In a default database installation, digest authentication is enabled, and basic authentication is disallowed. Digest verifiers are automatically generated for all users.

After an upgrade from a release prior to Oracle Database 12c Release 1 (12.1.0.1), digest authentication is appended to the list of allowed authentication mechanisms. But basic authentication remains the current authentication method if it was enabled before the upgrade. This is for backward compatibility only.

1. Configure basic authentication as the first allowed authentication mechanism in the Oracle XML DB configuration file, xdbconfig.xml. This ensures that basic authentication can be used for HTTP access.
2. Expire all passwords for those users who do not have digest verifiers. This query returns those users:

   SELECT USERNAME FROM DBA_DIGEST_VERIFIERS
     WHERE HAS_DIGEST_VERIFIERS = 'NO' AND DIGEST_TYPE is NULL;
   

3. After the passwords for all such users have been changed, configure xdbconfig.xml to re-enable digest as the first or (preferably) the only allowed authentication mechanism.

If you downgrade to a release where digest authentication was not supported, digest authentication is disabled and made unavailable as an authentication choice.

All digest verifiers are erased during a downgrade. This means, in particular, that if a downgrade is followed by an upgrade then users who were able to authenticate prior to the downgrade are denied digest authentication after the downgrade and the subsequent upgrade.

Element xdbconfig is the top-level element of the Oracle XML DB configuration file.

<xdbconfig> 
    <sysconfig> ... </sysconfig> 
    <userconfig> ... </userconfig> 
</xdbconfig>

Element sysconfig is a child of xdbconfig.

<sysconfig> 
    general parameters
    <protocolconfig> ... </protocolconfig> 
</sysconfig> 

Element userconfig is a child of xdbconfig. It contains any parameters that you may want to add.

Element protocolconfig is a child of sysconfig.

<protocolconfig> 
  <common> ... </common> 
  <ftpconfig> ... </ftpconfig> 
  <httpconfig> ... </httpconfig> </protocolconfig> 

Element httpconfig, which is a child of protocolconfig, is described.

<httpconfig>
  ...
  <webappconfig>
    ...
    <servletconfig>
      ...
      <servlet-list>
        <servlet> ... </servlet>
        ...
      </servlet-list>
    </servletconfig>
  </webappconfig>
  ...
  <plsql> ... </plsql>
</httpconfig>

Element servlet is a descendent of element httpconfig. It is used to configure servlets, including Java servlets and embedded PL/SQL gateway servlets.

A sample Oracle XML DB configuration file is presented.

<xdbconfig xmlns="http://xmlns.oracle.com/xdb/xdbconfig.xsd" 
                 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
                 xsi:schemaLocation="http://xmlns.oracle.com/xdb/xdbconfig.xsd 
                                    http://xmlns.oracle.com/xdb/xdbconfig.xsd">
   <sysconfig>
      <acl-max-age>900</acl-max-age>
      <acl-cache-size>32</acl-cache-size> 
      <invalid-pathname-chars>,</invalid-pathname-chars>
      <case-sensitive>true</case-sensitive>       
      <call-timeout>300</call-timeout>
      <max-link-queue>65536</max-link-queue> 
      <max-session-use>100</max-session-use>
      <persistent-sessions>false</persistent-sessions> 
      <default-lock-timeout>3600</default-lock-timeout>
      <xdbcore-logfile-path>/sys/log/xdblog.xml</xdbcore-logfile-path>
      <xdbcore-log-level>0</xdbcore-log-level>
      <resource-view-cache-size>1048576</resource-view-cache-size> 
    
      <protocolconfig> 
          <common>
             <extension-mappings>
                <mime-mappings>
                  <mime-mapping>
                    <extension>au</extension>
                    <mime-type>audio/basic</mime-type>
                  </mime-mapping>
                  <mime-mapping>
                    <extension>avi</extension>
                    <mime-type>video/x-msvideo</mime-type>
                  </mime-mapping>
                  <mime-mapping>
                    <extension>bin</extension>
                    <mime-type>application/octet-stream</mime-type>
                  </mime-mapping>
                </mime-mappings> 

                <lang-mappings>
                  <lang-mapping>
                    <extension>en</extension>
                    <lang>english</lang>
                  </lang-mapping>
                </lang-mappings>

                <charset-mappings>
                </charset-mappings>

                <encoding-mappings>
                  <encoding-mapping>
                    <extension>gzip</extension>
                    <encoding>zip file</encoding>      
                  </encoding-mapping>
                  <encoding-mapping>
                    <extension>tar</extension>
                    <encoding>tar file</encoding>        
                  </encoding-mapping>
                </encoding-mappings>
             </extension-mappings>

             <session-pool-size>50</session-pool-size>
             <session-timeout>6000</session-timeout>
          </common>

          <ftpconfig>
            <ftp-port>2100</ftp-port>
            <ftp-listener>local_listener</ftp-listener>
            <ftp-protocol>tcp</ftp-protocol>
            <logfile-path>/sys/log/ftplog.xml</logfile-path>
            <log-level>0</log-level>
            <session-timeout>6000</session-timeout>
            <buffer-size>8192</buffer-size> 
          </ftpconfig>

          <httpconfig>
            <http-port>8080</http-port>
            <http-listener>local_listener</http-listener>
            <http-protocol>tcp</http-protocol>
            <max-http-headers>64</max-http-headers> 
            <session-timeout>6000</session-timeout>
            <server-name>XDB HTTP Server</server-name>
            <max-header-size>16384</max-header-size>
            <max-request-body>2000000000</max-request-body>
            <logfile-path>/sys/log/httplog.xml</logfile-path>
            <log-level>0</log-level>    
            <servlet-realm>Basic realm="XDB"</servlet-realm>
            <webappconfig>
              <welcome-file-list>
                <welcome-file>index.html</welcome-file>
                <welcome-file>index.htm</welcome-file>
              </welcome-file-list>
              <error-pages>
              </error-pages>
              <servletconfig> 
                <servlet-mappings>
                  <servlet-mapping>
                    <servlet-pattern>/oradb/*</servlet-pattern>
                    <servlet-name>DBURIServlet</servlet-name>
                  </servlet-mapping>
                </servlet-mappings>
                               
                <servlet-list>
                  <servlet>
                    <servlet-name>DBURIServlet</servlet-name>
                    <display-name>DBURI</display-name>
                    <servlet-language>C</servlet-language>
                    <description>Servlet for accessing DBURIs</description>
                    <security-role-ref>
                      <role-name>authenticatedUser</role-name>
                      <role-link>authenticatedUser</role-link>
                    </security-role-ref>
                  </servlet>
                </servlet-list>
              </servletconfig>
            </webappconfig>
          </httpconfig> 
      </protocolconfig>
    <xdbcore-xobmem-bound>1024</xdbcore-xobmem-bound> 
    <xdbcore-loadableunit-size>16</xdbcore-loadableunit-size> 
   </sysconfig>
</xdbconfig>

You can access the Oracle XML DB configuration file, xdbconfig.xml, the same way you access any other XML schema-based resource. You can use FTP, HTTP(S), WebDAV, Oracle Enterprise Manager, or any of the resource and Document Object Model (DOM) APIs for Java, PL/SQL, or C (OCI).

For convenience, you can use PL/SQL package DBMS_XDB_CONFIG package for configuration access. It exposes the following functions and procedures:

• cfg_get – Returns the configuration information for the current session.

• cfg_refresh – Refreshes the session configuration information using the current configuration file. Typical uses of cfg_refresh include the following:

  • You have modified the configuration and now want the session to pick up the latest version of the configuration information.

  • It has been a long running session, the configuration has been modified by a concurrent session, and you want the current session to pick up the latest version of the configuration information.

• cfg_update – Updates the configuration information, writing the configuration file. A COMMIT is performed.

Example 34-2 updates parameters ftp-port and http-port in the configuration file.

If you have many parameters to update, then it can be easier to use FTP, HTTP(S), or Oracle Enterprise Manager to update the configuration.

DECLARE
  v_cfg XMLType;
BEGIN
  SELECT XMLQuery('declare default element namespace
                   "http://xmlns.oracle.com/xdb/xdbconfig.xsd";
                   copy $i := $cfg 
                   modify for $j in $i/xdbconfig
                   return (replace value of node $j/descendant::ftp-port with
                             "2121",
                           replace value of node $j/descendant::http-port with
                             "19090")
                   return $i'
                  PASSING DBMS_XDB_CONFIG.cfg_get() AS "cfg"
                  RETURNING CONTENT)
    INTO v_cfg FROM DUAL; 
  DBMS_XDB_CONFIG.cfg_update(v_cfg);
END;
/ 

Oracle XML DB provides a mechanism to configure default XML schema location mappings.

Oracle XML DB identifies XML Schema-based XMLType instances by pre-parsing input XML documents. If the appropriate xsi:schemaLocation or xsi:noNamespaceSchemaLocation attribute is found, then the specified schema location URL is used to consult the registered schema.

If the appropriate xsi: attribute is not found, the XML document is considered to be non-schema-based. Oracle XML DB provides a mechanism to configure default schema location mappings. If the appropriate xsi: attribute is not specified in the XML document, the default schema location mappings is used.

Element schemaLocation-mappings of the Oracle XML DB configuration XML schema, xdbconfig.xsd, can be used to specify the mapping between (namespace, element) pairs and the default schema location. If the element value is empty, the mapping applies to all global elements in the specified namespace. If the namespace value is empty, it corresponds to the null namespace.

The definition of the schemaLocation-mappings element is as follows:

 <element name="schemaLocation-mappings"
          type="xdbc:schemaLocation-mapping-type" minOccurs="0"/> 
 <complexType name="schemaLocation-mapping-type"><sequence>
      <element name="schemaLocation-mapping"
               minOccurs="0" maxOccurs="unbounded">
      <complexType><sequence>
        <element name="namespace" type="string"/>
        <element name="element" type="string"/>
        <element name="schemaURL" type="string"/>
      </sequence></complexType>
      </element></sequence> 
 </complexType> 

The schema location used depends on mappings in the Oracle XML DB configuration file for the namespace used and the root document element. For example, assume that the document does not have the appropriate xsi: attribute to indicate the schema location. Consider a document root element R in namespace N. The algorithm for identifying the default schema location is as follows:

1. If the Oracle XML DB configuration file has a mapping for N and R, the corresponding schema location is used.

2. If the configuration file has a mapping for N, but not R, the schema location for N is used.

3. If the document root R does not have any namespace, the schema location for R is used.

For example, suppose that your Oracle XML DB configuration file includes the following mapping:

      <schemaLocation-mappings>
         <schemaLocation-mapping>
            <namespace>http://www.oracle.com/example</namespace>
            <element>root</element>
            <schemaURL>http://www.oracle.com/example/sch.xsd</schemaURL>
         </schemaLocation-mapping>
         <schemaLocation-mapping>
            <namespace>http://www.oracle.com/example2</namespace>
            <element></element>
            <schemaURL>http://www.oracle.com/example2/sch.xsd</schemaURL>
         </schemaLocation-mapping>
         <schemaLocation-mapping>
           <namespace></namespace>
           <element>specialRoot</element>
           <schemaURL>http://www.oracle.com/example3/sch.xsd</schemaURL>
         </schemaLocation-mapping>
      </schemaLocation-mappings>
 

The following schema locations are used:

• Root element = root

  • Namespace = http://www.oracle.com/example

  • Schema URL = http://www.oracle.com/example/sch.xsd

  This mapping is used when the instance document specifies:

  <root xmlns="http://www.oracle.com/example">
  

• Root element = null (any global element in the namespace)

  • Namespace = http://www.oracle.com/example2

  • Schema URL = http://www.oracle.com/example2/sch.xsd

  This mapping is used when the instance document specifies:

  <root xmlns="http://www.oracle.example2">
  

• Root element = specialRoot

  • Namespace = null (i.e null namespace)

  • Schema URL = http://www.oracle.com/example3/sch.xsd

  This mapping is used when the instance document specifies:

  <specialRoot>

Oracle XML DB Repository treats certain files as XML documents, based on their file extensions. When such files are inserted into the repository, Oracle XML DB pre-parses them to identify the XML schema location (or uses the default mapping if present) and inserts the document into the appropriate default table.

By default, the following extensions are considered as XML file extensions: xml, xsd, xsl, xlt. In addition, Oracle XML DB provides a mechanism for applications to specify other file extensions as XML file extensions. The xml-extensions element is defined in the configuration schema, http://xmlns.oracle.com/xdb/xdbconfig.xsd, as follows:

 <element name="xml-extensions"
          type="xdbc:xml-extension-type" minOccurs="0"/>
 
 <complexType name="xml-extension-type"><sequence>
      <element name="extension" type="xdbc:exttype"
               minOccurs="0" maxOccurs="unbounded">
      </element></sequence> 
  </complexType> 

For example, the following fragment from the Oracle XML DB configuration file, xdbconfig.xml, specifies that files with extensions vsd, vml, and svgl should be treated as XML files:

 <xml-extensions>
   <extension>vsd</extension>
   <extension>vml</extension>
   <extension>svgl</extension>
 </xml-extensions>