7 Understanding Modules

7.1 List of Modules

Table 7-1 lists all the Oracle HTTP Server modules discussed in this chapter.

7.2 mod_access

Controls access to the server based on characteristics of a request, such as hostname or IP address.

7.3 mod_actions

Enables execution of CGI scripts based on file type or request method.

7.4 mod_alias

Enables manipulation of URLs in processing requests. It provides mapping between URLs and file system paths, and URL redirection capabilities.

7.5 mod_asis

Enables sending files that contain their own HTTP headers.

7.6 mod_auth

Enables user authentication with files based user lists.

7.7 mod_auth_anon

Enables anonymous user access to protected areas (similar to anonymous FTP, where the email addresses can be logged).

7.8 mod_auth_dbm

Uses DBM files to provide user authentication.

7.9 mod_autoindex

Generates directory indexes automatically.

7.10 mod_cern_meta

Emulates CERN (Conseil Europeen pour le Recherche Nucleaire) HTTPD metafile semantics. Metafiles are additional HTTP headers that can be produced for each file the server accesses, in addition to the typical set.

7.11 mod_certheaders

Allows reverse proxies that terminate SSL connections in front of Oracle HTTP Server, such as OracleAS Web Cache, to transfer information regarding SSL connection, such as SSL client certificate information, to Oracle HTTP Server, and applications running behind Oracle HTTP Server. This information is transferred from the reverse proxy to Oracle HTTP Server using HTTP headers. The information is transferred from the headers to the standard CGI environment variable, which mod_ossl or mod_ssl populates if the SSL connection is terminated by Oracle HTTP Server. It is an Oracle module.

It also allows certain requests to be treated as HTTPS requests even though they are received through HTTP. This is done using the SimulateHttps and AddCertHeader directives.

SimulateHttps takes the container it is contained within, such as <VirtualHost>, <Location>, and so on, and treats all requests received for this container as if they were received through HTTPS, regardless of the real protocol that the request was received through.

AddCertHeader is specifically for use with OracleAS Web Cache. For OracleAS Web Cache, it adds a special header that indicates to Oracle HTTP Server which requests OracleAS Web Cache received through HTTPS. mod_certheaders triggers Oracle HTTP Server to only treat those cases where OracleAS Web Cache received the request as HTTPS as if Oracle HTTP Server received it through HTTPS.

Perform the following steps to configure mod_certheaders:

1. Configure Oracle HTTP Server to load mod_certheaders. To do this, add a LoadModule directive to httpd.conf file:

   • UNIX: LoadModule certheaders_module libexec/mod_certheaders.so

   • Windows: LoadModule certheaders_module modules/ApacheModuleCertHeaders.dll

2. Specify which headers should be translated to CGI environment variables. This can be achieved by using the AddCertHeader directive. This directive takes a single argument, which is the CGI environment variable that should be populated from a HTTP header on incoming requests. For example, to populate the SSL_CLIENT_CERT CGI environment variable, add the following line to httpd.conf:

   AddCertHeader SSL_CLIENT_CERT
   
   

   The AddCertHeader directive can be a global setting if it is placed in the base virtual server section of httpd.conf. It can be specific to a single virtual host by placing it within a virtual host container, or it can be specific to a set of URIs by placing it within a <Directory> or <Location> container directive within httpd.conf. The combination of these directives are additive, so that for a given URI, all directives that are specific to that URI will be added to any that are specific to that request's virtual host, which will be added to any that is defined for that base virtual host.

   Table 7-2 lists all the supported CGI environment variables with their corresponding HTTP header names.

   Table 7-2 CGI Environment Variables with Corresponding Header Names

   CGI Variable	Header Name	CGI Variable	Header Name
   SSL_PROTOCOL	SSL-Protocol	SSL_SESSION_ID	SSL-Session_Id
   SSL_CIPHER	SSL-Cipher	SSL_CIPHER_EXPORT	SSL-Cipher-Export
   SSL_CIPHER_ALGKEYSIZE	SSL-Cipher-Algkeysize	SSL_VERSION_LIBRARY	SSL-Version-Library
   SSL_CLIENT_CERT	SSL-Client-Cert	SSL_VERSION_INTERFACE	SSL-Version-Interface
   SSL_CLIENT_CERT_CHAIN_n	SSL-Client-Cert-Chain-n	SSL_CIPHER_USEKEYSIZE	SSL-Cipher-Usekeysize
   SSL_CLIENT_VERIFY	SSL-Client-Verify	SSL_SERVER_CERT	SSL-Server-Cert
   SSL_CLIENT_M_VERSION	SSL-Client-M-Version	SSL_SERVER_M_VERSION	SSL-Server-M-Version
   SSL_CLIENT_M_SERIAL	SSL-Client-M-Serial	SSL_SERVER_M_SERIAL	SSL-Server-M-Serial
   SSL_CLIENT_V_START	SSL-Client-V-Start	SSL_SERVER_V_END	SSL-Server-V-End
   SSL_CLIENT_V_END	SSL-Client-V-End	SSL_SERVER_V_END	SSL-Server-V-End
   SSL_CLIENT_S_DN	SSL-Client-S-DN	SSL_SERVER_S_DN	SSL-Server-S-DN
   SSL_CLIENT_S_DN_C	SSL-Client-S-DN-C	SSL_SERVER_S_DN_C	SSL-Server-S-DN-C
   SSL_CLIENT_S_DN_ST	SSL-Client-S-DN-ST	SSL_SERVER_S_DN_ST	SSL-Server-S-DN-ST
   SSL_CLIENT_S_DN_L	SSL-Client-S-DN-L	SSL_SERVER_S_DN_L	SSL-Server-S-DN-L
   SSL_CLIENT_S_DN_O	SSL-Client-S-DN-O	SSL_SERVER_S_DN_O	SSL-Server-S-DN-O
   SSL_CLIENT_S_DN_OU	SSL-Client-S-DN-OU	SSL_SERVER_S_DN_OU	SSL-Server-S-DN-OU
   SSL_CLIENT_S_DN_CN	SSL-Client-S-DN-CN	SSL_SERVER_S_DN_CN	SSL-Server-S-DN-CN
   SSL_CLIENT_S_DN_T	SSL-Client-S-DN-T	SSL_SERVER_S_DN_T	SSL-Server-S-DN-T
   SSL_CLIENT_S_DN_I	SSL-Client-S-DN-I	SSL_SERVER_S_DN_I	SSL-Server-S-DN-I
   SSL_CLIENT_S_DN_G	SSL-Client-S-DN-G	SSL_SERVER_S_DN_G	SSL-Server-S-DN-G
   SSL_CLIENT_S_DN_S	SSL-Client-S-DN-S	SSL_SERVER_S_DN_S	SSL-Server-S-DN-S
   SSL_CLIENT_S_DN_D	SSL-Client-S-DN-D	SSL_SERVER_S_DN_D	SSL-Server-S-DN-D
   SSL_CLIENT_S_DN_UID	SSL-Client-S-DN-Uid	SSL_SERVER_S_DN_UID	SSL-Server-S-DN-Uid
   SSL_CLIENT_S_DN_Email	SSL-Client-S-DN-Email	SSL_SERVER_S_DN_Email	SSL-Server-S-DN-Email
   SSL_CLIENT_I_DN	SSL-Client-I-DN	SSL_SERVER_I_DN	SSL-Server-I-DN
   SSL_CLIENT_I_DN_C	SSL-Client-I-DN-C	SSL_SERVER_I_DN_C	SSL-Server-I-DN-C
   SSL_CLIENT_I_DN_ST	SSL-Client-I-DN-ST	SSL_SERVER_I_DN_ST	SSL-Server-I-DN-ST
   SSL_CLIENT_I_DN_L	SSL-Client-I-DN-L	SSL_SERVER_I_DN_L	SSL-Server-I-DN-L
   SSL_CLIENT_I_DN_O	SSL-Client-I-DN-O	SSL_SERVER_I_DN_O	SSL-Server-I-DN-O
   SSL_CLIENT_I_DN_OU	SSL-Client-I-DN-OU	SSL_SERVER_I_DN_OU	SSL-Server-I-DN-OU
   SSL_CLIENT_I_DN_CN	SSL-Client-I-DN-CN	SSL_SERVER_I_DN_CN	SSL-Server-I-DN-CN
   SSL_CLIENT_I_DN_T	SSL-Client-I-DN-T	SSL_SERVER_I_DN_T	SSL-Server-I-DN-T
   SSL_CLIENT_I_DN_I	SSL-Client-I-DN-I	SSL_SERVER_I_DN_I	SSL-Server-I-DN-I
   SSL_CLIENT_I_DN_G	SSL-Client-I-DN-G	SSL_SERVER_I_DN_G	SSL-Server-I-DN-G
   SSL_CLIENT_I_DN_S	SSL-Client-I-DN-S	SSL_SERVER_I_DN_S	SSL-Server-I-DN-S
   SSL_CLIENT_I_DN_D	SSL-Client-I-DN-D	SSL_SERVER_I_DN_D	SSL-Server-I-DN-D
   SSL_CLIENT_I_DN_UID	SSL-Client-I-DN-Uid	SSL_SERVER_I_DN_UID	SSL-Server-I-DN-Uid
   SSL_CLIENT_I_DN_Email	SSL-Client-I-DN-Email	SSL_SERVER_I_DN_Email	SSL-Server-I-DN-Email
   SSL_CLIENT_A_SIG	SSL-Client-A-Sig	SSL_SERVER_A_SIG	SSL-Server-A-Sig
   SSL_CLIENT_A_KEY	SSL-Client-A-Key	SSL_SERVER_A_KEY	SSL-Server-A-Key

   
   

3. mod_certheaders can be used to instruct Oracle HTTP Server to treat certain requests as if they were received through HTTPS even though they were received through HTTP. This is useful when Oracle HTTP Server is front-ended by a reverse proxy or load balancer, which acts as a termination point for SSL requests, and forwards the requests to Oracle HTTP Server through HTTPS.

   If OracleAS Web Cache is being used as the load balancer, it sends an HTTP header that identifies all requests it received through HTTPS. This means that mod_certheaders automatically detects which requests should be treated as HTTPS requests by simply looking for this header. To enable this, add the following directive to httpd.conf:

   AddCertHeader HTTPS
   
   

   This affects all URLs processed by Oracle HTTP Server.

   For other load balancers, mod_certheaders must be explicitly configured to determine which requests should be treated as HTTPS requests. To do this, use the following directive:

   SimulateHttps on
   
   

   SimulateHttps can be embedded within a virtual host, such as:

   <VirtualHost localhost:7777>
       SimulateHttps on
       .
       .
       .
   </VirtualHost>
   
   

   This tells mod_certheaders to treat every request handled by this virtual host as HTTPS, or the directive can be placed within a <LocationMatch>, <Directory>, or <DirectoryMatch> directive container such as:

   <Location /foo/>
       SimulateHttps on
   </Location>
   
   

   This limits it to URLs starting with /foo/.

4. Edit the $ORACLE_HOME/sso/conf/sso_apache.conf, and comment out the following line:

   #SSLOptions +ExportCertData +StdEnvVars 
   
   

5. Runthe following command:

   dcmctl updateconfig -ct ohs 
   
   

6. Run the following command:

   opmnctl restartproc type=ohs
   
   

7. Test that the SSO server can be logged into with client authentication.

7.12 mod_cgi

Enables the server to run CGI scripts.

7.13 mod_cgid

Except for the optimizations and the additional ScriptSock directive, this module functions similarly to mod_cgi. The ScriptSock directive sets the name of the socket to use for communication with the CGI daemon. The socket will be opened using the permissions of the user who starts Apache (usually root).

7.14 mod_dir

Enables the server to perform slash (/) redirects. Directories must contain a trailing slash. If a request for a URL without a trailing slash is received, mod_dir redirects the request to the same URL followed by a trailing slash. For example:

http://myserver/documents/mydirectory

is redirected to

http://myserver/documents/mydirectory/

7.15 mod_env

Enables you to control the environment for CGI scripts and SSI (Server Side Includes) pages by passing, setting, and unsetting environment variables.

ModifyEnv appends or prepends a value to an existing ENV variable's value, and passes it into the Oracle HTTP Server environment. The following is the usage:

Let $FOO = "foo":

ModifyEnv FOO "bar" modifies the value of $FOO from "foo" to "foo:bar"

ModifyEnv FOO "+bar" modifies the value of $FOO from "foo" to "bar:foo"

Let $FOO be undefined:

Modify Foo "bar" sets the value of $FOO to "bar"

7.16 mod_expires

Enables the server to generate Expires HTTP headers, which provide information to the client about document validity. Documents are served from the source if, based on the expiration criteria, the cached copy has expired.

7.17 mod_fastcgi

Supports the FastCGI protocol, which enables you to maintain a pool of running servers for CGI applications, thereby eliminating start-up and initialization overhead.

7.18 mod_file_cache

Provides techniques for caching frequently requested static files. This module should be used with care as you can easily create a broken site.

7.19 mod_headers

Enables you to merge, replace, or remove HTTP response headers.

7.20 mod_imap

Enables server-side image map processing.

7.21 mod_include

Provides a filter that processes documents for SSI (Server Side Includes) directives.

7.22 mod_info

Summarizes the entire server configuration, including all installed modules and directive settings.

7.23 mod_log_config

Provides configurable, customizable logging of server activities. You can choose the log format, and select or exclude individual requests for logging, based on characteristics of the requests.

7.24 mod_logio

Provides the logging of input and output numbers of bytes received and sent per request. The numbers reflect the actual bytes as received on the network, which then takes into account the headers and bodies of requests and responses.

7.25 mod_mime

Enables the server to determine the type of a file from its filename, and associate files with handlers for processing.

7.26 mod_mime_magic

Enables the server to determine the MIME type of a file by examining a few bytes of its content. It is used in cases when mod_mime cannot determine a file type. Make sure that mod_mime appears before mod_mime_magic in the configuration file, so that mod_mime processes the files first.

7.27 mod_negotiation

Enables the server for content negotiation (selection of documents based on the client's capabilities).

7.28 mod_oc4j

Routes requests from the Oracle HTTP Server to Oracle Application Server Containers for J2EE (OC4J), through the AJP 1.3 protocol. It is an Oracle module.

mod_oc4j is enabled by default. During installation, the oc4j_deploy_tool.jar adds mount points to mod_oc4j.conf for applications deployed into OC4J instances. Requests that come in for specific mount points in mod_oc4j are routed to the OC4J instance for that mount point.

OC4J instances are started and managed by Oracle Process Manager and Notification Server (OPMN).

This section discusses the following topics:

• Configuring mod_oc4j

• Load Balancing Using mod_oc4j

• Enabling SSL between mod_oc4j and OC4J

include "ORACLE_HOME/ohs/conf/mod_oc4j.conf"

Oc4jMount /servlet/* 

<Location /servlet> 
    SetHandler oc4j-handler 
</Location> 

Oc4JMount /servlet/*
Oc4JMount /*.jsp
Oc4JMount /j2ee/*

7.29 mod_onsint

Provides integration support with Oracle Notification Service (ONS) and Oracle Process Manager and Notification Server (OPMN). It is an Oracle module.

OpmnHostPort localhost: 7778

7.30 mod_ossl

Enables strong cryptography for Oracle HTTP Server. This Oracle module is a plug-in to Oracle HTTP Server that enables the server to use SSL. It is very similar to the OpenSSL module, mod_ssl. However, in contrast to the OpenSSL module, mod_ossl is based on the Oracle implementation of SSL, which supports SSL, version 3, and is based on Certicom and RSA Security technology.

7.31 mod_osso

Enables single sign-on for Oracle HTTP Server. mod_osso examines incoming requests and determines whether the resource requested is protected, and if so, retrieves the Oracle HTTP Server cookie for you. It is an Oracle module.

7.32 mod_perl

Embeds the Perl interpreter into the Oracle HTTP Server. This eliminates start-up overhead and enables you to write modules in Perl. Oracle Application Server uses Perl version 5.8.3.

#!<ORACLE_HOME>/perl/bin/perl -w 
  use DBI; 
  my $dataSource = "host=<hostname.domain>;sid=<orclsid>;port=1521"; 
  my $userName = "scott"; 
  my $password = "tiger"; 
  my $dbhandle = DBI->connect("dbi:Oracle:$dataSource", $userName, $password) 
    or die "Can't connect to the Oracle Database: $DBI::errstr\n"; 
  print "Content-type: text/plain\n\n"; 
  print "Database connection successful.\n"; 
  ### Now disconnect from the database 
  $dbhandle->disconnect 
    or warn "Database disconnect failed; $DBI::errstr\n"; 
  exit;

http://<hostname.domain>:<port>/cgi-bin/<scriptname>
http://<hostname.domain>:<port>/perl/<scriptname>

##### Perl script start ###### 
use DBI;
print "Content-type: text/plain\n\n"; 
$dbh = DBI->connect("dbi:Oracle:", "scott/tiger", "") || die $DBI::errstr;   $stmt = $dbh->prepare("select * from emp order by empno")|| die $DBI::errstr; 
$rc = $stmt->execute() || die $DBI::errstr; 
while (($empno, $name) = $stmt->fetchrow()) { print "$empno $name\n"; } 
warn $DBI::errstr if $DBI::err; 
die "fetch error: " . $DBI::errstr if $DBI::err; 
$stmt->finish() || die "can't close cursor"; 
$dbh->disconnect() || die "cant't log off Oracle"; 
##### Perl script End ###### 

# declare to use the constants for character forms
use DBD::Oracle qw(:ora_forms);
# connect to the database and get the database handle
$dbh = DBI->connect( ... );
# prepare the statement and get the statement handle
$sth = $dbh->prepare( 'SELECT * FROM TABLE_N WHERE NCOL1 = :nchar1' );
# bind the parameter of a NCHAR type
$sth->bind_param( ':nchar1', $param_1 );
# set the character form to NCHAR
$sth->func( { ':nchar1' => ORA_NCHAR } , 'set_form' );
$sth->execute;

# specify the default form to be NCHAR
$dbh->func( ORA_NCHAR, 'set_default_form' );

# a declaration example for the constants ORA_IMPLICIT and ORA_NCHAR
use DBD::Oracle qw(:ora_forms);
# set the character form for the placeholder :nchar1 to NCHAR
$sth->func( { ':nchar1' => ORA_NCHAR } , 'set_form' );
# set the character form using the positional index
$sth->func( { 2 => ORA_NCHAR } , 'set_form' );
# set the character form for multiple placeholders at once
$sth->func( { 1 => ORA_NCHAR, 2 => ORA_NCHAR } , 'set_form' );

$dbh->func( ORA_NCHAR , 'set_default_form' );

7.33 mod_php

PHP (recursive acronym for "PHP: Hypertext Preprocessor") is an open source, widely-used, general-purpose, client-side scripting language, that is embedded in standard HTML. It is used to generate dynamic HTML pages. On Oracle HTTP Server, PHP support is provided through mod_php and has Oracle database support enabled. It uses PHP version 4.3.9.

7.34 mod_proxy

Orovides proxy capability for FTP, CONNECT (for SSL), HTTP/0.9, HTTP/1.0, and HTTP/1.1.

7.35 mod_rewrite

Oracle HTTP Server provides mod_rewrite as a tool for URL manipulation. A rewriting engine based on a regular-expression parser is used by mod_rewrite to rewrite requested URLs. The granularity of URL manipulations can be affected by the formats of server variables, environment variables, HTTP headers, and time stamps.

This module operates on the full URLs (including the path-info part) both in per-server context (httpd.conf) and per-directory context (.htaccess) and can generate query-string parts on result.

The following topics are discussed in subsequent sections:

• mod_rewrite Rules Processing

• mod_rewrite Directives

• Rewrite Rules Hints

• Redirection Examples

RewriteRule ^/oldpath(.*) /newpath$1 [R]

RewriteRule ^/+somepath(.*) /otherpath$1 [R]

## /abc/def/.htaccess - - per-dir config file for directory /abc/def
 # /abc/def is the physical path of /xyz,
RewriteEngine On
RewriteBase /xyz
RewriteRule ^oldstuff\.html$ newstuff.html

RewriteRule /demo. /alldemos [R]

RewriteRule /demo [123] /alldemos [R]

RewriteRule /demo [123] /alldemos [R, NC]

RewriteRule ^/demo* /alldemos [R, NC]

RewriteRule ^/demos1(.*)$ //alldemos/$1 [R NC]

RewriteEngine On
RewriteRule ^/(.*)$ /newroot/$1 [R]

RewriteEngine On
RewriteRule ^/olddir(.*)$ /newdir/$1 [R] 

RewriteEngine On
RewriteCond %{REQUEST_METHOD} ^TRACE
RewriteRule .* - [F]

7.36 mod_setenvif

Enables you to set environment variables based on characteristics of a request.

7.37 mod_speling

Attempts to correct misspelled or miscapitalized URLs.

7.38 mod_status

Displays an HTML page of server activity and performance.

7.39 mod_unique_id

Creates a unique ID for each request. This module is available on UNIX only.

7.40 mod_userdir

Maps requests to user-specific directories.

7.41 mod_usertrack

Tracks user activity by creating a log.

7.42 mod_vhost_alias

Enables dynamically configured mass virtual hosting.

7.43 mod_wchandshake

Provides automatic discovery of Oracle HTTP Server by OracleAS Web Cache. If OracleAS Web Cache is not used, this module can be disabled. It is an Oracle module.