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uri - URI utilities
package require Tcl 8.2
package require uri ?1.0?
This package contains two parts. First it provides regular expressions for a number of url/uri schemes. Second it provides a number of commands 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.
uri::split takes a single url, decodes it and then returns a list of key/value pairs suitable for array set containing the constituents of the url. If the scheme is missing from the url it defaults to http. Currently only the schemes http, ftp, mailto and file are supported. See section EXTENDING on how to expand that range.
uri::join takes a list of key/value pairs (generated by uri::split, for example) and returns the canonical url they represent. Currently only the schemes http, ftp, mailto and file are supported. See section EXTENDING on how to expand that range.
uri::isrelative determines whether the specified url is absolute or relative.
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::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 has the same name as the scheme itself (including possible capitalization). It further assumes that the package 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 handle 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 dispatched to.
uri::canonicalize returns the canonical form of a URI. The canonical form of a URI is one where relative path specifications, ie. . and .., have been resolved.
In addition to the commands mentioned above this package provides regular 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 boldt uri::schemes] contains a list of all supported schemes. Currently these are ftp, file, http, gopher, mailto, news, wais and prospero.
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.
Original code by Andreas Kupries. Modularisation by Steve Ball.
uri, url, fetching information, www, http, ftp, mailto, gopher, wais, prospero, file