THE NULL POINTER
  ================
  {% set fhost_url = url_for("fhost", _external=True).rstrip("/") %}
  HTTP POST files here:
      curl -F'file=@yourfile.png' {{ fhost_url }}
  You can also POST remote URLs:
      curl -F'url=http://example.com/image.jpg' {{ fhost_url }}
  If you don't want the resulting URL to be easy to guess:
      curl -F'file=@yourfile.png' -Fsecret= {{ fhost_url }}
      curl -F'url=http://example.com/image.jpg' -Fsecret= {{ fhost_url }}
  Or you can shorten URLs:
      curl -F'shorten=http://example.com/some/long/url' {{ fhost_url }}
  You can also paste a file blob from your system's clipboard.

  It is possible to append your own file name to the URL:
      {{ fhost_url }}/aaa.jpg/image.jpeg
  
  File URLs are valid for at least 30 days and up to a year (see below).
  Shortened URLs do not expire.
  
  Files can be set to expire sooner by adding an "expires" parameter (in hours)
      curl -F'file=@yourfile.png' -Fexpires=24 {{ fhost_url }}
  OR by setting "expires" to a timestamp in epoch milliseconds
      curl -F'file=@yourfile.png' -Fexpires=1681996320000 {{ fhost_url }}
  
  Expired files won't be removed immediately, but will be removed as part of
  the next purge.
  
  Whenever a file that does not already exist or has expired is uploaded,
  the HTTP response header includes an X-Token field. You can use this
  to perform management operations on the file.
  
  To delete the file immediately:
      curl -Ftoken=token_here -Fdelete= {{ fhost_url }}/abc.txt
  To change the expiration date (see above):
      curl -Ftoken=token_here -Fexpires=3 {{ fhost_url }}/abc.txt
  
  {% set max_size = config["MAX_CONTENT_LENGTH"]|filesizeformat(True) %}
  Maximum file size: {{ max_size }}
  Not allowed: {{ config["FHOST_MIME_BLACKLIST"]|join(", ") }}
  
  
  FILE RETENTION PERIOD
  ---------------------
  
  retention = min_age + (-max_age + min_age) * pow((file_size / max_size - 1), 3)
  
     days
   {{'{: 6}'.format(config.get("FHOST_MAX_EXPIRATION", 31536000000)//86400000)}} |  \
          |   \
          |    \
          |     \
          |      \
          |       \
          |        ..
          |          \
   {{'{: 6.1f}'.format((config.get("FHOST_MIN_EXPIRATION", 2592000000)/2 + config.get("FHOST_MAX_EXPIRATION", 31536000000)/2)/86400000)}} | ----------..-------------------------------------------
          |             ..
          |               \
          |                ..
          |                  ...
          |                     ..
          |                       ...
          |                          ....
          |                              ......
   {{'{: 6}'.format(config.get("FHOST_MIN_EXPIRATION", 2592000000)//86400000)}} |                                    ....................
            0{{ ((config["MAX_CONTENT_LENGTH"]/2)|filesizeformat(True)).split(" ")[0].rjust(27) }}{{ max_size.split(" ")[0].rjust(27) }}
             {{ max_size.split(" ")[1].rjust(54) }}