CODEWITHSUNDEEP
javascriptgoogle-chrometry-catch
Eric Phillips
Eric Phillips

Reputation: 920

Cannot catch Chrome's 'Cannot Load Local Resource' error in try/catch block

I am attempting to open a local folder by setting window.location.href to file://folder/, which I can do in IE, cannot in Chrome.

My goal is to catch whenever a browser blocks local file access so I can call some other code. Chrome's console is showing me 'Not allowed to load local resource:...' but I am not able to catch it with a try/catch block

Attempt: 

 function OpenLocalResource() {
   try {
     //Fails in Chrome (expected)
     window.location.href = 'file://folder/whatever/';
   } catch (err) {
     //Chrome gives script error 'Not allowed to load local resource:' 
     //I am expecting to hit this catch block but it does not 
     alert("Error hit!");
   }
 }

 OpenLocalResource();

How can I detect when a browser does not allow local resource access?

Upvotes: 5

Views: 1118

Answers (4)

Tschallacka
Tschallacka

Reputation: 28722

To see if it's allowed on chrome:

function OpenLocalResource($file) {
     var img = $('<img>');
     img.load(function() {
     	console.log(this)
     })
     img.error(function(err) {
        if(err.originalEvent.path[0].currentSrc.length == 0) {	
           console.log('localfile fail',$file)
        }
        else {
     	    console.log('regular http/image format fail',$file, err);
          
            // Add here an eventual other check for incase a file DID get loaded, but it's format failed or something.
            // Usually you can check via $file == err.originalEvent.path[0].currentSrc 
            //because chrome will turn C:\userlog.txt into file:///C:/userlog.txt 
            //whilst http:// image urls will remain the same.
        }
     })
     img.attr('src',$file);
     
 }

 OpenLocalResource('C:\\userdata.txt');
 OpenLocalResource('http://www.google.com');
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Upvotes: 0

tnt-rox
tnt-rox

Reputation: 5548

Use ajax to test if the file exists before using window.location. I don't believe it is possible to catch the error any other way, because the location is set even with an error, and the JavaScript handler is lost from scope. 

var xhr = new XMLHttpRequest();
xhr.open('GET', '/folder/whatever/myfile.html', true);
xhr.onreadystatechange = function () {
    if (xhr.readyState == 4) {
        if (xhr.status == 200) {
            window.location.href = '/folder/whatever/myfile.html';
        } else {
            alert("Error hit!");
        }
    }
};

Upvotes: 0

Bug
Bug

Reputation: 528

Try this, but you may need to point the image src to an actual image on the client.

function noLocalAccess() {
    alert('Error hit!');
}
function OpenLocalResource() {
    var myImage=new Image();
    myImage.onerror=new Function("noLocalAccess()");
    myImage.src='file:///c:/';

    window.location.href = 'file://folder/whatever/';
}
OpenLocalResource();

Upvotes: 0

Jannik Rasmussen
Jannik Rasmussen

Reputation: 397

It's a security setting, I don't think you can catch it. But you could start chrome using the cmd prompt and adding --allow-file-access.

Upvotes: 1

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