Great, Hive account@lantto answering you question about get_transaction, you put transaction tx as input, it works already:
http://steemroll.io/api-explorer/#method=get_transaction&params=["cd378a9da6f087f40c8baeb3e533ed09cea7dabe"]
this gives data of transaction you used to create this article
https://steemd.com/tx/cd378a9da6f087f40c8baeb3e533ed09cea7dabe