Error dialog of ajax viewer should be refined

[christinebao]

Report from Autodesk QA:

1. Use Studio to create an ajax viewer, at least one of its layer should be selectable. Uncheck the option of "Keep connection alive".
   
2. Open the ajax viewer in browser.
   
3. Select one feature in the viewer.
   
4. waiting for timeout.
   
5. Click the ajax viewer to select another feature.

Result:

1. If in IE, there is an error dialog pops up saying: "<?x".
   
2. If in Firefox, there is an error dialog pops up saying: "No ".
   

Please see the attached screen shots.

[christinebao]

Error message box from IE:

Error message box from Firefox:

[christinebao]

[Tech assessment]

This defect is caused by r4402 ajaxmappane.templ, which is introduced by ticket ​http://trac.osgeo.org/mapguide/ticket/1195 (Implement RFC 87 - SiteInformation enhancements)

Take IE for example, when the exception happens, function OnSelectionOverlayImageLoadedError(e) is triggered.

function OnSelectionOverlayImageLoadedError(e)
{
    var text = this.req.responseText;
    
    var startPos = text.indexOf("<h2>");
    startPos = startPos + 4;
    var endPos = text.indexOf("</h2>", startPos);
    var message = text.substring(startPos, endPos);
    alert(message);

    return false;
}

In the above scenario, text is the following content:

<?xml version="1.0" encoding="UTF-8"?>
<FeatureInformation>
<FeatureSet xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="FeatureSet-1.0.0.xsd"></FeatureSet><Tooltip />
<Hyperlink />
</FeatureInformation>

As you can see, there is no <h2>...</h2> in text, so the message content parsed is meaningless. The result is message = "<?x".

Take Firefox for example, it calls function QueryFeatureInfo(geom, append, maxfeatures, which) is triggered.

function QueryFeatureInfo(geom, append, maxfeatures, which)
{    ...

    if(selRequest.responseXML)
    {
        ProcessFeatureInfo(selRequest.responseXML.documentElement, append, which);
    }
    else
        RequestFailed("No response");
}

Please note the last line RequestFailed("No response"). The function RequestFailed(text) is this:

function RequestFailed(text)
{
    var startPos = text.indexOf("<h2>");
    startPos = startPos + 4;
    var endPos = text.indexOf("</h2>", startPos);
    var message = text.substring(startPos, endPos);    
    alert(message);
}

There are two problems here:

1. QueryFeatureInfo should pass selRequest.responseText because it contains the exception message. It should not always pass the hard coded string "No response".
   
2. RequestFailed() should check whether the text contains <h2>...</h2>. In this case, the message is meaningless.

[christinebao]

Attach patch ​http://trac.osgeo.org/mapguide/attachment/ticket/1237/RefineAjaxErrorMsg.patch for fixing this.

[christinebao]

Hi Bruce,

Would you please review this patch? Thank you.

I have a question about function OnSelectionOverlayImageLoadedError(e). It's used in function RequestSelectionImage(reqId, viewParams), the code is:

   url = webAgent + "?OPERATION=GETDYNAMICMAPOVERLAYIMAGE&FORMAT=PNG&VERSION=2.1.0&SESSION=" + sessionId + "&MAPNAME=" + encodeComponent(mapName) + "&SEQ=" + Math.random() + "&CLIENTAGENT=" + encodeComponent(clientAgent) + "&BEHAVIOR=5&SELECTIONCOLOR=" + selectionColor;
    url += viewParams;
    document.getElementById('selOverlay').innerHTML =
        '<img class="mapImage" name="' + reqId + '" id="selectionImage" src="' + url + '" width=' + mapDevW + ' height=' + mapDevH + ' border=0 vspace=0 hspace=0 style="visibility: hidden; width: ' + mapDevW + 'px; height: ' + mapDevH + 'px;" onload="return OnSelectionOverlayImageLoaded(event)" onerror="return OnSelectionOverlayImageLoadedError(event)">';

It seems that if error happens during GETDYNAMICMAPOVERLAYIMAGE request, OnSelectionOverlayImageLoadedError(e) will be triggered. However the response text is not as expceted. I use a hard coded information "No feature available." temporiraly. Is there any better way to really get the exception message?

Thanks & regards,
Christine

[brucedechant]

Christine,

Patch looks good. Unfortunately, given the response returned you don't have much choice but to create the temporary string.

Thanks, Bruce

[christinebao]

Submit r4518 to sandbox/adsk/2.2gp.

Submit r4519 to trunk/MgDev.