Apache模块 mod_dav

说明	允许Apache提供DAV协议支持
状态	扩展(E)
模块名	dav_module
源文件	mod_dav.c

概述

This module provides class 1 and class 2 WebDAV ('Web-based Distributed Authoring and Versioning') functionality for Apache. This extension to the HTTP protocol allows creating, moving, copying, and deleting resources and collections on a remote web server.

Enabling WebDAV

To enablemod_dav, add the following to a container in yourhttpd.conffile:

Dav On

This enables the DAV file system provider, which is implemented by themod_dav_fsmodule. Therefore, that module must be compiled into the server or loaded at runtime using theLoadModuledirective.

In addition, a location for the DAV lock database must be specified in the global section of yourhttpd.conffile using theDavLockDBdirective:

DavLockDB /usr/local/apache2/var/DavLock

The directory containing the lock database file must be writable by theUser和Groupunder which Apache is running.

You may wish to add aclause inside thedirective to limit access to DAV-enabled locations. If you want to set the maximum amount of bytes that a DAV client can send at one request, you have to use theLimitXMLRequestBodydirective. The "normal"LimitRequestBodydirective has no effect on DAV requests.

Full Example

DavLockDB /usr/local/apache2/var/DavLock Dav On AuthType Basic AuthName DAV AuthUserFile user.passwd require user admin

mod_davis a descendent of Greg Stein's mod_dav for Apache 1.3. More information about the module is available from that site.

安全问题

Since DAV access methods allow remote clients to manipulate files on the server, you must take particular care to assure that your server is secure before enablingmod_dav.

Any location on the server where DAV is enabled should be protected by authentication. The use of HTTP Basic Authentication is not recommended. You should use at least HTTP Digest Authentication, which is provided by themod_auth_digestmodule. Nearly all WebDAV clients support this authentication method. An alternative is Basic Authentication over an SSL enabled connection.

In order formod_davto manage files, it must be able to write to the directories and files under its control using theUser和Groupunder which Apache is running. New files created will also be owned by thisUser和Group. For this reason, it is important to control access to this account. The DAV repository is considered private to Apache; modifying files outside of Apache (for example using FTP or filesystem-level tools) should not be allowed.

mod_davmay be subject to various kinds of denial-of-service attacks. TheLimitXMLRequestBodydirective can be used to limit the amount of memory consumed in parsing large DAV requests. TheDavDepthInfinitydirective can be used to preventPROPFINDrequests on a very large repository from consuming large amounts of memory. Another possible denial-of-service attack involves a client simply filling up all available disk space with many large files. There is no direct way to prevent this in Apache, so you should avoid giving DAV access to untrusted users.

Complex Configurations

One common request is to usemod_davto manipulate dynamic files (PHP scripts, CGI scripts, etc). This is difficult because aGETrequest will always run the script, rather than downloading its contents. One way to avoid this is to map two different URLs to the content, one of which will run the script, and one of which will allow it to be downloaded and manipulated with DAV.

Alias /phparea /home/gstein/php_files Alias /php-source /home/gstein/php_files DAV On ForceType text/plain

With this setup,http://example.com/phpareacan be used to access the output of the PHP scripts, andhttp://example.com/php-sourcecan be used with a DAV client to manipulate them.

Dav 指令

说明	Enable WebDAV HTTP methods
语法	`Dav On\|Off\|provider-name`
默认值	`Dav Off`
作用域	directory
状态	扩展(E)
模块	mod_dav

Use theDavdirective to enable the WebDAV HTTP methods for the given container:

Dav On

The valueOnis actually an alias for the default providerfilesystemwhich is served by themod_dav_fsmodule. Note, that once you have DAV enabled for some location, itcannotbe disabled for sublocations. For a complete configuration example have a look at the section above.

Do not enable WebDAV until you have secured your server. Otherwise everyone will be able to distribute files on your system.

DavDepthInfinity 指令

说明	Allow PROPFIND, Depth: Infinity requests
语法	`DavDepthInfinity on\|off`
默认值	`DavDepthInfinity off`
作用域	server config, virtual host, directory
状态	扩展(E)
模块	mod_dav

Use theDavDepthInfinitydirective to allow the processing ofPROPFINDrequests containing the header 'Depth: Infinity'. Because this type of request could constitute a denial-of-service attack, by default it is not allowed.

DavMinTimeout 指令

说明	Minimum amount of time the server holds a lock on a DAV resource
语法	`DavMinTimeoutseconds`
默认值	`DavMinTimeout 0`
作用域	server config, virtual host, directory
状态	扩展(E)
模块	mod_dav

When a client requests a DAV resource lock, it can also specify a time when the lock will be automatically removed by the server. This value is only a request, and the server can ignore it or inform the client of an arbitrary value.

Use theDavMinTimeoutdirective to specify, in seconds, the minimum lock timeout to return to a client. Microsoft Web Folders defaults to a timeout of 120 seconds; theDavMinTimeoutcan override this to a higher value (like 600 seconds) to reduce the chance of the client losing the lock due to network latency.

示例

DavMinTimeout 600

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