0Document Access and Specification7

HFRD Hypertext Services - Environment Overview

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3 - Document Access and Specification




0 Arbitrary documents may not be accessed.

K The server can only access files where the path is allowed according to a Bspecified set of rules specified within the hypertext environment.

* Documents must be read-accessable.

K The server can only access files that are world readable, or that have an DACL specifically controlling access for ``HTTP$SERVER'', the server account. 

Document Types



I Document (file) retrieval is initiated by providing the server with the Nfile specification as a URL path. Server configuration determines the format Lin which the file is returned to the client. It may contain text or images Nimmediately diplayable by the browser, or by a viewer external to the browser Mmay be spawned. The server may automatically activate a script to provide a egateway to non-native information (see 2.1 - Auto-Scripting). The Nfile type (extension) determines the content type by which the server returns (and/or interprets) the file. 

L The following table lists some of the current file types (as examples) and Gtheir associated MIME-style content type. HTML documents are presentedMlayed-up according to the full HTML-capabilities of the browser. Plain-text Hdocuments are presented in a fixed-font format. Other types require an external viewer to be activated.9

  .C          C source                    text/plain4  .COM        DCL procedure               text/plain4  .CONF       configuration file          text/plain4  .CPP        C++ source                  text/plainM  .DBF        dBaseIV database            text/html, gateway script activatedM  .DECW$BOOK  Bookreader document         text/html, gateway script activated4  .FOR        Fortran source              text/plain3  .GIF        GIF image                   image/gif4  .H          C header                    text/plainM  .HLB        VMS Help library            text/html, gateway script activated3  .HTML       HyperText Markup Language   text/html3  .HTM        HyperText Markup Language   text/html4  .JPG        JPEG image                  image/jpeg4  .LIS        Listing                     text/plain4  .MAR        Macro source                text/plain5  .MENU       Menu                        text/x-menu5  .MNU        Menu                        text/x-menu4  .PAS        Pascal source               text/plain4  .PRO        IDL source                  text/plain@  .PS         PostScript                  application/PostScript4  .TEXT       Text                        text/plainM  .TLB        VMS text library            text/html, gateway script activated4  .TXT        Text                        text/plainA  .SHTML      HyperText Markup Language   pre-processed text/htmlA  .SHT        HyperText Markup Language   pre-processed text/html9  .XBM        X bitmap                    image/x-xbitmap<  .ZIP        zipped file                 application/binary


D If other file types are required to be defined contact VMS systems management. %

3.1 - Document Specification



G File and directory locations are specified using URL path syntax whereIslash-separated (``/'') elements delineate a hierarchy leading to a data Nitem. Anyone familiar with the syntax of the Unix file system, or the MS-DOS Mfile system (where back-slashes are hierarchy delimiters), will feel at home Cwith URL syntax. Specifications under VMS are not case-sensitive. 

 A VMS directory specification (

  HYPERDATA:[TECHNICAL.HTML-PRIMER]
& would be represented in URL syntax as(
  /hyperdata/technical/html-primer/
 and a VMS file specification 8
  HYPERDATA:[TECHNICAL.HTML-PRIMER]HTML-PRIMER.HTML
 represented as8
  /hyperdata/technical/html-primer/html-primer.html


Note:

FIt is not required (although not forbidden) to supply a VMS master Efile directory component (``[000000]'', ``[000000.'', etc.) in a 1URL specification. Hence the file specification "
  HYPERDATA:[000000]HOME.HTML
 should be represented as
  /hyperdata/home.html
 #

3.1.1 - Absolute File Path




G A file may be specified using an absolute, or full path. This ?must specify the location of the file exactly. Absolute paths @always begin with a forward-slash (``/''). For example: 7

  /hyperdata/committee/minutes/1994/1994-09-27.txt'  /hyperdata/committee/constitution.txt1  /hyperdata/committee/membership/fred-bloggs.txt
0

3.1.2 - Partial (or Relative) File Path




: (Strictly speaking, it is a function of the client to Lconstruct a full URL from such a relative URL before sending the request to the server.)

C A file may be specified relative to its current location. HThat is, a current document (or menu) may specify another document file Mrelative to itself. This may be at the current level, a subdirectory, or in Kanother part of the directory tree related to the current. Relative paths /never begin with forward-slash (``/''). 

J For example, documents at the same level as the current may be specified &without any hierachy being indicated: 

  1994-07-22.txt  1994-08-24.txt  1994-09-27.txt


L Documents at an inferior point in the hierarchy may be specified as in the following example: 

  1993/1993-02-17.txt  1993/reports/membership.txt  other/etc.txt


J Documents in a related part of the hierarchy may be referenced using the ?``../'' construct. As with MS-DOS and Unix this syntax .indicates the immediately superior directory. -

  ../other_committee/1993/1993-02-17.txt3  ../other_committee/1993/reports/balance-sheet.txt0  ../../other_section/committee/constitution.txt





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