aws.js

/**
 * Google Apps Script wrapper for API requests to Amazon Web Services.
 *
 * Forked from https://github.com/smithy545/aws-apps-scripts which has no
 * express license listed.
 */
var AWS = (function() {
  // option constants
  var PARAM_BUCKET_NAME = "Bucket";

  // Keys cannot be retrieved once initialized but can be changed
  var accessKey;
  var secretKey;

  return {
    /**
     * Sets keys for authentication to make requests. Keys are not externally
     * once added.
     * @param {string} access_key - your aws access key
     * @param {string} secret_key - your aws secret key
     */
    init: function AWS(access_key, secret_key) {
      if (access_key == undefined) {
        throw "Error: No access key provided";
      }
      if (secret_key == undefined) {
        throw "Error: No secret key provided";
      }
      accessKey = access_key;
      secretKey = secret_key;
    },
    /**
     * Authenticates and sends the given parameters for an AWS api request.
     * @param {string} service - AWS service (e.g. ec2, iam, codecommit)
     * @param {string} region - AWS region (e.g. us-east-1)
     * @param {string} action - API action to call
     * @param {Object} params - Parameters to call on the action. Defaults to
     *        {}.
     * @param {string} method - HTTP method (e.g. GET, POST). Defaults to GET.
     * @param {(string|object)} payload - Payload to send. Defults to ''.
     * @param {Object} headers - Headers to attach to the request. Properties
     *        'Host' and 'X-Amz-Date' are populated in this method.
     * @param {string} uri - Path for the action. Defaults to '/'.
     * @param {Object} opts - Additional service specific values. Defaults to
     *        {}.
     * @throws {Object} AWS error on failure.
     * @return {string} AWS server response to the request.
     */
    request: function(service, region, action, params, method, payload, headers,
                      uri, opts) {
      if (service == undefined) {
        throw "Error: Service undefined";
      }
      if (region == undefined) {
        throw "Error: Region undefined";
      }
      if (action == undefined) {
        throw "Error: Action undefined";
      }

      opts = opts || {};
      var bucket = opts[PARAM_BUCKET_NAME];
      if (service == "s3" && action != "ListAllMyBuckets" && bucket == undefined) {
        throw "Error: S3 Bucket undefined";
      }

      var Crypto = loadCrypto();

      var dateTimeString = Utilities.formatDate(new Date(), "GMT", "yyyyMMdd'T'HHmmss'Z'");
      var dateString = dateTimeString.substring(0, 8);

      method = method || "GET";
      uri = uri || "/";
      host = getHost(service, region, bucket);
      headers = headers || {};

      if (payload == undefined) {
        payload = "";
      } else if (typeof payload !== "string") {
        payload = JSON.stringify(payload);
      }
      var hashedPayload = Crypto.SHA256(payload);

      var request;
      var query;
      if (method.toLowerCase() == "post") {
        request = "https://" + host + uri;
        query = "";
      } else {
        query = "Action=" + action;
        if (params) {
          Object.keys(params)
          .sort(function(a,b) { return (a < b ? -1 : 1); })
          .forEach(function(name) {
            query += "&" + name + "=" + fixedEncodeURIComponent(params[name]);
          });
        }
        request = "https://" + host + uri + "?" + query;
      }

      var canonQuery = getCanonQuery(query);
      var canonHeaders = "";
      var signedHeaders = "";
      headers["Host"] = host;
      headers["X-Amz-Date"] = dateTimeString;
      headers["X-Amz-Target"] = action;
      headers["X-Amz-Content-SHA256"] = hashedPayload;
      Object.keys(headers)
      .sort(function(a,b) { return (a < b ? -1 : 1); })
      .forEach(function(h, index, ordered) {
        canonHeaders += h.toLowerCase() + ":" + headers[h] + "\n";
        signedHeaders += h.toLowerCase() + ";";
      });
      signedHeaders = signedHeaders.substring(0, signedHeaders.length-1);

      var canonicalString = method+"\n"
      + uri + "\n"
      + query + "\n"
      + canonHeaders + "\n"
      + signedHeaders + "\n"
      + hashedPayload;
      var canonHash = Crypto.SHA256(canonicalString);

      var algorithm = "AWS4-HMAC-SHA256";
      var scope = dateString + "/" + region + "/" + service + "/aws4_request";

      var stringToSign = algorithm + "\n"
      + dateTimeString + "\n"
      + scope + "\n"
      + canonHash;

      var key = getSignatureKey(Crypto, secretKey, dateString, region, service);
      var signature = Crypto.HMAC(Crypto.SHA256, stringToSign,
                                  key, { asBytes: false });

      var authHeader = algorithm + " Credential=" + accessKey + "/" + scope
                        + ", SignedHeaders=" + signedHeaders + ", Signature="
                        + signature;

      headers["Authorization"] = authHeader;
      delete headers["Host"];
      var options = {
        method: method,
        headers: headers,
        muteHttpExceptions: true,
        payload: payload,
      };

      return handleError(UrlFetchApp.fetch(request, options));
    },
    /**
     * Sets new authorization keys
     * @param {string} access_key - the new access_key
     * @param {string} secret_key - the new secret key
     */
    setNewKey: function(access_key, secret_key) {
      if(access_key == undefined) {
        throw "Error: No access key provided";
      } else if(secret_key == undefined) {
        throw "Error: No secret key provided";
      }
      accessKey = access_key;
      secretKey = secret_key;
    }
  };

  function getHost(service, region, bucket) {
    var is_s3 = (service == "s3");
    return [
      bucket,
      service,
      (is_s3 ? undefined : region),
      "amazonaws.com"
    ].filter(Boolean).join(".");
  }

  function getCanonQuery(r) {
    var query = r.split("&").sort().join("&");

    var canon = "";
    for(var i = 0; i < query.length; i++) {
      var element = query.charAt(i);
      if(isCanon(element)) {
        canon += element;
      } else {
        canon += "%"+element.charCodeAt(0).toString(16)
      }
    }

    return canon;
  }

  // For characters only
  function isCanon(c) {
    return /[a-z0-9-_.~=&]/i.test(c);
  }

  /**
   * Source: http://docs.aws.amazon.com/general/latest/gr/signature-v4-examples.html#signature-v4-examples-jscript
   */
  function getSignatureKey(Crypto, key, dateStamp, regionName, serviceName) {
    var kDate = Crypto.HMAC(Crypto.SHA256, dateStamp, "AWS4" + key, { asBytes: true});
    var kRegion = Crypto.HMAC(Crypto.SHA256, regionName, kDate, { asBytes: true });
    var kService = Crypto.HMAC(Crypto.SHA256, serviceName, kRegion, { asBytes: true });
    var kSigning = Crypto.HMAC(Crypto.SHA256, "aws4_request", kService, { asBytes: true });
    return kSigning;
  }

  function loadCrypto() {
    var window = {};
    var Crypto = undefined;
    /*
     * Crypto-JS v2.5.3
     * http://code.google.com/p/crypto-js/
     * (c) 2009-2012 by Jeff Mott. All rights reserved.
     * http://code.google.com/p/crypto-js/wiki/License
     */
    // start sha256/CryptoJS
    (typeof Crypto=="undefined"||!Crypto.util)&&function(){var d=window.Crypto={},k=d.util={rotl:function(b,a){return b<<a|b>>>32-a},rotr:function(b,a){return b<<32-a|b>>>a},endian:function(b){if(b.constructor==Number)return k.rotl(b,8)&16711935|k.rotl(b,24)&4278255360;for(var a=0;a<b.length;a++)b[a]=k.endian(b[a]);return b},randomBytes:function(b){for(var a=[];b>0;b--)a.push(Math.floor(Math.random()*256));return a},bytesToWords:function(b){for(var a=[],c=0,e=0;c<b.length;c++,e+=8)a[e>>>5]|=(b[c]&255)<<
      24-e%32;return a},wordsToBytes:function(b){for(var a=[],c=0;c<b.length*32;c+=8)a.push(b[c>>>5]>>>24-c%32&255);return a},bytesToHex:function(b){for(var a=[],c=0;c<b.length;c++)a.push((b[c]>>>4).toString(16)),a.push((b[c]&15).toString(16));return a.join("")},hexToBytes:function(b){for(var a=[],c=0;c<b.length;c+=2)a.push(parseInt(b.substr(c,2),16));return a},bytesToBase64:function(b){if(typeof btoa=="function")return btoa(g.bytesToString(b));for(var a=[],c=0;c<b.length;c+=3)for(var e=b[c]<<16|b[c+1]<<
        8|b[c+2],p=0;p<4;p++)c*8+p*6<=b.length*8?a.push("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".charAt(e>>>6*(3-p)&63)):a.push("=");return a.join("")},base64ToBytes:function(b){if(typeof atob=="function")return g.stringToBytes(atob(b));for(var b=b.replace(/[^A-Z0-9+\/]/ig,""),a=[],c=0,e=0;c<b.length;e=++c%4)e!=0&&a.push(("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".indexOf(b.charAt(c-1))&Math.pow(2,-2*e+8)-1)<<e*2|"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".indexOf(b.charAt(c))>>>
        6-e*2);return a}},d=d.charenc={};d.UTF8={stringToBytes:function(b){return g.stringToBytes(unescape(encodeURIComponent(b)))},bytesToString:function(b){return decodeURIComponent(escape(g.bytesToString(b)))}};var g=d.Binary={stringToBytes:function(b){for(var a=[],c=0;c<b.length;c++)a.push(b.charCodeAt(c)&255);return a},bytesToString:function(b){for(var a=[],c=0;c<b.length;c++)a.push(String.fromCharCode(b[c]));return a.join("")}}}();
        Crypto = window.Crypto;
        (function(){var d=Crypto,k=d.util,g=d.charenc,b=g.UTF8,a=g.Binary,c=[1116352408,1899447441,3049323471,3921009573,961987163,1508970993,2453635748,2870763221,3624381080,310598401,607225278,1426881987,1925078388,2162078206,2614888103,3248222580,3835390401,4022224774,264347078,604807628,770255983,1249150122,1555081692,1996064986,2554220882,2821834349,2952996808,3210313671,3336571891,3584528711,113926993,338241895,666307205,773529912,1294757372,1396182291,1695183700,1986661051,2177026350,2456956037,2730485921,
          2820302411,3259730800,3345764771,3516065817,3600352804,4094571909,275423344,430227734,506948616,659060556,883997877,958139571,1322822218,1537002063,1747873779,1955562222,2024104815,2227730452,2361852424,2428436474,2756734187,3204031479,3329325298],e=d.SHA256=function(b,c){var f=k.wordsToBytes(e._sha256(b));return c&&c.asBytes?f:c&&c.asString?a.bytesToString(f):k.bytesToHex(f)};e._sha256=function(a){a.constructor==String&&(a=b.stringToBytes(a));var e=k.bytesToWords(a),f=a.length*8,a=[1779033703,3144134277,
            1013904242,2773480762,1359893119,2600822924,528734635,1541459225],d=[],g,m,r,i,n,o,s,t,h,l,j;e[f>>5]|=128<<24-f%32;e[(f+64>>9<<4)+15]=f;for(t=0;t<e.length;t+=16){f=a[0];g=a[1];m=a[2];r=a[3];i=a[4];n=a[5];o=a[6];s=a[7];for(h=0;h<64;h++){h<16?d[h]=e[h+t]:(l=d[h-15],j=d[h-2],d[h]=((l<<25|l>>>7)^(l<<14|l>>>18)^l>>>3)+(d[h-7]>>>0)+((j<<15|j>>>17)^(j<<13|j>>>19)^j>>>10)+(d[h-16]>>>0));j=f&g^f&m^g&m;var u=(f<<30|f>>>2)^(f<<19|f>>>13)^(f<<10|f>>>22);l=(s>>>0)+((i<<26|i>>>6)^(i<<21|i>>>11)^(i<<7|i>>>25))+
              (i&n^~i&o)+c[h]+(d[h]>>>0);j=u+j;s=o;o=n;n=i;i=r+l>>>0;r=m;m=g;g=f;f=l+j>>>0}a[0]+=f;a[1]+=g;a[2]+=m;a[3]+=r;a[4]+=i;a[5]+=n;a[6]+=o;a[7]+=s}return a};e._blocksize=16;e._digestsize=32})();
              (function(){var d=Crypto,k=d.util,g=d.charenc,b=g.UTF8,a=g.Binary;d.HMAC=function(c,e,d,g){e.constructor==String&&(e=b.stringToBytes(e));d.constructor==String&&(d=b.stringToBytes(d));d.length>c._blocksize*4&&(d=c(d,{asBytes:!0}));for(var f=d.slice(0),d=d.slice(0),q=0;q<c._blocksize*4;q++)f[q]^=92,d[q]^=54;c=c(f.concat(c(d.concat(e),{asBytes:!0})),{asBytes:!0});return g&&g.asBytes?c:g&&g.asString?a.bytesToString(c):k.bytesToHex(c)}})();
    // end sha256/CryptoJS

    return window.Crypto;
  }

  /**
   * Strictly adhere to RFC3986 for URI encoding
   *
   * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent
   *
   * @param str
   * @returns {string}
   */
  function fixedEncodeURIComponent(str) {
    return encodeURIComponent(str).replace(/[!'()*]/g, function(c) {
      return "%" + c.charCodeAt(0).toString(16);
    });
  }

  /**
   * Parses UrlFetchApp.fetch and throws an object based on the XML returned by
   * AWS. Based on code from project
   * https://github.com/eschultink/S3-for-Google-Apps-Script and used under the
   * following license.
   *
   * @license Copyright 2014-15 Eng Etc LLC - All Rights Reserved
   *
   * LICENSE (Modified BSD) - Redistribution and use in source and binary forms,
   * with or without modification, are permitted provided that the following
   * conditions are met:
   *   1) Redistributions of source code must retain the above copyright notice,
   *      this list of conditions and the following disclaimer.
   *   2) Redistributions in binary form must reproduce the above copyright
   *      notice, this list of conditions and the following disclaimer in the
   *      documentation and/or other materials provided with the distribution.
   *   3) Neither the name of the Eng Etc LLC, S3-for-Google-Apps-Script, nor
   *      the names of its contributors may be used to endorse or promote
   *      products derived from this software without specific prior written
   *      permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL ENG ETC LLC BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * @param {Object} response result of UrlFetchApp.fetch() call
   * @throws {Object} AWS error on failure
   * @return {Object} the original parameter, unchanged
   */
  function handleError(response) {
    if (response.getResponseCode() >= 300) {
      var error = {};
      error.name = "AwsError";

      try {
        // traverse XML document and add nodes to error object
        var elements = XmlService
          .parse(response.getContentText())
          .getRootElement()
          .getChildren();
        for (i in elements) {
          var name = elements[i].getName();
          name = name.charAt(0).toLowerCase() + name.slice(1);
          error[name] = elements[i].getText();
        }
        error.toString = function() {
          return "AWS Error - " + this.code + ": " + this.message;
        };
      } catch (e) {
        // failed to parse content as XML
        error.message = "AWS returned HTTP code " + response.getResponseCode()
                      + ", but error content could not be parsed."
        error.toString = function () { return this.message; };
      }

      throw error;
    }
    return response;
  }
})();