Module: Get Protocol Handlers

Summary

• Objective: Identify protocol handlers supported in a browser

• Authors: bcoles

• Browsers: Firefox, IE

• Code

Internal Working

This module launches invisible iframes to attempt to load a resource with different protocols schemes, then detects if they load or not to determine availability of a protocol handler.

Firefox users are prompted to launch the application for which the protocol handler is responsible. (if applicable)

Firefox users are warned when there is no application assigned to a protocol handler. (in the js console of the browser)

The possible return values are: unknown, exists, does not exist.

//implementation for firefox

var protocol_iframe = document.createElement('iframe');
protocol_iframe.setAttribute('id', "protocol_iframe_<%= @command_id %>");
protocol_iframe.setAttribute('src', "");
protocol_iframe.setAttribute('style', "display:none;height:1px;width:1px;border:none");
document.body.appendChild(protocol_iframe);

for (var i=0; i<handler_protocol.length; i++) {
        var result = "";
        var protocol = handler_protocol[i];
        try {
                document.getElementById('protocol_iframe_<%= @command_id %>').contentWindow.location = protocol+"://"+handler_addr;
        } catch(e) {
                if (e.name == "NS_ERROR_UNKNOWN_PROTOCOL")
                     result = protocol + " does not exist";
                else result = protocol + " unknown";
        }
        if (!result) result = protocol + " exists";
        handler_results.push(result);
}

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