WebHDFS REST API

Apache Hadoop’s HTTP interface to HDFS, introduced in 2011 — a complete file-system vocabulary over REST (list, status, open with offset and length, mkdirs, rename, delete, permissions, owners, content summary) with a two-step write in which the namenode answers a CREATE or APPEND with a 307 redirect to the datanode that will take the bytes. It is the clearest production precedent for “send metadata first, receive an upload target, then send bytes,” and the documentation says exactly why it was built that way.