Implemented: Flag for edit script to avoid overwrite of existing topic text and form data

This pages describes a workaround for accidential overwriting of Form data when using HTML forms to create new topics

1 Problem

If you use a HTML form to associate a TWiki Form with a TWiki template (as described in TWiki Topic templates in Action) you will without warning overwrite existing TWiki Form data, if you accidentially enter an exiting Topic name.

See TWikiTemplates#TemplateTopicOverwritingExisting for HansruediHaenni original problem describtion.

2 Quick patch

2.1 Idea

Add CGI parameter to TWiki edit script, making it possible to abandon edit, if topic exists.

2.2 The patch

2.2.a Patch .../twiki/bin/edit script

Locate the edit script.

Right after the text:

    if( ! &TWiki::Store::webExists( $webName ) ) {
        my $url = &TWiki::getOopsUrl( $webName, $topic, "oopsnoweb" );
        TWiki::redirect( $query, $url );
        return;
    }

You add:

    # Prevent editing existing topic?
    if($query->param( 'onlynewtopic' ) && &TWiki::Store::topicExists( $webName, $topic ))
    {
       # Topic exists and user requested oops if it exists
       my $url = &TWiki::getOopsUrl( $webName, $topic, "oopscreatenewtopic" );
       print $query->redirect( $url );
       return;       
    }    

2.2.b Create new oops template

In your .../twiki/templates directory create a template file called oopscreatenewtopic.tmpl with the following content:

%TMPL:INCLUDE{"twiki"}%
%TMPL:DEF{"titleaction"}%(oops, topic exists)%TMPL:END%
%TMPL:DEF{"webaction"}% *Attention* %TMPL:END%
%TMPL:DEF{"heading"}%The "%TOPIC%" topic already exists%TMPL:END%
%TMPL:DEF{"message"}%
  Cannot create %TOPIC% because it already exists.

  Please go _back_ in browser and try a new name %TMPL:END%
%TMPL:DEF{"topicaction"}% %TMPL:END%

3 Then the workaround becomes...

Instead of writing

<form name="new" action="%SCRIPTURLPATH%/edit%SCRIPTSUFFIX%/%INTURLENCODE{"%WEB%"}%/">
   * New example topic: 
     <input type="text" name="topic" value="ExampleTopic%SERVERTIME{$yearx$mox$day}%" size="23" />
     <input type="hidden" name="templatetopic" value="ExampleTopicTemplate" />
     <input type="hidden" name="topicparent" value="%TOPIC%" />
     <input type="hidden" name="onlywikiname" value="on" />
     <input type="submit" value="Create" />
     (date format is <nop>YYYYxMMxDD)
</form>

as described in TWiki Topic templates in Action write:

<form name="new" action="%SCRIPTURLPATH%/edit%SCRIPTSUFFIX%/%INTURLENCODE{"%WEB%"}%/">
   * New example topic: 
     <input type="text" name="topic" value="ExampleTopic%SERVERTIME{$yearx$mox$day}%" size="23" />
     <input type="hidden" name="templatetopic" value="ExampleTopicTemplate" />
     <input type="hidden" name="topicparent" value="%TOPIC%" />
     <input type="hidden" name="onlywikiname" value="on" />
     <input type="hidden" name="onlynewtopic" value="on" />
     <input type="submit" value="Create" />
     (date format is <nop>YYYYxMMxDD)
</form>

Now you will get an error, if you try to create an already existing topic

Contributors:
-- NielsKoldso - 30 Dec 2003
-- PeterThoeny - 31 Dec 2003

Discussions

Thanks Niels for the patch. Good idea, can be taken into the core code. Changes I did:

• Moved the topic from the TWiki web to the Codev web
• Changed the name of the flag from existsoops to onlynewtopic to make it consistent with the onlywikiname flag name
• Renamed oopstopicexists2.tmpl to oopsonlynewtopic.tmpl

-- PeterThoeny - 31 Dec 2003

This is now in TWikiAlphaRelease and TWiki.org.

-- PeterThoeny - 31 Dec 2003