Oracle WebServer FAQ

$Date: 10-May-98 $
$Revision: 2.6 $
$Authors: Frank Naudé and Steve Kilbane $

+-CLIENT-+                +--------------S E R V E R---------------+
|        |                |                                        |
|   Web  | <--Internet--> | Oracle Web <-> Oracle Web <->  Oracle  |
| Browser|      HTTP      |  Listener      Agent (OWA)    Database |
|        |                |                                        |
+--------+                +----------------------------------------+

V1:   wlctl   start <port_number>       eg. wlctl   start 8888
      wlctl   stop  <port_number>

V2.0: wlctl2  start <listener_name>     eg. wlctl2  start admin
      wlctl2  stop  <listener_name>

V2.1: wlctl21 start <listener_name>     eg. wlctl21 start admin
      wlctl21 stop  <listener_name>

V3.0: Starting the webserver (note the sequence):
      owsctl start wrb   ... starts webrequest broker
      owsctl start admin ... start admin listener
      owsctl start yourweb ... start your weblistener

      Stopping the webserver (note the sequence):
      owsctl stop yourweb
      owsctl stop admin
      owsctl stop wrb

• HTP - Hypertext Procedures
  
• HTF - Hypertext Functions
  
• OWA_UTIL - Oracle Web Agent Utilities

CREATE OR REPLACE PROCEDURE HelloWorld AS
BEGIN
   htp.htitle('My first dynamic Web page');
   htp.print('Hello world');
   htp.line;
END HelloWorld;
/

http://your.host.name/oracle_connect_descriptor/owa/HelloWorld

   for c1 in (select rowid, a.* from emp a) loop
      htp.FormHidden('the_rowid', c1.rowid);
      htp.Print('Enter new Employee Name:');
      htp.FormHidden('old_ename', c1.ename);
      htp.FormText('new_ename', c1.ename);
   end loop;

   UPDATE emp SET ename = new_ename
   WHERE rowid = the_rowid
     AND ename = old_ename;

   if (SQL%ROWCOUNT = 0) then
      htp.print('Someone else changed this row, please re-query before updating.');
   else
      htp.print('1 row updated.');
   end if;

From Designer/2000 1.3W one can generate applications that can do Insert, Update and Delete operations. 1.3W also generates JavaScript (NOT JAVA!) code to do client side validation!!!

With version 2.0 you have a CGI-BIN program called OWA that works with any webserver, in addition to a Web Request Broker (WRB) OWA cartridge. The WRB cartridge with 2.0 works with the Oracle Web Server (with 2.0 you can still use the web agent with any server, but you can't use the WRB component with any other server).

With version 2.1 you have the CGI-BIN program... in addition to a Web Request Broker OWA cartridge. The WRB cartridge with 2.1 works with the Oracle Web Server and/or the Netscape Fasttrack Server.

With version 3.0 you will have the CGI-BIN program... the cartridge... which works with Oracle Web Server, Netscape fasttrack/enterprise/commerce server, MSIIS, and perhaps others.

Note that the OWS-BIN OWA program's configuration parameters are stored in the SV*.CFG file while the WRB OWA is configured from SV*.APP.

• using Netscape-style cookies in conjunction with some sort of login form. The PL/SQL procedure that processes the form returns a cookie to the browser which the browser will hold on to and include with future requests, until you send it a new cookie, or the browser session ends. This avoids having to have user identifiers in the URL.
• Look at OWA2, a replacement for Oracle's PL/SQL Cartridge. With OWA2 you can control authentication from a PL/SQL function in your database.

************
[Security]
Basic {
(Users)
users: passwords
(Groups)
groups: users   <-----   Single group should not exceed 200 users
(Realms)
realms: groups  <-----   Be sure to include all groups
}
;
[Protection]
/secret-dir/         Basic(Realm)
************

     could be replaced with....

************
[Security]
Basic @/path/to/user/authentication/file
;
[Protection]
/secret-dir/         Basic(Realm)
************

    The file referred to above should contain the following information...

************
(Users)
users: passwords
(Groups)
groups: users   <-----   Single group should not exceed 200 users
(Realms)
realms: groups  <-----   Be sure to include all groups
************

OWA2 is a replacement for the Oracle PL/SQL Web Request Broker Cartridge. Other than Oracle's PL/SQL Cartridge, OWA2 :

• Can call a user definable PL/SQL function to do authentication
• Can stream multiple IMAGES concurrently from a database table to Web Browsers
• Send simple mail messages
• Add parameters to enable/disable timing, logging, database tracing, etc.
• Keep database sessions open for performance reasons

If you find OWA2 useful, PLEASE tell me!!!

Download the source code for OWA2 V0.96 (13-Jul-97)

• Oracle freely distributes a few unsupported CGI utilities that can do just that. Ask them for their IMGLOAD/ OWAI/ OWAUP utilities.
• If you want to stream multiple IMAGES concurrently from a database table to Web Browsers look at OWA2.

Look at this code example:

   owa_util.mime_header ('text/html', FALSE);
   owa_cookie.send (cuid, xsession_id, sysdate);
   owa_util.http_header_close;

<HTML>
<HEAD>
<META HTTP-EQUIV="REFRESH" CONTENT="3; URL=any_valid_url">
<TITLE>Stay tuned!  3 Seconds until relocation</TITLE>
...
</HTML>

http://host:port/ows-bin/service/owa/proc

Causes:

• This is due to there not being a mapping in the service listener's Virtual Directory Mappings configuration, of the form: /home/oracle/ows2/bin/ CN /ows-bin/service/ so the "owa" program isn't found.
  
• You're accessing a directory, /xxxx/, and the directory isn't readable by the Web Server process.
  
• The Web Server is configured to not generate directory listings automatically, and there isn't an index.html file (or whatever you've picked as your index file name).
  

Fix:

• Create the virtual directory mapping, halt the listener, and restart it.
  
• Check and fix the directory permissions. Note also the directory rescanning issue below.
  
• Make sure that either the Web Server will create indices itself, or that there is a readable index file under the name you've specified. If altering the server configuration, halt and restart the server. If changing file ownership or permissions, note the directory rescanning issue below.
  

http://host:port/ows-bin/service/owa/proc

Cause:

• The listener can't read the configuration file owa.cfg.
  
• The listener is attempting to invoke the PL/SQL procedure named, but can't, for some reason.

Fix:

• Make sure that the file /home/oracle/owa2/admin/owa.cfg (or whatever is the moral equivalent on your system) is readable by the user running the Web Server.
  
• • Check that the user for the listener has the permissions to invoke such functions: do "exec tw.ping" in sqlplus. There won't be any output, but it should say that it ran ok. If necessary, try reloading the stored procedures into the database.
    
  • Make sure that the names of the input fields in the form match up exactly with the names of the parameters in the script. There must be a one-to-one mapping.
    
  • If you've got multiple-value fields, such as SELECTs, make sure they're of the right type (defined in the OWA_UTIL package), and that there's an extra value supplied by a hidden field to force at least one value to be selected.
    
• If all else fails, the procedure is probably raising an exception. Put OTHERS exception handlers around everything and call barf(errstr('procedure name')), or the moral equivalent on your system.

The webserver caches the modification time of the directory, and of all the files within it. If a URL is not available because of permissions problems, and you fix that, the webserver will continue to say that the URL is not available, because the directory modification date hasn't changed, so it doesn't bother to check the file itself. Renaming the file to something and back again will make the webserver see the change. This is configurable, however. On the Web Listener configuration page, there is a parameter which determines how long the Web Server will go without re-scanning a directory that appears to have not changed yet, including the ability to never rescan unless the modification date changes.