WASD Web Environment

3.Directory Listing

A directory listing is sometimes refered to as a document Index, and is generally titled "Index of …".

Unless disabled by the server's configuration, a directory listing is recognised by the server whenever a wildcard is present in a specification and there is no query string directing another activity (e.g. a document search). Compliant with other web implementations, a directory listing is also generated if a URL specifies a directory only and that directory contains no home page.

All specifications must be made using URL-style paths. See 2.3 Document Specification.

The directory listing is designed to look very much like the basic layout of other servers, except that all directories are grouped at the top. In the opinion of the author, this looks and functions better than when interspersed with the files, as is otherwise common. The default listing provides:

• iconic indication of the data type
• file name
• last revison date/time
• size
• description

The description can be either just that, a description of the role of that type of file under VMS, or if presented within quotes, an HTML document's own internal description taken from the "<title></title>" element.

Note that directory listings only processes the physical file system. This may or may not correspond to the web environment's virtual mappings.

The following link illustrates the directory listing format: /wasd_root/wasdoc/*.*

VMS-ish Format

The default listing has a generic WWW look about it, however it can be made to look a little more like the format of the VMS "DIRECTORY" command. In this mode the directories are presented as VMS subdirectories, the version number is shown, if a version wildcard was included in the specification then all matching versions are shown, the size is presented in used and allocated blocks, and automatic script activation is disabled. The VMS-style format is enabled by providing an explicit or wildcard version number with the specification, as in the following example: /wasd_root/wasdoc/*.*;

Listing Icons

By default (and generally) WASD installations are configured to return a binary file for unknown content-types (usually triggering a browser "save-as" dialog). For such files, and in fact all files in general, a directory listing icon is usually a link to a plain-text version of the file (regardless of the actual content). This becomes convenient way to access the content for files with "interesting" file name extensions and the actual markup of HTML source files, etc. Of course some files containing non-textual data will be variously displayed as gibberish depending on the browser.

3.1Controlling Access To A Directory

The following files (empty, or not), when within a specific directory regulate access to that directory, and the listing of any parent directory or subdirectories.

• .WWW_HIDDEN – Renders the directory completely invisible to the directory listing mechanism. Files within the directory may still be accessed if specified explicitly but the directory content itself cannot be listed by any means.
• .WWW_NOWILD – Renders the directory incapable of being listed using "*.*" characters at the end of the path, even if allowed by the server. This is a little different to .WWW_HIDDEN, which hides the directory completely. The no-wild still allows a directory without a home page to list as a directory, it does however prevent the forced listing using the "*.*" syntax.
• .WWW_NOP – Any parent directory is not listed.
• .WWW_NOS – Any subdirectories are not listed.
• .WWW_NOPS – Any parent directory or subdirectories are not listed.

3.2"Hidden" Files

Any file name beginning with a period is hidden from the directory listing mechanism (i.e. in VMS parlance it has only a type/suffix/extension). If specifically accessed they will be retrieved however. Hence the following files would not appear in a directory listing:

3.3Server Directives

The WASD server behaviour can be modified using server directives. For directory listings this involves the inclusion of a query string beginning with "?httpd=index". The server detects this URI query string and processes it internally, changing the default action of directory listings.

Multiple directives can be combined by concatenating them with intervening ampersands, as per normal URI syntax.

Server directives specified in the URI propagate when moving between directories unless the query string also contains

3.3.1.WWW_WASD

The control file .WWW_WASD can be used to contain server directives. Directives are generally included one per line with "#" prefixed comment lines allowed.

When a .WWW_WASD file is present in a directory it takes precedence over any SSI or URI (query string) directives also being applied, unless it includes an override=yes directive. When this is present any SSI and/or URI directive string is also applied to the request.

3.3.2Layout

Allows specification of the directory listing layout from the URL, overriding the server default. The layout directive is a short, case-insensitive string that specifies the included fields, relative placement and optionally the width of the fields in a directory listing. Each field is controlled by a single letter (one with colon-separated parameter) and optional leading decimal number specifying the width. When a width is not specified an appropriate default applies. An underscore is used to indicate a single space and is used to separate the fields (two consecutive works well).

• C – creation date
• D – description (often best specified last)
  • D:L – for files, make a link out of the description text
• I – icon (takes no field-width attribute)
  • L – link (highlighted anchor using the name of the file)
  • L:F – file-system name (for ODS-5 displays spaces, etc.)
  • L:N – name-only, do not display the extension
  • L:U – force name to upper-case
• N – name (no link, why bother? who knows!)
• O – owner (can be disabled)
• R – revision date
• S – size
  • S:B – in bytes (comma-formatted)
  • S:D – decimal kilos (see below)
  • S:F – kilo and mega are displayed to one decimal place
  • S:K – in kilo-bytes (and fractions thereof)
  • S:M – in mega-bytes (and fractions thereof)
• U – upper-case file and directory names (must be the first character)

The default layout is:

The following provide other examples:

By default the size of files is calculated as 1024 byte kilos.

When using the "S:D", the size is displayed as per "F" with 1000 byte kilos. If it is prefered to have the default display in 1000 byte kilos then set the directory listing layout using:

If unsure of the kilo value being used check the "<meta>" information in the directory listing.

The following links illustrate this functionality by listing this document's directory in various formats.

3.3.3Directory Style

WASD has a default directory listing style where the page title is a series of links to the various directories in the path, then column labels are separated from directory links by a horizontal line, the after the listed directories a blank line, and the listed files, followed by another horizontal line, all in monospace font. There have been a small number of variations on this over the years. The current default (post-v10.4) style is implemented using an HTML table and differs from the historical preformatted text approach.

For each style there is a second variant where the horizontal lines partitioning the listing are not present.

The various directory listing styles are illustrated below.

Sortable Listing

There is also a useful alternate style that allows manual, automatic and programmatic sorting of the listing content. The sort is performed by JavaScript and does not require a re-request of the server. A sortable listing is indicated by ▼▲  in the header icon column (if present). When a column has been sorted ascending/descending symbols are present adjacent to the column label. The taper of the symbol shape ▼  indicating larger/later to smaller/earlier top to bottom (descending), and ▲  smaller/earlier to larger/later top to bottom (ascending). Manual sorting is accomplished by clicking on the column label. This reverses the current sort order.

The examples above include the basic sortable listing.

The sortable listing by default generates the standard WASD ascending by name listing. It is also possible to automatically sort a listing on a particular column when it is generated. This is done with an additional parameter specifying the layout column character as used in . The default is to list top-to-bottom ascending order. An optional "-" lists top-to-bottom in descending order (the redundant "+") is also accepted.

Examples of automatic sort on size, descending size, revision data and descending revision date are below.

Programmatic listing from JavaScript embedded in a README.HTML or enclosing SSI document can be performed by calling the wasdDirSort() function with a string parameter containing the column character and optional order character. The following example sorts descending by size.

To make all directory listings for a server or site sortable, place the following mapping rule appropriately close to the top of relevant mapping rules.

3.3.4Selective Listing

The WASD directory listing permits the use of VMS wildcards in the file specification. This directly allows selected listings of files. For example, all files, all the SDML files in this document's directory, all the HTML files, and finally all the files containing 01 in the name.

In addition, it is possible to selectively include and/or exclude selected files using the server directive httpd=index&these=. The parameter is one or more, comma-separated file name specifications which may contain wildcards. The directory listing usually would have file name and type wildcard (though can be a selector in itself) and then files are selected using using the above directive. If a selector is preceded by an exclamation point ("!") this excludes matching files. Matching is first to last and the first match hit is applied.

The following examples provide the equivalent listings to the examples above.

This example lists all of the files above in the one listing.

This example lists all files except those with an .HTML type.

3.3.5Listing Font

Historically and by default, directory listings are provided in a monospace font. The parent document or browser (proprtional) font may be used instead with the httpd=index&font=inherit directive. This can only be used with the sortable and tabular (post-v10.4) listings. Historical listing styles are only suitable for monospace fonts.

There is the per-path SET dir=font=inherit mapping rule equivalent.

3.3.6File Versions

As described above, a directory listing can be requested in a VMSish style by appending a version delimter to the URL file specification, with multiple versions of the file, where they exist, displayed with version number.

Multiple versions may also be selectively listed using the httpd=index&versions= directive. The parameter can be an integer representing the maximum number of versions to be listed, or an asterisk wildcard indicating all versions should be listed.

There is the per-path SET dir=versions= mapping rule equivalent.

3.3.7Readme Files

When a directory listing is generated any "README.", "README.TXT" or "README.HTML" file (or others as configured for the particular server) in the directory will have the contents displayed immediately below the title of the page. This allows additional information on the directory's contents, function, etc., to be presented. This can be suppressed by appending the following query-string to the directory specification, as in the accompanying example:

Read-me files can be SSI documents if configured by the server administrator. General SSI guidelines apply to these, see 4. Server Side Includes (SSI)

3.3.8Listing Delimiters

A directory listing is normally delimited by a header, comprising an "Index of", column headings and horizontal line, and a footer, comprising a horizintal line. This default behaviour may be modified using the "delimit=" directive.

• header – a header comprising a horizontal rule and column heading is generated
• footer – a footer comprising a horizontal rule is generated
• none – no header or footer is generated
• both – both header and footer is generated (default)

3.3.9Suppressing Directories

Parent and subdirectories may be suppressed in a listing using the "nop", "nops" and "nos" directives. These parallel the purpose of the directory listing control files described in 3.1 Controlling Access To A Directory, and if set to true suppress the listing of the corresponding directories.

• nop – any parent directory is not listed
• nops – any subdirectories are not listed
• nos – any parent directory or subdirectories are not listed

3.3.10Listing Refresh and Expiry

Directory listings and trees may be pre-expired. That is, the listing is reloaded each time the page is referenced. This is convenient in some environments where directory contents change frequently, but adds considerable over-head and so is often disabled by default. Individual directory listings may have either default behaviour over-ridden using syntax similar to the following examples:

3.3.11Scripting From Directory Listings

When a directory listing is requested a script name can be specified to be used as a prefix to all of the file links in the listing. When the client selects a file link the script specified is implicitly activated.

The following link illustrates this facility by specifying the liner script. When a link is selected the liner script presents the file with preprended line numbers:

3.3.12Auto-Scripting

The server's auto-scripting facility (see description of [AddType] configuration directive in the Technical Overview) can be suppressed by appending the following query-string to the directory specification, as in the accompanying example:

This implies that any file accessed from the listing will be transfered without any data conversion possible due to script activation. The browser must then process the document in some fashion (often by activating a save as dialog).

3.3.13Target Window

Files generally open in the current browser window. It is possible to open a file in another window using the target= directive.

Browser (HTML) Supported Targets

3.3.14Specifying Content-Type

When accessing files it is possible to explicitly specify the identifying content-type to be returned to the browser in the HTTP response header. Of course this does not change the actual content of the file, just the header content-type! This is primarily provided to allow access to plain-text documents that have obscure, non"-standard" or non-configured file extensions. See 2.2 Explicitly Specifying Content-Type.

It could also be used for other purposes, "forcing" the browser to accept a particular file as a particular content-type. This can be useful if the extension is not configured (as mentioned above) or in the case where the file contains data of a known content-type but with an extension conflicting with an already configured extension specifying data of a different content-type.

It is posssible to "force" the content-type for all files in a particular directory. Enter the path to the directory and then add

(or what-ever type is desired). Links to files in the listing will contain the appropriate "?httpd=content&type=..." appended as a query string.

This is an example:

3.3.15Icon Plain Text Link

Directory listing icons are generally links to the content of the file displayed as plain-text (‘Listing Icons’ in 3. Directory Listing). This can be disabled using the ilink directive.

3.3.16Query String

The query=<string> directive can be used to propagate an explicit query string to subsequent directory requests. This is intended to be applied from a .WWW_WASD control file because actual URI query strings are propagated by default.

3.3.17Allowing Override

When a .WWW_WASD file is present in a directory it takes precedence over any SSI or URI (query string) directives also available, unless it includes an override=yes directive. When this is present any SSI and/or URI directive string is also applied to the request.

3.4Directory Tree

The "Tree" internal script allows a directory tree to be generated. This script is supplied with a directory name from which it displays all subdirectories in a hierarchical layout, showing subordinancies. Selecting any one of the subdirectories displayed generates a directory listing (see 3. Directory Listing).

Appending a file specification (with or without wildcards) to the directory name results in the any directory listing displaying only files matching the specification. To display all files a "*.*" should always be appended.

Note that this script only processes the physical file system. This may or may not correspond to the web environment's virtual mappings.

To enable the VMS-style directory listing format, or to use any of the directory server directives, append one, or a combination of, the following query strings to the directory specification:

The following links provide online demonstrations:

Note that this activity is I/O intensive, and can take a considerable period if the tree is extensive.