1. Password prompt routine
Hello again folks!
Ok I've got a routine I've called "getpw". You give it a prompt string, it
displays this prompt and then accepts a line of input which is terminated
when you press return. The routine returns the typed line. When you type
a character it prints a single '*' character so you know you've typed the
character but has the nice effect that what you type is hidden from prying
eyes. Hence GET PassWord 
I detect the backspace key (ASCII code 8) and deal with it accordingly
(i.e. throw away the last character typed). I was hoping to print a
"backspace, space, backspace" sequence to rub out the last '*' character
but can't get this to work. Instead I'm currently printing a '#' character
to indicate that the last character has been "erased". If someone can help
me achieve the "backspace, space, backspace" effect I'm after I'd be very
grateful.
Regards.
FP.
function getpw(sequence prompt)
sequence pw
integer key
integer lenpw
printf(1, "%s", {prompt})
pw = ""
while 1 do
lenpw = length(pw)
key = wait_key()
if ( (key = 10) or (key = 13) ) then
if lenpw > 0 then
exit
end if
end if
if ( (key = 8) or (key = 127) ) then
if (lenpw > 0) then
printf(1, "#", {})
if (lenpw = 1) then
pw = ""
else
pw = pw[2..lenpw]
end if
end if
end if
if ( (key >= 32) and (key <= 126) )
then
printf(1, "*", {})
pw = append(pw, key)
end if
end while
printf(1, "\n", {})
return(pw)
end function
End of message.
2. Re: Password prompt routine
- Posted by euman at bellsouth.net
Aug 17, 2001
If you know the key values already which it sounds
like you do, why couldnt you trap the key presses
and process screen output based on the trapped key.
I had a demo for this very thing somewhere, I went looking
for it but it has misteriously been placed somewhere on
my HD but because I have no method for nameing things
it's lost at the moment.... hehe funny huh?
Euman
euman at bellsouth.net
----- Original Message -----
From: <freeplay at mailandnews.com>
To: "EUforum" <EUforum at topica.com>
Sent: Friday, August 17, 2001 18:00
Subject: Password prompt routine
>
> Hello again folks!
>
> Ok I've got a routine I've called "getpw". You give it a prompt string, it
> displays this prompt and then accepts a line of input which is terminated
> when you press return. The routine returns the typed line. When you type
> a character it prints a single '*' character so you know you've typed the
> character but has the nice effect that what you type is hidden from prying
> eyes. Hence GET PassWord
>
> I detect the backspace key (ASCII code 8) and deal with it accordingly
> (i.e. throw away the last character typed). I was hoping to print a
> "backspace, space, backspace" sequence to rub out the last '*' character
> but can't get this to work. Instead I'm currently printing a '#' character
> to indicate that the last character has been "erased". If someone can help
> me achieve the "backspace, space, backspace" effect I'm after I'd be very
> grateful.
>
> Regards.
>
> FP.
>
>
> function getpw(sequence prompt)
> sequence pw
> integer key
> integer lenpw
>
> printf(1, "%s", {prompt})
>
> pw = ""
>
> while 1 do
> lenpw = length(pw)
>
> key = wait_key()
>
> if ( (key = 10) or (key = 13) ) then
> if lenpw > 0 then
> exit
> end if
> end if
>
> if ( (key = 8) or (key = 127) ) then
> if (lenpw > 0) then
> printf(1, "#", {})
>
> if (lenpw = 1) then
> pw = ""
> else
> pw = pw[2..lenpw]
> end if
> end if
> end if
>
> if ( (key >= 32) and (key <= 126) )
> then
> printf(1, "*", {})
> pw = append(pw, key)
> end if
> end while
>
> printf(1, "\n", {})
>
> return(pw)
>
> end function
>
>
> End of message.
>
>
>
>
>
3. Re: Password prompt routine
Hello again,
Thanks for all the suggestions. In the end I worked out that a:
printf(1, "\r", {})
puts the cursor back to the beginnning of the line. So to erase the last
character printed I would need to goto the beginning of the line, print out
the line again but have the last character in the line be a space (to
erase) and then goto the beginning of the line again and reprint the line
minus the last character. You can detect a bit of cursor flicker but it's
good enough for me
Here is the revised routine:
function getpw(sequence prompt)
sequence pw
integer key
integer lenpw
printf(1, "%s", {prompt})
pw = ""
while 1 do
lenpw = length(pw)
key = wait_key()
if ( (key = 10) or (key = 13) ) then
if lenpw > 0 then
exit
end if
end if
if ( (key = 8) or (key = 127) ) then
if (lenpw > 0) then
if (lenpw = 1) then
pw = ""
else
pw = pw[2..lenpw]
end if
lenpw = lenpw - 1
printf(1, "\r%s", {prompt})
for i = 1 to lenpw do
printf(1, "*", {})
end for
printf(1, " ", {})
printf(1, "\r%s", {prompt})
for i = 1 to lenpw do
printf(1, "*", {})
end for
end if
end if
if ( (key >= 32) and (key <= 126) ) then
if (lenpw < MAXPWLENGTH) then
printf(1, "*", {})
pw = append(pw, key)
end if
end if
end while
printf(1, "\n", {})
return(pw)
end function
At 00:00 18/08/01 +0100, I wrote:
>
>Hello again folks!
>
>Ok I've got a routine I've called "getpw". You give it a prompt string, it
>displays this prompt and then accepts a line of input which is terminated
>when you press return. The routine returns the typed line. When you type
>a character it prints a single '*' character so you know you've typed the
>character but has the nice effect that what you type is hidden from prying
>eyes. Hence GET PassWord
>
>I detect the backspace key (ASCII code 8) and deal with it accordingly
>(i.e. throw away the last character typed). I was hoping to print a
>"backspace, space, backspace" sequence to rub out the last '*' character
>but can't get this to work. Instead I'm currently printing a '#' character
>to indicate that the last character has been "erased". If someone can help
>me achieve the "backspace, space, backspace" effect I'm after I'd be very
>grateful.
>
>Regards.
>
>FP.
<snipped>
