id(request.dbsession, revision.node_id)
+    if node:
+        namespace = node.root.namespace
+        denied = check_namespace_api_access(request, namespace)
+        if denied:
+            return denied
+
+    from_lines = revision.data.splitlines(keepends=True)
+    to_lines = other.data.splitlines(keepends=True)
+    diff = difflib.unified_diff(
+        from_lines,
+        to_lines,
+        fromfile="revision {}".format(revision.revision_number),
+        tofile="revision {}".format(other.revision_number),
+    )
+
+    return {
+        "from_revision": str(revision.id),
+        "to_revision": str(other.id),
+        "from_number": revision.revision_number,
+        "to_number": other.revision_number,
+        "node_id": str(revision.node_id),
+        "diff": "".join(diff),
+    }

remarkbox/templates/show-node.j2

@@ -70,6 +70,10 @@
 
   <div class="node-actions">
   {{ snippets.actions(request.node) }}
+  {% if request.node.is_root %}
+  {{ snippets.export_menu(request.node) }}
+  {{ snippets.wiki_actions(request.node) }}
+  {% endif %}
   </div>
 
 </div>
@@ -145,6 +149,7 @@
     <div class="node-actions">
     {{ snippets.permalinks(parent, prev_parent, request.root_node) }}
     {{ snippets.actions(parent) }}
+    {{ snippets.export_node_menu(parent) }}
     {%- if children_ids %}
     {{ snippets.button_collapse(parent) }}
     {% endif -%}

remarkbox/templates/snippets/snippets.j2

@@ -239,6 +239,42 @@
   {% endif %}
 {% endmacro %}
 
+{% macro export_menu(node) %}
+<details class="export-menu">
+  <summary class="action link">export</summary>
+  <div class="export-options">
+    <a href="/api/v1/export/threads/{{ node.id }}.md" class="export-link">markdown</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.html" class="export-link">html</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.pdf" class="export-link">pdf</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.epub" class="export-link">epub</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.docx" class="export-link">docx</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.rst" class="export-link">rst</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.latex" class="export-link">latex</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.odt" class="export-link">odt</a>
+    <a href="/api/v1/export/threads/{{ node.id }}.plain" class="export-link">plain text</a>
+  </div>
+</details>
+{% endmacro %}
+
+{% macro export_node_menu(node) %}
+<details class="export-menu">
+  <summary class="action link">export</summary>
+  <div class="export-options">
+    <a href="/api/v1/export/nodes/{{ node.id }}.md" class="export-link">markdown</a>
+    <a href="/api/v1/export/nodes/{{ node.id }}.html" class="export-link">html</a>
+    <a href="/api/v1/export/nodes/{{ node.id }}.pdf" class="export-link">pdf</a>
+    <a href="/api/v1/export/nodes/{{ node.id }}.epub" class="export-link">epub</a>
+    <a href="/api/v1/export/nodes/{{ node.id }}.docx" class="export-link">docx</a>
+  </div>
+</details>
+{% endmacro %}
+
+{% macro wiki_actions(node) %}
+{% if request.namespace.wiki and node.is_root and request.user and request.user.authenticated %}
+  <a href="/api/v1/nodes/{{ node.id }}/revisions" class="action" target="_blank">history</a>
+{% endif %}
+{% endmacro %}
+
 {% macro namespace_actions(namespace) %}
     {% if request.mode != "embed" %}
 

remarkbox/tests/test_undigg.py

@@ -676,6 +676,122 @@ class TestWikiModeAndRevisions(UndiggFunctionalTests):
         self.assertEqual(res.status_int, 404)
 
 
+class TestRevisionDiff(UndiggFunctionalTests):
+    """Test GET /api/v1/revisions/{id}/diff/{other_id}."""
+
+    @classmethod
+    def setUpClass(cls):
+        try:
+            UndiggFunctionalTests.setUpClass.im_func(cls)
+        except AttributeError:
+            UndiggFunctionalTests.setUpClass.__func__(cls)
+
+    def setUp(self):
+        ns = get_or_create_namespace(self.dbsession, "diff-test.example.com")
+        ns.allow_anonymous = True
+        ns.subscription_type = "production"
+        ns.wiki = True
+        self.dbsession.add(ns)
+        self.dbsession.flush()
+        self.namespace_name = str(ns.name)
+        self.namespace_id = ns.id
+        self.tm.commit()
+
+    def tearDown(self):
+        super(TestRevisionDiff, self).tearDown()
+        self.dbsession.query(Revision).filter(
+            Revision.node_id.in_(
+                self.dbsession.query(Node.id).filter(
+                    Node.namespace_id == self.namespace_id
+                )
+            )
+        ).delete(synchronize_session=False)
+        self.dbsession.query(UserSurrogate).filter(
+            UserSurrogate.namespace_id == self.namespace_id
+        ).delete(synchronize_session=False)
+        self.dbsession.query(Node).filter(
+            Node.namespace_id == self.namespace_id
+        ).delete(synchronize_session=False)
+        self.dbsession.flush()
+        self.tm.commit()
+
+    def _create_thread(self, title="Diff Thread", data="Original content."):
+        res = self.testapp.post_json(
+            "/api/v1/threads",
+            {
+                "namespace": self.namespace_name,
+                "title": title,
+                "data": data,
+                "anonymous_name": "Bot",
+            },
+            expect_errors=True,
+        )
+        return res.json["node"]["id"]
+
+    def _create_revisions(self, node_id, data_v1, data_v2):
+        """Manually create two revisions for a node."""
+        node = self.dbsession.query(Node).get(node_id)
+        rev1 = Revision(node=node, data=data_v1, revision_number=1)
+        rev2 = Revision(node=node, data=data_v2, revision_number=2)
+        self.dbsession.add(rev1)
+        self.dbsession.add(rev2)
+        self.dbsession.flush()
+        rev1_id = str(rev1.id)
+        rev2_id = str(rev2.id)
+        self.tm.commit()
+        return rev1_id, rev2_id
+
+    def test_diff_same_revision(self):
+        node_id = self._create_thread()
+        rev1_id, rev2_id = self._create_revisions(
+            node_id, "Same content.", "Same content."
+        )
+        res = self.testapp.get(
+            "/api/v1/revisions/{}/diff/{}".format(rev1_id, rev1_id),
+            expect_errors=True,
+        )
+        self.assertEqual(res.status_int, 200)
+        self.assertEqual(res.json["diff"], "")
+        self.assertEqual(res.json["from_revision"], rev1_id)
+        self.assertEqual(res.json["to_revision"], rev1_id)
+
+    def test_diff_different_revisions(self):
+        node_id = self._create_thread()
+        rev1_id, rev2_id = self._create_revisions(
+            node_id, "Original content.", "Updated content."
+        )
+        res = self.testapp.get(
+            "/api/v1/revisions/{}/diff/{}".format(rev1_id, rev2_id),
+            expect_errors=True,
+        )
+        self.assertEqual(res.status_int, 200)
+        self.assertIn("from_revision", res.json)
+        self.assertIn("to_revision", res.json)
+        self.assertEqual(res.json["from_number"], 1)
+        self.assertEqual(res.json["to_number"], 2)
+        self.assertIn("Original", res.json["diff"])
+        self.assertIn("Updated", res.json["diff"])
+
+    def test_diff_not_found(self):
+        res = self.testapp.get(
+            "/api/v1/revisions/00000000-0000-0000-0000-000000000000/diff/00000000-0000-0000-0000-000000000001",
+            expect_errors=True,
+        )
+        self.assertEqual(res.status_int, 404)
+
+    def test_diff_different_nodes(self):
+        node1_id = self._create_thread(title="Thread 1", data="Content 1.")
+        node2_id = self._create_thread(title="Thread 2", data="Content 2.")
+        rev1_id, _ = self._create_revisions(node1_id, "A", "B")
+        rev2_id, _ = self._create_revisions(node2_id, "C", "D")
+        res = self.testapp.get(
+            "/api/v1/revisions/{}/diff/{}".format(rev1_id, rev2_id),
+            expect_errors=True,
+        )
+        self.assertEqual(res.status_int, 400)
+        self.assertIn("different nodes", res.json["error"])
+
+
 # ---------------------------------------------------------------------------
 # Theme API
 # ---------------------------------------------------------------------------