zhuzhuor/background.js

## background.js
var xip_url = 'http://127.0.0.1.xip.io:5000/api';

chrome.webRequest.onBeforeRequest.addListener(
    function(info) {
        console.log(info.url + ' is redirected to ' + xip_url);
        return {redirectUrl: xip_url};
    }, {
        urls: [
            'http://127.0.0.1:5000/notexist',
            'http://127.0.0.1.xip.io:5000/notexist'
        ]
    }, ['blocking']
);

## manifest.json
{
    "name": "Test",
    "version": "1.0",
    "permissions": ["webRequest", "webRequestBlocking", "<all_urls>"],
    "background": {
        "scripts": ["background.js"]
    },
    "manifest_version": 2
}

## server.py
#!/usr/bin/env python

from flask import Flask
app = Flask(__name__, static_folder='')

xip_url = 'http://127.0.0.1.xip.io:5000/api'


@app.route("/")
def idx():
    return app.send_static_file('test.html')


@app.route("/redirect")
def rdr():
    return '', 302, {
        'Access-Control-Allow-Origin': '*',
        'Location': xip_url
    }


@app.route("/api")
def api():
    return 'Passed', 200, {'Access-Control-Allow-Origin': '*'}


if __name__ == "__main__":
    app.debug = True
    app.run(host='127.0.0.1', port=5000)

## test.html
<!DOCTYPE html>
<html>
    <head>
        <title>Test Cross-domain XHRs with Redirects</title>
    </head>
    <body>
        <p>Directly access cross-domain resource: <span id="req1">N/A</span></p>
        <p>Local request redirect to cross-domain resource: <span id="req2">N/A</span></p>
        <p>Cross-domain request redirect to cross-domain resource: <span id="req3">N/A</span></p>
        <p>Local request redirected by extension to cross-domain resource: <span id="req4">N/A</span></p>
        <p>Cross-domain request redirected by extension to cross-domain resource: <span id="req5">Silently Failed</span></p>

        <script type="text/javascript">
            var xhr1 = new XMLHttpRequest();
            xhr1.onreadystatechange = function() {
                if (xhr1.readyState === 4){
                    if (xhr1.responseText === 'Passed') {
                        document.getElementById("req1").innerHTML = 'Passed';
                    } else {
                        document.getElementById("req1").innerHTML = 'Failed';
                    }
                }
            };
            xhr1.open("GET", "api", true);
            xhr1.send();

            var xhr2 = new XMLHttpRequest();
            xhr2.onreadystatechange = function() {
                if (xhr2.readyState === 4) {
                    if (xhr2.responseText === 'Passed') {
                        document.getElementById("req2").innerHTML = 'Passed';
                    } else {
                        document.getElementById("req2").innerHTML = 'Failed';
                    }
                }
            };
            xhr2.open("GET", "redirect", true);
            xhr2.send();

            var xhr3 = new XMLHttpRequest();
            xhr3.onreadystatechange = function() {
                if (xhr3.readyState === 4) {
                    if (xhr3.responseText === 'Passed') {
                        document.getElementById("req3").innerHTML = 'Passed';
                    } else {
                        document.getElementById("req3").innerHTML = 'Failed';
                    }
                }
            };
            xhr3.open("GET", "http://127.0.0.1.xip.io:5000/redirect", true);
            xhr3.send();

            var xhr4 = new XMLHttpRequest();
            xhr4.onreadystatechange = function() {
                if (xhr4.readyState === 4) {
                    if (xhr4.responseText === 'Passed') {
                        document.getElementById("req4").innerHTML = 'Passed';
                    } else if (xhr4.status === 404) {
                        document.getElementById("req4").innerHTML = 'Ext not installed.';
                    } else {
                        document.getElementById("req4").innerHTML = 'Failed';
                    }
                }
            };
            xhr4.open("GET", "notexist", true);
            xhr4.send();

            var xhr5 = new XMLHttpRequest();
            xhr5.onreadystatechange = function() {
                if (xhr5.readyState === 5) {
                    if (xhr5.responseText === 'Passed') {
                        document.getElementById("req5").innerHTML = 'Passed';
                    } else if (xhr5.status === 404) {
                        document.getElementById("req5").innerHTML = 'Ext not installed.';
                    } else {
                        document.getElementById("req5").innerHTML = 'Failed';
                    }
                }
            };
            xhr5.open("GET", "http://127.0.0.1.xip.io:5000/notexist", true);
            xhr5.send();
        </script>
    </body>
</html>
	var xip_url = 'http://127.0.0.1.xip.io:5000/api';

	chrome.webRequest.onBeforeRequest.addListener(
	function(info) {
	console.log(info.url + ' is redirected to ' + xip_url);
	return {redirectUrl: xip_url};
	}, {
	urls: [
	'http://127.0.0.1:5000/notexist',
	'http://127.0.0.1.xip.io:5000/notexist'
	]
	}, ['blocking']
	);
	{
	"name": "Test",
	"version": "1.0",
	"permissions": ["webRequest", "webRequestBlocking", "<all_urls>"],
	"background": {
	"scripts": ["background.js"]
	},
	"manifest_version": 2
	}
	#!/usr/bin/env python

	from flask import Flask
	app = Flask(__name__, static_folder='')

	xip_url = 'http://127.0.0.1.xip.io:5000/api'


	@app.route("/")
	def idx():
	return app.send_static_file('test.html')


	@app.route("/redirect")
	def rdr():
	return '', 302, {
	'Access-Control-Allow-Origin': '*',
	'Location': xip_url
	}


	@app.route("/api")
	def api():
	return 'Passed', 200, {'Access-Control-Allow-Origin': '*'}


	if __name__ == "__main__":
	app.debug = True
	app.run(host='127.0.0.1', port=5000)
	<!DOCTYPE html>
	<html>
	<head>
	<title>Test Cross-domain XHRs with Redirects</title>
	</head>
	<body>
	<p>Directly access cross-domain resource: <span id="req1">N/A</span></p>
	<p>Local request redirect to cross-domain resource: <span id="req2">N/A</span></p>
	<p>Cross-domain request redirect to cross-domain resource: <span id="req3">N/A</span></p>
	<p>Local request redirected by extension to cross-domain resource: <span id="req4">N/A</span></p>
	<p>Cross-domain request redirected by extension to cross-domain resource: <span id="req5">Silently Failed</span></p>

	<script type="text/javascript">
	var xhr1 = new XMLHttpRequest();
	xhr1.onreadystatechange = function() {
	if (xhr1.readyState === 4){
	if (xhr1.responseText === 'Passed') {
	document.getElementById("req1").innerHTML = 'Passed';
	} else {
	document.getElementById("req1").innerHTML = 'Failed';
	}
	}
	};
	xhr1.open("GET", "api", true);
	xhr1.send();

	var xhr2 = new XMLHttpRequest();
	xhr2.onreadystatechange = function() {
	if (xhr2.readyState === 4) {
	if (xhr2.responseText === 'Passed') {
	document.getElementById("req2").innerHTML = 'Passed';
	} else {
	document.getElementById("req2").innerHTML = 'Failed';
	}
	}
	};
	xhr2.open("GET", "redirect", true);
	xhr2.send();

	var xhr3 = new XMLHttpRequest();
	xhr3.onreadystatechange = function() {
	if (xhr3.readyState === 4) {
	if (xhr3.responseText === 'Passed') {
	document.getElementById("req3").innerHTML = 'Passed';
	} else {
	document.getElementById("req3").innerHTML = 'Failed';
	}
	}
	};
	xhr3.open("GET", "http://127.0.0.1.xip.io:5000/redirect", true);
	xhr3.send();

	var xhr4 = new XMLHttpRequest();
	xhr4.onreadystatechange = function() {
	if (xhr4.readyState === 4) {
	if (xhr4.responseText === 'Passed') {
	document.getElementById("req4").innerHTML = 'Passed';
	} else if (xhr4.status === 404) {
	document.getElementById("req4").innerHTML = 'Ext not installed.';
	} else {
	document.getElementById("req4").innerHTML = 'Failed';
	}
	}
	};
	xhr4.open("GET", "notexist", true);
	xhr4.send();

	var xhr5 = new XMLHttpRequest();
	xhr5.onreadystatechange = function() {
	if (xhr5.readyState === 5) {
	if (xhr5.responseText === 'Passed') {
	document.getElementById("req5").innerHTML = 'Passed';
	} else if (xhr5.status === 404) {
	document.getElementById("req5").innerHTML = 'Ext not installed.';
	} else {
	document.getElementById("req5").innerHTML = 'Failed';
	}
	}
	};
	xhr5.open("GET", "http://127.0.0.1.xip.io:5000/notexist", true);
	xhr5.send();
	</script>
	</body>
	</html>