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2012-10-18T21:53:32Z

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JAL2: Created page with "This page demonstrates some of the concepts of the $Web_Sel* functions. The application is a simple form which lets the user select a day of the week. To show how this can exploi..."

2012-10-18T21:53:28Z

Created page with "This page demonstrates some of the concepts of the $Web_Sel* functions. The application is a simple form which lets the user select a day of the week. To show how this can exploi..."

← Older revision		Revision as of 21:53, 18 October 2012
Line 89:		Line 89:
	The following approach can be used to handle this situation		The following approach can be used to handle this situation
	when the web form is built.		when the web form is built.
	the <var>NOCAN</var> option of $Web_Selp is used to see if a new language		the <var>NOCAN</var> option of <var>$Web_Selp</var> is used to see if a new language
	is in use:		is in use:
	<p class="code">Begin		<p class="code">Begin

JAL2: Created page with "This page demonstrates some of the concepts of the $Web_Sel* functions. The application is a simple form which lets the user select a day of the week. To show how this can exploi..."

2011-09-20T19:48:01Z

New page

This page demonstrates some of the concepts of the $Web_Sel* functions.
The application is a simple form which lets the user select a day of
the week.
To show how this can exploit metadata, assume that you have a <var class="product">Model 204</var>
file with the days of the week in several languages, and that you have saved
the user's language in a cookie named <code>LANG</code>.
Note that by giving values of <code>DN0</code>, <code>DN1</code>, etc., the code does not
need to deal with the actual day names (the option descriptions).

Assume you have records like the following:
<p class="code">IN META STORE RECORD
TYPE = LANG
LANG = ENGLISH
END STORE

IN META STORE RECORD
TYPE = DAY
LANG = ENGLISH
DAY = Sunday
END STORE
IN META STORE RECORD
TYPE = DAY
LANG = ENGLISH
DAY = Monday
END STORE
...
</p>

<var>[[$Web_Save_Sel]]</var> is used to save one global select element for each language.
You can do this when you start the online, but a later example shows how a
language can be dynamically added.
Assume the following procedure:
<p class="code">PROCEDURE GEN_DAYS
SUBROUTINE GEN_DAYS(%LANG IS STRING LEN 20, -
%NDAY IS FLOAT OUTPUT)ut)
%NDAY = 0
%L1 FLOAT
%L2 FLOAT
%X FLOAT
%L1 = $LISTNEW
%L2 = $LISTNEW
IN META FR WHERE TYPE=DAY AND LANG=%LANG
%X = $LISTADD(%L1, 'DAY' WITH %NDAY)
%X = $LISTADD(%L2, DAY)
%NDAY = %NDAY + 1
END FOR
IF %NDAY THEN
%x = $WEB_SAVE_SEL('DAYS.' WITH %LANG, -
DEL
%L1, %L2)
END IF
END SUBROUTINE
END PROC
</p>
You can use this procedure at the start of the online:
<p class="code">//CCAIN ...
...
BEGIN
IN META FR WHERE TYPE=LANG
CALL GEN_DAYS(LANG, %RC)
END FOR
INCLUDE GEN_DAYS
END
</p>

You can use the global select elements to create a drop-down list in an
HTML form.
<var>[[$Web_Selp]]</var> is used with the same second argument (the parameter
name, <code>DN</code>) as the <code>name=</code> attribute of the <code>select</code> element; this is
how you can easily "pre-select" the same day chosen before when the
form is redisplayed to the user:
<p class="code">B
%lang string len 20
%rc float
%lang = $web_cookie_parm('LANG')
print '<form method=post action="' with -
$web_hdr_parm('URL') with'">'
print 'Select day: <select name=DN><br>'
%RC = $web_selp('DAYS.' with %lang, 'DN')
print '<input type=submit><br>'
print '</form>'
End
</p>

This approach works fine, except that if a language is added while
the online is running, a user who acquires this language in his or
her cookie will have the <var>User Language</var> request cancelled, because
<var>$Web_Selp</var> will not find the desired global select element.
The following approach can be used to handle this situation
when the web form is built.
the <var>NOCAN</var> option of $Web_Selp is used to see if a new language
is in use:
<p class="code">Begin
%lang string len 20
%rc float
%lang = $web_cookie_parm('LANG')
print '<form method=post action="' with -
$web_hdr_parm('URL') with '">'
print 'Select day: <select name=DN><br>'
%rc = $web_selp('DAYS.' with %lang, 'DN', -
'NOCAN')
if %rc ne 0 then
call gen_days(%lang, %rc)
%rc = $web_selp('DAYS.' with %lang, 'DN')
end if
print '<input type=submit><br>'
print '</form>'
include gen_days
End
</p>

If you want to remove a language from further processing, you can
call <var>[[$Web_Del_Sel]]</var>:
<p class="code">Begin
%rc = $web_del_sel('DAYS.ESPERANTO')
End
</p>
However, it is then possible that a "stale cookie" may be left
around in a user's browser.
In that case, you will want to set a default language,
but if the deleted language was Romulac, and a day beyond the 7th
had been selected, you might also want to force
the pre-selected day to be the middle of the week.
The following code contains changes that do the following:
<ul>
<li>Set a default language (with <var>[[$Web_Set_Cookie]]</var>)
<li>Use <var>[[$Web_Selp_Check]]</var> to ensure that the user's form parameter <var>DN</var>
(which, remember, will contain the language-independent values <code>DN0</code>, <code>DN1</code>, etc.)
is within the range of the default language.
If <var>DN</var> is outside that range,
<var>$Web_Sel</var> is used so that the pre-selected day is the "hand-coded"
<code>DN3</code>.
</ul>
<p class="code">B
%lang string len 20
%rc float
%lang = $web_cookie_parm('LANG')
print '<form method=post action="' with -
$web_hdr_parm('URL') with '">'
print 'Select day: <select name=DN><br>'
%rc = $web_selp('DAYS.' with %lang, 'DN', -
'NOCAN')
if %rc ne 0 then
call gen_days(%lang, %rc)
if %rc ne 0 then
%lang = 'ENGLISH'
%rc = $web_set_cookie('LANG', 'ENGLISH')
end if
%rc = $web_selp_check('DAYS.' with %lang, -
'DN')
if %rc ne 0 then
%rc = $web_sel('DAYS.' with %lang, 'DN3')
else
%rc = $web_selp('DAYS.' with %lang, 'DN')
end if
end if
print '<input type=submit><br>'
print '</form>'
include gen_days
End
</p>

[[Category:Janus Web Server]]

$Web Sel* example - Revision history

JALWiccan: 1 revision

JAL2: Created page with "This page demonstrates some of the concepts of the $Web_Sel* functions. The application is a simple form which lets the user select a day of the week. To show how this can exploi..."

JAL2: Created page with "This page demonstrates some of the concepts of the $Web_Sel* functions. The application is a simple form which lets the user select a day of the week. To show how this can exploi..."