Added tag filtering @viglioni.

org-roam#109 (reply in thread)

org-roam-ui.el

@@ -400,8 +400,28 @@ unchanged."
      ("FILELESS" . t))
    'nil))
 
-(defun org-roam-ui--make-graphdata ()
-  "Get roam data and make JSON"
+(defun org-roam-ui--get-nodes-by-tags (&optional export-tags)
+  "Return all nodes that contain at least one tag in EXPORT-TAGS."
+  (if export-tags
+       (org-roam-db-query [:select [id
+                                     file
+                                     title
+                                     level
+                                     pos
+                                     olp
+                                     properties
+                                     (funcall group-concat tag
+                                              (emacsql-escape-raw \\\, ))]
+                                    :as tags
+                                    :from nodes
+                                    :left-join tags
+                                    :on (= id node_id)
+                                    :where (in tag $v1)
+                                    :group :by id] (vconcat export-tags))
+    (org-roam-ui--get-nodes)))
+
+(defun org-roam-ui--make-graphdata (&optional export-tags)
+  "Get roam data and make JSON. EXPORT-TAGS are the tags to filter by."
   (let* ((nodes-names
           [id
            file
@@ -425,7 +445,7 @@ unchanged."
                                    (lambda (link)
                                      (nth 1 link))
                                    links-with-empty-refs)))
-         (nodes-db-rows (org-roam-ui--get-nodes))
+         (nodes-db-rows (org-roam-ui--get-nodes-by-tags export-tags))
          (fake-nodes (seq-map #'org-roam-ui--create-fake-node empty-refs))
            ;; Try to update real nodes that are reference with a title build
            ;; from their bibliography entry. Check configuration here for avoid
@@ -460,9 +480,9 @@ This database model won't be supported in the future, please consider upgrading.
   "Send roam data through websocket to org-roam-ui."
   (websocket-send-text org-roam-ui-ws-socket (org-roam-ui--make-graphdata)))
 
-(defun org-roam-ui--export-graphdata (file)
-  "Create a JSON-file containting graphdata."
-  (write-region (org-roam-ui--make-graphdata) nil file))
+(defun org-roam-ui--export-graphdata (file &optional export-tags)
+  "Create a FILE in JSON format containting graphdata. Filter by EXPORT-TAGS if provided."
+  (write-region (org-roam-ui--make-graphdata export-tags) nil file))
 
 (defun org-roam-ui--filter-citations (links)
   "Filter out the citations from LINKS."
@@ -666,12 +686,15 @@ Hides . directories."
 
 ;;;###autoload
 (defun org-roam-ui-export ()
-  "Export `org-roam-ui's-data for usage as static webserver."
-  (interactive)
+  "Export `org-roam-ui's-data for usage as static webserver.
+Get only nodes that has at least one tag of EXPORT-TAGS.
+If none is provided, get all nodes."
+  (interactive) ;; and here
   (let* ((dir (read-file-name "Specify output directory:"))
-        (graphdata-file (concat (file-name-as-directory dir) "graphdata.json"))
-        (notes-dir (concat (file-name-as-directory dir) "notes/")))
-    (org-roam-ui--export-graphdata graphdata-file)
+         (export-tags (delete-dups (completing-read-multiple "Select (multiple with comma): " (org-roam-db-query [:select :distinct tag :from tags]))))
+         (graphdata-file (concat (file-name-as-directory dir) "graphdata.json"))
+         (notes-dir (concat (file-name-as-directory dir) "notes/")))
+    (org-roam-ui--export-graphdata graphdata-file export-tags)
     (make-directory notes-dir :parents)
     (mapcar (lambda (id)
               (let* ((cid (car id))