(* $Id: add.ml 1004 2006-09-25 16:01:06Z gerd $
* ----------------------------------------------------------------------
*
*)
open Netcgi;;
open Printf;;
(***********************************************************************
* This example demonstrates a very simple CGI page that refers to itself
* using the GET method.
***********************************************************************)
let text = Netencoding.Html.encode_from_latin1;;
(* This function encodes "<", ">", "&", double quotes, and Latin 1 characters
* as character entities. E.g. text "<" = "<", and text "ä" = "ä"
*)
let begin_page cgi title =
(* Output the beginning of the page with the passed [title]. *)
let out = cgi # output # output_string in
out "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0//EN\" \"http://www.w3.org/TR/REC-html40/strict.dtd\">\n";
out "<HTML>\n";
out "<HEAD>\n";
out ("<TITLE>" ^ text title ^ "</TITLE>\n");
out ("<STYLE TYPE=\"text/css\">\n");
out "body { background: white; color: black; }\n";
out "</STYLE>\n";
out "</HEAD>\n";
out "<BODY>\n";
out ("<H1>" ^ text title ^ "</H1>\n")
;;
let end_page cgi =
let out = cgi # output # output_string in
out "</BODY>\n";
out "</HTML>\n"
;;
let generate_query_page (cgi : cgi_activation) =
(* Display the query form. *)
begin_page cgi "Add Two Numbers";
let out = cgi # output # output_string in
out "<P>This CGI page can perform additions. Please enter two integers,\n";
out "and press the button!\n";
out (sprintf "<P><FORM METHOD=GET ACTION=\"%s\">\n"
(text (cgi#url())));
(* Note that cgi#url() returns the URL of this script (without ? clause).
* We pass this string through the text function to avoid problems with
* some characters.
*)
out "<INPUT TYPE=TEXT NAME=\"x\"> + <INPUT TYPE=TEXT NAME=\"y\"> = ";
out "<INPUT TYPE=SUBMIT NAME=\"button\" VALUE=\"Go!\">\n";
(* The hidden field only indicates that now the result page should
* be consulted.
*)
out "<INPUT TYPE=HIDDEN NAME=\"page\" VALUE=\"result\">\n";
out "</FORM>\n";
end_page cgi
;;
let generate_result_page (cgi : cgi_activation) =
(* Compute the result, and display it *)
begin_page cgi "Sum";
let out = cgi # output # output_string in
out "<P>The result is:\n";
let x = cgi # argument_value "x" in
let y = cgi # argument_value "y" in
let sum = (int_of_string x) + (int_of_string y) in
out (sprintf "<P>%s + %s = %d\n" x y sum);
out (sprintf "<P><A HREF=\"%s\">Add further numbers</A>\n"
(text (cgi#url
~with_query_string:
(`Args [new simple_argument "page" "query"])
()
)));
(* Here, the URL contains the CGI argument "page", but no other arguments. *)
end_page cgi
;;
let generate_page (cgi : cgi_activation) =
(* Set the header. The header specifies that the page must not be
* cached. This is important for dynamic pages called by the GET
* method, otherwise the browser might display an old version of
* the page.
* Furthermore, we set the content type and the character set.
* Note that the header is not sent immediately to the browser because
* we have enabled HTML buffering.
*)
cgi # set_header
~cache:`No_cache
~content_type:"text/html; charset=\"iso-8859-1\""
();
(* Check which page is to be displayed. This is contained in the CGI
* argument "page".
*)
match cgi # argument_value "page" with
"" ->
(* The argument is the empty string, or the argument is missing.
* This is the same like the page "query".
*)
generate_query_page cgi
| "query" ->
generate_query_page cgi
| "result" ->
generate_result_page cgi
| _ ->
assert false
;;
