add an rss example

examples/pythonbytes/README.md

@@ -0,0 +1,9 @@
+# pythonbytes
+
+Load an rss feed and then query it.
+
+This example is read-only.
+
+```
+python examples/pythonbytes/rssfeed.py
+```

examples/pythonbytes/requirements.txt

@@ -0,0 +1,2 @@
+alkali
+feedparser

examples/pythonbytes/rssfeed.py

@@ -0,0 +1,51 @@
+import feedparser
+import alkali
+from alkali import fields
+
+class RssLoader(alkali.Storage):
+
+    def __init__(self, url):
+        self.filename = url
+
+    def read(self, model_class):
+        feed = feedparser.parse(self.filename)
+        for item in feed['items']:
+            yield item
+
+
+class Episode(alkali.Model):
+
+    class Meta:
+        storage = RssLoader('https://pythonbytes.fm/episodes/rss')
+
+    guid           = fields.UUIDField(primary_key=True)
+    title          = fields.StringField()
+    published      = fields.DateTimeField()
+    itunes_episode = fields.IntField()
+    link           = fields.StringField()
+    description    = fields.StringField()
+
+    def __str__(self):
+        return f"<Epsiode {self.itunes_episode} - {self.title}>"
+
+    @property
+    def num(self):
+        return self.itunes_episode
+
+
+db = alkali.Database(models=[Episode])
+db.load()
+
+# or directly but non-traditionally
+# Episode.objects.load(Episode.Meta.storage)
+
+print("last 10 episodes with 'python' in the title")
+for ep in Episode.objects.filter(title__rei=r"\bpython\b").order_by('-published').limit(10):
+    print('  ', ep)
+
+print("total episode count:", Episode.objects.count)
+
+e = Episode.objects.get(itunes_episode=100)
+print(e.title, e.published.date())
+
+print("episode featuring alkali:", Episode.objects.get(title__rei='alkali').link)