The SimpleWeb interface fetches the contents of a URL. If there are any errors or if the URL is not of an acceptable type, an approrpriate message is returned as the contents of the page. In addition, the SimpleWeb interface maintains a cache of pages.

INTERFACE SimpleWeb;

IMPORT Thread, Web;

TYPE
  ExtensionType =
    RECORD
      ext: TEXT;
      type: Web.MIMEType;
      subType: TEXT;
    END;

CONST
  DefaultAccepts = ARRAY OF TEXT {(* no wild cards; sorry *)
                     "text/html",
                     "text/plain",
                     "image/x-xbitmap",
                     "image/gif",
                     "image/jpeg",
                     "image/ppm",
                     "image/pbm",
                     "image/pgm",
                     "image/pnm"};

PROCEDURE Setup(READONLY a: ARRAY OF ExtensionType);

PROCEDURE Fetch (         url    : TEXT;
                 READONLY accepts: ARRAY OF TEXT := DefaultAccepts;
                          reload : BOOLEAN       := FALSE;
                          server : Web.T         := NIL             ):
  Web.Page RAISES {Thread.Alerted};

Fetch the URL and return its contents. By default, pages are grabbed from a local cache, if url is in the cache, or from the server's local cache, if the server maintains a cache. When reload is TRUE, the request always goes to the server; moreover, the server will explicitly not use its own cache, if it maintains one.

If the url cannot be retreived for any reason, or if the requested url is not of type listed in the accepts parameter, then an object of type text/plain is returned whose body contains an appropriate message.

END SimpleWeb.