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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Examples and Usage</title><link rel="stylesheet" href="rivet.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.66.1"><link rel="start" href="index.en.html" title="Apache Rivet"><link rel="up" href="index.en.html" title="Apache Rivet"><link rel="prev" href="commands.en.html#id4764506" title="unescape_string"><link rel="next" href="tcl_packages.en.html" title="Rivet Tcl Packages"></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">Examples and Usage</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="commands.en.html#id4764506"><img src="images/prev.png" alt="Prev"></a></td><th width="60%" align="center"></th><td width="20%" align="right"><a accesskey="n" href="tcl_packages.en.html"><img src="images/next.png" alt="Next"></a></td></tr></table></div><div class="section" lang="en"><div class="titlepage"><div><div><hr><h2 class="title" style="clear: both"><a name="examples"></a>Examples and Usage</h2></div></div></div><p style="width:90%">
Some examples of Rivet usage follow. Some prior Tcl knowledge
is assumed. If you don't know much Tcl, don't worry, it's easy,
and there are some good resources available on the web that will
get you up to speed quickly. Go to the <a href="help.en.html#websites" title="Web Sites">web sites</a> section and have a look.
</p><div class="example"><a name="hello world"></a><p class="title"><b>Example1.Hello World</b></p><p style="width:90%">
As with any tool, it's always nice to see something work, so
let's create a small "Hello World" page.</p><p style="width:90%">
Assuming you have Apache configured correctly, create a file
called <tt class="filename">hello.rvt</tt> where Apache can find
it, with the following content:
</p><pre style="background:#bbffbb ; width:90ex ; margin: 2ex ; padding: 1ex; border: solid black 1px ; white-space: pre; font-family:monospace ; " class="programlisting"><?
puts "Hello World"
?>
</pre><p style="width:90%">
If you then access it with your browser, you should see a
blank page with the text "Hello World" (without the quotes) on
it.
</p></div><div class="example"><a name="table"></a><p class="title"><b>Example2.Generate a Table</b></p><p style="width:90%">
In another simple example, we dynamically generate a table:
</p><pre style="background:#bbffbb ; width:90ex ; margin: 2ex ; padding: 1ex; border: solid black 1px ; white-space: pre; font-family:monospace ; " class="programlisting"><? puts "<table>\n"
for {set i 1} { $i <= 8 } {incr i} {
puts "<tr>\n"
for {set j 1} {$j <= 8} {incr j} {
set num [ expr $i * $j * 4 - 1]
puts [ format "<td bgcolor=\"%02x%02x%02x\" > $num $num $num </td>\n" \
$num $num $num ]
}
puts "</tr>\n"
}
puts "</table>\n" ?>
</pre><p style="width:90%">
If you read the code, you can see that this is pure Tcl. We
could take the same code, run it outside of Rivet, and it
would generate the same HTML!
</p><p style="width:90%">
The result should look something like this:
</p><div><img src="table.png"></div></div><div class="example"><a name="variable_access"></a><p class="title"><b>Example3.Variable Access</b></p><p style="width:90%">
Here, we demonstrate how to access variables set by GET or
POST operations.
</p><p style="width:90%">
Given an HTML form like the following:
</p><pre style="background:#bbffbb ; width:90ex ; margin: 2ex ; padding: 1ex; border: solid black 1px ; white-space: pre; font-family:monospace ; " class="programlisting"> <form action="vars.rvt">
<table>
<tbody>
<tr>
<td><b>Title:</b></td>
<td><input name="title"></td>
</tr>
<tr>
<td><b>Salary:</b></td>
<td><input name="salary"></td>
</tr>
<tr>
<td><b>Boss:</b></td>
<td><input name="boss"></td></tr>
<tr>
<td><b>Skills:</b></td>
<td>
<select name="skills" multiple="multiple">
<option>c</option>
<option>java</option>
<option>Tcl</option>
<option>Perl</option>
</select>
</td>
</tr>
<tr>
<td><input type="submit"></td>
</tr>
</tbody>
</table>
</form>
</pre><p style="width:90%">
We can use this Rivet script to get the variable values:
</p><pre style="background:#bbffbb ; width:90ex ; margin: 2ex ; padding: 1ex; border: solid black 1px ; white-space: pre; font-family:monospace ; " class="programlisting"><?
set errlist {}
if { [var exists title] } {
set title [var get title]
} else {
set errlist "You need to enter a title"
}
if { [var exists salary] } {
set salary [var get salary]
if { ! [string is digit $salary] } {
lappend errlist "Salary must be a number"
}
} else {
lappend errlist "You need to enter a salary"
}
if { [var exists boss] } {
set boss [var get boss]
} else {
set boss "Mr. Burns"
}
if { [var exists skills] } {
set skills [var list skills]
} else {
lappend errlist "You need to enter some skills"
}
if { [llength $errlist] != 0 } {
foreach err $errlist {
puts "<b> $err </b>"
}
} else {
puts "Thanks for the information!"
?>
<table>
<tbody>
<tr>
<td><b>Title:</b></td>
<td><? puts $title ?></td>
</tr>
<tr>
<td><b>Boss:</b></td>
<td><? puts $boss ?></td>
</tr>
<tr>
<td><b>Salary:</b></td>
<td><? puts $salary ?></td>
</tr>
<tr>
<td><b>Skills:</b></td>
<td><? puts $skills ?></td>
</tr>
</tbody>
</table>
<?
}
?>
</pre><p style="width:90%">
The first statement checks to make sure that the
<tt class="varname">boss</tt> variable has been passed to the
script, and then does something with that information. If
it's not present, an error is added to the list of errors.
</p><p style="width:90%">
In the second block of code, the variable
<tt class="varname">salary</tt> is fetched, with one more error
check - because it's a number, it needs to be composed of
digits.
</p><p style="width:90%">
The <tt class="varname">boss</tt> variable isn't required to have
been sent - we set it to "Mr. Burns" if it isn't among the
information we received.
</p><p style="width:90%">
The last bit of variable handing code is a bit trickier.
Because <tt class="varname">skills</tt> is a listbox, and can
potentially have multiple values, we opt to receive them as a
list, so that at some point, we could iterate over them.
</p><p style="width:90%">
The script then checks to make sure that
<tt class="varname">errlist</tt> is empty and outputting a thankyou
message. If <tt class="varname">errlist</tt> is not empty, the list
of errors it contains is printed.
</p></div><div class="example"><a name="upload"></a><p class="title"><b>Example4.File Upload</b></p><p style="width:90%">
The following HTML in one file, say,
<tt class="filename">upload.html</tt>
</p><pre style="background:#bbffbb ; width:90ex ; margin: 2ex ; padding: 1ex; border: solid black 1px ; white-space: pre; font-family:monospace ; " class="programlisting"><form action="foo.rvt" enctype="multipart/form-data" method="post">
<input type="file" name="MyUpload"></input>
<input type="submit" value="Send File"></input>
</form>
</pre><p style="width:90%">
Can be used with the following Tcl code, in a second file
(<tt class="filename">upload.rvt</tt> for instance)
in order to create a file upload form.
</p><pre style="background:#bbffbb ; width:90ex ; margin: 2ex ; padding: 1ex; border: solid black 1px ; white-space: pre; font-family:monospace ; " class="programlisting"><?
upload save MyUpload /tmp/uploadfiles/file1
puts "Saved file [upload filename MyUpload] \
([upload size MyUpload] bytes) to server"
?></pre></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="commands.en.html#id4764506"><img src="images/prev.png" alt="Prev"></a></td><td width="20%" align="center"><a accesskey="u" href="index.en.html"><img src="images/up.png" alt="Up"></a></td><td width="40%" align="right"><a accesskey="n" href="tcl_packages.en.html"><img src="images/next.png" alt="Next"></a></td></tr><tr><td width="40%" align="left" valign="top">unescape_string</td><td width="20%" align="center"><a accesskey="h" href="index.en.html"><img src="images/home.png" alt="Home"></a></td><td width="40%" align="right" valign="top">Rivet Tcl Packages</td></tr></table></div></body></html>
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