


uri(n)      Tcl Uniform Resource Identifier Management     uri(n)


______________________________________________________________________________

NAME
       uri - URI utilities

SYNOPSIS
       package require Tcl  8.2

       package require uri  ?1.2.1?

       uri::split url ?defaultscheme?

       uri::join ?key value?...

       uri::resolve base url

       uri::isrelative url

       uri::geturl url ?options...?

       uri::canonicalize uri

       uri::register schemeList script

_________________________________________________________________

DESCRIPTION
       This  package contains two parts. First it provides regular expressions
       for a number of url/uri schemes. Second it provides a  number  of  com-
       mands  for  manipulating urls/uris and fetching data specified by them.
       For the latter this package analyses the  requested  url/uri  and  then
       dispatches  it  to  the appropriate package (http, ftp, ...) for actual
       fetching.

       The package currently does not conform to RFC 2396 (http://www.rfc-edi-
       tor.org/rfc/rfc2396.txt), but quite likely should be. Patches and other
       help are welcome.

COMMANDS
       uri::split url ?defaultscheme?
              uri::split takes an url, decodes it and then returns a  list  of
              key/value  pairs  suitable  for  array  set  containing the con-
              stituents of the url. If the scheme is missing from the  url  it
              defaults  to  the value of defaultscheme if it was specified, or
              http else. Currently only the schemes http,  ftp,  mailto,  urn,
              news,  ldap  and  file are supported by the package itself.  See
              section EXTENDING on how to expand that range.

              The set of constituents of an url (= the  set  of  keys  in  the
              returned  dictionary) is dependent on the scheme of the url. The
              only key which is therefore always present is  scheme.  For  the
              following schemes the constituents and their keys are known:

              ftp    user, pwd, host, port, path, type



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uri(n)      Tcl Uniform Resource Identifier Management     uri(n)


              http(s)
                     user,  pwd,  host, port, path, query, fragment. The frag-
                     ment is optional.

              file   path, host. The host is optional.

              mailto user, host. The host is optional.

              news   Either message-id or newsgroup-name.


       uri::join ?key value?...
              uri::join  takes  a  list  of  key/value  pairs  (generated   by
              uri::split, for example) and returns the canonical url they rep-
              resent. Currently only the schemes http, ftp, mailto, urn, news,
              ldap  and  file  are  supported. See section EXTENDING on how to
              expand that range.

       uri::resolve base url
              uri::resolve resolves the specified url  relative  to  base.  In
              other  words:  A non-relative url is returned unchanged, whereas
              for a relative url the missing parts are  taken  from  base  and
              prepended  to  it. The result of this operation is returned. For
              an empty url the result is base.

       uri::isrelative url
              uri::isrelative determines whether the specified url is absolute
              or relative.

       uri::geturl url ?options...?
              uri::geturl  decodes  the  specified url and then dispatches the
              request to the package appropriate for the scheme found  in  the
              url.  The  command  assumes that the package to handle the given
              scheme either has the same name as the scheme itself  (including
              possible  capitalization)  followed  by ::geturl, or, in case of
              this failing, has the same name as the scheme itself  (including
              possible capitalization). It further assumes that whatever pack-
              age was loaded provides a geturl-command in the namespace of the
              same name as the package itself. This command is called with the
              given url and all given options. Currently geturl does not  han-
              dle any options itself.

              Note:  file-urls  are  an exception to the rule described above.
              They are handled internally.

              It is not possible to  specify  results  of  the  command.  They
              depend on the geturl-command for the scheme the request was dis-
              patched to.

       uri::canonicalize uri
              uri::canonicalize returns the canonical  form  of  a  URI.   The
              canonical  form  of  a URI is one where relative path specifica-
              tions, ie. . and .., have been resolved.




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uri(n)      Tcl Uniform Resource Identifier Management     uri(n)


       uri::register schemeList script
              uri::register registers the first element of schemeList as a new
              scheme and the remaining elements as aliases for this scheme. It
              creates the namespace for the scheme and executes the script  in
              the  new namespace. The script has to declare variables contain-
              ing the regular expressions relevant to the scheme. At least the
              variable  schemepart  has  to be declared as that one is used to
              extend the variables keeping track of the registered schemes.


SCHEMES
       In addition to the commands mentioned above this package provides regu-
       lar expression to recognize urls for a number of url schemes.

       For  each  supported  scheme a namespace of the same name as the scheme
       itself is provided inside of the namespace uri containing the  variable
       url  whose  contents are a regular expression to recognize urls of that
       scheme. Additional variables may contain regular expressions for  parts
       of urls for that scheme.

       The  variable  uri::schemes  contains  a list of all supported schemes.
       Currently these are ftp, ldap, file, http, gopher, mailto,  news,  wais
       and prospero.

EXTENDING
       Extending the range of schemes supported by uri::split and uri::join is
       easy because both commands do not handle the request by themselves  but
       dispatch it to another command in the uri namespace using the scheme of
       the url as criterion.

       uri::split  and  uri::join  call  Split[string  totitle  <scheme>]  and
       Join[string totitle <scheme>] respectively.

CREDITS
       Original code (regular expressions) by Andreas Kupries.  Modularisation
       by Steve Ball, also the split/join/resolve functionality.

BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will  undoubtedly  contain
       bugs and other problems.  Please report such in the category uri of the
       Tcllib  SF  Trackers  [http://sourceforge.net/tracker/?group_id=12883].
       Please  also  report any ideas for enhancements you may have for either
       package and/or documentation.

KEYWORDS
       fetching information, file, ftp,  gopher,  http,  ldap,  mailto,  news,
       prospero, rfc 2255, rfc 2396, uri, url, wais, www

CATEGORY
       Networking







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