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Calculated tv using EVAL

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    • 51 Posts
    andyflan Reply #1, 17 years, 11 months ago
    I want to create a calculated template variable using EVAL. I’m going to use this for a ditto sort. My EVAL needs to look at field (a), see if it has a value and return that value if it does. If it doesn’t it looks at field b and returns that value instead. I want to place my EVAL in the ’Default’ field of the tv. The user will never edit this value.

    If I enter the following in the default field:
    @EVAL return 'test';


    Then I see this in the tv when editing a document:
    @EVAL return 'test';


    When I expect to see this:
    test


    We’re running 0.9.6.2

    Thank you in advance modx chums
      Hmmmmm.

      It's all a delusion
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      opengeek Reply #2, 17 years, 11 months ago
      @EVAL is calculated at runtime, i.e. when the page is rendered in the front-end.  It does not get executed when editing a document.
        Jason Coward
        Chief Architect @ MODX
        http://www.jasoncoward.com | http://twitter.com/drumshaman | https://github.com/opengeek
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        andyflan Reply #3, 17 years, 11 months ago
        Ah ha,

        Well that would certainly explain it. Thanks as ever opengeek wink
          Hmmmmm.

          It's all a delusion
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          agilero Reply #4, 17 years, 10 months ago
          Just shout if I’m wrong but what OpenGeek said goes for the content of a tv only. When you use @EVAL in the input options of a tv, for example, it is evaluated when the backend is rendered.
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            dev_cw Reply #5, 17 years, 10 months ago
            Quote from: agilero at Dec 18, 2008, 02:20 PM

            Just shout if I’m wrong but what OpenGeek said goes for the content of a tv only. When you use @EVAL in the input options of a tv, for example, it is evaluated when the backend is rendered.
            Correct, you can render input in certain TV types with EVAL binding. For example populate a drop down menu with chunk names.
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              2frags Reply #6, 17 years, 9 months ago
              @EVAL is calculated at runtime, i.e. when the page is rendered in the front-end. It does not get executed when editing a document
              OpenGeek, thanks for explanation!
              Bad news for me.
              I spended 3days for nothing((
              I need to execute some snippet from TV after backend edit.
              Any possibilities to do this?
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                Everett Reply #7, 17 years, 9 months ago
                If you need to run PHP code after an edit, you probably need to write a Plugin. Snippets are triggered when a page loads (on the front-end), whereas a Plugin is triggered by a system event (such as editing a page).
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                  2frags Reply #8, 17 years, 9 months ago
                  Thanks, Everett!
                  Plugin - new word for me wink
                  I tried  to set parent`s Pagetitle into TV of cildren docs automatically:
                  TV "city"
                  @EVAL $params['tvname'] = 'parent'; return $modx->runSnippet('parentTV', $params);

                  Snippet "parentTV"
                  $params['tvname'] = 'parent'; 
//get parent`s Pagetitle
$parent = $modx->getParent($id=-1,1,pagetitle);
$value = ($parent[pagetitle]);
$docID = ($modx->documentIdentifier);
//---write TV values to DB
if (!function_exists('setTemplateVar')) {
  function setTemplateVar($value, $docID, $tplVarName) {
    global $modx;
    //-- get tmplvar id
$tplName = $modx->getFullTableName('site_tmplvars');
$tplRS = $modx->db->select('id', $tplName, 'name="' . $tplVarName . '"');
$tplRow = $modx->db->getRow($tplRS);

    $tblName = $modx->getFullTableName('site_tmplvar_contentvalues');
    $selectQuery = $modx->db->select("*", $tblName, 'contentid=' . $docID . ' AND tmplvarid=' . $tplRow);
    $updFields = array ( 'value' => $value );
    $insFields = array (
    'tmplvarid' => $tplRow,
    'contentid' => $docID,
    'value' => $value );
    if ($modx->db->getRecordCount($selectQuery) < 1) {
      $modx->db->insert($insFields, $tblName);
    } else { 
    $modx->db->update($updFields, $tblName, 'contentid=' . $docID . ' AND tmplvarid=' . $tplRow);
    }
  }
}
@ setTemplateVar($value, $docID, $tplVarName);

                  It writes TV value into DB.
                  But it`s happening only after opening page with this TV from frontend - damn @EVAL!

                  And now..
                  i have no idea how to connect Plugin and TV together.
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                    Everett Reply #9, 17 years, 9 months ago
                    When exactly do you want your script to be run? Do you want this value calculated when a manager edits a page?

                    If I understand you correctly, you have 2 fields in your templates, let’s say a and b. Your plugin could read the values, then choose which one to output. The event that would trigger its execution would be when someone edits a document... I’m not sure exactly which one to use, but login to the control panel --> Resources --> Manage Resources --> Plugin, then choose to create a new Plugin and look at its "System Events" tab. There you get a list of all system events. The following caught my eye under the "Documents" section:

                    • OnDocFormPrerender
                    • OnDocFormRender

                    Here’s one example of how to read a document’s page title:
                    $doc = $modx->getDocument(1);
echo $doc[‘pagetitle’];


                    You can probably use the document object api to put values back into a document before it renders. Does that make sense.

                    There isn’t much documentation on Plugins sad but here’s the official page:
                    http://modxcms.com/plugin-examples.html

                    You might learn more by looking at the Document Object: http://modxcms.com/the-document-object.html

                    The one thing I’m not seeing is how to access template variables using the document api... I know how to get them using a sql query, but that’s sort of a pain.

                    Hope this gets you started.
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                      Everett Reply #10, 17 years, 9 months ago
                      Ok, I found the template variable stuff. You can read template variables using the getTemplateVar method:
                      http://modxcms.com/gettemplatevar.html
                      http://modxcms.com/gettemplatevars.html
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