Amazon File upload - stop if duplicate file

[monit]

I have an issue with the Amazon File upload that I've been struggling with for 2 days.

In the After File Select, I have an Xbasic callback to check if a file exists in the database and this works. I then set a state variable (have also tried a control), and based on the variable or control decide whether to continue or not.

It all works, but the timing is off somewhere such that it can't read the variable or control until after the callback and by then it's already completed the upload which I want to abort by using "return false", but it uploads anyway.

I have tried using timeouts and moving things around but nothing has yet worked for me.

Please help. Can post my (mostly) working code if needed.

[monit]

I'm attaching my current code in case someone is able to suggest anything.

portion of Xbasic code to set the control or state variable (this works):

    countfiles=p.rs.data(1)
    if countfiles>0 then
        e._state.canUpload="no"
        e._set.upload.value="no"
         dim js as c =<<%js%
        var obj = {};
        obj['canUpload'] = 'no';        
        {dialog.object}.setStateInfo(obj);
        %js%
    else
        e._state.canUpload="yes"
        e._set.upload.value="yes"
         dim js as c =<<%js%
        var obj = {};
        obj['canUpload'] = 'yes';        
        {dialog.object}.setStateInfo(obj);
        %js%
    end if

checkDuplicates=js​

current Javascript in the "After File Select" of the S3 Upload Action:

{dialog.object}.setValue('upload','');

for(var i=0; i < e.length; i++) {
    //check for invalid characters
    var match = (new RegExp('[<>:*"?&#%(){}+\\\/\|]|\\.\\.|^\\.|\\.$')).test(e[i]["name"]);
    if (match) {
        {dialog.object}.setValue('upload','no');
        var title = 'Invalid Filename';
        var html = '<p style="padding:10px;text-align:center;">Invalid file name. The name of the attached file (<b>'+e[i]["name"]+'</b>) contains invalid characters. <br><br>Please rename your file without special characters before attaching.</p>'
        var type = 'o';
        var onClose = function (btn) {};
        A5.msgBox.show(title, html, type,onClose);
        return false;
    }

    //check for duplicate filenames
    var network={dialog.object}.getSessionVariable('Network');
    var addData ='_shortname='+e[i]["name"]+
    '&_network='+network;
           {dialog.Object}.ajaxCallback('','','checkDuplicates','',addData);
           thisFilename=e[i]["name"];    

    //wait for callback to complete and get updated value of upload control
    canUpload={dialog.object}.getValue('upload');
    if(canUpload=="no"){
        var title = 'Duplicate Found';
        var html = '<p style="padding:10px;text-align:center;">A file with the name '+ thisFilename+' already exists.<br><br>Please Delete or Update instead.</p>'
        var type = 'o';
        var onClose = function (btn) {};
        A5.msgBox.show(title, html, type,onClose);
        return false;
    }          



}​

The filename invalid characters works like a charm.
The Ajax callback works, but it checks the "canUpload" value before it completes the callback. I have tried wrapping things in a setTimeout, putting the checks in the OnComplete portion of the Ajax Callback, and many other options, but I have not been able to get it to correctly get the value returned from the callback, which means it will ALWAYS continue to upload a file even though I've checked and marked it as a duplicate.

Very, very frustrating!

[Ted Giles]

Silly question.
Why are you uploading dupe named files anyway?
Any reason you cannot tag a file when it is uploaded and check at the source?
Else, try splitting the process into 2.

[madtowng]

My guess he’s trying to prevent end users from uploading duplicate files.

[Ted Giles]

Yep, my guess too but he hasn't said that as yet.
What constitutes a duplicate? Not just a file name IMHO.
Something like "if exists, rename +1" on upload ?

Not sure we know enough about the process. We'll me, anyway.

What about "object cancel" if there is a dupe?

[madtowng]

we can’t see all his code, but based on what we can see it looks like he’s doing a query that is likely to involve the file name; and if he gets any number of rows greater than 0, it’s considered a duplicate.

[monit]

Yes the last is the correct guess. I'm trying
to prevent users uploading a file with an existing name because by default, it will overwrite the file already in S3 and, in this case, add a new entry to the database. If they need to replace an existing file with a newer version, I'll need them to specifically update the file and maintain the same reference in the database. Links to files are used in other parts of the system so it needs to be maintained.

From what I can work out, there is no other place I can check what filename the user has selected until the After File Select occurs so I have to do the comparison there.

There is also no other place to cancel the upload after the file has been selected except for in that same section, because the next process is the On Progress event.

If I could check the database in JavaScript without doing an Ajax callback, I believe it would work ok. It's just the waiting for the callback that seems to mess with the timing.

Ted's suggestion to rename if exists wouldn't work either, because I'd have to wait for an Ajax callback to see if the filename exists, which is what I'm already doing. The JavaScript continues before the callback has finished, which is the exact same problem I'm having. And I don't want to rename it for reasons I mentioned above, just abort it and give them a message.

[madtowng]

You can , but it depends on how many items you have in your database.
Until I get the IAM user policy stuff figured out for my Wasabi account, I'm making creative guesses.

Have you considered a 2-step (one step to the user), where you get the filename(s) first, then if they are not duplicates,
process the upload procedure ?

[monit]

Have you considered a 2-step (one step to the user), where you get the filename(s) first, then if they are not duplicates,
process the upload procedure ?

I'm not even sure where to begin making it a 2-step process.

The Upload to S3 action is an all-in-one so by your suggestion, I could only see doing this 2 times - once to select the file to upload, store it somewhere and check it, then doing it again to continue uploading or remove the temporary stored file?

[madtowng]

I would do the file check when the user submits the file name,.
proceed with the upload if the file is not a duplicate .

[monit]

I understand the process you're suggesting. Not sure how to execute.

How do I get the user to submit a file name, and then process that file if it's not a duplicate?

[madtowng]

I would run the ajax callback, setting a state variable to either proceed or halt. In the javascript action, i would configure before select to return false if that state variable == halt.

[madtowng]

you can do this all in the javascript action, be sure to check the run synchronous box.

[monit]

I would run the ajax callback, setting a state variable to either proceed or halt. In the javascript action, i would configure before select to return false if that state variable == halt.

You're suggesting in the Upload to Amazon S3 action that in the Before File Select event I return false based on whether it's a duplicate or not? If that's the case, I don't have access to the filename until the After File Select event.

In the Javascript action, there is only one action - File Upload - Amazon S3 Storage. It contains the Before File Select and After File Select javascript options. Unless you mean create another Action javascript insde the After File Select event, that does things in order - I'll try that.

[madtowng]

I hope this helps.

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