Use server-side markdown renderer in WYSIWYG preview

Fixes #117

app/blueprints/api/endpoints.py

@@ -19,8 +19,10 @@ from flask import *
 from flask_user import *
 from . import bp
 from .auth import is_api_authd
+from app import csrf
 from app.models import *
 from app.utils import is_package_page
+from app.markdown import render_markdown
 from app.querybuilder import QueryBuilder
 
 @bp.route("/api/packages/")
@@ -107,3 +109,9 @@ def whoami(token):
 		return jsonify({ "is_authenticated": False, "username": None })
 	else:
 		return jsonify({ "is_authenticated": True, "username": token.owner.username })
+
+
+@bp.route("/api/markdown/", methods=["POST"])
+@csrf.exempt
+def clean_markdown():
+	return render_markdown(request.data.decode("utf-8"))

app/public/static/markdowntextarea.js

@@ -0,0 +1,34 @@
+$("textarea.markdown").each(function() {
+	async function render(plainText, preview) {
+		const response = await fetch(new Request("/api/markdown/", {
+			method: "POST",
+			credentials: "same-origin",
+			body: plainText,
+			headers: {
+				"Accept": "text/html; charset=UTF-8",
+			},
+		}));
+
+		preview.innerHTML = await response.text();
+	}
+
+	let timeout_id = null;
+
+	new EasyMDE({
+		element: this,
+		hideIcons: ["image"],
+		forceSync: true,
+		previewRender: (plainText, preview) => {
+			if (timeout_id) {
+				clearTimeout(timeout_id);
+			}
+
+			timeout_id = setTimeout(() => {
+				render(plainText, preview);
+				timeout_id = null;
+			}, 500);
+
+			return preview.innerHTML;
+		}
+	});
+})

app/templates/base.html

@@ -148,12 +148,9 @@
 	<script src="/static/bootstrap.min.js"></script>
 	<script src="/static/easymde.min.js"></script>
 	<link rel="stylesheet" type="text/css" href="/static/easymde.min.css">
-	<script>
-		$("textarea.markdown").each(function() {
-			new EasyMDE({ element: this, hideIcons: ["image"], forceSync: true });
-		})
-	</script>
 	<link href="/static/fa/css/all.css" rel="stylesheet">
+	<script src="/static/markdowntextarea.js"></script>
+
 	{% block scriptextra %}{% endblock %}
 </body>
 </html>