NaviServer ADP Development - NaviServer ADP Development
TABLE OF CONTENTS
DESCRIPTION
What Are ADPs?
When to Use ADPs
When to Use Tcl Libraries
Configuring ADP Processing
Required Configuration Parameters
List of Configuration Parameters
Building ADPs
Debugging ADPs with TclPro
ADP Syntax
Registered ADP Tags
Example ADPs
Probably the easiest way to make NaviServer output dynamic content is to embed a Tcl script in an HTML page with NaviServer Dynamic Pages (ADPs). ADPs are HTML pages that are parsed and run on the server when the page is accessed. ADPs contain HTML tags and Tcl scripts that are embedded within the HTML tags. The embedded Tcl scripts can call other Tcl scripts that reside in separate files, allowing you to reuse Tcl code.
ADPs are ideal in situations where you want to generate all or part of a specific page dynamically. You can re-use code by storing Tcl scripts in Tcl libraries and invoking them from within multiple ADPs. You can also include files and parse other ADPs from within your ADPs.
Here are some examples of applications you can use ADPs for:
The alternative to embedding Tcl scripts in HTML pages using ADPs, is to store Tcl scripts in Tcl libraries and register them to handle specific URLs or URL hierarchies. There are some situations, such as those listed below, that are better suited to the Tcl libraries approach.
Since you will be creating HTML pages that contain Tcl scripts, you will need to specify which pages the server will need to parse for Tcl commands and process.
The following table describes all the parameters that can be set within the ADP section of the configuration file:
Section ns/server/servername/adp:
Map "/*.adp" Map "/*.asp" Map "/usr/pages/myadps" |
To debug your ADPs with TclPro, follow these steps:
There are three different syntaxes you can use to embed a Tcl script into an HTML page. Not all syntaxes are available with all ADP parsers. You must be using the appropriate ADP parser to process a specific syntax.
Insert Tcl commands between any of the following sets of HTML tags:
<script language=tcl runat=server stream=on> ... </script> |
You can define your own ADP tags with the ns_adp_registertag or the ns_register_adptag Tcl functions.
This section contains the following ADP examples:
Example 1: Return partial HTML page conditionally
Example 2: Return full HTML page conditionally
Example 3: Return information from the database
Example 4: Get form information and insert into the database
Example 5: ADP sampler with includes, recursion, and streaming
Example 1: Return partial HTML page conditionally
This ADP example tests for various browsers and returns a different message in each case.
<%
ns_puts "Hello"
set ua [ns_set get [ns_conn headers] "user-agent"]
ns_puts "$ua "
if [string match "*MSIE*" $ua] {
ns_puts "This is MS Internet Explorer"
} elseif [string match "*Mozilla*" $ua] {
ns_puts "This is Netscape or a Netscapecompatible browser"
} else {
ns_puts "Couldn't determine the browser"
}
%>
|
Example 2: Return full HTML page conditionally
This example consists of a form, cookbook.html, that asks the user whether they want to view a page with or without frames, and an ADP, cookbook.adp, that determines the response and displays the appropriate page, either the page with frames or the page without frames.
This is the cookbook.html file containing the form:
<HTML> <HEAD><TITLE>The ABC's of Fruit Cookbook</TITLE></HEAD> <BODY BGCOLOR="#ffffff"> <H1>The ABC's of Fruit Cookbook</H1> <P> How would you like to view this cookbook? <FORM ACTION="cookbook.adp" METHOD="POST"> <INPUT TYPE="radio" NAME="question" VALUE="yes" CHECKED>With Frames<BR> <INPUT TYPE="radio" NAME="question" VALUE="no">Without Frames <P> <INPUT TYPE=submit VALUE="View Cookbook"> </FORM> <P> </BODY> </HTML> |
This is the ADP, cookbook.adp, that determines the response and displays the appropriate page:
<HTML><HEAD><TITLE>The ABC's of Fruit Cookbook</TITLE></HEAD>
<BODY BGCOLOR="#ffffff">
<%
# Get form data and assign to variables
set r [ns_conn form $conn]
set question [ns_set get $r question]
# Display cookbook in appropriate format
if {$question == "yes"} {ns_adp_include cookset.html} \
else {ns_adp_include cook.html}
%>
</BODY></HTML>
|
The cookset.html file contains a frame set for the cookbook. The cook.html file contains the cookbook without frames.
Example 3: Return information from the database
This example retrieves information from the database -- a list of tables -- and returns it as the options in a select box. When the user chooses a table from the list, another ADP is run as the POST for the form which retrieves information from the database on the chosen table.
The first ADP, db.adp, creates a form with a select box with the list of database tables:
<HTML><HEAD><TITLE>DB Example</TITLE></HEAD>
<BODY>
<H1>DB Example</H1>
<P>
Select a db table from the default db pool:
<FORM METHOD=POST ACTION=db2.adp>
<SELECT NAME=Table>
<%
set db [ns_db gethandle]
set sql "select * from tables"
set row [ns_db select $db $sql]
while {[ns_db getrow $db $row]} {
set table [ns_set get $row name]
ns_puts "<OPTION VALUE=\"$table\">$table"
}
%>
</SELECT>
<INPUT type=submit value="Show Data">
</FORM>
</BODY>
</HTML>
|
The second ADP, db2.adp, is used as the POST from the first ADP:
<HTML><HEAD><TITLE>DB Example page 2</TITLE></HEAD>
<BODY>
<H1>DB Example page 2</H1>
<%
set table [ns_set get [ns_conn form $conn] Table]
set db [ns_db gethandle]
%>
Contents of <%=$table%>:
<Table border=1>
<%
set row [ns_db select $db "select * from $table"]
set size [ns_set size $row]
while {[ns_db getrow $db $row]} {
ns_puts "<tr>"
for {set i 0} {$i < $size} {incr i} {
ns_puts "<td>[ns_set value $row $i]</td>"
}
ns_puts "</tr>"
}
%>
</table>
</BODY>
</HTML>
|
Example 4: Get form information and insert into the database
This is another database example, but one where the user types information into a form, and the submit runs an ADP that enters the information into the database. Then it sends an email message to both the db administrator and the user that the record was updated. The survey.html file contains the form and calls the survey.adp file as the POST action.
Here is the survey.html file, which consists of a simple form and a submit button which calls an ADP:
<HTML><HEAD><TITLE>Survey Form</TITLE> </HEAD> <BODY BGCOLOR="#ffffff"> <H2>Online Newsletter Subscription</H2> <P> <I>Sign up to be notified when this web site changes, or to receive an ASCII version via email. Thanks!</I> <FORM ACTION="survey.adp" METHOD="POST"> <B>Name</B> <INPUT TYPE="text" NAME="name" SIZE="40"> <P> <B>Title </B> <INPUT TYPE="text" NAME="title" SIZE="40" MAXLENGTH="80"> <P> <INPUT TYPE="checkbox" NAME="notify" VALUE="1">Notify me by email when this newsletter changes online <P> <INPUT TYPE="checkbox" NAME="sendemail" VALUE="1">Send me an ASCII version of this newsletter by email <P> <B>Email Address </B> <INPUT TYPE="text" NAME="emailaddr" SIZE="40" MAXLENGTH="60"> <P> <INPUT TYPE=submit> </FORM> <P> </BODY> </HTML> |
Here is the survey.adp file, which gets the form data from the survey, inserts it into the database, sends email to the subscription administrator and the user, and displays a confirmation message:
<HTML><HEAD><TITLE>Subscription Processed Successfully</TITLE>
</HEAD>
<BODY BGCOLOR="#ffffff">
<H2>Online Newsletter Subscription</H2>
<P>
Thank You for subscribing to our newsletter!
<%
# Get form data and assign to variables
set r [ns_conn form $conn]
set name [ns_set get $r name]
set title [ns_set get $r title]
set notify [ns_set get $r notify]
set sendemail [ns_set get $r sendemail]
set emailaddr [ns_set get $r emailaddr]
# Set subscription options explicity to 0 if not checked
if {$notify != 1} {set notify 0}
if {$sendemail != 1} {set sendemail 0}
# Update database with new subscription
set db [ns_db gethandle]
ns_db dml $db "insert into test values ([ns_dbquotevalue $name],
[ns_dbquotevalue $title], $notify, $sendemail,
[ns_dbquotevalue $emailaddr])"
# Send email message to subscription administrator
set body "A new newsletter subscription was added for "
append body $name
append body ". The database has been updated."
ns_sendmail "subscript@thecompany.com" "dbadmin@thecompany.com" "New Subscription" $body
# Send email message to user
set body "Your online newsletter subscription has been successfully processed."
ns_sendmail $emailaddr "dbadmin@thecompany.com" "Your Online Subscription" $body
# Show type of subscription to user
if {$notify == 1} {
ns_puts "You will be notified via email when the online newsletter changes."
}
if {$sendemail == 1} {
ns_puts "Future issues of the newsletter will be sent to you via email."
}
%>
</BODY>
</HTML>
|
Example 5: ADP sampler with includes, recursion, and streaming
The following HTML is an example of a page containing several Tcl scripts using the various ADP syntaxes. It invokes some Tcl functions, includes a file, executes another ADP, and uses streaming.
<HTML><HEAD><TITLE>This is a test of ADP</TITLE>
</HEAD>
<BODY>
<H1>This is a test of ADP</H1>
<%
## Proxies should cache this page for a maximum of 1 hour:
ns_setexpires $conn 3600
set host [ns_set iget [ns_conn headers $conn] host]
## How many times has this page been accessed
## since the server was started?
ns_share -init {set count 0} count
incr count
%>
Number of accesses since server start: <%=$count%><br>
tcl_version: <%=$tcl_version%><br>
tcl_library: <%=$tcl_library%><br>
Host: <%= $host %><br>
<!-- Include the contents of a file: -->
<%
ns_adp_include standard-header
%>
<script language=tcl runat=server>
## You can do recursive ADP processing as well:
ns_adp_include time.adp
</script>
<P>Here's an example of streaming:
<script stream=on runat="server">
ns_puts "<br>1...<br>"
ns_sleep 2
ns_puts "2...<br>"
ns_sleep 2
ns_puts "3!<br>"
</script>
<p>
<b>End</b>
</BODY>
</HTML>
|
The standard-header file referenced in the above example looks like this:
This is a standard header.
The time.adp file referenced in the example looks like this:
The time is: <%=[ns_httptime [ns_time]]%>
Because of the streaming used in the last script, the "1...", "2...", "3!" and "End" part of the page will be displayed gradually.