SWI-Prolog -- iostream:open_hook/6

Documentation
- Reference manual
- Packages
  - SWI-Prolog HTTP support
    - The HTTP client libraries
      - library(http/http_open): HTTP client library
        
        http_open/3
        
        map_method/2
        
        disable_encoding_filter/1
        
        http_set_authorization/2
        
        open_hook/6
        
        http_close_keep_alive/1
        
        open_options/2
        
        write_cookies/3
        
        update_cookies/3

Source

[semidet,multifile]iostream:open_hook(+Spec, +Mode, -Stream, -Close, +Options0, -Options)

Hook implementation that makes open_any/5 support http and https URLs for Mode == read.