Difference between revisions of "Web Application"

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BaseX can also be deployed as web servlet in a servlet container or with Maven:
 
BaseX can also be deployed as web servlet in a servlet container or with Maven:
 
==Embedded==
 
  
 
==Servlet Container==
 
==Servlet Container==

Revision as of 13:10, 12 November 2019

This page is part of the Getting Started Section. It describes how BaseX can be used to both provide simple APIs and build complex web applications.

Startup

  • Run one of the basexhttp or basexhttp.bat scripts. Call the script with the stop keyword to gracefully shut down the server.
  • If you have installed BaseX on Windows, click on the BaseX HTTP Server icon.

The command-line output will look something like that (the JSP warning message can be ignored):

BaseX [HTTP Server]
[main] INFO org.eclipse.jetty.util.log - Logging initialized @375ms to org.eclipse.jetty.util.log.Slf4jLog
[main] INFO org.eclipse.jetty.server.Server - jetty-9.4.21.v20190926; built: 2019-09-26T16:41:09.154Z; git: 72970db61a2904371e1218a95a3bef5d79788c33; jvm 13+33
[main] INFO org.eclipse.jetty.webapp.StandardDescriptorProcessor - NO JSP Support for /, did not find org.eclipse.jetty.jsp.JettyJspServlet
...
Server was started (port: 1984).
HTTP Server was started (port: 80).
HTTP STOP Server was started (port: 8985).

You can adjust the Jetty logging level by adding the following properties to the start script:

-Dorg.eclipse.jetty.util.log.class=org.eclipse.jetty.util.log.StdErrLog -D{classref}.LEVEL=DEBUG

After that, you can e. g. open your browser and navigate to the RESTXQ start page http://localhost:8984.

Various command-line options are available to simplify batch processing. The start script can be adjusted for individual purposed (e.g. if the default memory limit is too restrictive).

BaseX can also be deployed as web servlet in a servlet container or with Maven:

Servlet Container

In order to deploy BaseX HTTP Services in a servlet container, you can download the WAR distribution of BaseX from the download site, or compile it by calling mvn compile war:war in the basex-api directory. The WAR file can then be deployed following the instructions of the corresponding servlet container (jetty, tomcat, etc.).

You can configure the port, context path, etc. by following the instructions of the corresponding servlet container. This is needed if you want to replace the default URL path (e.g. http://localhost:8080/rest) with a custom one (e.g. http://localhost:8984/basex/rest).

If you use Jetty (which is the default HTTP server of BaseX), the server configuration is available via the jetty.xml file, which is stored in the WEB-INF directory next to the web.xml. For detailed configuration refer to the Jetty Documentation.

To run on Apache Tomcat, start the Tomcat server and add any *.war distribution to deploy via the Tomcat web interface. By default, the interface is accessible via http://localhost:8080/manager/html/.

Maven

Check out the BaseX sources via Eclipse or Git. Execute mvn install in the main project directory and then mvn install jetty:run in the basex-api sub-directory. This will start a Jetty instance in which the servlets will be deployed.

The same options as in the case of deployment apply in a servlet container. In this case, however, there is no WAR archive. Instead, Jetty looks up all files in the directory basex-api/src/main/webapp. Jetty and servlet options can be configured in the jetty.xml and web.xml files as described above in the Servlet Container Configuration. The Jetty stop port can be changed in the Maven Jetty Plugin sesion in the pom.xml file.

Services

The following services are available and enabled by default:

Name Standard Path Description
RESTXQ / Write enriched APIs and full web applications with XQuery.
WebSockets ws/ Bidirectional client/server communication.
REST rest/ Straightforward access to XML databases and its resources.
WebDAV webdav/ Database access via the file system.
Default static/ Access to static server resources (HTML, JavaScript, CSS, images, …).

Configuration

Initial database options can be specified in the web.xml file. They need to be defined as context parameters and prefixed with org.basex.. The most important options for the web application context are as follows:

Option Default Description
USER admin If a user is specified, no credentials must be passed on by the client.
HTTPLOCAL false Operation mode. By default, a database server instance will be started, as soon as the first HTTP service is called. The database server can be disabled by setting this flag to true.
RESTXQPATH . Relative or absolute directory referencing the RESTXQ modules. By default, the option points to the standard web application directory.
RESTPATH . Relative or absolute directory referencing queries and command-scripts that can be invoked via the run operation of REST. By default, the option points to the standard web application directory.
AUTHMETHOD Basic The default authentication method proposed by the server. The available methods are Basic and Digest.

Local file paths in options may be absolute or relative. If a relative path is specified, its root will be the servlet (webapp) path:

 
<context-param>
  <param-name>org.basex.dbpath</param-name>
  <!-- will be rewritten to ..../webapp/WEB-INF/data -->
  <param-value>WEB-INF/data</param-value>
</context-param>
<context-param>
  <param-name>org.basex.repopath</param-name>
  <!-- will be kept as is -->
  <param-value>f:/basex/repository</param-value>
</context-param>

Context parameters can be requested from XQuery via proc:property-names and proc:property. How to set these options is specific to the servlet container. For example, in Jetty it can be done by overriding the web.xml file. Another option is to directly edit the WEB-INF/web.xml file in the WAR archive (WAR files are simple ZIP files). Refer to the sample web.xml of the basex-api package.

To enable or disable a specific service, the corresponding servlet entry in the web.xml file needs to be removed/commented.

Authentication

Different credentials can be assigned to a service by specifying local init parameters. In the following example, an alternative user is specified for the REST service:

 
<servlet>
  <servlet-name>REST</servlet-name>
  <servlet-class>org.basex.http.rest.RESTServlet</servlet-class>
  <init-param>
    <param-name>org.basex.user</param-name>
    <param-value>rest-user</param-value>
  </init-param>
</servlet>

If the HTTP server is started with no pre-defined user, the credentials must be passed on by the client via Basic Authentication or Digest Authentication (depending on the server setting).

With cURL, internet browsers, and other tools, you can specify basic authentication credentials within the request string as plain text, using the format USER:PASSWORD@URL. An example:

http://admin:admin@localhost:8984/

Users are specified in a users.xml file, which is stored in the database directory (see User Management for more information).

Changelog

Version 9.0
  • Updated: jetty.xml configuration file (required for Jetty 9).
Version 8.6
  • Updated: Authentication readded to RESTXQ.
  • Updated: No password must be specified in the web.xml file anymore.
  • Updated: Server-side user and authentication method is now enforced (cannot be overwritten by client).
Version 8.0
  • Added: digest authentication
  • Updated: user management
  • Updated: default user/password disabled in web.xml
Version 7.7
  • Added: service-specific permissions
Version 7.5
  • Added: jetty.xml: configuration for Jetty Server
  • Updated: server replaced with httplocal mode
Version 7.3
  • Updated: client mode replaced with server mode
Version 7.2
  • Web Application concept revised