SYNOPSIS

ns_adp_argc
ns_adp_argv ?index?
ns_adp_bind_args var1 ?var2...?
ns_adp_dir
ns_adp_eval page ?arg ...?
ns_adp_ident ?string?
ns_adp_include ?-cache seconds? ?-nocache? file ?arg ...?
ns_adp_parse ?-file file? ?-string string? ?-savedresult varName? ?-cwd path? ?args ... ?
ns_adp_safeeval page ?arg ...?

DESCRIPTION

These commands enable execution of ADP files or strings. Each call to ns_adp_include results in a new ADP "call frame" similar to a Tcl procedure with local variable scope. Variables may be passed to these call frames as optional arguements and then accessed via the ns_adp_argc, ns_adp_argv, and ns_adp_bind_args commands. The ns_adp_eval, ns_adp_safeeval, or ns_adp_parse can also accept arguments via the same mechanism but execute in the same ADP call frame as their parent, i.e., with the same local variables. See the ns_adp page for details on ADP syntax and control flow.

ns_adp_argc

This command returns the number of optional arguments passed to the ADP. The count includes the argument for the ADP file or string.

ns_adp_argv ?index ?default??

This command returns the list of arguments passed to the ADP. If the optional index argument is specified, only the given argument is returned instead of the full list. If the optional default argument is specified along with an index argument, it serves as the value to return if the cooresponding index was not passed to the call frame.

ns_adp_bind_args var1 ?var2...?

This command can be used to set multiple optional ADP arguments to a list of local variables. Argument binding begins with argument number 1, i.e., the first argument beyond the ADP file or script.

ns_adp_dir

This command returns the directory in which the ADP currently being processed resides and which relative ADP files will be found.

ns_adp_eval page ?arg ...?

This command evaluates the ADP specified by page and returns the output as the result. If any arguments are specified, they will be passed to the ADP.

ns_adp_ident ?string?

This command returns and/or sets an arbitrary version management string for the given ADP file. It could be used to specify a header replaced via a CVS/RCS checkin:

<% ns_adp_ident {$Header: /cvsroot/aolserver/aolserver/doc/ns_adp_include.n,v 1.1 2006/04/13 19:07:12 jgdavidson Exp $} %>

ns_adp_include ?-cache seconds? ?-nocache? file ?arg ...?

This command parses the specified file as an ADP, including the text blocks and any output generated by script blocks in the current output buffer. The execution occurs in a new call frame with private local variables similar to a Tcl procedure. The filename is the file containing the ADP to be parsed. If the file is not an absolute filename, the file is considered relative to the current ADP working directory which is the directory of the previously included file. Optional arguments (arg...) can be passed to the included ADP; see the ns_adp_argv command above for details on accessing the values of these variables. The optional -cache seconds argument specifies the time to cache the results of execution. All output generated by any scripts and included ADP's are saved for subsequent requests unless an included ADP has a -nocache option. The use of -cache and -nocache can be used to increase performance of ADP used to generated a mix of personalized, non-cacheable, content and shared content which changes more slowly. Under high load, the performance improvement can be substaintial, especially in cases where the cached content is the result of accessing a slow databases or web services. See the EXAMPLES section for an example of using cached output.

ns_adp_parse ?-file file? ?-string string? ?-savedresult varName? ?-cwd path? ?args ... ?

This function processes the specified ADP file or string and returns the result as a string. Processing a second ADP from inside an ADP is normally best done with ns_adp_include as that command resolves relative pathnames passed to it. Also note that ns_adp_parse will ignore any directives to turn on streaming. Tcl_Eval is used to evaluate the Tcl commands in the ADP.

The -string adp option can be used to parse a string of ADP text. Although the <% ... %> syntax is allowed in the string, if you have this embedded in an ADP, you have to be careful in constructing the string that you do not prematurely terminate an enclosing script.

The -file file option can be used to parse ADP contained in the given file. This use is similar to that of ns_adp_include except the result is returned by the command instead of automatically being appended to the output stream.

The -global and -local options are deprecated. All calls are now local to the current ADP call frame such that the -local option is ignored and the -global option generates an error.

Additional arguments are passed to the ADP execution and can be accessed via the ns_adp_argc, ns_adp_argv, and ns_adp_bind_args commands.

ns_adp_safeeval string ?arg ...?

The command evaluates the given ADP string in a safe environment which ignores all cases of <% ... %> and <%= ... %> commands, only allowing execution of per-defined registered tags. This usage can be helpful to expose a limited set of dynamic functionality to publishing staff without exposing the full command set.

EXAMPLE

The following example demonstrates passing an argument to an included ADP file:

<% ns_adp_include included.adp arg1 arg2 arg3 %>

The variables could be accessed within included.adp with:

ns_adp_argc
--> return 4
ns_adp_argv 1
--> returns "arg1"
ns_adp_argv 10 MyDefault
--> returns "MyDefault" as there is no 10th argument

The followiong example demonstrates using the -cache and -nocache options to the ns_adp_include command to enhance performance through caching execution output. Given the following files:

top.adp:

<% ns_adp_include -cache 60 cached.adp %>

cached.adp:

<%
ns_adp_puts "Time at cache: [ns_time]"
ns_adp_include -nocache nocache.adp
%>

nocache.adp:

<% ns_adp_puts "Time now: [ns_time]" %>

the results of cached.adp will only update once every 60 seconds while the results of nocache.adp will be executed on each request, even though it's included withing cached.adp.

KEYWORDS

ADP, dynamic pages, execution