Advanced Topic

Some of our reports are very important and you don't want they can be printed more than once.

Therefore we needed a software that can enable us to send the print directly to printer. (If the user can preview, they can save it to file system and print it later.

Now you choose RepExpert . Repexpert can output oracle report to printer directly, Repexpert can also hide the source code of HTML report.

To let the customer print report with RepExpert, you can append "&callrepexpert=yes" to the url, please see here for more information.

Problem

1. Perhaps some user uninstalls the RepExpert from his computer, the output will be previewed by IE, so the user can print the report multiple times.
2. You use web.show_document() bulti-in to show report output. If the link(URL) is caught by browser (e.g. MS-IE), end users can see the source code and save it.

How to figure it out

There is a solution to solve this problem. Try the following steps.

1) Encrypt the link(URL) in your forms, pass the encrypted URL to a redirect script named 'getreports.jsp' ;

Example :
Suppose you use the following sample code to get reports .
web.show_document( v_url ,'_blank');

You can change to sample code to :

DECLARE
v_url VARCHAR2(700);
v_encrypted_url VARCHAR2(1000);
BEGIN
-- encrypt the url
v_encrypted_url:=encrypt_url(v_url); --A sample below. You should change the encryption algorithm .
web.show_document('http://servername:7777/getreports.jsp?filepath='||v_encrypted_url||'&callrepexpert=yes','_blank');
END ;

Just a sample. You should change the encryption algorithm.

FUNCTION encrypt_url(p_url varchar) RETURN varchar IS
v_len number(5);
v_cur number(5);
v_url varchar2(2000):=NULL;
v_chr varchar2(1);
v_num number(3);
v_num_high number(3);
v_num_low number(3);
BEGIN
--TODO : Change the encryption algorithm, you should change the corresponding decryption algorithm
-- in getreports.jsp
v_len := lengthb(p_url);
v_cur:=1;
loop
exit when v_cur>v_len;
v_chr := substrb(p_url,v_cur,1);
v_num := ascii(v_chr);
if v_num=32 then
v_url:=v_url||'+';
elsif (v_num>=65 and v_num<=90) THEN -- A - Z
v_url:=v_url||v_chr;
elsif (v_num>=97 and v_num<=122) THEN -- a - z
v_url:=v_url||v_chr;
ELSIF (v_num>=48 and v_num<=57) THEN -- 0 - 9
--encrypt the number
-- 0 -> 1
-- 1 -> 6
-- 2 -> 3
-- 3 -> 8
-- 4 -> 5
-- 5 -> 9
-- 6 -> 4
-- 7 -> 0
-- 8 -> 2
-- 9 -> 7
IF v_chr IN ('0','2','4') THEN
v_chr := v_chr+1;
ELSIF v_chr IN ('1','3') THEN
v_chr := v_chr+5;
ELSIF v_chr IN ('6','9') THEN
v_chr := v_chr-2;
ELSIF v_chr = '5' THEN
v_chr := '9' ;
ELSIF v_chr = '7' THEN
v_chr := '0' ;
ELSIF v_chr = '8' THEN
v_chr := '2' ;
END IF ;
v_url:=v_url||v_chr;
else
v_url:=v_url||'%';
v_num_high := floor(v_num/16);
if v_num_high>=10 then
v_chr:=chr(v_num_high+55);
else
v_chr:=chr(v_num_high+48);
end if;
v_url:=v_url||v_chr;
v_num_low:=mod(v_num,16);
if v_num_low>=10 then
v_chr:=chr(v_num_low+55);
else
v_chr:=chr(v_num_low+48);
end if;
v_url:=v_url||v_chr;
end if;
v_cur:=v_cur+1;
end loop;
return v_url;
END;

2) RepExpert catchs the link to 'getreports.jsp', open this link instead of browser.

3) The redirect script program (getreports.jsp) determine whether the request is from RepExpert or not . If the request is send by Repexpert , the program will decrypted the URL, and return the original link. If not, the program will return error message.

Example:
The sample code of getreports.jsp :
<%
// Usage: http://server-name:port/getreports.jsp?filepath=[encrypted_url]
// Author: Lion Van
// Email: support@lv2000.com
try{
String userAgent=request.getHeader("User-Agent");
if (userAgent.compareToIgnoreCase("Repexpert")==0) //Request comes from Repexpert.
{
String filepath=request.getParameter("filepath");
//Decrypt the url
String original_url="";
int ilen=filepath.length();
for (int i=0;i<ilen;i++)
{
char chr=filepath.charAt(i);
if (chr=='1'){chr='0';}
else if (chr=='6'){chr='1';}
else if (chr=='3'){chr='2';}
else if (chr=='8'){chr='3';}
else if (chr=='5'){chr='4';}
else if (chr=='9'){chr='5';}
else if (chr=='4'){chr='6';}
else if (chr=='0'){chr='7';}
else if (chr=='2'){chr='8';}
else if (chr=='7'){chr='9';}
original_url+=chr;
}
// out.println(original_url);
response.sendRedirect(original_url);
}else{
out.println("<p>Hey! you should install RepExpert on your pc</p>");
out.println("If you have installed Repexpert, please contact your network administrator");
//TODO: Record the event
}
}catch(Exception e){System.out.println(e);}
finally{
}
%>

4) Repexpert use the original link to download report output files.

Please click here to download the example.