3.17 library(http/http_log): HTTP Logging module
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Availability::- use_module(library(http/http_log)).
Source[semidet,multifile]nolog_post_content_type(+Type)
Multifile hook called with the Content-type header. If the hook succeeds, the POST data is not logged. For example, to stop logging anything but application/json messages: 
:- multifile http_log:nolog_post_content_type/1.

http_log:nolog_post_content_type(Type) :-
   Type \= (application/json).
Type is a term MainType/SubType