Twilio CF Worker request validation

twilio-validation.js

addEventListener('fetch', event => {
    event.respondWith(fetchAndApply(event.request))
});

/* WARNING:
    Anything starting with REPLACEABLE_SECRET_VDB12_ shouldn't be renamed,
    because they are used in deployment transformations.
    Do not remove the comment below,
    it is required to timestamp workers on upload.
    Sent from npm.
*/
/* REPLACEABLE_SECRET_VDB12_TIMESTAMP */
async function fetchAndApply(request) {
    let twilioToken = 'REPLACEABLE_SECRET_VDB12_TWILIO_TOKEN';
    let content = await readStreamToEnd(request.body.getReader());
    let twilioSignature = request.headers.get('X-Twilio-Signature');
    let twilioPayload = await getSignatureData(request.url, content);
    let reproduced = CryptoJS.HmacSHA1(twilioPayload, twilioToken).toString(CryptoJS.enc.Base64);
    if (twilioSignature !== reproduced) {
        return new Response('Request must be signed by Twilio. Provided signature ' + twilioSignature +
            ' Twilio Signature Data ' + twilioPayload,
            { status: 403, statusText: 'Forbidden' })
    }
    const response = await fetch(new Request(request.url, {
        method: 'POST',
        headers: { 'X-Twilio-Signature': twilioSignature },
        body: content
    }));
    return response;
}

function decodeUriComponentPlusesToSpaces(data) {
    data = data.replace('+', ' ');
    return decodeURIComponent(data);
}

async function getSignatureData(url, body) {
    let text = url;
    body.split('&').sort().forEach(function(kvp) {
        let splitPair = kvp.split('=');
        text = text +
            decodeUriComponentPlusesToSpaces(splitPair[0]) +
            decodeUriComponentPlusesToSpaces(splitPair[1]);
    });
    return text;
}

async function readStreamToEnd(reader) {
    let readResult;
    let text = '';
    while (true) {
        readResult = await reader.read();
        if (!readResult.done) {
            let values = readResult.value;
            for (let index = 0; index < values.length; index += 1) {
                text += String.fromCharCode(readResult.value[index]);
            }
        } else {
            break;
        }
    }
    reader.releaseLock();
    return text;
}

/*
hmac-sha1.js

CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
var CryptoJS=CryptoJS||function(g,l){var e={},d=e.lib={},m=function(){},k=d.Base={extend:function(a){m.prototype=this;var c=new m;a&&c.mixIn(a);c.hasOwnProperty("init")||(c.init=function(){c.$super.init.apply(this,arguments)});c.init.prototype=c;c.$super=this;return c},create:function(){var a=this.extend();a.init.apply(a,arguments);return a},init:function(){},mixIn:function(a){for(var c in a)a.hasOwnProperty(c)&&(this[c]=a[c]);a.hasOwnProperty("toString")&&(this.toString=a.toString)},clone:function(){return this.init.prototype.extend(this)}},
    p=d.WordArray=k.extend({init:function(a,c){a=this.words=a||[];this.sigBytes=c!=l?c:4*a.length},toString:function(a){return(a||n).stringify(this)},concat:function(a){var c=this.words,q=a.words,f=this.sigBytes;a=a.sigBytes;this.clamp();if(f%4)for(var b=0;b<a;b++)c[f+b>>>2]|=(q[b>>>2]>>>24-8*(b%4)&255)<<24-8*((f+b)%4);else if(65535<q.length)for(b=0;b<a;b+=4)c[f+b>>>2]=q[b>>>2];else c.push.apply(c,q);this.sigBytes+=a;return this},clamp:function(){var a=this.words,c=this.sigBytes;a[c>>>2]&=4294967295<<
            32-8*(c%4);a.length=g.ceil(c/4)},clone:function(){var a=k.clone.call(this);a.words=this.words.slice(0);return a},random:function(a){for(var c=[],b=0;b<a;b+=4)c.push(4294967296*g.random()|0);return new p.init(c,a)}}),b=e.enc={},n=b.Hex={stringify:function(a){var c=a.words;a=a.sigBytes;for(var b=[],f=0;f<a;f++){var d=c[f>>>2]>>>24-8*(f%4)&255;b.push((d>>>4).toString(16));b.push((d&15).toString(16))}return b.join("")},parse:function(a){for(var c=a.length,b=[],f=0;f<c;f+=2)b[f>>>3]|=parseInt(a.substr(f,
            2),16)<<24-4*(f%8);return new p.init(b,c/2)}},j=b.Latin1={stringify:function(a){var c=a.words;a=a.sigBytes;for(var b=[],f=0;f<a;f++)b.push(String.fromCharCode(c[f>>>2]>>>24-8*(f%4)&255));return b.join("")},parse:function(a){for(var c=a.length,b=[],f=0;f<c;f++)b[f>>>2]|=(a.charCodeAt(f)&255)<<24-8*(f%4);return new p.init(b,c)}},h=b.Utf8={stringify:function(a){try{return decodeURIComponent(escape(j.stringify(a)))}catch(c){throw Error("Malformed UTF-8 data");}},parse:function(a){return j.parse(unescape(encodeURIComponent(a)))}},
    r=d.BufferedBlockAlgorithm=k.extend({reset:function(){this._data=new p.init;this._nDataBytes=0},_append:function(a){"string"==typeof a&&(a=h.parse(a));this._data.concat(a);this._nDataBytes+=a.sigBytes},_process:function(a){var c=this._data,b=c.words,f=c.sigBytes,d=this.blockSize,e=f/(4*d),e=a?g.ceil(e):g.max((e|0)-this._minBufferSize,0);a=e*d;f=g.min(4*a,f);if(a){for(var k=0;k<a;k+=d)this._doProcessBlock(b,k);k=b.splice(0,a);c.sigBytes-=f}return new p.init(k,f)},clone:function(){var a=k.clone.call(this);
            a._data=this._data.clone();return a},_minBufferSize:0});d.Hasher=r.extend({cfg:k.extend(),init:function(a){this.cfg=this.cfg.extend(a);this.reset()},reset:function(){r.reset.call(this);this._doReset()},update:function(a){this._append(a);this._process();return this},finalize:function(a){a&&this._append(a);return this._doFinalize()},blockSize:16,_createHelper:function(a){return function(b,d){return(new a.init(d)).finalize(b)}},_createHmacHelper:function(a){return function(b,d){return(new s.HMAC.init(a,
        d)).finalize(b)}}});var s=e.algo={};return e}(Math);
(function(){var g=CryptoJS,l=g.lib,e=l.WordArray,d=l.Hasher,m=[],l=g.algo.SHA1=d.extend({_doReset:function(){this._hash=new e.init([1732584193,4023233417,2562383102,271733878,3285377520])},_doProcessBlock:function(d,e){for(var b=this._hash.words,n=b[0],j=b[1],h=b[2],g=b[3],l=b[4],a=0;80>a;a++){if(16>a)m[a]=d[e+a]|0;else{var c=m[a-3]^m[a-8]^m[a-14]^m[a-16];m[a]=c<<1|c>>>31}c=(n<<5|n>>>27)+l+m[a];c=20>a?c+((j&h|~j&g)+1518500249):40>a?c+((j^h^g)+1859775393):60>a?c+((j&h|j&g|h&g)-1894007588):c+((j^h^
        g)-899497514);l=g;g=h;h=j<<30|j>>>2;j=n;n=c}b[0]=b[0]+n|0;b[1]=b[1]+j|0;b[2]=b[2]+h|0;b[3]=b[3]+g|0;b[4]=b[4]+l|0},_doFinalize:function(){var d=this._data,e=d.words,b=8*this._nDataBytes,g=8*d.sigBytes;e[g>>>5]|=128<<24-g%32;e[(g+64>>>9<<4)+14]=Math.floor(b/4294967296);e[(g+64>>>9<<4)+15]=b;d.sigBytes=4*e.length;this._process();return this._hash},clone:function(){var e=d.clone.call(this);e._hash=this._hash.clone();return e}});g.SHA1=d._createHelper(l);g.HmacSHA1=d._createHmacHelper(l)})();
(function(){var g=CryptoJS,l=g.enc.Utf8;g.algo.HMAC=g.lib.Base.extend({init:function(e,d){e=this._hasher=new e.init;"string"==typeof d&&(d=l.parse(d));var g=e.blockSize,k=4*g;d.sigBytes>k&&(d=e.finalize(d));d.clamp();for(var p=this._oKey=d.clone(),b=this._iKey=d.clone(),n=p.words,j=b.words,h=0;h<g;h++)n[h]^=1549556828,j[h]^=909522486;p.sigBytes=b.sigBytes=k;this.reset()},reset:function(){var e=this._hasher;e.reset();e.update(this._iKey)},update:function(e){this._hasher.update(e);return this},finalize:function(e){var d=
        this._hasher;e=d.finalize(e);d.reset();return d.finalize(this._oKey.clone().concat(e))}})})();

/*
enc-base64-min.js

CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
(function(){var h=CryptoJS,j=h.lib.WordArray;h.enc.Base64={stringify:function(b){var e=b.words,f=b.sigBytes,c=this._map;b.clamp();b=[];for(var a=0;a<f;a+=3)for(var d=(e[a>>>2]>>>24-8*(a%4)&255)<<16|(e[a+1>>>2]>>>24-8*((a+1)%4)&255)<<8|e[a+2>>>2]>>>24-8*((a+2)%4)&255,g=0;4>g&&a+0.75*g<f;g++)b.push(c.charAt(d>>>6*(3-g)&63));if(e=c.charAt(64))for(;b.length%4;)b.push(e);return b.join("")},parse:function(b){var e=b.length,f=this._map,c=f.charAt(64);c&&(c=b.indexOf(c),-1!=c&&(e=c));for(var c=[],a=0,d=0;d<
    e;d++)if(d%4){var g=f.indexOf(b.charAt(d-1))<<2*(d%4),h=f.indexOf(b.charAt(d))>>>6-2*(d%4);c[a>>>2]|=(g|h)<<24-8*(a%4);a++}return j.create(c,a)},_map:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="}})();