<-
Apache > HTTP Server > Documentation > Version 2.5 > Modules

Apache Module mod_proxy_express

Available Languages:  en 

Description:Dynamic mass reverse proxy extension for mod_proxy
Status:Extension
Module Identifier:proxy_express_module
Source File:mod_proxy_express.c

Summary

This module creates dynamically configured mass reverse proxies, by mapping the Host: header of the HTTP request to a server name and backend URL stored in a DBM file. This allows for easy use of a huge number of reverse proxies with no configuration changes. It is much less feature-full than mod_proxy_balancer, which also provides dynamic growth, but is intended to handle much, much larger numbers of backends. It is ideally suited as a front-end HTTP switch.

This module requires the service of mod_proxy.

Warning

Do not enable proxying until you have secured your server. Open proxy servers are dangerous both to your network and to the Internet at large.

Limitations

  • This module is not intended to replace the dynamic capability of mod_proxy_balancer. Instead, it is intended to be mostly a lightweight and fast alternative to using mod_rewrite with RewriteMap and the [P] flag for mapped reverse proxying.
  • It does not support regex or pattern matching at all.
  • It emulates:
    <VirtualHost *:80>
       ServerName front.end.server
       ProxyPass / back.end.server:port
       ProxyPassReverse / back.end.server:port
    </VirtualHost>
    That is, the entire URL is appended to the mapped backend URL. This is in keeping with the intent of being a simple but fast reverse proxy switch.

Directives

See also

top

ProxyExpressDBMFile Directive

Description:Pathname to DBM file.
Syntax:ProxyExpressDBMFile <pathname>
Default:None
Context:server config, virtual host
Status:Extension
Module:mod_proxy_express
Compatibility:Available in Apache 2.3.13 and later

The ProxyExpressDBMFile directive points to the location of the Express map DBM file. This file serves to map the incoming server name, obtained from the Host: header, to a backend URL.

Note

The file is constructed from a plain text file format using the httxt2dbm utility.

ProxyExpress map file

##
##express-map.txt:
##

www1.example.com http://192.168.211.2:8080
www2.example.com http://192.168.211.12:8088
www3.example.com http://192.168.212.10

Create DBM file

httxt2dbm -i express-map.txt -o emap

Configuration

ProxyExpressEnable on
ProxyExpressDBMFile emap

top

ProxyExpressDBMType Directive

Description:DBM type of file.
Syntax:ProxyExpressDBMFile <type>
Default:"default"
Context:server config, virtual host
Status:Extension
Module:mod_proxy_express
Compatibility:Available in Apache 2.3.13 and later

The ProxyExpressDBMType directive controls the DBM type expected by the module. The default is the default DBM type created with httxt2dbm.

Possible values are (not all may be available at run time):

ValueDescription
db Berkeley DB files
gdbm GDBM files
ndbm NDBM files
sdbm SDBM files (always available)
default default DBM type
top

ProxyExpressEnable Directive

Description:Enable the module functionality.
Syntax:ProxyExpressEnable [on|off]
Default:off
Context:server config, virtual host
Status:Extension
Module:mod_proxy_express
Compatibility:Available in Apache 2.3.13 and later

The ProxyExpressEnable directive controls whether the module will be active.

Available Languages:  en 

top

Comments

Notice:
This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.