From b49a0500e06296ba1efd58926e060772b6a8d866 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Fri, 13 Apr 2018 12:18:54 -0500
Subject: [PATCH] Add ARTICLE_RESTRICT_TO_TAGS setting

---
 docs/settings.rst     | 6 ++++++
 pelican/generators.py | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/docs/settings.rst b/docs/settings.rst
index 0ae26ca4..3ec7e9ff 100644
--- a/docs/settings.rst
+++ b/docs/settings.rst
@@ -179,6 +179,12 @@ Basic settings
    A list of directories to exclude when looking for articles in addition to
    ``PAGE_PATHS``.
 
+.. data:: ARTICLE_RESTRICT_TO_TAGS = []
+
+    All articles that do not have all tags in this list will be excluded from
+    the output. This is useful, for example, for generating multiple versions
+    of a site with overlapping content--e.g. a professional and a personal one.
+
 .. data:: OUTPUT_SOURCES = False
 
    Set to True if you want to copy the articles and pages in their original
diff --git a/pelican/generators.py b/pelican/generators.py
index 069da0c1..2f5316da 100644
--- a/pelican/generators.py
+++ b/pelican/generators.py
@@ -564,6 +564,9 @@ class ArticlesGenerator(CachingGenerator):
     def generate_context(self):
         """Add the articles into the shared context"""
 
+        restrict_all_articles_to_tags = set(
+                self.settings.get("ARTICLES_RESTRICT_TO_TAGS", []))
+
         all_articles = []
         all_drafts = []
         for f in self.get_files(
@@ -592,6 +595,10 @@ class ArticlesGenerator(CachingGenerator):
 
                 self.cache_data(f, article)
 
+            if not restrict_all_articles_to_tags <= set(
+                    getattr(article, 'tags', [])):
+                continue
+
             if article.status == "published":
                 all_articles.append(article)
             elif article.status == "draft":