Adds token metadata handler.

apps/cic-ussd/cic_ussd/metadata/tokens.py

@@ -0,0 +1,54 @@
+# standard imports
+from typing import Dict, Optional
+
+# external imports
+import json
+
+from cic_types.condiments import MetadataPointer
+
+# local imports
+from .base import UssdMetadataHandler
+from cic_ussd.cache import cache_data
+from cic_ussd.error import MetadataNotFoundError
+
+
+class TokenMetadata(UssdMetadataHandler):
+    def __init__(self, identifier: bytes, **kwargs):
+        super(TokenMetadata, self).__init__(identifier=identifier, **kwargs)
+
+
+def token_metadata_handler(metadata_client: TokenMetadata) -> Optional[Dict]:
+    """
+    :param metadata_client:
+    :type metadata_client:
+    :return:
+    :rtype:
+    """
+    result = metadata_client.query()
+    token_metadata = result.json()
+    if not token_metadata:
+        raise MetadataNotFoundError(f'No metadata found at: {metadata_client.metadata_pointer} for: {metadata_client.identifier.decode("utf-8")}')
+    cache_data(metadata_client.metadata_pointer, json.dumps(token_metadata))
+    return token_metadata
+
+
+def query_token_metadata(identifier: bytes):
+    """
+    :param identifier:
+    :type identifier:
+    :return:
+    :rtype:
+    """
+    token_metadata_client = TokenMetadata(identifier=identifier, cic_type=MetadataPointer.TOKEN_META_SYMBOL)
+    return token_metadata_handler(token_metadata_client)
+
+
+def query_token_info(identifier: bytes):
+    """
+    :param identifier:
+    :type identifier:
+    :return:
+    :rtype:
+    """
+    token_info_client = TokenMetadata(identifier=identifier, cic_type=MetadataPointer.TOKEN_PROOF_SYMBOL)
+    return token_metadata_handler(token_info_client)