Add tx_metadata RPC

files/grest/rpc/transactions/tx_metadata.sql

@@ -0,0 +1,37 @@
+DROP FUNCTION IF EXISTS grest.tx_metadata (text[]);
+
+CREATE FUNCTION grest.tx_metadata (_tx_hashes text[])
+  RETURNS TABLE (
+    tx_hash text,
+    metadata json)
+  LANGUAGE PLPGSQL
+  AS $$
+BEGIN
+  RETURN QUERY
+  SELECT
+    T1.tx_hash,
+    METADATA_T.metadata
+  FROM (
+    SELECT
+      tx.id,
+      ENCODE(tx.hash, 'hex') as tx_hash
+    FROM
+      public.tx
+    WHERE
+      tx.hash::bytea = ANY (
+        SELECT
+          DECODE(hashes, 'hex')
+        FROM
+          UNNEST(_tx_hashes) AS hashes)) T1
+  LEFT JOIN LATERAL (
+    SELECT
+      JSON_OBJECT_AGG(tx_metadata.key, tx_metadata.json) as metadata
+    FROM
+      tx_metadata
+    WHERE
+      tx_id = T1.id) METADATA_T ON TRUE;
+END;
+$$;
+
+COMMENT ON FUNCTION grest.tx_metadata IS 'Get transaction metadata.';
+