Editing Web server (section)

===== Directory listings =====
[[File:Web server directory list.png|thumb|271x161px|right|Directory listing dynamically generated by a web server]]
{{Main|Web server directory index}}

A web server program may be capable to manage the dynamic generation (on the fly) of a '''[[Web server directory index|directory index list]]''' of files and sub-directories.<ref name="ws-directory-listings">{{Cite web|url=https://cwiki.apache.org/confluence/display/HTTPD/DirectoryListings|title=Directory listings|author=ASF Infrabot|publisher=Apache foundation: HTTPd server project|date=2019-05-22|access-date=2021-11-16|language=en|archive-date=7 June 2019|archive-url=https://web.archive.org/web/20190607234544/https://cwiki.apache.org/confluence/display/HTTPD/DirectoryListings|url-status=live}}</ref>

If a web server program is configured to do so and a requested URL path matches an existing directory and its access is allowed and no static index file is found under that directory then a web page (usually in HTML format), containing the list of files and/or subdirectories of above mentioned directory, is ''dynamically generated'' (on the fly).  If it cannot be generated an error is returned.

Some web server programs allow the customization of directory listings by allowing the usage of a web page template (an HTML document containing placeholders, e.g. <code>$(FILE_NAME), $(FILE_SIZE)</code>, etc., that are replaced with the field values of each file entry found in directory by web server), e.g. <code>index.tpl</code> or the usage of HTML and embedded source code that is interpreted and executed on the fly, e.g. <code>index.asp</code>, and / or by supporting the usage of dynamic index programs such as CGIs, SCGIs, FCGIs, e.g. <code>index.cgi</code>, <code>index.php</code>, <code>index.fcgi</code>.

Usage of dynamically generated ''directory listings'' is usually avoided or limited to a few selected directories of a website because that generation takes much more OS resources than sending a static index page.

The main usage of ''directory listings'' is to allow the download of files (usually when their names, sizes, modification date-times or [[file attribute]]s may change randomly / frequently) ''as they are, without requiring to provide further information to requesting user''.<ref name="ws-apache-dir">{{Cite web|url=https://archive.apache.org/dist/httpd/|title=Apache: directory listing to download files|author=|publisher=Apache: HTTPd server|access-date=2021-12-16|archive-date=2 December 2021|archive-url=https://web.archive.org/web/20211202004258/http://archive.apache.org/dist/httpd/|url-status=live}}</ref>