added last_tx switch to the TX get query to only get the latest TX for a given asset.

Signed-off-by: Juergen Eckel <juergen@riddleandcode.com>

bigchaindb/lib.py

@@ -261,7 +261,7 @@ class BigchainDB(object):
     def get_transactions(self, txn_ids):
         return backend.query.get_transactions(self.connection, txn_ids)
 
-    def get_transactions_filtered(self, asset_id, operation=None):
+    def get_transactions_filtered(self, asset_id, operation=None, last_tx=None):
         """Get a list of transactions filtered on some criteria
         """
         txids = backend.query.get_txids_filtered(self.connection, asset_id,

bigchaindb/web/views/transactions.py

@@ -41,19 +41,31 @@ class TransactionApi(Resource):
 
         return tx.to_dict()
 
-
 class TransactionListApi(Resource):
+
     def get(self):
         parser = reqparse.RequestParser()
         parser.add_argument('operation', type=parameters.valid_operation)
         parser.add_argument('asset_id', type=parameters.valid_txid,
                             required=True)
+        parser.add_argument('last_tx', type=parameters.valid_bool,
+                    required=False)
         args = parser.parse_args()
 
         with current_app.config['bigchain_pool']() as bigchain:
             txs = bigchain.get_transactions_filtered(**args)
+            print( txs )
+            if args['last_tx'] and args['last_tx']==True:
+                lastTX = None
+                for x in txs:
+                    lastTX = x
 
-        return [tx.to_dict() for tx in txs]
+                if lastTX:
+                    return [ lastTX.to_dict() ]
+                else:
+                    return []
+            else:
+                return [tx.to_dict() for tx in txs]
 
     def post(self):
         """API endpoint to push transactions to the Federation.

docs/server/source/http-client-server-api.rst

@@ -91,7 +91,7 @@ Transactions
    Requests to the ``/api/v1/transactions`` endpoint
    without any query parameters will get a response status code ``400 Bad Request``.
 
-.. http:get:: /api/v1/transactions?asset_id={asset_id}&operation={CREATE|TRANSFER}
+.. http:get:: /api/v1/transactions?asset_id={asset_id}&operation={CREATE|TRANSFER}&last_tx={true|false}
 
    Get a list of transactions that use an asset with the ID ``asset_id``.
 
@@ -106,12 +106,18 @@ Transactions
    If ``operation`` is not included, then *every* transaction involving
    the asset with ID ``asset_id`` will be returned.
 
+   if ``last_tx`` is set to ``true``, only the last transaction is returned
+   instead of all transactions with the given ``asset_id``.
+
    This endpoint returns transactions only if they are in committed blocks.
 
    :query string operation: (Optional) ``CREATE`` or ``TRANSFER``.
 
    :query string asset_id: asset ID.
 
+   :query string last_tx: (Optional) ``true`` or ``false``.
+
+
    **Example request**:
 
    .. literalinclude:: http-samples/get-tx-by-asset-request.http