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Search Pattern Cookbook

The Search function in TWiki is very powerful. Especially searches using a RegularExpression play an important part of tapping TWiki's full potential. Unfortunately RegularExpressions can be incredibly obscure to the uninitiated.

Most people not familiar (enough) with Regular Expressions mostly cut and paste (and maybe tweak) from existing examples. This page intends to collect lots of examples together.

Pattern 1: Extract values from a table

Problem definition

Suppose there is a topic with a table defining entries in a TWikiForm. I.e. they define select menu items in a form template. They are then formatted like:

| *Name* | *Type* | *Tooltip message* |
| option1 | option | |
| option2 | option | |
| option3 | option | |

How to extract the 'name' values, i.e. 'option1', 'option2' and 'option3' and put them in a HTML form select input?

Solution

The following search pattern can be employed:

<form>
<select>
%SEARCH{ "^\|[^\|]*\| *option *\|" topic="%TOPIC%" regex="on" multiple="on" nosearch="on" nototal="on" format="<option>$pattern(^\| *(.*?) *\|.*)</option>" }%
</select>
</form>

which is, in effect:

Pattern 2: List generated from form classification

Problem

Imagine a TWiki form-based topic classification, i.e. every page has a form with several fields. How to:

create a search to display all topics where one form field is set to a certain value
create a search to filter the list above based on the values of a second form field

Test case

In practice:
Image a TWiki form with two fields:

TopicClassification = One, Two or Three
TopicStatus = Test or Final

We will:

List all topics where the TopicClassification field is set to 'Two'
Enable the user to filter this list based on the values of TopicStatus

Solution

%SEARCH{"[T]opicClassification.*value\=.*Two;[T]opicStatus.*value\=.*%URLPARAM{type}%"
regex="on" casesensitive="on" nosearch="on" 
format="   * $topic - <font face=\"arial,helvetica\" size=\"1\"> 
_last modified by_ $wikiusername _on_ $date </font> %BR% &nbsp;&nbsp;&nbsp; 
<font face=\"arial,helvetica\" size=\"1\"> $formfield(TopicStatus) </font>" 
sort="topic"}%

The filtering select dialogue is created as in Pattern 1:

%STARTSIDEBAR%
*Filter:* %BR%
<form name="selectType" action="%SCRIPTURLPATH{"view"}%/%WEB%/" >
<select name="type" size="1" onchange="document.location=this.value;"> 
%SEARCH{ "^\|[^\|]*\| *option *\|" topic="TopicClassification" web="%WEB%" regex="on" 
multiple="on" nosearch="on" nototal="on" format="<option value=%INCLUDINGTOPIC%?type=$pattern(^\| *(.*?) *\|.*)>$pattern(^\| *(.*?) *\|.*)</option>" }% 
<option value=%INCLUDINGTOPIC%>All pages</option> </select>
</form>
%STOPSIDEBAR%

This will create similar functionality as TWiki:Plugins.TopicClassificationAddOn

Pattern 3a: listbox with all user names

Problem

How to populate a list box with all usernames of registered TWiki users

Solution

<form name="testing" action="%SCRIPTURLPATH{"view"}%/%MAINWEB%" method="get">
<select name="topic">
<option>Select user...</option>
%SEARCH{ "Name:;Email:;Country:" web="%MAINWEB%" type="regex" nosearch="on" nototal="on" format="<option>$topic</option>" }%
</select>
<input type="submit" value="Go" />
</form>

Which expands to this: (here limited to all Z* users because TWiki.org has so many)

This searches all topics in the Main web that contain "Name", "Email" and "Country" bullets. Alternatively, do a FormattedSearch with multiple="on" on the Main.TWikiUsers topic.

Pattern 3b: listbox with all user names - select multiple names

Problem

Suppose you want to send mail from a form on topic page to a selected list of multiple TWikiUsers

Solution

The example of Pattern 3a produces the list box. Add a MULTIPLE to the select statement, i.e.:

<select name="topic" size="2" MULTIPLE>

Please note that the Search pattern is unchanged compared to Pattern 3a. The change is in the HTML form element.

Test case

The Search pattern 3a with the abovementioned modification is, in effect:

Pattern 4: Extract the parent of a given topic

Problem

How to get to the parent of the current topic to display on the page?

Solution

You might think that the following Search would do the trick:

%SEARCH{ "^%BASETOPIC%$" scope="topic" nosearch="on" type="regex" nototal="on" format="[[$parent][parent_link]]" }%

However, the [[$parent][parent_link]] link fails if the topic has no parent set ($parent will be empty). You can use some SpreadSheetPlugin^? magic to conditionally link to the parent or to WebHome: [[$percntCALC{$IF($EXACT($parent,), %HOMETOPIC%, $parent)}$percnt][parent_link]]

So the total Search query to find a topic's parent topic is:

%SEARCH{ "^%BASETOPIC%$" scope="topic" nosearch="on" type="regex" nototal="on" format="[<nop>[$percntCALC{$IF($EXACT($parent,), <nop>%HOMETOPIC%, $parent)}$percnt][parent_link]]" }%

Test Case

The parent topic of this topic is: WebHome

Pattern 5: Search and display the home topics of public webs in a list

Problem

How to find and display public webs in a drop down list box.

Solution

Thanks to TWiki:Main.PeterThoeny for these solutions.

<form>
<select name="topic">
<option value="%TOPIC%">Select...</option>
%SEARCH{ "%HOMETOPIC%" scope="topic" web="all" topic="%HOMETOPIC%" format="<option value=\"$web.$topic\">$web</option>" separator=" " }%
</select>
<input type="submit"  value="Go" />
</form>

Test case

Public webs of TWiki.

For private webs, or any other webs you wish to exclude from the display, use "on" for the Exclude web from a web="all" search setting in the relevant web's WebPreferences topic.

Alternative solution

This result can also be accomplished with the %WEBLIST% variable.

Pattern 6: Extract a value from a bullet list

Problem

Display the user name in the user's topic title

Solution

Search for the Name: entry.

%SEARCH{"   * [N]ame: " topic="%TOPIC%" regex="on" casesensitive="on" nosummary="on" nosearch="on" noheader="on" nototal="on" format="---+!! $pattern(.*   \* Name: ([^\n]*).*)"}%

Test case

To create a test case, we will put a name entry here:

Name: John Doe

Search result:

John Doe

Pattern 7: Search for Form and Meta data: explained

Problem

Below is an example of a search that searches form data. The questions are:

why is this searching the metadata, shouldn't it just search the text?
what is the meaning of the td..td in the search expression?

%SEARCH{ "[S]tatus.*(td..td|value\=).*[W]aiting" casesensitive="on" regex="on" 
nosearch="on" nototal="on" format="| [[$topic]]<br /> ($date - $rev - 
[[%SCRIPTURLPATH{rdiff}%/$web/$topic][Diffs]]) |"}%

Solution

%SEARCH depends on grep, and grep searches the whole file, including the meta data.

An example meta data form field is:

%META:FIELD{name="OperatingSystem" title="OperatingSystem" value="OsWin"}%

So a search for a form field could look like:

%SEARCH{ "[O]peratingSystem.*value\=.*[O]sWin" regex="on" ... }%

Using square brackets is a trick to avoid a hit on the topic doing the search.
The .* indicate that there can be any number of any character between OperatingSystem and value in the (whole) file

Now the original file format of the category table (the predecessor of the TWiki forms) looks like this:

<td valign="top" align="right"> OperatingSystem:  </td><td>  OsWin </td>

The following search finds topics in the old and new format:

%SEARCH{ "[O]peratingSystem.*(td..td|value\=).*[O]sWin" regex="on" ... }%

The td..td matches td<>td; a simple search on "[O]peratingSystem.*[O]sWin" could find a hit in the topic text by coincidence.

A simple %SEARCH{ "[O]peratingSystem.*value\=.*[O]sWin" ...}% search is sufficient if you do not have topics in the old format.

Pattern 8: Search all topics that have been moved

Problem

How would I go about listing all moved topics ?

Solution

Search for the META:TOPICMOVED meta data. Type this:

Moved topics: %SEARCH{ "%META\:TOPICMOVED" regex="on" format="$topic, " nosearch="on" noheader="on" nosummary="on" }%

to get this (limited to 10 results):

Moved topics: AppendixFileSystem, NatSkinTemplates, SiteUsageStatistics, TWikiUpgradeTo01Dec2001, TWikiUpgradeTo01Feb2003, TagMeDebugSearch, TagMeSearch,

Number of topics: 7

Contributors

TWiki:Main.AntonAylward, TWiki:Main.ArthurClemens, TWiki:Main.JosMaccabiani, TWiki:Main.PeterThoeny, TWiki:Main.SueLocke

Related Topics: UserDocumentationCategory

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