HTML5 File API simple check if file exists

Question

I have a temporary File API store (HTML5) but I can't check whether a file exists or not. Is there a simple way to check it? Do I have to actually try and read the file to find out?

A search around has yielded me nothing concrete

A synchronous check would be nice is this possible?

Rob W · Accepted Answer · 2012-05-06 15:56:26Z

7

You have to read the file. The following example is based on this demo from HTML5Rocks (it catches all errors, you might want to filter the different error types):

    var errorHandler = function() {
        // File is not readable or does not exist!
    };
    fs.root.getFile('log.txt', {}, function(fileEntry) {
        fileEntry.file(function(file) {
            var reader = new FileReader();
            reader.onloadend = function() {
                // The file exists and is readable
            };
            reader.readAsText(file);
        }, errorHandler);
    }, errorHandler);

The synchronous method is only available to Web Workers, due to their blocking nature. The error handling is slightly different.

answered May 6, 2012 at 15:56

Rob W

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1 Comment

jedi Over a year ago

on the errorHandler i recive only the error... but i want download the file if doesn't exist

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