title: How does Postman Rest Client create Oauth Signature ? Unable to resolve Oauth_Signature in android
body: <p>I am trying to hit the Oauth webservice which is of 1.0 Version. 
  I can get this done succesfully over postman client but just can't get this done in 
  android app. </p>
  
  <p>Library used :-
  signpost-commonshttp4-1.2.1.2.jar</p>
  
  <p>Parameters needed for the API :-
  oauth_consumer_key
  oauth_nonce
  oauth_version
  oauth_signature
  oauth_signature_method
  oauth_timestamp</p>
  
  <p>Code :-</p>
  
  <pre><code>HttpClient httpclient = new DefaultHttpClient();
  
  
              // generate the oauth_signature
              String urlParamsForSignature = "oauth_consumer_key="+consumerKey + 
                      "&amp;oauth_nonce=" + "pT6c0H"+
                      "&amp;oauth_signature_method=HMAC-SHA1" +
                      "&amp;oauth_timestamp=" + timestamp +
                      "&amp;oauth_version=1.0";
              String baseString = "https://oauth.withings.com/account/request_token?" + urlParamsForSignature;
              String signature = computeHmac(URLEncoder.encode(baseString), consumerSecret);
              // add it to params list
              qparams.add(new BasicNameValuePair("oauth_signature", signature));
  
              // generate URI which lead to access_token and token_secret.
              String urlParams = "oauth_consumer_key="+consumerKey + 
                          "&amp;oauth_nonce=" + "pT6c0H"+
                          "&amp;oauth_signature=" + signature +
                          "&amp;oauth_signature_method=HMAC-SHA1" +
                          "&amp;oauth_timestamp=" + timestamp +
                          "&amp;oauth_version=1.0";
  
              String url = "https://oauth.withings.com/account/request_token?" + urlParams;
  
              HttpGet httpget = new HttpGet(url);
              // output the response content.
              System.out.println("oken and Token Secrect:");
  
              HttpResponse response = httpclient.execute(httpget);
              HttpEntity entity = response.getEntity();
              if (entity != null) {
                  InputStream instream = entity.getContent();
                  int len;
                  byte[] tmp = new byte[2048];
                  while ((len = instream.read(tmp)) != -1) {
                      System.out.println(new String(tmp, 0, len, ENC));
                  }
              }
  
  
  
  public String computeHmac(String baseString, String key)
  {
      try {
          Mac mac = Mac.getInstance("HmacSHA1");
          SecretKeySpec secret = new SecretKeySpec(key.getBytes(), mac.getAlgorithm());
          mac.init(secret);
          byte[] digest = mac.doFinal(baseString.getBytes());
          return new String(Base64.encodeBase64(digest));
      } catch (InvalidKeyException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
          return null;
      } catch (NoSuchAlgorithmException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
          return null;
      } catch (IllegalStateException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
          return null;
      }
  }
  </code></pre>