Patlaf » Query Twitter API with Pentaho PDI (Kettle)

Query Twitter API with Pentaho PDI (Kettle)

posted on 05/06/2014 by patlaf | 29 Comments

There are a lot of libraries or tools to query the Twitter API using Python, PHP, Javascript and other programming languages, but there is nothing to query it using Pentaho PDI (aka Kettle). So with a little research and time, i successfully implemented the OAUTH authentication required to use the Twitter REST API using native Kettle steps. I can now query Twitter with Pentaho Data Integration !

1 – Register an application with Twitter to get the your API and Consumer Key

Before stepping into Kettle, you will need to register an Application to obtain your OAUTH Access Token. Create an application using the “tokens from dev.twitter.com” (follow the steps from the previous link.. this is pretty straight forward). Once the application registered, you have the minimum information to build the OAUTH request:

API Key
API Secret
Access Token
Access Token Secret

The information can be found in the API Keys tab of your Application.

2- Understanding how it works

The Twitter API is based on HTTP Protocol and authentication relies on OAUTH Protocol. So basically, all the HTTP requests have to provide OAUTH information in the HTTP Authorization Header as per the image below:

I suggest to read the Authorization Request page of the API Documentation to understand the specifications. Read it twice. The challenge with Kettle is to generate the HTTP Header.

3- Create a transformation

This is where the fun starts! Now that you have read Authorization Request page twice, you know that some information like OAUTH_NONCE and OAUTH_TIMESTAMPS have to be generated for each request. Before stepping into details, let’s see the big picture with an example.

I will do a request using the Search/Tweet call and search for the word “#pentaho”.

I need the URL where to send the request
I need specific parameters to the Search/Tweet call
I need to generate the HTTP Header
I need to send the HTTP request
I need to extract the data from the JSON result

The transformation should look like:

Let’s see each step in details

3.1 – Data Grid

I use 2 different Data Grids, the first is all the static data needed to create OAUTH authentication. The second is the API URI and HTTP Method used to do the call. The OAUTH data grid is always the same whatever the call is, so it can be copied/pasted in other transformation if needed. It also allows creating a more advanced transformation using subtransformation.

3.2 – Modified Java Script Value – Generate Header

It is possible to achieve almost anything with the Java Script step. I used it to generate the HTTP Header with 2 libraries I found on Internet. All the credit goes to Netflix Inc and Paul Johnston for publishing the libraries that do the magic. I just added a few lines at the end of the script.

Make sure to edit the variable URL_PARM at line 763 to reflect the specific parameters corresponding to the API Call.

For the Search/Tweets call, the parameters are
https://api.twitter.com/1.1/search/tweets.json?q=%23pentaho&count=4&result_type=mixed

So the line 763 will be

var URL_PARAM = 'q=' + encodeURIComponent('#pentaho') + '&count=2&result_type=mixed';

1	var URL_PARAM = 'q=' + encodeURIComponent('#pentaho') + '&count=2&result_type=mixed';

encodeURIComponent is used to “URL ENCODE” the string.

Here is the full script.

/*
 * A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined
 * in FIPS PUB 180-1
 * Version 2.1a Copyright Paul Johnston 2000 - 2002.
 * Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet
 * Distributed under the BSD License
 * See http://pajhome.org.uk/crypt/md5 for details.
 */

/*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */
var hexcase = 0;  /* hex output format. 0 - lowercase; 1 - uppercase        */
var b64pad  = ""; /* base-64 pad character. "=" for strict RFC compliance   */
var chrsz   = 8;  /* bits per input character. 8 - ASCII; 16 - Unicode      */

/*
 * These are the functions you'll usually want to call
 * They take string arguments and return either hex or base-64 encoded strings
 */


function hex_sha1(s){return binb2hex(core_sha1(str2binb(s),s.length * chrsz));}
function b64_sha1(s){return binb2b64(core_sha1(str2binb(s),s.length * chrsz));}
function str_sha1(s){return binb2str(core_sha1(str2binb(s),s.length * chrsz));}
function hex_hmac_sha1(key, data){ return binb2hex(core_hmac_sha1(key, data));}
function b64_hmac_sha1(key, data){ return binb2b64(core_hmac_sha1(key, data));}
function str_hmac_sha1(key, data){ return binb2str(core_hmac_sha1(key, data));}

/*
 * Perform a simple self-test to see if the VM is working
 */
function sha1_vm_test()
{
  return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";
}

/*
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 */
function core_sha1(x, len)
{
  /* append padding */
  x[len >> 5] |= 0x80 << (24 - len % 32);
  x[((len + 64 >> 9) << 4) + 15] = len;

  var w = Array(80);
  var a =  1732584193;
  var b = -271733879;
  var c = -1732584194;
  var d =  271733878;
  var e = -1009589776;

  for(var i = 0; i < x.length; i += 16)
  {
    var olda = a;
    var oldb = b;
    var oldc = c;
    var oldd = d;
    var olde = e;

    for(var j = 0; j < 80; j++)
    {
      if(j < 16) w[j] = x[i + j];
      else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
      var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),
                       safe_add(safe_add(e, w[j]), sha1_kt(j)));
      e = d;
      d = c;
      c = rol(b, 30);
      b = a;
      a = t;
    }

    a = safe_add(a, olda);
    b = safe_add(b, oldb);
    c = safe_add(c, oldc);
    d = safe_add(d, oldd);
    e = safe_add(e, olde);
  }
  return Array(a, b, c, d, e);

}

/*
 * Perform the appropriate triplet combination function for the current
 * iteration
 */
function sha1_ft(t, b, c, d)
{
  if(t < 20) return (b & c) | ((~b) & d);
  if(t < 40) return b ^ c ^ d;
  if(t < 60) return (b & c) | (b & d) | (c & d);
  return b ^ c ^ d;
}

/*
 * Determine the appropriate additive constant for the current iteration
 */
function sha1_kt(t)
{
  return (t < 20) ?  1518500249 : (t < 40) ?  1859775393 :
         (t < 60) ? -1894007588 : -899497514;
}

/*
 * Calculate the HMAC-SHA1 of a key and some data
 */
function core_hmac_sha1(key, data)
{
  var bkey = str2binb(key);
  if(bkey.length > 16) bkey = core_sha1(bkey, key.length * chrsz);

  var ipad = Array(16), opad = Array(16);
  for(var i = 0; i < 16; i++)
  {
    ipad[i] = bkey[i] ^ 0x36363636;
    opad[i] = bkey[i] ^ 0x5C5C5C5C;
  }

  var hash = core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);
  return core_sha1(opad.concat(hash), 512 + 160);
}

/*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
function safe_add(x, y)
{
  var lsw = (x & 0xFFFF) + (y & 0xFFFF);
  var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xFFFF);
}

/*
 * Bitwise rotate a 32-bit number to the left.
 */
function rol(num, cnt)
{
  return (num << cnt) | (num >>> (32 - cnt));
}

/*
 * Convert an 8-bit or 16-bit string to an array of big-endian words
 * In 8-bit function, characters >255 have their hi-byte silently ignored.
 */
function str2binb(str)
{
  var bin = Array();
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < str.length * chrsz; i += chrsz)
    bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (32 - chrsz - i%32);
  return bin;
}

/*
 * Convert an array of big-endian words to a string
 */
function binb2str(bin)
{
  var str = "";
  var mask = (1 << chrsz) - 1;
  for(var i = 0; i < bin.length * 32; i += chrsz)
    str += String.fromCharCode((bin[i>>5] >>> (32 - chrsz - i%32)) & mask);
  return str;
}

/*
 * Convert an array of big-endian words to a hex string.
 */
function binb2hex(binarray)
{
  var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i++)
  {
    str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) +
           hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8  )) & 0xF);
  }
  return str;
}

/*
 * Convert an array of big-endian words to a base-64 string
 */
function binb2b64(binarray)
{
  var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var str = "";
  for(var i = 0; i < binarray.length * 4; i += 3)
  {
    var triplet = (((binarray[i   >> 2] >> 8 * (3 -  i   %4)) & 0xFF) << 16)
                | (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )
                |  ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);
    for(var j = 0; j < 4; j++)
    {
      if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;
      else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);
    }
  }
  return str;
}


/*
 * Copyright 2008 Netflix, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* Here's some JavaScript software for implementing OAuth.

   This isn't as useful as you might hope.  OAuth is based around
   allowing tools and websites to talk to each other.  However,
   JavaScript running in web browsers is hampered by security
   restrictions that prevent code running on one website from
   accessing data stored or served on another.

   Before you start hacking, make sure you understand the limitations
   posed by cross-domain XMLHttpRequest.

   On the bright side, some platforms use JavaScript as their
   language, but enable the programmer to access other web sites.
   Examples include Google Gadgets, and Microsoft Vista Sidebar.
   For those platforms, this library should come in handy.
*/

// The HMAC-SHA1 signature method calls b64_hmac_sha1, defined by
// http://pajhome.org.uk/crypt/md5/sha1.js

/* An OAuth message is represented as an object like this:
   {method: "GET", action: "http://server.com/path", parameters: ...}

   The parameters may be either a map {name: value, name2: value2}
   or an Array of name-value pairs [[name, value], [name2, value2]].
   The latter representation is more powerful: it supports parameters
   in a specific sequence, or several parameters with the same name;
   for example [["a", 1], ["b", 2], ["a", 3]].

   Parameter names and values are NOT percent-encoded in an object.
   They must be encoded before transmission and decoded after reception.
   For example, this message object:
   {method: "GET", action: "http://server/path", parameters: {p: "x y"}}
   ... can be transmitted as an HTTP request that begins:
   GET /path?p=x%20y HTTP/1.0
   (This isn't a valid OAuth request, since it lacks a signature etc.)
   Note that the object "x y" is transmitted as x%20y.  To encode
   parameters, you can call OAuth.addToURL, OAuth.formEncode or
   OAuth.getAuthorization.

   This message object model harmonizes with the browser object model for
   input elements of an form, whose value property isn't percent encoded.
   The browser encodes each value before transmitting it. For example,
   see consumer.setInputs in example/consumer.js.
 */

/* This script needs to know what time it is. By default, it uses the local
   clock (new Date), which is apt to be inaccurate in browsers. To do
   better, you can load this script from a URL whose query string contains
   an oauth_timestamp parameter, whose value is a current Unix timestamp.
   For example, when generating the enclosing document using PHP:

   <script src="oauth.js?oauth_timestamp=<?=time()?>" ...

   Another option is to call OAuth.correctTimestamp with a Unix timestamp.
 */

var OAuth; if (OAuth == null) OAuth = {};

OAuth.setProperties = function setProperties(into, from) {
    if (into != null && from != null) {
        for (var key in from) {
            into[key] = from[key];
        }
    }
    return into;
}

OAuth.setProperties(OAuth, // utility functions
{
    percentEncode: function percentEncode(s) {
        if (s == null) {
            return "";
        }
        if (s instanceof Array) {
            var e = "";
            for (var i = 0; i < s.length; ++s) {
                if (e != "") e += '&';
                e += OAuth.percentEncode(s[i]);
            }
            return e;
        }
        s = encodeURIComponent(s);
        // Now replace the values which encodeURIComponent doesn't do
        // encodeURIComponent ignores: - _ . ! ~ * ' ( )
        // OAuth dictates the only ones you can ignore are: - _ . ~
        // Source: http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Reference:Global_Functions:encodeURIComponent
        s = s.replace(/\!/g, "%21");
        s = s.replace(/\*/g, "%2A");
        s = s.replace(/\'/g, "%27");
        s = s.replace(/\(/g, "%28");
        s = s.replace(/\)/g, "%29");
        return s;
    }
,
    decodePercent: function decodePercent(s) {
        if (s != null) {
            // Handle application/x-www-form-urlencoded, which is defined by
            // http://www.w3.org/TR/html4/interact/forms.html#h-17.13.4.1
            s = s.replace(/\+/g, " ");
        }
        return decodeURIComponent(s);
    }
,
    /** Convert the given parameters to an Array of name-value pairs. */
    getParameterList: function getParameterList(parameters) {
        if (parameters == null) {
            return [];
        }
        if (typeof parameters != "object") {
            return OAuth.decodeForm(parameters + "");
        }
        if (parameters instanceof Array) {
            return parameters;
        }
        var list = [];
        for (var p in parameters) {
            list.push([p, parameters[p]]);
        }
        return list;
    }
,
    /** Convert the given parameters to a map from name to value. */
    getParameterMap: function getParameterMap(parameters) {
        if (parameters == null) {
            return {};
        }
        if (typeof parameters != "object") {
            return OAuth.getParameterMap(OAuth.decodeForm(parameters + ""));
        }
        if (parameters instanceof Array) {
            var map = {};
            for (var p = 0; p < parameters.length; ++p) {
                var key = parameters[p][0];
                if (map[key] === undefined) { // first value wins
                    map[key] = parameters[p][1];
                }
            }
            return map;
        }
        return parameters;
    }
,
    getParameter: function getParameter(parameters, name) {
        if (parameters instanceof Array) {
            for (var p = 0; p < parameters.length; ++p) {
                if (parameters[p][0] == name) {
                    return parameters[p][1]; // first value wins
                }
            }
        } else {
            return OAuth.getParameterMap(parameters)[name];
        }
        return null;
    }
,
    formEncode: function formEncode(parameters) {
        var form = "";
        var list = OAuth.getParameterList(parameters);
        for (var p = 0; p < list.length; ++p) {
            var value = list[p][1];
            if (value == null) value = "";
            if (form != "") form += '&';
            form += OAuth.percentEncode(list[p][0])
              +'='+ OAuth.percentEncode(value);
        }
        return form;
    }
,
    decodeForm: function decodeForm(form) {
        var list = [];
        var nvps = form.split('&');
        for (var n = 0; n < nvps.length; ++n) {
            var nvp = nvps[n];
            if (nvp == "") {
                continue;
            }
            var equals = nvp.indexOf('=');
            var name;
            var value;
            if (equals < 0) {
                name = OAuth.decodePercent(nvp);
                value = null;
            } else {
                name = OAuth.decodePercent(nvp.substring(0, equals));
                value = OAuth.decodePercent(nvp.substring(equals + 1));
            }
            list.push([name, value]);
        }
        return list;
    }
, 
    setParameter: function setParameter(message, name, value) {
        var parameters = message.parameters;
        if (parameters instanceof Array) {
            for (var p = 0; p < parameters.length; ++p) {
                if (parameters[p][0] == name) {
                    if (value === undefined) {
                        parameters.splice(p, 1);
                    } else {
                        parameters[p][1] = value;
                        value = undefined;
                    }
                }
            }
            if (value !== undefined) {
                parameters.push([name, value]);
            }
        } else {
            parameters = OAuth.getParameterMap(parameters);
            parameters[name] = value;
            message.parameters = parameters;
        }
    }
,
    setParameters: function setParameters(message, parameters) {
        var list = OAuth.getParameterList(parameters);
        for (var i = 0; i < list.length; ++i) {
            OAuth.setParameter(message, list[i][0], list[i][1]);
        }
    }
,
    /** Fill in parameters to help construct a request message.
        This function doesn't fill in every parameter.
        The accessor object should be like:
        {consumerKey:'foo', consumerSecret:'bar', accessorSecret:'nurn', token:'krelm', tokenSecret:'blah'}
        The accessorSecret property is optional.
     */
    completeRequest: function completeRequest(message, accessor) {
        if (message.method == null) {
            message.method = "GET";
        }
        var map = OAuth.getParameterMap(message.parameters);
        if (map.oauth_consumer_key == null) {
            OAuth.setParameter(message, "oauth_consumer_key", accessor.consumerKey || "");
        }
        if (map.oauth_token == null && accessor.token != null) {
            OAuth.setParameter(message, "oauth_token", accessor.token);
        }
        if (map.oauth_version == null) {
            OAuth.setParameter(message, "oauth_version", "1.0");
        }
        if (map.oauth_timestamp == null) {
            OAuth.setParameter(message, "oauth_timestamp", OAuth.timestamp());
        }
        if (map.oauth_nonce == null) {
            OAuth.setParameter(message, "oauth_nonce", OAuth.nonce(6));
        }
        OAuth.SignatureMethod.sign(message, accessor);
    }
,
    setTimestampAndNonce: function setTimestampAndNonce(message) {
        OAuth.setParameter(message, "oauth_timestamp", OAuth.timestamp());
        OAuth.setParameter(message, "oauth_nonce", OAuth.nonce(6));
    }
,
    addToURL: function addToURL(url, parameters) {
        newURL = url;
        if (parameters != null) {
            var toAdd = OAuth.formEncode(parameters);
            if (toAdd.length > 0) {
                var q = url.indexOf('?');
                if (q < 0) newURL += '?';
                else       newURL += '&';
                newURL += toAdd;
            }
        }
        return newURL;
    }
,
    /** Construct the value of the Authorization header for an HTTP request. */
    getAuthorizationHeader: function getAuthorizationHeader(realm, parameters) {
        var header = 'OAuth realm="' + OAuth.percentEncode(realm) + '"';
        var list = OAuth.getParameterList(parameters);
        for (var p = 0; p < list.length; ++p) {
            var parameter = list[p];
            var name = parameter[0];
            if (name.indexOf("oauth_") == 0) {
                header += ',' + OAuth.percentEncode(name) + '="' + OAuth.percentEncode(parameter[1]) + '"';
            }
        }
        return header;
    }
,
    /** Correct the time using a parameter from the URL from which the last script was loaded. */
    correctTimestampFromSrc: function correctTimestampFromSrc(parameterName) {
        parameterName = parameterName || "oauth_timestamp";
        var scripts = document.getElementsByTagName('script');
        if (scripts == null || !scripts.length) return;
        var src = scripts[scripts.length-1].src;
        if (!src) return;
        var q = src.indexOf("?");
        if (q < 0) return;
        parameters = OAuth.getParameterMap(OAuth.decodeForm(src.substring(q+1)));
        var t = parameters[parameterName];
        if (t == null) return;
        OAuth.correctTimestamp(t);
    }
,
    /** Generate timestamps starting with the given value. */
    correctTimestamp: function correctTimestamp(timestamp) {
        OAuth.timeCorrectionMsec = (timestamp * 1000) - (new Date()).getTime();
    }
,
    /** The difference between the correct time and my clock. */
    timeCorrectionMsec: 0
,
    timestamp: function timestamp() {
        var t = (new Date()).getTime() + OAuth.timeCorrectionMsec;
        return Math.floor(t / 1000);
    }
,
    nonce: function nonce(length) {
        var chars = OAuth.nonce.CHARS;
        var result = "";
        for (var i = 0; i < length; ++i) {
            var rnum = Math.floor(Math.random() * chars.length);
            result += chars.substring(rnum, rnum+1);
        }
        return result;
    }
});

OAuth.nonce.CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";

/** Define a constructor function,
    without causing trouble to anyone who was using it as a namespace.
    That is, if parent[name] already existed and had properties,
    copy those properties into the new constructor.
 */
OAuth.declareClass = function declareClass(parent, name, newConstructor) {
    var previous = parent[name];
    parent[name] = newConstructor;
    if (newConstructor != null && previous != null) {
        for (var key in previous) {
            if (key != "prototype") {
                newConstructor[key] = previous[key];
            }
        }
    }
    return newConstructor;
}

/** An abstract algorithm for signing messages. */
OAuth.declareClass(OAuth, "SignatureMethod", function OAuthSignatureMethod(){});

OAuth.setProperties(OAuth.SignatureMethod.prototype, // instance members
{
    /** Add a signature to the message. */
    sign: function sign(message) {
        var baseString = OAuth.SignatureMethod.getBaseString(message);
        var signature = this.getSignature(baseString);
        OAuth.setParameter(message, "oauth_signature", signature);
        return signature; // just in case someone's interested
    }
,
    /** Set the key string for signing. */
    initialize: function initialize(name, accessor) {
        var consumerSecret;
        if (accessor.accessorSecret != null
            && name.length > 9
            && name.substring(name.length-9) == "-Accessor")
        {
            consumerSecret = accessor.accessorSecret;
        } else {
            consumerSecret = accessor.consumerSecret;
        }
        this.key = OAuth.percentEncode(consumerSecret)
             +"&"+ OAuth.percentEncode(accessor.tokenSecret);
    }
});

/* SignatureMethod expects an accessor object to be like this:
   {tokenSecret: "lakjsdflkj...", consumerSecret: "QOUEWRI..", accessorSecret: "xcmvzc..."}
   The accessorSecret property is optional.
 */
// Class members:
OAuth.setProperties(OAuth.SignatureMethod, // class members
{
    sign: function sign(message, accessor) {
        var name = OAuth.getParameterMap(message.parameters).oauth_signature_method;
        if (name == null || name == "") {
            name = "HMAC-SHA1";
            OAuth.setParameter(message, "oauth_signature_method", name);
        }
        OAuth.SignatureMethod.newMethod(name, accessor).sign(message);
    }
,
    /** Instantiate a SignatureMethod for the given method name. */
    newMethod: function newMethod(name, accessor) {
        var impl = OAuth.SignatureMethod.REGISTERED[name];
        if (impl != null) {
            var method = new impl();
            method.initialize(name, accessor);
            return method;
        }
        var err = new Error("signature_method_rejected");
        var acceptable = "";
        for (var r in OAuth.SignatureMethod.REGISTERED) {
            if (acceptable != "") acceptable += '&';
            acceptable += OAuth.percentEncode(r);
        }
        err.oauth_acceptable_signature_methods = acceptable;
        throw err;
    }
,
    /** A map from signature method name to constructor. */
    REGISTERED : {}
,
    /** Subsequently, the given constructor will be used for the named methods.
        The constructor will be called with no parameters.
        The resulting object should usually implement getSignature(baseString).
        You can easily define such a constructor by calling makeSubclass, below.
     */
    registerMethodClass: function registerMethodClass(names, classConstructor) {
        for (var n = 0; n < names.length; ++n) {
            OAuth.SignatureMethod.REGISTERED[names[n]] = classConstructor;
        }
    }
,
    /** Create a subclass of OAuth.SignatureMethod, with the given getSignature function. */
    makeSubclass: function makeSubclass(getSignatureFunction) {
        var superClass = OAuth.SignatureMethod;
        var subClass = function() {
            superClass.call(this);
        };
        subClass.prototype = new superClass();
        // Delete instance variables from prototype:
        // delete subclass.prototype... There aren't any.
        subClass.prototype.getSignature = getSignatureFunction;
        subClass.prototype.constructor = subClass;
        return subClass;
    }
,
    getBaseString: function getBaseString(message) {
        var URL = message.action;
        var q = URL.indexOf('?');
        var parameters;
        if (q < 0) {
            parameters = message.parameters;
        } else {
            // Combine the URL query string with the other parameters:
            parameters = OAuth.decodeForm(URL.substring(q + 1));
            var toAdd = OAuth.getParameterList(message.parameters);
            for (var a = 0; a < toAdd.length; ++a) {
                parameters.push(toAdd[a]);
            }
        }
        return OAuth.percentEncode(message.method.toUpperCase())
         +'&'+ OAuth.percentEncode(OAuth.SignatureMethod.normalizeUrl(URL))
         +'&'+ OAuth.percentEncode(OAuth.SignatureMethod.normalizeParameters(parameters));
    }
,
    normalizeUrl: function normalizeUrl(url) {
        var uri = OAuth.SignatureMethod.parseUri(url);
        var scheme = uri.protocol.toLowerCase();
        var authority = uri.authority.toLowerCase();
        var dropPort = (scheme == "http" && uri.port == 80)
                    || (scheme == "https" && uri.port == 443);
        if (dropPort) {
            // find the last : in the authority
            var index = authority.lastIndexOf(":");
            if (index >= 0) {
                authority = authority.substring(0, index);
            }
        }
        var path = uri.path;
        if (!path) {
            path = "/"; // conforms to RFC 2616 section 3.2.2
        }
        // we know that there is no query and no fragment here.
        return scheme + "://" + authority + path;
    }
,
    parseUri: function parseUri (str) {
        /* This function was adapted from parseUri 1.2.1
           http://stevenlevithan.com/demo/parseuri/js/assets/parseuri.js
         */
        var o = {key: ["source","protocol","authority","userInfo","user","password","host","port","relative","path","directory","file","query","anchor"],
                 parser: {strict: /^(?:([^:\/?#]+):)?(?:\/\/((?:(([^:@\/]*):?([^:@\/]*))?@)?([^:\/?#]*)(?::(\d*))?))?((((?:[^?#\/]*\/)*)([^?#]*))(?:\?([^#]*))?(?:#(.*))?)/ }};
        var m = o.parser.strict.exec(str);
        var uri = {};
        var i = 14;
        while (i--) uri[o.key[i]] = m[i] || "";
        return uri;
    }
,
    normalizeParameters: function normalizeParameters(parameters) {
        if (parameters == null) {
            return "";
        }
        var list = OAuth.getParameterList(parameters);
        var sortable = [];
        for (var p = 0; p < list.length; ++p) {
            var nvp = list[p];
            if (nvp[0] != "oauth_signature") {
                sortable.push([ OAuth.percentEncode(nvp[0])
                              + " " // because it comes before any character that can appear in a percentEncoded string.
                              + OAuth.percentEncode(nvp[1])
                              , nvp]);
            }
        }
        sortable.sort(function(a,b) {
                          if (a[0] < b[0]) return  -1;
                          if (a[0] > b[0]) return 1;
                          return 0;
                      });
        var sorted = [];
        for (var s = 0; s < sortable.length; ++s) {
            sorted.push(sortable[s][1]);
        }
        return OAuth.formEncode(sorted);
    }
});

OAuth.SignatureMethod.registerMethodClass(["PLAINTEXT", "PLAINTEXT-Accessor"],
    OAuth.SignatureMethod.makeSubclass(
        function getSignature(baseString) {
            return this.key;
        }
    ));

OAuth.SignatureMethod.registerMethodClass(["HMAC-SHA1", "HMAC-SHA1-Accessor"],
    OAuth.SignatureMethod.makeSubclass(
        function getSignature(baseString) {
            b64pad = '=';
            var signature = b64_hmac_sha1(this.key, baseString);
            return signature;
        }
    ));

try {
    OAuth.correctTimestampFromSrc();
} catch(e) {
}


/***************************************************************************************
*
* Build the header
*
***************************************************************************************/

var URL_PARAM = 'q=' + encodeURIComponent('pentaho') + '&count=2&result_type=mixed';

var accessor = { consumerSecret: oauth_consumer_secret
                   , tokenSecret   : oauth_token_secret};

var message = { method: HTTP_METHOD
                  , action: URL
                  , parameters: OAuth.decodeForm(URL_PARAM)
                  };
var oauth_timestamp = Math.round(new Date().getTime()/1000.0);
var oauth_nonce = OAuth.nonce(11);

 message.parameters.push(['oauth_consumer_key', oauth_consumer_key]);
 message.parameters.push(['oauth_nonce', oauth_nonce]);
 message.parameters.push(['oauth_signature_method', oauth_signature_method]);
 message.parameters.push(['oauth_timestamp', oauth_timestamp]);
 message.parameters.push(['oauth_token', oauth_token]);
 message.parameters.push(['oauth_version', oauth_version]);

OAuth.SignatureMethod.sign(message, accessor);

var REST_HEADER = OAuth.getAuthorizationHeader("", message.parameters);
var REST_URL = URL+'?'+URL_PARAM

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* A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined

* in FIPS PUB 180-1

* Version 2.1a Copyright Paul Johnston 2000 - 2002.

* Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet

* Distributed under the BSD License

* See http://pajhome.org.uk/crypt/md5 for details.

* Configurable variables. You may need to tweak these to be compatible with

* the server-side, but the defaults work in most cases.

var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */

var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance */

var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode */

* These are the functions you'll usually want to call

* They take string arguments and return either hex or base-64 encoded strings

function hex_sha1(s){return binb2hex(core_sha1(str2binb(s),s.length * chrsz));}

function b64_sha1(s){return binb2b64(core_sha1(str2binb(s),s.length * chrsz));}

function str_sha1(s){return binb2str(core_sha1(str2binb(s),s.length * chrsz));}

function hex_hmac_sha1(key, data){ return binb2hex(core_hmac_sha1(key, data));}

function b64_hmac_sha1(key, data){ return binb2b64(core_hmac_sha1(key, data));}

function str_hmac_sha1(key, data){ return binb2str(core_hmac_sha1(key, data));}

* Perform a simple self-test to see if the VM is working

function sha1_vm_test()

{

return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";

}

* Calculate the SHA-1 of an array of big-endian words, and a bit length

function core_sha1(x, len)

{

/* append padding */

x[len >> 5] |= 0x80 << (24 - len % 32);

x[((len + 64 >> 9) << 4) + 15] = len;

var w = Array(80);

var a = 1732584193;

var b = -271733879;

var c = -1732584194;

var d = 271733878;

var e = -1009589776;

for(var i = 0; i < x.length; i += 16)

{

var olda = a;

var oldb = b;

var oldc = c;

var oldd = d;

var olde = e;

for(var j = 0; j < 80; j++)

{

if(j < 16) w[j] = x[i + j];

else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);

var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),

safe_add(safe_add(e, w[j]), sha1_kt(j)));

e = d;

d = c;

c = rol(b, 30);

b = a;

a = t;

}

a = safe_add(a, olda);

b = safe_add(b, oldb);

c = safe_add(c, oldc);

d = safe_add(d, oldd);

e = safe_add(e, olde);

}

return Array(a, b, c, d, e);

}

* Perform the appropriate triplet combination function for the current

* iteration

function sha1_ft(t, b, c, d)

{

if(t < 20) return (b & c) | ((~b) & d);

if(t < 40) return b ^ c ^ d;

if(t < 60) return (b & c) | (b & d) | (c & d);

return b ^ c ^ d;

}

* Determine the appropriate additive constant for the current iteration

function sha1_kt(t)

{

return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 :

(t < 60) ? -1894007588 : -899497514;

}

* Calculate the HMAC-SHA1 of a key and some data

function core_hmac_sha1(key, data)

{

var bkey = str2binb(key);

if(bkey.length > 16) bkey = core_sha1(bkey, key.length * chrsz);

var ipad = Array(16), opad = Array(16);

for(var i = 0; i < 16; i++)

{

ipad[i] = bkey[i] ^ 0x36363636;

opad[i] = bkey[i] ^ 0x5C5C5C5C;

}

var hash = core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);

return core_sha1(opad.concat(hash), 512 + 160);

}

* Add integers, wrapping at 2^32. This uses 16-bit operations internally

* to work around bugs in some JS interpreters.

function safe_add(x, y)

{

var lsw = (x & 0xFFFF) + (y & 0xFFFF);

var msw = (x >> 16) + (y >> 16) + (lsw >> 16);

return (msw << 16) | (lsw & 0xFFFF);

}

* Bitwise rotate a 32-bit number to the left.

function rol(num, cnt)

{

return (num << cnt) | (num >>> (32 - cnt));

}

* Convert an 8-bit or 16-bit string to an array of big-endian words

* In 8-bit function, characters >255 have their hi-byte silently ignored.

function str2binb(str)

{

var bin = Array();

var mask = (1 << chrsz) - 1;

for(var i = 0; i < str.length * chrsz; i += chrsz)

bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (32 - chrsz - i%32);

return bin;

}

* Convert an array of big-endian words to a string

function binb2str(bin)

{

var str = "";

var mask = (1 << chrsz) - 1;

for(var i = 0; i < bin.length * 32; i += chrsz)

str += String.fromCharCode((bin[i>>5] >>> (32 - chrsz - i%32)) & mask);

return str;

}

* Convert an array of big-endian words to a hex string.

function binb2hex(binarray)

{

var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";

var str = "";

for(var i = 0; i < binarray.length * 4; i++)

{

str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) +

hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8 )) & 0xF);

}

return str;

}

* Convert an array of big-endian words to a base-64 string

function binb2b64(binarray)

{

var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

var str = "";

for(var i = 0; i < binarray.length * 4; i += 3)

{

var triplet = (((binarray[i >> 2] >> 8 * (3 - i %4)) & 0xFF) << 16)

| (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )

| ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);

for(var j = 0; j < 4; j++)

{

if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;

else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);

}

return str;

}

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

* http://www.apache.org/licenses/LICENSE-2.0

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

/* Here's some JavaScript software for implementing OAuth.

This isn't as useful as you might hope. OAuth is based around

allowing tools and websites to talk to each other. However,

JavaScript running in web browsers is hampered by security

restrictions that prevent code running on one website from

accessing data stored or served on another.

Before you start hacking, make sure you understand the limitations

posed by cross-domain XMLHttpRequest.

On the bright side, some platforms use JavaScript as their

language, but enable the programmer to access other web sites.

Examples include Google Gadgets, and Microsoft Vista Sidebar.

For those platforms, this library should come in handy.

// The HMAC-SHA1 signature method calls b64_hmac_sha1, defined by

// http://pajhome.org.uk/crypt/md5/sha1.js

/* An OAuth message is represented as an object like this:

{method: "GET", action: "http://server.com/path", parameters: ...}

The parameters may be either a map {name: value, name2: value2}

or an Array of name-value pairs [[name, value], [name2, value2]].

The latter representation is more powerful: it supports parameters

in a specific sequence, or several parameters with the same name;

for example [["a", 1], ["b", 2], ["a", 3]].

Parameter names and values are NOT percent-encoded in an object.

They must be encoded before transmission and decoded after reception.

For example, this message object:

{method: "GET", action: "http://server/path", parameters: {p: "x y"}}

... can be transmitted as an HTTP request that begins:

GET /path?p=x%20y HTTP/1.0

(This isn't a valid OAuth request, since it lacks a signature etc.)

Note that the object "x y" is transmitted as x%20y. To encode

parameters, you can call OAuth.addToURL, OAuth.formEncode or

OAuth.getAuthorization.

This message object model harmonizes with the browser object model for

input elements of an form, whose value property isn't percent encoded.

The browser encodes each value before transmitting it. For example,

see consumer.setInputs in example/consumer.js.

/* This script needs to know what time it is. By default, it uses the local

clock (new Date), which is apt to be inaccurate in browsers. To do

better, you can load this script from a URL whose query string contains

an oauth_timestamp parameter, whose value is a current Unix timestamp.

For example, when generating the enclosing document using PHP:

Another option is to call OAuth.correctTimestamp with a Unix timestamp.

var OAuth; if (OAuth == null) OAuth = {};

OAuth.setProperties = function setProperties(into, from) {

if (into != null && from != null) {

for (var key in from) {

into[key] = from[key];

}

return into;

}

OAuth.setProperties(OAuth, // utility functions

{

percentEncode: function percentEncode(s) {

if (s == null) {

return "";

}

if (s instanceof Array) {

var e = "";

for (var i = 0; i < s.length; ++s) {

if (e != "") e += '&';

e += OAuth.percentEncode(s[i]);

}

return e;

}

s = encodeURIComponent(s);

// Now replace the values which encodeURIComponent doesn't do

// encodeURIComponent ignores: - _ . ! ~ * ' ( )

// OAuth dictates the only ones you can ignore are: - _ . ~

// Source: http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Reference:Global_Functions:encodeURIComponent

s = s.replace(/\!/g, "%21");

s = s.replace(/\*/g, "%2A");

s = s.replace(/\'/g, "%27");

s = s.replace(/\(/g, "%28");

s = s.replace(/\)/g, "%29");

return s;

}

decodePercent: function decodePercent(s) {

if (s != null) {

// Handle application/x-www-form-urlencoded, which is defined by

// http://www.w3.org/TR/html4/interact/forms.html#h-17.13.4.1

s = s.replace(/\+/g, " ");

}

return decodeURIComponent(s);

}

/** Convert the given parameters to an Array of name-value pairs. */

getParameterList: function getParameterList(parameters) {

if (parameters == null) {

return [];

}

if (typeof parameters != "object") {

return OAuth.decodeForm(parameters + "");

}

if (parameters instanceof Array) {

return parameters;

}

var list = [];

for (var p in parameters) {

list.push([p, parameters[p]]);

}

return list;

}

/** Convert the given parameters to a map from name to value. */

getParameterMap: function getParameterMap(parameters) {

if (parameters == null) {

return {};

}

if (typeof parameters != "object") {

return OAuth.getParameterMap(OAuth.decodeForm(parameters + ""));

}

if (parameters instanceof Array) {

var map = {};

for (var p = 0; p < parameters.length; ++p) {

var key = parameters[p][0];

if (map[key] === undefined) { // first value wins

map[key] = parameters[p][1];

}

return map;

}

return parameters;

}

getParameter: function getParameter(parameters, name) {

if (parameters instanceof Array) {

for (var p = 0; p < parameters.length; ++p) {

if (parameters[p][0] == name) {

return parameters[p][1]; // first value wins

}

} else {

return OAuth.getParameterMap(parameters)[name];

}

return null;

}

formEncode: function formEncode(parameters) {

var form = "";

var list = OAuth.getParameterList(parameters);

for (var p = 0; p < list.length; ++p) {

var value = list[p][1];

if (value == null) value = "";

if (form != "") form += '&';

form += OAuth.percentEncode(list[p][0])

+'='+ OAuth.percentEncode(value);

}

return form;

}

decodeForm: function decodeForm(form) {

var list = [];

var nvps = form.split('&');

for (var n = 0; n < nvps.length; ++n) {

var nvp = nvps[n];

if (nvp == "") {

continue;

}

var equals = nvp.indexOf('=');

var name;

var value;

if (equals < 0) {

name = OAuth.decodePercent(nvp);

value = null;

} else {

name = OAuth.decodePercent(nvp.substring(0, equals));

value = OAuth.decodePercent(nvp.substring(equals + 1));

}

list.push([name, value]);

}

return list;

}

setParameter: function setParameter(message, name, value) {

var parameters = message.parameters;

if (parameters instanceof Array) {

for (var p = 0; p < parameters.length; ++p) {

if (parameters[p][0] == name) {

if (value === undefined) {

parameters.splice(p, 1);

} else {

parameters[p][1] = value;

value = undefined;

}

if (value !== undefined) {

parameters.push([name, value]);

}

} else {

parameters = OAuth.getParameterMap(parameters);

parameters[name] = value;

message.parameters = parameters;

}

setParameters: function setParameters(message, parameters) {

var list = OAuth.getParameterList(parameters);

for (var i = 0; i < list.length; ++i) {

OAuth.setParameter(message, list[i][0], list[i][1]);

}

/** Fill in parameters to help construct a request message.

This function doesn't fill in every parameter.

The accessor object should be like:

{consumerKey:'foo', consumerSecret:'bar', accessorSecret:'nurn', token:'krelm', tokenSecret:'blah'}

The accessorSecret property is optional.

completeRequest: function completeRequest(message, accessor) {

if (message.method == null) {

message.method = "GET";

}

var map = OAuth.getParameterMap(message.parameters);

if (map.oauth_consumer_key == null) {

OAuth.setParameter(message, "oauth_consumer_key", accessor.consumerKey || "");

}

if (map.oauth_token == null && accessor.token != null) {

OAuth.setParameter(message, "oauth_token", accessor.token);

}

if (map.oauth_version == null) {

OAuth.setParameter(message, "oauth_version", "1.0");

}

if (map.oauth_timestamp == null) {

OAuth.setParameter(message, "oauth_timestamp", OAuth.timestamp());

}

if (map.oauth_nonce == null) {

OAuth.setParameter(message, "oauth_nonce", OAuth.nonce(6));

}

OAuth.SignatureMethod.sign(message, accessor);

}

setTimestampAndNonce: function setTimestampAndNonce(message) {

OAuth.setParameter(message, "oauth_timestamp", OAuth.timestamp());

OAuth.setParameter(message, "oauth_nonce", OAuth.nonce(6));

}

addToURL: function addToURL(url, parameters) {

newURL = url;

if (parameters != null) {

var toAdd = OAuth.formEncode(parameters);

if (toAdd.length > 0) {

var q = url.indexOf('?');

if (q < 0) newURL += '?';

else newURL += '&';

newURL += toAdd;

}

return newURL;

}

/** Construct the value of the Authorization header for an HTTP request. */

getAuthorizationHeader: function getAuthorizationHeader(realm, parameters) {

var header = 'OAuth realm="' + OAuth.percentEncode(realm) + '"';

var list = OAuth.getParameterList(parameters);

for (var p = 0; p < list.length; ++p) {

var parameter = list[p];

var name = parameter[0];

if (name.indexOf("oauth_") == 0) {

header += ',' + OAuth.percentEncode(name) + '="' + OAuth.percentEncode(parameter[1]) + '"';

}

return header;

}

/** Correct the time using a parameter from the URL from which the last script was loaded. */

correctTimestampFromSrc: function correctTimestampFromSrc(parameterName) {

parameterName = parameterName || "oauth_timestamp";

var scripts = document.getElementsByTagName('script');

if (scripts == null || !scripts.length) return;

var src = scripts[scripts.length-1].src;

if (!src) return;

var q = src.indexOf("?");

if (q < 0) return;

parameters = OAuth.getParameterMap(OAuth.decodeForm(src.substring(q+1)));

var t = parameters[parameterName];

if (t == null) return;

OAuth.correctTimestamp(t);

}

/** Generate timestamps starting with the given value. */

correctTimestamp: function correctTimestamp(timestamp) {

OAuth.timeCorrectionMsec = (timestamp * 1000) - (new Date()).getTime();

}

/** The difference between the correct time and my clock. */

timeCorrectionMsec: 0

timestamp: function timestamp() {

var t = (new Date()).getTime() + OAuth.timeCorrectionMsec;

return Math.floor(t / 1000);

}

nonce: function nonce(length) {

var chars = OAuth.nonce.CHARS;

var result = "";

for (var i = 0; i < length; ++i) {

var rnum = Math.floor(Math.random() * chars.length);

result += chars.substring(rnum, rnum+1);

}

return result;

}

});

OAuth.nonce.CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";

/** Define a constructor function,

without causing trouble to anyone who was using it as a namespace.

That is, if parent[name] already existed and had properties,

copy those properties into the new constructor.

OAuth.declareClass = function declareClass(parent, name, newConstructor) {

var previous = parent[name];

parent[name] = newConstructor;

if (newConstructor != null && previous != null) {

for (var key in previous) {

if (key != "prototype") {

newConstructor[key] = previous[key];

}

return newConstructor;

}

/** An abstract algorithm for signing messages. */

OAuth.declareClass(OAuth, "SignatureMethod", function OAuthSignatureMethod(){});

OAuth.setProperties(OAuth.SignatureMethod.prototype, // instance members

{

/** Add a signature to the message. */

sign: function sign(message) {

var baseString = OAuth.SignatureMethod.getBaseString(message);

var signature = this.getSignature(baseString);

OAuth.setParameter(message, "oauth_signature", signature);

return signature; // just in case someone's interested

}

/** Set the key string for signing. */

initialize: function initialize(name, accessor) {

var consumerSecret;

if (accessor.accessorSecret != null

&& name.length > 9

&& name.substring(name.length-9) == "-Accessor")

{

consumerSecret = accessor.accessorSecret;

} else {

consumerSecret = accessor.consumerSecret;

}

this.key = OAuth.percentEncode(consumerSecret)

+"&"+ OAuth.percentEncode(accessor.tokenSecret);

}

});

/* SignatureMethod expects an accessor object to be like this:

{tokenSecret: "lakjsdflkj...", consumerSecret: "QOUEWRI..", accessorSecret: "xcmvzc..."}

The accessorSecret property is optional.

// Class members:

OAuth.setProperties(OAuth.SignatureMethod, // class members

{

sign: function sign(message, accessor) {

var name = OAuth.getParameterMap(message.parameters).oauth_signature_method;

if (name == null || name == "") {

name = "HMAC-SHA1";

OAuth.setParameter(message, "oauth_signature_method", name);

}

OAuth.SignatureMethod.newMethod(name, accessor).sign(message);

}

/** Instantiate a SignatureMethod for the given method name. */

newMethod: function newMethod(name, accessor) {

var impl = OAuth.SignatureMethod.REGISTERED[name];

if (impl != null) {

var method = new impl();

method.initialize(name, accessor);

return method;

}

var err = new Error("signature_method_rejected");

var acceptable = "";

for (var r in OAuth.SignatureMethod.REGISTERED) {

if (acceptable != "") acceptable += '&';

acceptable += OAuth.percentEncode(r);

}

err.oauth_acceptable_signature_methods = acceptable;

throw err;

}

/** A map from signature method name to constructor. */

REGISTERED : {}

/** Subsequently, the given constructor will be used for the named methods.

The constructor will be called with no parameters.

The resulting object should usually implement getSignature(baseString).

You can easily define such a constructor by calling makeSubclass, below.

registerMethodClass: function registerMethodClass(names, classConstructor) {

for (var n = 0; n < names.length; ++n) {

OAuth.SignatureMethod.REGISTERED[names[n]] = classConstructor;

}

/** Create a subclass of OAuth.SignatureMethod, with the given getSignature function. */

makeSubclass: function makeSubclass(getSignatureFunction) {

var superClass = OAuth.SignatureMethod;

var subClass = function() {

superClass.call(this);

};

subClass.prototype = new superClass();

// Delete instance variables from prototype:

// delete subclass.prototype... There aren't any.

subClass.prototype.getSignature = getSignatureFunction;

subClass.prototype.constructor = subClass;

return subClass;

}

getBaseString: function getBaseString(message) {

var URL = message.action;

var q = URL.indexOf('?');

var parameters;

if (q < 0) {

parameters = message.parameters;

} else {

// Combine the URL query string with the other parameters:

parameters = OAuth.decodeForm(URL.substring(q + 1));

var toAdd = OAuth.getParameterList(message.parameters);

for (var a = 0; a < toAdd.length; ++a) {

parameters.push(toAdd[a]);

}

return OAuth.percentEncode(message.method.toUpperCase())

+'&'+ OAuth.percentEncode(OAuth.SignatureMethod.normalizeUrl(URL))

+'&'+ OAuth.percentEncode(OAuth.SignatureMethod.normalizeParameters(parameters));

}

normalizeUrl: function normalizeUrl(url) {

var uri = OAuth.SignatureMethod.parseUri(url);

var scheme = uri.protocol.toLowerCase();

var authority = uri.authority.toLowerCase();

var dropPort = (scheme == "http" && uri.port == 80)

|| (scheme == "https" && uri.port == 443);

if (dropPort) {

// find the last : in the authority

var index = authority.lastIndexOf(":");

if (index >= 0) {

authority = authority.substring(0, index);

}

var path = uri.path;

if (!path) {

path = "/"; // conforms to RFC 2616 section 3.2.2

}

// we know that there is no query and no fragment here.

return scheme + "://" + authority + path;

}

parseUri: function parseUri (str) {

/* This function was adapted from parseUri 1.2.1

http://stevenlevithan.com/demo/parseuri/js/assets/parseuri.js

var o = {key: ["source","protocol","authority","userInfo","user","password","host","port","relative","path","directory","file","query","anchor"],

parser: {strict: /^(?:([^:\/?#]+):)?(?:\/\/((?:(([^:@\/]*):?([^:@\/]*))?@)?([^:\/?#]*)(?::(\d*))?))?((((?:[^?#\/]*\/)*)([^?#]*))(?:\?([^#]*))?(?:#(.*))?)/ }};

var m = o.parser.strict.exec(str);

var uri = {};

var i = 14;

while (i--) uri[o.key[i]] = m[i] || "";

return uri;

}

normalizeParameters: function normalizeParameters(parameters) {

if (parameters == null) {

return "";

}

var list = OAuth.getParameterList(parameters);

var sortable = [];

for (var p = 0; p < list.length; ++p) {

var nvp = list[p];

if (nvp[0] != "oauth_signature") {

sortable.push([ OAuth.percentEncode(nvp[0])

+ " " // because it comes before any character that can appear in a percentEncoded string.

+ OAuth.percentEncode(nvp[1])

, nvp]);

}

sortable.sort(function(a,b) {

if (a[0] < b[0]) return -1;

if (a[0] > b[0]) return 1;

return 0;

});

var sorted = [];

for (var s = 0; s < sortable.length; ++s) {

sorted.push(sortable[s][1]);

}

return OAuth.formEncode(sorted);

}

});

OAuth.SignatureMethod.registerMethodClass(["PLAINTEXT", "PLAINTEXT-Accessor"],

OAuth.SignatureMethod.makeSubclass(

function getSignature(baseString) {

return this.key;

}

));

OAuth.SignatureMethod.registerMethodClass(["HMAC-SHA1", "HMAC-SHA1-Accessor"],

OAuth.SignatureMethod.makeSubclass(

function getSignature(baseString) {

b64pad = '=';

var signature = b64_hmac_sha1(this.key, baseString);

return signature;

}

));

try {

OAuth.correctTimestampFromSrc();

} catch(e) {

}

/***************************************************************************************

* Build the header

***************************************************************************************/

var URL_PARAM = 'q=' + encodeURIComponent('pentaho') + '&count=2&result_type=mixed';

var accessor = { consumerSecret: oauth_consumer_secret

, tokenSecret : oauth_token_secret};

var message = { method: HTTP_METHOD

, action: URL

, parameters: OAuth.decodeForm(URL_PARAM)

};

var oauth_timestamp = Math.round(new Date().getTime()/1000.0);

var oauth_nonce = OAuth.nonce(11);

message.parameters.push(['oauth_consumer_key', oauth_consumer_key]);

message.parameters.push(['oauth_nonce', oauth_nonce]);

message.parameters.push(['oauth_signature_method', oauth_signature_method]);

message.parameters.push(['oauth_timestamp', oauth_timestamp]);

message.parameters.push(['oauth_token', oauth_token]);

message.parameters.push(['oauth_version', oauth_version]);

OAuth.SignatureMethod.sign(message, accessor);

var REST_HEADER = OAuth.getAuthorizationHeader("", message.parameters);

var REST_URL = URL+'?'+URL_PARAM

The oauth_xxxxxx variables come from previous Data Grids. The final result is the REST_HEADER and REST_URL. Both variables are sent to next transformation’s step (REST Client).

3.3 – Rest Client

The Rest Client step is pretty simple because all parameters have been defined in the previous steps. The Headers tab enables you to define the content of any HTTP headers using an existing field. This is where the REST_HEADER variable is defined as Authentification header.

The answer from Twitter is sent to the “result” variable. It could be the expected answer but it could be an error message too. A good error handling mechanism has to be developed. For the sake of the demo, I assume getting the expected answer.

3.4 – JSON and Text Output

Twitter sends the result with a JSON format. The first “Text Output Raw Json” step is a debugging step I use to develop the transformation. It’s very useful to have the original JSON answer to build a good JsonPath expression in the JSON step.

For the demo, I created 2 CSV, the first for the twit message and the second for each hashtags of each twit message.

Conclusion

As you can see, it’s pretty easy to retrieve data from Twitter. You can call another API’s function by changing the URI (in the datagrid), the parameter string (in Javascript) and the Jsonpath (JSON Step). And there you go ! You now have data to create analysis!
You can download the demo transformation from my github repo: https://github.com/patlaf/pdi_scripts