websh/quickref/command_dispatching_and_session_management.html (347 lines of code) (raw):
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Command dispatching and session management</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.1"><link rel="home" href="index.html" title="Websh Reference 3.6.0b5"><link rel="up" href="index.html" title="Websh Reference 3.6.0b5"><link rel="prev" href="configuration.html" title="Configuration"><link rel="next" href="request_data_handling.html" title="Request data handling"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Command dispatching and session management</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="configuration.html">Prev</a>�</td><th width="60%" align="center">�</th><td width="20%" align="right">�<a accesskey="n" href="request_data_handling.html">Next</a></td></tr></table><hr></div><div class="section" title="Command dispatching and session management"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="command_dispatching_and_session_management"></a>Command dispatching and session management</h2></div></div></div><p style="width:90%">
Websh provides a command dispatching mechanism to produce,
for example, different HTML pages within one "application",
which is most likely one file on the file system. The name of
the command to be used for a particular page is encoded in the
querystring (see <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span> for details on
how to produce such querystrings). Command dispatching is
initiated with the command <span style="font-family:monospace"><span class="command"><strong>web::dispatch</strong></span></span>.
Commands are defined with <span style="font-family:monospace"><span class="command"><strong>web::command</strong></span></span>.
</p><div class="section" title="web::command"><div class="titlepage"><div><div><h3 class="title"><a name="web::command"></a><span style="font-family:monospace"><span class="command"><strong>web::command</strong></span></span></h3></div></div></div><p style="width:90%">
</p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::command</code></span> ?<em class="replaceable"><code>cmdName</code></em>? <em class="replaceable"><code>cmdBody</code></em></span></div><p style="width:90%">
Registers <tt>cmdBody</tt> as
<tt>cmdName</tt>. If <tt>cmdName</tt> is
omitted, "default" is used.
</p><div class="example"><a name="id2679606"></a><p class="title"><b>Example�2.�Simple command dispatching</b></p><div class="example-contents"><pre style="background:#bbffbb ; width:75%" class="programlisting">
proc page {title code} {
web::put "<html><title>[web::htmlify $title]</title><body>"
web::put "<h1>[web::htmlify $title]</h1>"
uplevel 1 $code
web::put {</body></html>}
}
web::command default {
page "Home" {
web::put "<a href=\"[web::cmdurl page1]\">Link to Page 1</a>"
web::put "<br/>"
web::put "<a href=\"[web::cmdurl page2]\">Link to Page 2</a>"
}
}
web::command page1 {
page "Page 1" {
web::put "<a href=\"[web::cmdurl default]\">Home</a>"
}
}
web::command page2 {
page "Page 2" {
web::put "<a href=\"[web::cmdurl default]\">Home</a>"
}
}
web::dispatch</pre></div></div><p style="width:90%"><br class="example-break">
</p></div><div class="section" title="web::getcommand"><div class="titlepage"><div><div><h3 class="title"><a name="web::getcommand"></a><span style="font-family:monospace"><span class="command"><strong>web::getcommand</strong></span></span></h3></div></div></div><p style="width:90%">
</p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::getcommand</code></span> ?<em class="replaceable"><code>cmdName</code></em>?</span></div><p style="width:90%">
Retrieves the body of the command <tt>commandName</tt>
or of the command "default" if
<tt>cmdName</tt> is omitted.
</p></div><div class="section" title="web::cmdurl"><div class="titlepage"><div><div><h3 class="title"><a name="web::cmdurl"></a><span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span></h3></div></div></div><p style="width:90%">
</p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::cmdurl</code></span> ?<em class="replaceable"><code>options</code></em>? <em class="replaceable"><code>cmdName</code></em> ?<em class="replaceable"><code>key-value-list</code></em>?</span></div><p style="width:90%">
</p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::cmdurl</code></span> ?<em class="replaceable"><code>options</code></em>? <em class="replaceable"><code>cmdName</code></em> ?<em class="replaceable"><code>k1 v1 ... kN vN</code></em>?</span></div><p style="width:90%">
</p><p style="width:90%">
Options are: <tt>-notimestamp</tt>, and
<tt>-urlformat</tt>
</p><p style="width:90%">
Generate URLs including querystring. By default, URLs are
self-referencing, but the exact output is subject to
configuration. The querystring is encrypted, using the
encryption method specified by configuration (see
<span style="font-family:monospace"><span class="command"><strong>web::config</strong></span></span>). If <tt>cmdName</tt>
is "", no command parameter is produced in the query
string.
</p><div class="variablelist"><dl><dt><span style="background:#bbbbff"><span class="term"><tt>-notimestamp</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Tells Websh not to add a timestamp to URLs.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-urlformat</tt> <tt><em class="replaceable"><code>list</code></em></tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Specifies which items will be used to format just this
URL. Default: <span style="font-family:monospace"><span class="command"><strong>{scriptname pathinfo
querystring}</strong></span></span>.
</div><div style="margin-bottom:6">
Note: Use <span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span> to define the
url format for all URLs produced by
<span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span> in one request.
</div><div style="margin-bottom:6">
<div class="variablelist"><dl><dt><span style="background:#bbbbff"><span class="term"><tt>scheme</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Includes the protocol, only "http"
and "https" are currently supported.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>host</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Includes the host name,
e.g. "websh.com".
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>port</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Includes the port,
e.g. "80"</div><div style="margin-bottom:6"> Trying to set
this item without host will throw an error.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>scriptname</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Includes scriptname,
e.g. "/cgi-bin/orderbooks".
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>pathinfo</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Includes pathinfo,
e.g. "/merchants/shop1".
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>querystring</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Includes the querystring,
e.g. "select=download".
</div></div></dd></dl></div>
</div></div></dd></dl></div><p style="width:90%">
</p><p style="width:90%">
</p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
Note that there are two more commands that control
the output of <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span>:
<span style="font-family:monospace"><span class="command"><strong>web::config</strong></span></span><tt>cmdparam</tt>
and
<span style="font-family:monospace"><span class="command"><strong>web::config</strong></span></span><tt>timeparam</tt>.
</div><p style="width:90%">
</p><div class="example"><a name="id2734743"></a><p class="title"><b>Example�3.�<span style="font-family:monospace"><span class="command">web::cmdurl</span></span></b></p><div class="example-contents"><pre style="background:#bbffbb ; width:75%" class="programlisting">
% web::cmdurl -notimestamp -urlformat [list scheme host scriptname pathinfo querystring] "test"
http://websh.com/bin/returnmail/member?XDZuRD2rnsfHjFH
% </pre></div></div><br class="example-break"></div><div class="section" title="web::cmdurlcfg"><div class="titlepage"><div><div><h3 class="title"><a name="web::cmdurlcfg"></a><span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span></h3></div></div></div><p style="width:90%">
</p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::cmdurlcfg</code></span> ?<em class="replaceable"><code>option</code></em>? ?<em class="replaceable"><code>key</code></em>? ?<em class="replaceable"><code>value</code></em>?</span></div><p style="width:90%">
</p><p style="width:90%">
Command options are exactly like those of
<span style="font-family:monospace"><span class="command"><strong>web::param</strong></span></span>.
</p><p style="width:90%">
</p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::cmdurlcfg</code></span> <em class="replaceable"><code>option</code></em> ?<em class="replaceable"><code>value</code></em>?</span></div><p style="width:90%">
</p><p style="width:90%">
Options are <tt>-scheme</tt>,
<tt>-host</tt>, <tt>-port</tt>,
<tt>-scriptname</tt>,
<tt>-pathinfo</tt>,
<tt>-querystring</tt>,
<tt>-urlformat</tt></p><p style="width:90%"> If
<tt>value</tt> is omitted, the current value is
returned. Otherwise, the <tt>value</tt> is stored.
Configuration for <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span>.
This command serves two purposes:
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><div style="margin-bottom:6">Management of static parameters</div></li><li class="listitem"><div style="margin-bottom:6">Configuration for
<span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span></div></li></ol></div><p style="width:90%">
By "static parameters", we mean those which are set for every
page, instead of set on a per-page basis.
</p></div><div class="section" title="Management of static parameters"><div class="titlepage"><div><div><h3 class="title"><a name="management_of_static_parameters"></a>Management of static parameters</h3></div></div></div><p style="width:90%">
In addition to the easy way of tracking parameters using
<span style="font-family:monospace"><span class="command"><strong>web::dispatch -track ...</strong></span></span>, specific values
for parameters can be set using <span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span>:
In order to explicitly set, retrieve, append or unset static
parameters, use the syntax of the <span style="font-family:monospace"><span class="command"><strong>web::param</strong></span></span>
command, for example:
</p><div class="variablelist"><dl><dt><span style="background:#bbbbff"><span class="term"><span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span> -set
<tt><em class="replaceable"><code>key</code></em></tt>
<tt><em class="replaceable"><code>value</code></em></tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Adds the static parameter <tt>key</tt>.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span> -names</span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Returns a list of all known static parameters.
</div></div></dd></dl></div><p style="width:90%">
</p><p style="width:90%">
<span class="emphasis"><em>Important</em></span>: <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span>
compares every key from the static parameters (see
<span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span>) against the keys from the
command line. The static parameter is only used if there is no
parameter of the same name given on the command line.
</p></div><div class="section" title="Configuration for web::cmdurl"><div class="titlepage"><div><div><h3 class="title"><a name="configuration_for_web_cmdurl"></a>Configuration for <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span></h3></div></div></div><p style="width:90%">
</p><div class="variablelist"><dl><dt><span style="background:#bbbbff"><span class="term"><tt>-scheme</tt> ?<span class="optional"><tt><em class="replaceable"><code>value</code></em></tt></span>?</span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Sets or gets protocol to be used. Defaults to the scheme used
to access the page, which is overridden if the user
sets a value.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-host</tt> ?<span class="optional"><tt><em class="replaceable"><code>value</code></em></tt></span>?</span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Sets or gets server name to be used. Default: taken from
request.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-port</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Sets or gets port number to be used. Default: taken from
request, 80 if not available.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-scriptname</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Sets or gets name of CGI executable. Default: taken from
request.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-pathinfo</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Sets or gets path info (path after scriptname). Default:
taken from request.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-urlformat</tt> <tt><em class="replaceable"><code>list</code></em></tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Sets or gets the urlformat permanently. See
<span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span> for the description of
this option.
</div></div></dd></dl></div><p style="width:90%">
In all these cases, "<span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg -option
<tt>value</tt></strong></span></span>" sets the value of the given
option and returns the value that was used before the change,
while "<span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg -option</strong></span></span>" returns
the current value. If no value has been set using
<span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span>, but is
requested for the URL generation, the value from the request
will be used. This value, however, can not be retrieved using
<span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span>.
</p><div class="variablelist"><dl><dt><span style="background:#bbbbff"><span class="term"><tt>-reset</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Resets the <span style="font-family:monospace"><span class="command"><strong>web::cmdurlcfg</strong></span></span> configuration.
Note however, that static parameters will not be reset by this
option. To get rid of static parameters configured with the
<span style="font-family:monospace"><span class="command"><strong>-set</strong></span></span> option, use <span style="font-family:monospace"><span class="command"><strong>-unset</strong></span></span>
with (for a specific parameter) or without (for all parameters)
key.
</div></div></dd></dl></div><p style="width:90%">
</p><p style="width:90%">
<span class="emphasis"><em>Note</em></span> that setting a value to an empty string
is the same as using <span style="font-family:monospace"><span class="command"><strong>-unset</strong></span></span>.
</p><p style="width:90%">
<span class="emphasis"><em>Also note</em></span>: <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span>
compares every key from the static parameters against
the keys from the command line. The static parameter is only
used if there is no such parameter on the command line.
</p><div class="example"><a name="id2735265"></a><p class="title"><b>Example�4.�<span style="font-family:monospace"><span class="command">web::cmdurl</span></span> and <span style="font-family:monospace"><span class="command">web::cmdurlcfg</span></span></b></p><div class="example-contents"><pre style="background:#bbffbb ; width:75%" class="programlisting">
% web::cmdurl ""
?XDqPtk34XvyPh41gUBo
% web::cmdurlcfg -scriptname bin/test_script
% web::cmdurl ""
bin/test_script?XDqPtk34XvyPh41gUBo
% web::cmdurlcfg -scriptname ""
% web::cmdurl ""
?XDqPtk34XvyPh41gUBo
% web::cmdurlcfg -urlformat {scheme host port querystring}
scriptname pathinfo querystring
% # for clearer view on what happens: disable querystring encryption
% web::config encryptchain {}
web::encryptd
% web::cmdurlcfg -set foo bar
bar
% web::cmdurlcfg -host tcl.apache.org
% web::cmdurl zoo
http://tcl.apache.org:80?foo=bar&cmd=zoo&t=1141776460
% web::cmdurlcfg -reset
% web::cmdurl zoo
?foo=bar&cmd=zoo&t=1141776496
% web::config cmdurltimestamp 0
1
% web::config cmdparam page
cmd
% web::cmdurl zoo
?foo=bar&page=zoo
% </pre></div></div><br class="example-break"></div><div class="section" title="web::dispatch"><div class="titlepage"><div><div><h3 class="title"><a name="web::dispatch"></a><span style="font-family:monospace"><span class="command"><strong>web::dispatch</strong></span></span></h3></div></div></div><p style="width:90%">
</p><div class="cmdsynopsis"><span style="background:#bbbbff"><span style="font-weight:bold"><code class="command">web::dispatch</code></span> ?<em class="replaceable"><code>options</code></em>?</span></div><p style="width:90%">
Options are: <tt>-cmd</tt>,
<tt>-querystring</tt>, <tt>-postdata</tt>,
<tt>-track</tt> and <tt>-hook</tt>.
</p><p style="width:90%">
Parse information and call a command.
</p><p style="width:90%">
</p><div class="variablelist"><dl><dt><span style="background:#bbbbff"><span class="term"><tt>-cmd</tt> <tt><em class="replaceable"><code>cmdName</code></em></tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Switches to command <tt>cmdName</tt>. If
<tt>cmdName</tt> is an empty string, no
command is called. By default,
<tt>cmdName</tt> is taken from the
querystring.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-querystring</tt>
<tt><em class="replaceable"><code>string</code></em></tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Parses <tt>string</tt> as the querystring. If
<tt>string</tt> is an empty string,
querystring parsing is turned off. By default,
querystring is taken from the request data (CGI
environment or apache module request object).
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-postdata</tt> <tt>""</tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Do not parse any post data.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term">
<tt>-postdata</tt> ?<span class="optional"><tt>#</tt></span>?<tt><em class="replaceable"><code>channelName</code></em></tt>
<tt><em class="replaceable"><code>?<span class="optional">content_length</span>?</code></em></tt>
<tt><em class="replaceable"><code>?<span class="optional">content_type</span>?</code></em></tt>
</span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Parse channel <tt>channelName</tt> (or variable
named <tt>channelName</tt> if <tt>#</tt> is
given) as POST data input with length
<tt>content_length</tt> and type
<tt>content_type</tt>. <tt>content_type</tt>
can be <code class="literal">application/x-www-form-urlencoded</code>
or <code class="literal">multipart/form-data;
boundary=xxx</code>.
In the case of multipat form data,
<tt>content-type</tt> must specify the
boundary as well. By default, POST data is taken from
the request data.</div><div style="margin-bottom:6"> Default for
<tt>content_type</tt> is <code class="literal">application/x-www-form-urlencoded</code>.
Default for <tt>content_length</tt> is to read a
channel up to EOF or the full content of the variable.
</div><div style="margin-bottom:6">
Use the keyword <code class="literal">end</code> for
<tt>content_length</tt> to indicate that
Websh should read all content.</div><div style="margin-bottom:6">
Supported content types are:
<div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><div style="margin-bottom:6"><code class="literal">multipart/form-data; boundary=xxxx</code></div></li><li class="listitem"><div style="margin-bottom:6"><code class="literal">application/x-www-form-urlencoded</code> (default)</div></li></ul></div>
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-track</tt> <tt><em class="replaceable"><code>paramKeyList</code></em></tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Track a parameter: register it as "static"
for the generation of URLs with
<span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span>. Thus,
each parameter with the key in
<tt>paramKeyList</tt> will be repeated in
every URL generated with <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span>.
See the documentation of <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span> for
details.
</div></div></dd><dt><span style="background:#bbbbff"><span class="term"><tt>-hook</tt> <tt><em class="replaceable"><code>code</code></em></tt></span></span></dt><dd><div style="padding:4 ; margin-top:3 ; margin-bottom:3 ; width:75%"><div style="margin-bottom:6">
Causes <span style="font-family:monospace"><span class="command"><strong>web::dispatch</strong></span></span> to eval
<tt>code</tt>
just before the command (from any source) is
evaluated. When <tt>code</tt> is evaluated,
the full request information has been parsed. That
is, <span style="font-family:monospace"><span class="command"><strong>web::param</strong></span></span>,
<span style="font-family:monospace"><span class="command"><strong>web::formvar</strong></span></span> etc. will have up-to-date
information when <tt>code</tt> is evaluated.
</div></div></dd></dl></div><p style="width:90%">
<span class="emphasis"><em>Note</em></span>: If no command is passed to
<span style="font-family:monospace"><span class="command"><strong>web::dispatch</strong></span></span> either in the querystring or with the
<tt>-cmd</tt> option, <span style="font-family:monospace"><span class="command"><strong>web::dispatch</strong></span></span> will
call the command "default".
</p><div class="example"><a name="id2735716"></a><p class="title"><b>Example�5.�<span style="font-family:monospace"><span class="command">web::command</span></span> and <span style="font-family:monospace"><span class="command">web::dispatch</span></span></b></p><div class="example-contents"><pre style="background:#bbffbb ; width:75%" class="programlisting">
% set tst {puts "On the hook"}
puts "On the hook"
% web::command acmd {puts "this is acmd"}
% web::dispatch -cmd acmd -querystring "" -postdata ""
this is acmd
% web::dispatch -cmd acmd -querystring "" -postdata "" -hook $tst
On the hook
this is acmd
% set data "a=b&c=d"
a=b&c=d
% web::dispatch -cmd "" -querystring "" -postdata #data
% web::formvar a
b
% web::formvar c
d
% </pre></div></div><br class="example-break"></div><div class="section" title="Session management"><div class="titlepage"><div><div><h3 class="title"><a name="session_management"></a>Session management</h3></div></div></div><p style="width:90%">
Websh session management consits of two parts:
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><div style="margin-bottom:6">Session id tracking</div></li><li class="listitem"><div style="margin-bottom:6">Session context management</div></li></ul></div><p style="width:90%">
</p><p style="width:90%">
Session context managers are described in detail below
(<span style="font-family:monospace"><span class="command"><strong>web::filecontext</strong></span></span>,
<span style="font-family:monospace"><span class="command"><strong>web::cookiecontext</strong></span></span>). Session id tracking is
managed by <span style="font-family:monospace"><span class="command"><strong>web::dispatch -track</strong></span></span>. The two
parts are connected with the <tt>-attachto</tt> option
of the session context manager. The control is as follows:
</p><p style="width:90%">
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><div style="margin-bottom:6">
A user uses the Websh script for the first
time.<span style="font-family:monospace"><span class="command"><strong>web::dispatch -track</strong></span></span> will not
see any session id, and, consequently, not set the
static parameter <code class="literal">id</code>.
</div></li><li class="listitem"><div style="margin-bottom:6">
Within the application, the session is initialized using
<span style="font-family:monospace"><span class="command"><strong>mgr::init</strong></span></span>. <span style="font-family:monospace"><span class="command"><strong>init</strong></span></span>
will find no static parameter <code class="literal">id</code> (which has been specified at
creation time of the session manager using the
<tt>-attachto</tt> option). Now, it tries to
create a new session id. This will be possible if a
session id generator has been specified when the manager
was created using the <tt>-idgen</tt> option.
From now, on the session id will be a static parameter,
and will therefore be present in every URL generated
with <span style="font-family:monospace"><span class="command"><strong>web::cmdurl</strong></span></span>.
</div></li><li class="listitem"><div style="margin-bottom:6">
The next time the user visits the Websh application
using one of these URLs,
<span style="font-family:monospace"><span class="command"><strong>web::dispatch</strong></span></span> will detect the
session id, and <span style="font-family:monospace"><span class="command"><strong>mgr::init</strong></span></span> will directly load
the corresponding session context without generating a
new session id.
</div></li></ul></div><p style="width:90%">
</p><div class="example"><a name="id2735900"></a><p class="title"><b>Example�6.�Examples</b></p><div class="example-contents"><p style="width:90%">
See <a class="ulink" href="http://tcl.apache.org/websh/examples/" target="_top">http://tcl.apache.org/websh/examples/</a>
for several sample application demonstrating Websh's
session management facilities.
</p></div></div><br class="example-break"></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="configuration.html">Prev</a>�</td><td width="20%" align="center">�</td><td width="40%" align="right">�<a accesskey="n" href="request_data_handling.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Configuration�</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">�Request data handling</td></tr></table></div></body></html>