Option to show only posts that have a specific tag or category.

- add configuration description in README.markdown
- add unit test with testmore.php for this very feature

README.markdown

@@ -17,3 +17,25 @@ Web hosting with PHP5 (PHP4 will not work).
 License
 -------
 Moonmoon is free software and is released under BSD license.
+
+
+Configuration options
+---------------------
+After installation, configuration is kept in a YAML formatted ```custom/config.yml```:
+
+```%yaml
+url: http://planet.example.net  # your planet base URL
+name: My Planet                 # your planet front page name
+locale: en                      # front page locale
+items: 10                       # how many items to show
+refresh: 240                    # feeds cache timeout (in seconds)
+cache: 10                       # front page cache timeout (in seconds)
+cachedir: ./cache               # where is cache stored
+postmaxlength: 0                # deprecated
+shuffle: 0                      # deprecated
+nohtml: 0                       # deprecated
+categories:                     # only list posts that have one
+                                # of these (tag or category)
+```
+
+---

app/classes/Planet.class.php

@@ -58,6 +58,10 @@ public function __construct($config=null)
      */
     public function getItems()
     {
+        $this->items = $this->_filterItemsByCategory(
+            $this->items,
+            $this->config->getCategories());
+
         return $this->items;
     }
 
@@ -152,4 +156,41 @@ public function sort()
     {
         usort($this->items, array('PlanetItem','compare'));
     }
+
+    /**
+     * Filter out items that do not match at least one
+     * of the defined categories.
+     *
+     * If there's no category, return all items.
+     *
+     * @param array  $items to filter
+     * @param string $categories to filter against; may be a single word
+     * or a comma-separated list of words.
+     *
+     * @return array resulting list of items
+    */
+    public function _filterItemsByCategory($items, $categories = null)
+    {
+        $categories = trim($categories);
+
+        if (empty($categories))
+            return $items;
+
+        $categories         = array_map('trim', explode(',', strtolower($categories)));
+        $cb_category_filter =
+            function ($item) use ($categories)
+            {
+                if (!is_array($item_categories = $item->get_categories()))
+                    return false;
+
+                $item_categories = array_map(
+                    function ($i) { return strtolower($i->get_label()); },
+                    $item_categories
+                );
+
+                return array_intersect($categories, $item_categories);
+            };
+
+        return array_values(array_filter($items, $cb_category_filter));
+    }
 }

app/classes/PlanetConfig.php

@@ -81,8 +81,25 @@ public function getPostMaxLength()
         return $this->conf['postmaxlength'];
     }
 
+    public function getCategories()
+    {
+        return $this->conf['categories'];
+    }
+
     public function toYaml()
     {
         return Spyc::YAMLDump($this->conf,4);
     }
+
+    /**
+     * Generic accessor for config.
+    */
+    public function __get($key)
+    {
+        $key = strtolower($key);
+
+        return array_key_exists($key, $this->conf) ?
+            $this->conf[$key] :
+            null;
+    }
 }