fix: live preview honors source_format — RST/HTML/mediawiki now render correctly

The /preview-post endpoint hardcoded markdown_to_html(), ignoring the
node's source_format. RST pages showed `..` comments verbatim, literal
`name_` references, and unrendered `.. _target: url` definitions, even
though Node.set_data dispatched correctly on save. Preview lied; save
told the truth.

Mirror set_data's dispatch in preview_post:
  - markdown → markdown_to_html (unchanged)
  - html     → pandoc clean → markdown_to_html (matches set_data)
  - any other → pandoc + namespace sanitizer

Plumb source_format from the edit textarea via data-source-format,
read by sendPreview in custom.js, sent as a form param.

remarkbox/static/js/custom.js

@@ -80,9 +80,14 @@ function previewAjax(textarea, div, show_raw, mathjax) {
 
 function sendPreview(textarea, div, mathjax) {
     var url = '/preview-post';
+    var ta = document.getElementById(textarea);
     var data = new FormData();
-    data.append('data', document.getElementById(textarea).value);
+    data.append('data', ta.value);
     data.append('csrf_token', csrf_token);
+    // textarea declares its source_format via data-source-format; the
+    // endpoint dispatches to pandoc for rst/html/mediawiki/latex when set.
+    var fmt = ta.dataset.sourceFormat;
+    if (fmt) data.append('source_format', fmt);
 
     fetch(url, {
         method: 'POST',

remarkbox/templates/snippets/forms.j2

@@ -76,6 +76,7 @@
         name        = "thread_data"
         id          = "edit-textarea-{{ node.id }}"
         class       = "common-textarea textarea_edit"
+        data-source-format = "{{ node.source_format or 'markdown' }}"
         onkeyup     = "previewAjax( 'edit-textarea-{{ node.id }}', 'node-data-{{ node.id }}', show_raw=false, mathjax={{ request.mathjax }} )"
         placeholder = "{% if request.namespace.placeholder_text %}{{ request.namespace.placeholder_text }}{% else %}What do you want to say? markdown{% endif %}"
         required>{{ node.data }}</textarea>

remarkbox/views/misc.py

@@ -54,12 +54,33 @@ def redirect_to_root(request):
 # This ajax endpoint should work whether a user is authenticated or not.
 @view_config(route_name="preview-post", renderer="string", xhr=True, require_csrf=False)
 def preview_post(request):
-    """AJAJ: Accept MarkDown data param, return HTML"""
+    """AJAJ: Accept data + optional source_format, return HTML.
+
+    Mirrors Node.set_data dispatch so the live preview matches what the
+    save path will produce. Without this, RST / HTML / mediawiki / latex
+    nodes silently fell through markdown rendering & previews lied —
+    e.g. an RST file showed `..` comments + literal `name_` references
+    instead of resolved hyperlinks.
+    """
+    data = request.params.get("data", "")
+    source_format = (request.params.get("source_format") or "markdown").strip().lower()
     try:
-        return markdown_to_html(request.params["data"], request.namespace,
-                                dbsession=request.dbsession)
-    except:
-        return "we could not create markdown to html preview."
+        if source_format in ("", "markdown"):
+            return markdown_to_html(data, request.namespace, dbsession=request.dbsession)
+        if source_format == "html":
+            # match set_data: clean HTML through markdown pipeline
+            from remarkbox.lib.pandoc import convert
+            cleaned = convert(data, from_format="html", to_format="markdown")
+            return markdown_to_html(cleaned, request.namespace, dbsession=request.dbsession)
+        # pandoc handles rst, mediawiki, latex, org, etc.
+        from remarkbox.lib.pandoc import convert
+        from remarkbox.lib.render import make_cleaner_from_namespace
+        from remarkbox.lib.sanitize_html import clean_raw_html
+        html = convert(data, from_format=source_format, to_format="html5",
+                       standalone=False)
+        return clean_raw_html(html, make_cleaner_from_namespace(request.namespace))
+    except Exception:
+        return "we could not create a preview for source_format=%s." % source_format
 
 
 @view_config(route_name="favicon")