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NAME
ns_adp_registeradp, ns_adp_registerproc, ns_adp_registerscript, ns_adp_registertag,
ns_register_adptag - ADP registered tags
SYNOPSIS
ns_adp_registeradp tag ?endtag? adp
ns_adp_registerproc tag ?endtag? proc
ns_adp_registerscript tag ?endtag? script
ns_adp_registertag tag ?endtag? adp
ns_register_adptag tag ?endtag? script
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DESCRIPTION
These commands enable definition of HTML tags within an ADP file which are expanded and
evaluated by the server before returning output to the client. Tags are defined as eitehr
a single tag with options, e.g., <mytag a=b c=d> or as an opening/closing tag pair, e.g.,
<mytag> text </mytag>. This approach is an alternative to direct calls via the <% script
%> syntax as described in the ns_adp man page.
ns_adp_registeradp tag ?endtag? adp
ns_adp_registertag tag ?endtag? adp
These commands are identical and register an ADP code fragment to be invoked when
the specified tag is encountered while parsing an ADP. The tag argument specifies
the tag that will trigger invocation of the ADP fragment, which is specified by the
adp argument.
If the endtag argument is specified, then the ADP fragment will be invoked with two
arguments: The first will be the enclosed content, and the second will be the name
of an ns_set with any attributes specified in the tag. If no endtag argument is
specified, the ADP fragment will only be passed the name of the ns_set. The
arguments may be retrieved using ns_adp_bindargs or ns_adp_argc and ns_adp_argv.
When the ADP fragment is invoked, its result is inserted in the output instead of
the tag (or, if the endtag was specified, in place of the tag, end tag, and the
enclosed content).
Note: Care must be taken when using this function from inside an ADP, because the
adpstring is likely to contain script delimiters (<% ... %>) which will prematurely
terminate script fragments. It is probably easier to restrict use of this function
to .tcl files.
ns_adp_registerproc tag ?endtag? proc
This commands register a Tcl procedure to be evaluated when the given tag is
encountered. The tag argument specifies the tag that will trigger a call to the
procedure specified by the proc argument.
The procedure will be called with a variable number of arguments, one for each of
the attributes provided in the tag. If the endtag argument is specified, the
procedure will also receive a final argument with the contents of the text enclosed
between the tags. No evaluation of the content will be performed, it will be
passed as a single text block.
When the procedure is invoked, its result is inserted in the output instead of the
tag (or, if the endtag was specified, in place of the tag, end tag, and the
enclosed content).
ns_adp_registerscript tag ?endtag? script
ns_register_adptag tag ?endtag? script
These commands are identical and register a Tcl script to be evaluated when the
given tag is encountered. The tag argument specifies the tag that will trigger
evaluation of the script specified by the script argument.
If the endtag argument is specified, then the script will be modified with two
arguments appended: The first will be the enclosed content, and the second will be
the name of an ns_set with any attributes specified in the tag. If no endtag
argument is specified, the script will be modified with just the name of the ns_set
appended.
When the script is evaluated, its result is inserted in the output instead of the
tag (or, if the endtag was specified, in place of the tag, end tag, and the
enclosed content).
EXAMPLES
The following is a simple way of handling conditional content in ADPs:
proc remember {input tagset} {
global _adp_memory
set tagname [ns_set iget $tagset name]
if {[string match "" $tagname]} {
set _adp_memory($tagname) $input
return ""
} else {
return $input
}
}
proc recall {name} {
global _adp_memory
if {[info exists _adp_memory($name)]} {
set parsecommand [list ns_adp_parse -string]
lappend parsecommand $_adp_memory($name)
ns_puts -nonewline [uplevel $parsecommand]
} else {
ns_log Error "[ns_adp_argv 0]: Unable to recall
}
}
If the preceding Tcl has been executed (perhaps during server startup), then the following
ADP fragment displays the results of a database query in a table, or shows "No rows in
result." if there are no rows:
<%
set rows {}
set db [ns_db gethandle]
ns_db exec "select somecolumn from sometable"
set row [ns_db bindargs $db]
while {[ns_db getrow $db $row] > 0} {
lappend rows [ns_set get $row "somecolumn"]
}
ns_db releasehandle $db
%>
<remember name="hasrows_header">
<table>
</remember>
<remember name="hasrows_rows">
<tr>
<td><%=$column%></td>
</tr>
</remember>
<remember name="hasrows_footer">
</table>
</remember>
No rows in result.
<remember name="norows">
<%
if {[llength $rows] > 0} {
recall "hasrows_header"
foreach row $rows {
set column $row
recall "hasrows_rows"
}
recall "hasrows_footer"
} else {
recall "norows"
}
%>
The following example demonstrates the use of ns_adp_registertag:
ns_adp_registertag printdate {
The current date is: <%=[ns_httptime [ns_time]]%>
}
Once defined, typically in a startup script, you could simple include the "<printdate>"
tag to append the text with current date into the output buffer.
SEE ALSO
ns_adp(1), ns_adp_eval(n), ns_adp_safeeval(n), ns_adp_include(n)
KEYWORDS
ADP, dynamic pages, registered tag