add LBRYMetadata.py

lbrynet/core/LBRYMetadata.py

@@ -0,0 +1,28 @@
+import json
+
+BASE_METADATA_FIELDS = ['title', 'description', 'author', 'language', 'license', 'content-type']
+OPTIONAL_METADATA_FIELDS = ['thumbnail', 'preview', 'fee', 'contact', 'pubkey']
+
+#v0.0.1 metadata
+METADATA_REVISIONS = {'0.0.1': {'required': BASE_METADATA_FIELDS, 'optional': OPTIONAL_METADATA_FIELDS}}
+
+#v0.0.2 metadata additions
+METADATA_REVISIONS['0.0.2'] = {'required': ['nsfw'], 'optional': []}
+
+
+class Metadata(dict):
+    def __init__(self, metadata):
+        dict.__init__(self)
+        self.metaversion = None
+        m = metadata.copy()
+        for version in METADATA_REVISIONS:
+            for k in METADATA_REVISIONS[version]['required']:
+                assert k in metadata, "Missing required metadata field: %s" % k
+                self.update({k: m.pop(k)})
+            for k in METADATA_REVISIONS[version]['optional']:
+                if k in metadata:
+                    self.update({k: m.pop(k)})
+            if not len(m):
+                self.metaversion = version
+                break
+        assert m == {}, "Unknown metadata keys: %s" % json.dumps(m.keys())