= cowboy_req:body_length(3) == Name cowboy_req:body_length - Body length == Description [source,erlang] ---- body_length(Req :: cowboy_req:req()) -> undefined | non_neg_integer() ---- Return the length of the request body. The length is not always known before reading the body. In those cases Cowboy will return `undefined`. The body length is available after the body has been fully read. == Arguments Req:: The Req object. == Return value The length of the request body, or `undefined` if it is not known. == Changelog * *2.0*: Only the length is returned, it is no longer wrapped in a tuple. * *1.0*: Function introduced. == Examples .Get the body length [source,erlang] ---- Length = cowboy_req:body_length(Req). ---- == See also link:man:cowboy_req(3)[cowboy_req(3)], link:man:cowboy_req:has_body(3)[cowboy_req:has_body(3)], link:man:cowboy_req:read_body(3)[cowboy_req:read_body(3)], link:man:cowboy_req:read_urlencoded_body(3)[cowboy_req:read_urlencoded_body(3)], link:man:cowboy_req:read_part(3)[cowboy_req:read_part(3)], link:man:cowboy_req:read_part_body(3)[cowboy_req:read_part_body(3)]