OpenLiteSpeed Web Server Users' Manual

Version 1.4 Rev. 2
Context

Rack/Rails Context

Table of Contents

Rack/Rails Context

URI | Location | Run-Time Mode | Max Connections | Environment | Enable Expires | Expires Default | Expires By Type | Extra Headers | Index Files | Auto Index | Realm | Authentication Name | Require (Authorized Users/Groups) | Access Allowed | Access Denied | Authorizer | Add Default Charset | Customized Default Charset | Enable Rewrite | Rewrite Inherit | Rewrite Base | Rewrite Rules | Enable IP Geolocation | 

Rack/Rails ContextGo to top
Description: A Rack/Rails Context provides an easy way to configure a Ruby Rack/Rails application. To add a Rack/Rails application through a Rack/Rails Context, only mounting the URL and the application's root directory is required. There is no need to go through all the troubles to define an external application, add a 404 handler, and rewrite rules, etc.
URIGo to top
Description: Specifies the URI for this context.
Syntax: The URI can be a plain URI (starting with "/") or a Perl compatible regular expression URI (starting with "exp:"). If a plain URI ends with a "/", then this context will include all sub-URIs under this URI. If the context maps to a directory on the file system, a trailing "/" must be added.
See Also: Location
LocationGo to top
Description: Specifies the corresponding location of this context in the file system.
Syntax: It can be an absolute path or path relative to $SERVER_ROOT, $VH_ROOT, or $DOC_ROOT. $DOC_ROOT is the default relative path, and can be omitted.

If the URI is a regular expression, then the matched sub-string can be used to form the "Root" string. The matched sub-string can be referenced with the values "$1" - "$9". "$0" and "&" can be used to reference the whole matched string. Additionally, a query string can be set by appending a "?" followed by the query string. Be careful. "&" should be escaped as "\&" in the query string.
Example: A plain URI like /examples/ with Location set to /home/john/web_examples will map the request "/examples/foo/bar.html" to file "/home/john/web_examples/foo/bar.html".
To simulate Apache's mod_userdir, set URI to exp: ^/~([A-Za-z0-9]+)(.*), set Location to /home/$1/public_html$2. With these settings, a request of URI /~john/foo/bar.html will map to file /home/john/public_html/foo/bar.html.
See Also: URI
Run-Time ModeGo to top
Description: Specifies which mode Rack/Rails will be running as: "Development", "Production", or "Staging". The default is "Production".
Syntax: Select from drop down list
Max ConnectionsGo to top
Description: Specifies the maximum number of concurrent connections that can be established between the server and an external application. This setting controls how many requests can be processed concurrently by an external application, however, the real limit also depends on the external application itself. Setting this value higher will not help if the external application is not fast enough or cannot scale to a large number of concurrent requests.
Syntax: Integer number
Tips: [Performance] Setting a high value does not directly translate to higher performance. Setting the limit to a value that will not overload the external application will provide the best performance/throughput.
EnvironmentGo to top
Description: Specifies extra environment variables for the external application.
Syntax: Key=value. Multiple variables can be separated by "ENTER"
Enable ExpiresGo to top
Description: Specifies whether to generate an Expires header for static files. If enabled, an Expires header will be generated based on Expires Default and Expires By Type.

This can be set at server, virtual host and context level. Lower level settings will override higher level ones, i.e. context settings will override virtual host settings and virtual host settings will override server settings.
Syntax: Select from radio box
Expires DefaultGo to top
Description: Specifies default settings for Expires header generation. This setting takes effect when Enable Expires is set to "Yes". It can be overridden by Expires By Type. Do not set this default at the server or virtual host level unless you have to, since it will generate Expires headers for all pages. Most of time this should be set at the context level for certain directories that do not change often. If there is no default setting, no Expires header will be generated for types not specified in Expires By Type.
Syntax: A|Mseconds
The file will expire after base time(A|M) plus specified seconds. Base time "A" sets the value to the client's access time and "M" to the file's last modified time.
Expires By TypeGo to top
Description: Specifies Expires header settings for individual MIME types.
Syntax: Comma delimited list of "MIME-type=A|Mseconds". The file will expire after base time (A|M) plus specified seconds.

Base time "A" sets the value to the client's access time and "M" to the file's last modified time. MIME-type accepts wildcard "*", like image/*.
Extra HeadersGo to top
Description: Specifies extra response headers to be added. Multiple headers can be added, one header per line. Put "NONE" to disable headers inherited from parent content.
Syntax: "[HeaderName]: [HeaderValue]" in each line.
Example: Cache-control: no-cache, no-store
My-header: Custom header value
Index FilesGo to top
Description: Specifies names of index files that will be searched sequentially when a URL is mapped to a directory. You can customize it at the server, virtual host, and context level.
Syntax: Comma-delimited list of index filenames.
Tips: [Performance] Only set index files that you need.
Auto IndexGo to top
Description: Specifies whether to generate a directory index on the fly when index files listed in Index Files are not available in a directory. This option is customizable at the virtual host and context level, and is inherited along the directory tree until it is explicitly overridden. You can customize the generated index page. Please check online wiki How-tos.
Syntax: Select from radio box
Tips: [Security] It is recommended to turn off Auto Index wherever possible to prevent revealing confidential data.
See Also: Index Files, Auto Index URI
RealmGo to top
Description: Specifies the authorization realm for this context. When specified, a valid username and password must be provided in order to access this context. Authorization Realms are set up in the Virtual Host Security section. This setting uses each realm's Realm Name.
Syntax: Select from drop down list
Authentication NameGo to top
Description: Specifies an alternative name for the authorization realm for the current context. If not specified, the original realm name will be used. The authentication name is displayed on the browser's login pop-up.
Require (Authorized Users/Groups)Go to top
Description: Specifies which user/group can access this context. This allows you to use one user/group database (specified in Realm) across a number of contexts, but only allow certain users/groups from that database to access this context.
Syntax: Syntax is compatible with Apache's Require directive. For example:
  • user username [username ...]
    Only listed users can access this context.
  • group groupid [groupid ...]
    Only users belonging to the listed groups can access this context.
If this setting is not specified, all valid users will be allowed to access this resource.
Access AllowedGo to top
Description: Specifies which IPs or sub-networks are allowed to access resources under this context. Together with Access Denied and server/virtual host level access control, accessibility is determined by the smallest scope that a client's IP address falls into.
Syntax: Comma-delimited list of IPs/sub-networks.
Example: Sub-networks can be written as 192.168.1.0/255.255.255.0, 192.168.1, or 192.168.1.*.
Access DeniedGo to top
Description: Specifies which IPs or sub-networks are NOT allowed to access resources under this context. Together with Access Allowed and server/virtual host-level access control, accessibility is determined by the smallest scope that a client's IP address falls into.
Syntax: Comma-delimited list of IPs/sub-networks.
Example: Sub-networks can be written as 192.168.1.0/255.255.255.0, 192.168.1, or 192.168.1.*.
AuthorizerGo to top
Description: Specifies an external application that can be used to generate authorized/unauthorized decisions. Currently, only the FastCGI Authorizer is available. For more details about the FastCGI Authorizer role, please visit http://www.fastcgi.com.
Syntax: Select from drop down list
Add Default CharsetGo to top
Description: Specifies whether to add a character set tag to the "Content-Type" response header, when content type is either "text/html" or "text/plain" without any parameters. When set to Off, this function is disabled. When set to On, either the character set specified by Customized Default Charset or the default "iso-8859-1" will be added.
Syntax: Select from radio box
Customized Default CharsetGo to top
Description: Specifies a character set to be used when Add Default Charset is On. This is optional. The default value is iso-8859-1. This entry has no effect when Add Default Charset is Off.
Syntax: Name of a character set.
Example: utf-8
Enable RewriteGo to top
Description: Specifies whether to enable LiteSpeed's URL rewrite engine. This option can be customized at the virtual host or context level, and is inherited along the directory tree until it is explicitly overridden.
Syntax: Select from radio box
Rewrite InheritGo to top
Description: Specifies whether to inherit rewrite rules from parent contexts. If rewrite is enabled and not inherited, rewrite base and rewrite rules defined in this context will be used.
Syntax: Select from radio box
Rewrite BaseGo to top
Description: Specifies the base URL for rewrite rules.
Syntax: URL
Rewrite RulesGo to top
Description: Specifies a list of rewrite rules at the virtual host or context level. A rewrite rule is comprised of one RewriteRule directive and optionally preceded by multiple RewriteCond directives.
  • Each directive should take only one line.
  • RewriteCond and RewriteRule follow Apache's rewrite directive syntax. Just copy and paste rewrite directives from your Apache configuration files.
  • There are minor differences between LiteSpeed and Apache mod_rewrite implementation:
    • %\{LA-U:variable\} and %\{LA-F:variable\} are ignored by the LiteSpeed rewrite engine
    • two new server variables are added in the LiteSpeed rewrite engine: %\{CURRENT_URI\} represents the current URI being processed by the rewrite engine and %\{SCRIPT_NAME\} has the same meaning as the corresponding CGI environment variable.
The implementation of LiteSpeed's rewrite engine follows the Apache's rewrite engine specifications. For more details about rewrite rules, please refer to Apache's mod_rewrite document and Apache's URL rewriting guide.
Syntax: string
Enable IP GeolocationGo to top
Description: Specifies whether to enable/disable IP Geolocation lookup. Can be set at server, virtual host, or context level. IP Geolocation is disabled by default when using value "Not Set".
Syntax: Select from radio box
See Also: Use Client IP in Header, DB File Path, DB Cache Type