@ToString(includeNames = true, includeFields = true, excludes = 'dateCreated,lastUpdated,metaClass')
@EqualsAndHashCode
class Item {
    String name
    Float price
    boolean active = true
    Date dateCreated
    Date lastUpdated
}

Before adding this annotation my domain class toString looks like this

Item item = new Item(name: "Chips", active: false, price: 15)
println "To String output -: " + item //To String output -: com.intelligrape.myapp.Item : null

Now I get the following output for Item object toString

Item item = new Item(name: "Chips", active: false, price: 15)
println "To String output -: " + item //To String output -: com.intelligrape.myapp.Item(name:Chips, price:15.0, active:false)

To get this annotation on all my domain classed I updated the template of grails domain classes so that whenever I do create-domain-class it give me the annotated domain classes

@artifact.package@
import groovy.transform.EqualsAndHashCode
import groovy.transform.ToString

@ToString(includeNames = true, includeFields = true, excludes = 'dateCreated,lastUpdated,metaClass')
@EqualsAndHashCode
class @artifact.name@ {

    Date dateCreated
    Date lastUpdated
}

Hope it helps

## Uday Pratap Singh ##
uday@intelligrape.com
http://www.IntelliGrape.com/
http://in.linkedin.com/in/meudaypratap

_

Note: This feature is available in groovy 1.8+

Well Let me Explain this Using Examples

Now suppose i have a function “distance” which calculates distance between two points.
Hence for it instead of writing a function(Method) lets write a closure for it.

        def distance = {x1, y1, x2, y2 ->
            sleep(200)  //just to add a delay for demo purposes
            Math.sqrt((x2 - x1)**2 + (y2 - y1)**2)
        }

       //To Call It 5 Times
       5.times {
            def t1 = System.currentTimeMillis()
            println distance(100, 20, 400, 10)
            println "took: ${System.currentTimeMillis() - t1} milliseconds to execute"
        }

Now if we will Run this the Output will be as follows:

300.1666203960727
took: 201 milliseconds to execute
300.1666203960727
took: 200 milliseconds to execute
300.1666203960727
took: 201 milliseconds to execute
300.1666203960727
took: 201 milliseconds to execute
300.1666203960727
took: 201 milliseconds to execute

Each time this closure is called all statements are executed again and hence re-computation. But if set of inputs are same then technically output should be same. hence a type of caching will help.
Also if several users are acessing the app then for each user if something is done again and again though the inputs are same then that is again a overhead, this issue can also be solved by memoizeing.

Now lets Do it with .memoize()

        def distance = {x1, y1, x2, y2 ->
            sleep(200)  //just to add a delay for demo purposes
            Math.sqrt((x2 - x1)**2 + (y2 - y1)**2)
        }.memoize() //Note now closure is memoized 

       //To Call It 5 Times
       5.times {
            def t1 = System.currentTimeMillis()
            println distance(100, 20, 400, 10)
            println "took: ${System.currentTimeMillis() - t1}"
        }

Now the result is:

300.1666203960727
took: 202 milliseconds to execute
300.1666203960727
took: 1 milliseconds to execute
300.1666203960727
took: 1 milliseconds to execute
300.1666203960727
took: 0 milliseconds to execute
300.1666203960727
took: 0 milliseconds to execute

We can definitely see the difference between time taken to execute.
AND HURRAY, ALL REPETITIVE CALLS WITH SAME INPUT DATA ARE NOW CACHED AND HENCE INCREASED PERFORMANCE.

Hope it helped
Regards
Kushal Likhi

But few days ago, Facebook announced that it is Removing App Profile Pages.
Now for adding facebook apps to fan page, we can either Create an Profile page for app or Add the app to Fan page using API.

I implemented the feature to attach any Facebook App to Facebook Fan page using API and thought it worth sharing.

I am assuming that you already have the Facebook Page Access Token with you, if not you can see how to Integrate facebook with web application and get access token here.

Get App Id from Facebook App page:-

To attach any Facebook Fan page, we need to issue an HTTP POST request to the facebook URL.
URL for POST request

URL :  https://graph.facebook.com/${FACEBOOK_PAGE_ID}/tabs

Values we will be requiring :

String FAN_PAGE_ACCESS_TOKEN = fan page access token.
String APP_ID = app id from the registered app.
String FACEBOOK_PAGE_ID = id of the facebook page to which app is to be attached.

Code to issue post request at the given URL:

        StringBuilder sb = new StringBuilder("access_token=");
        sb.append(URLEncoder.encode(FAN_PAGE_ACCESS_TOKEN, "UTF-8"));
        sb.append("&app_id=");
        sb.append(URLEncoder.encode(APP_ID, "UTF-8"));

        URL url = new URL("https://graph.facebook.com/${FACEBOOK_PAGE_ID}/tabs");
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        String publishedPostId
        try {
            connection.setDoOutput(true);
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            connection.setRequestProperty("Content-Length", "" + sb.toString().length());
            OutputStreamWriter outputStreamWriter = new OutputStreamWriter(connection.getOutputStream());
            outputStreamWriter.write(sb.toString());
            outputStreamWriter.flush();
            log.debug("Response code ${connection.responseCode} , Message : ${connection.responseMessage}")
            if (connection.responseCode != 200) {
                log.debug("Unable to attach app to facebook fan page")
            }
        } finally {
            connection?.disconnect()
        }

So, we can attach any Facebook App to the Facebook Fan Page using the above code.

This worked for me.
Hope it helps.

Cheers !!!
Vishal Sahu
vishal@intelligrape.com
http://www.linkedin.com/in/vishalsahu
http://www.intelligrape.com

There are basically 3 steps to fetch data from Google.

1. Register an application.

We need to register an application at Google API Console. Go to the Google console page using the link provided and create an aplication.

Steps involve in registering an application are:-

a.) Create project by providing name to the project.

b.) Turn ON the service required, in our case it is Google Plus API.

c.) Create a Oauth 2.0 Client ID.

d.) Create the OAuth 2.0 ClientId and provide the callback URL where google will send the authorization token.

e.) Note down Client ID and Client Secret as generated in the above step.

2. Obtain an Access Token from the Google Authorization Server.

Obtaining an access token involves 2 steps.

a.) Request for Authorization Code.

In this step, we will request the Google server for authorization code by providing registered application client ID in the URL to Google server.

I created an action to redirect to Goolge, when someone want to connect to google plus.

String CLIENT_ID =client_id_obtained from registered app
String CALLBACK_URL = callback_url_as_mentioned in the registered app.
String GOOGLE_PLUS_SCOPE='https://www.googleapis.com/auth/plus.me'    // scope is the permissions we are requesting.

Action code is as:

def registerOnGooglePlus = {
String authorizeUrl = "https://accounts.google.com/o/oauth2/auth?scope=${GOOGLE_PLUS_SCOPE}&
redirect_uri=${CALLBACK_URL}&response_type=code&client_id=${CLIENT_ID}&access_type=offline"
URL urlForGooglePlus = new URL(authorizeUrl)
redirect(url: urlForGooglePlus)
}

The Redirect will take user to permissions page, if the user is already logged-in or will take to login page and then permissions page.

After approving the required permissions, user will redirect back to the application’s registered Callback URL with the authorization code.

b.) Request for Access Token with the authorization code obtained from the above action.

Access Token can be received by a POST request using the Client Secret and authorization code received.

The POST call requires 5 properties to be send in the body of the request in the encoded form.

	code : The authorization code returned from the initial request
	client_id : The client_id obtained during application registration
	client_secret : The client secret obtained during application registration
	redirect_uri : The URI registered with the application
	grant_type : authorization_code

// Sample action to receive authorization code

def callBack={
StringBuilder sb = new StringBuilder("code=");
sb.append(URLEncoder.encode(code, "UTF-8"));
sb.append("&client_id=");
sb.append(URLEncoder.encode(clientId, "UTF-8"));
sb.append("&client_secret=");
sb.append(URLEncoder.encode(clientSecret, "UTF-8"));
sb.append("&redirect_uri=");
sb.append(URLEncoder.encode(callbackUrl, "UTF-8"));
sb.append("&grant_type=");
sb.append(URLEncoder.encode('authorization_code', "UTF-8"));

String URL_TO_REQUEST_TOKEN= 'https://accounts.google.com/o/oauth2/token'

URL url = new URL(URL_TO_REQUEST_TOKEN);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
try {
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setRequestProperty("Content-Length", "" + sb.toString().length());
connection.setRequestProperty("Host", "accounts.google.com");
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(connection.getOutputStream());
outputStreamWriter.write(sb.toString());
outputStreamWriter.flush();
log.debug("Response code ${connection.responseCode} , Message : ${connection.responseMessage}")
String resultData = connection.content.text
def responseJson = JSON.parse(resultData)
String ACCESS_TOKEN = responseJson?.access_token
}
catch (Exception e) {
e.printStackTrace()
}
}

3. Calling Google API.

Now, with the help of access token, we can call google API to fetch Data by appending the access token in the GET request.

Example:

To fetch person’s profile data

GET :  https://www.googleapis.com/oauth2/v1/userinfo?access_token=ACCESS_TOKEN

To get list of profile acitivties

 GET :  https://www.googleapis.com/plus/v1/people//activities/public?access_token=ACCESS_TOKEN

References:-
http://code.google.com/apis/accounts/docs/OAuth2WebServer.html

http://code.google.com/apis/accounts/docs/OAuth2.html

Hope this helps..!!!

Vishal Sahu
vishal[at]intelligrape[dot]com
www.intelligrape.com

import org.apache.commons.validator.GenericValidator

assert GenericValidator.isEmail("bhagwat@intelligrape.com")  //valid email
assert !GenericValidator.isEmail("bhagwatintelligrape.com")  // invalid email

assert GenericValidator.isUrl("http://www.intelligrape.com")  //valid URL
assert !GenericValidator.isUrl("www.intelligrape.com") //invalid URL

assert GenericValidator.isCreditCard("4111111111111111") // valid visa card number
assert !GenericValidator.isCreditCard("4111111111111112") // invalid visa card number

assert GenericValidator.isDate("2011-12-30", "yyyy-MM-dd", true) // valid date(last argument for checking strict)
assert GenericValidator.isDate("2011-02-28", "yyyy-MM-dd", true) // valid date - 28th Feb
assert !GenericValidator.isDate("2011-02-29", "yyyy-MM-dd", false) // invalid date - 29th Feb 2011

For other useful methods and their details follow the link :
http://commons.apache.org/validator/apidocs/org/apache/commons/validator/GenericValidator.html.

In addition to GennericValdator class there are separate classes for validating date, email, credit card, ISBN validator in the org.apache.commons.validator package viz. DateValidator, CreditCardValidator, EmailValidator, ISBNValidator, UrlValidator and so on. Here is the sample code for using DateValidator class.

import org.apache.commons.validator.DateValidator

DateValidator dateValidator=DateValidator.getInstance()
assert dateValidator.isValid("11-02-28", "yy-MM-dd", true)
assert !dateValidator.isValid("11-02-29", "yy-MM-dd", true)

Hope it helps you.

Bhagwat Kumar
bhagwat(at)intelligrape(dot)com

Map map=["groovy":1,"grails":2,"index":3,"element":4]
assert 3 == map.findIndexOf{it.key=="element"}
assert 0 == map.findIndexOf{it.value==1}

import org.apache.log4j.Level
import org.apache.log4j.Logger

public static def execute(Closure closure) {
        Logger sqlLogger = Logger.getLogger("org.hibernate.SQL");
        Level currentLevel = sqlLogger.level
        sqlLogger.setLevel(Level.TRACE)
        def result = closure.call()
        sqlLogger.setLevel(currentLevel)
        result
}

Now when I want to see the logs I do something like following.

String name = "Uday"
Person person
LogSql.execute {
       person = Person.findByName(name)
}

This prints the sql statement for all the sql fired in the given piece of code block.

Hope it helps

## Uday Pratap Singh ##
uday@intelligrape.com
http://www.IntelliGrape.com/
http://in.linkedin.com/in/meudaypratap

For example:

int a = "20" as int
assert a==20

The ‘as’ operator can be used to provide implementation to interface as well. Here is an example of the same:

interface Eatable{
   void eat()
}

def x =  {println "It's groovy style" } as Eatable
x.eat()

Had it been java, this could have been achieved through an annonymous class like this:

new Eatable(){
  void eat(){
    System.out.println "Its java style"
  }
}.eat()

The class has been named GoogleAjaxSearch because it uses the Google AJAX Search API

//Case 1 Simple Search
String searchQuery = "my search Query"
GoogleAjaxSearch googleAjaxSearch = new GoogleAjaxSearch(searchQuery)
println googleAjaxSearch.results //Type List<Expando>, Just print it to see available properties

//Case 2: Get Number Of Indexed Pages in Google
String searchQuery = "site:intelligrape.com"
GoogleAjaxSearch googleAjaxSearch = new GoogleAjaxSearch(searchQuery)
println googleAjaxSearch.estimatedResultCount

//Case 3: Redo a search with same SearchQuery or a different Search Query
String searchQuery = "search string"
GoogleAjaxSearch googleAjaxSearch = new GoogleAjaxSearch(searchQuery)
googleAjaxSearch.redo() //Re-Search with same query
googleAjaxSearch.redo("New Query") // Re-Search With New Query

//Case 4: All Details Available
String searchQuery = "site:intelligrape.com"
GoogleAjaxSearch googleAjaxSearch = new GoogleAjaxSearch(searchQuery)
println googleAjaxSearch.estimatedResultCount //Gives the result count, indexed pages count
println googleAjaxSearch.currentPageIndex    //Search result server side pagination - current page
println googleAjaxSearch.results  //List<Expando> containing results
println googleAjaxSearch.responseStatus //HTTP Status Code
println googleAjaxSearch.responseDetails //Details for response, if any
println googleAjaxSearch.searchQuery     //Search Query
println googleAjaxSearch.moreResultsUrl // Url to hit for next Page of results
println googleAjaxSearch.jsonResult // Complete raw JSON Result from google
println googleAjaxSearch.pages  // Pagination Pages Details

The Class Code Is As Follows:

package myPackage.googleSearch

import grails.converters.JSON

class GoogleAjaxSearch {

    public String searchQuery
    public String responseDetails
    public String moreResultsUrl
    public String jsonResult

    public Integer responseStatus
    public Integer currentPageIndex
    public Integer estimatedResultCount

    public def pages

    public List<Expando> results = []

    private static final String ajaxSearchTarget = "http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=###SEARCHQUERY###&filter=0"

    public GoogleAjaxSearch(String searchQuery) {
        this.searchQuery = searchQuery
        search()
    }

    public GoogleAjaxSearch() {
        this(null)
    }

    public void redo() {
        search()
    }

    public void redo(String newSearchQuery) {
        this.searchQuery = newSearchQuery
        search()
    }

    private void search() {
        if (searchQuery) {
            URL url = new URL(ajaxSearchTarget.replace('###SEARCHQUERY###', searchQuery))
            URLConnection connection = url.openConnection()
            connection.setDoInput(true)
            InputStream inStream = connection.getInputStream()
            BufferedReader searchResultContent = new BufferedReader(new InputStreamReader(inStream))
            jsonResult = searchResultContent.getText()
            parseJsonAndPopulateObject()
        }
    }

    private void parseJsonAndPopulateObject() {
        def jsonArray = JSON.parse(jsonResult)
        this.responseStatus = Integer.parseInt(jsonArray.responseStatus as String, 10)
        this.responseDetails = jsonArray.responseDetails
        this.moreResultsUrl = jsonArray.responseData.cursor.moreResultsUrl
        this.currentPageIndex = Integer.parseInt(jsonArray.responseData.cursor.currentPageIndex as String, 10)
        this.pages = jsonArray.responseData.cursor.pages
        this.estimatedResultCount = Integer.parseInt(jsonArray.responseData.cursor.estimatedResultCount as String, 10)
        results = jsonArray.responseData.results.collect {
            new Expando(
                    content: it.content,
                    GsearchResultClass: it.GsearchResultClass,
                    titleNoFormatting: it.titleNoFormatting,
                    title: it.title,
                    cacheUrl: it.cacheUrl,
                    unescapedUrl: it.unescapedUrl,
                    url: it.url,
                    visibleUrl: it.visibleUrl
            )
        }
    }
}

Hope That Helps
Regards
Kushal Likhi

All the projects I have worked on had login functionality where we put the userId and projectId into the session. Then in my code I use to get the user from session.userId. Something like

def books = {
   User user = User.get(session.userId)
   Project project = Project.get(session.projectId)
   ......
   .....
}

The above code fails when user directly hits this action because there is no check to verify the user is not null. The simple answer for this problem is either use beforeInterceptor or filters. So we started checking the session.userId in filters. But again there are cases where you dont want to check this session value or you can say there are public urls as well. Now we have to put few if else statements in filter.

Here I got my use case to implement an annotation for controllers and actions which checks for the required fields in the session before getting into the action. So I created an annotation in src/groovy folder

import java.lang.annotation.ElementType
import java.lang.annotation.Retention
import java.lang.annotation.RetentionPolicy
import java.lang.annotation.Target

@Target([ElementType.FIELD, ElementType.TYPE]) // Annotation is for actions as well as controller so target is field and for class
@Retention(RetentionPolicy.RUNTIME) // We need it at run time to identify the annotated controller and action
@interface RequiredSession {
    String[] exclude() default [] // To exclude some of the actions of controller

    String[] fields() default ["userId","projectId"] // The default value is set to userId and projectId that can be overridden while using the   annotation on controller or action.

    String onFailController() default "home" // Default controller when the field not in session is set to index page

    String onFailAction() default "index" // Default action when the field not in session is set to index page
}

Now I created a ApplicationFilters and before redirected the request to any action I check for the condition of session fields if the requested action or controller is annotated. The code in the filter is something like

class ApplicationFilters {
    def filters = {
        validateSession(controller: '*', action: '*') {
            before = {
                if (controllerName) {

//Get the instance of controller class from string value i.e; controllerName
                    def controllerClass = grailsApplication.controllerClasses.find {it.logicalPropertyName == controllerName}

//Read the RequiredSession annotation from controller class
                    def annotation = controllerClass.clazz.getAnnotation(RequiredSession)

//Get the current action from actionName otherwise read default action of controller
                    String currentAction = actionName ?: controllerClass.defaultActionName

//Look for the annotation on action if controller is not annotated or the action name is excluded
                    if (!annotation || currentAction in annotation.exclude()) {

//Get the action field from string value i.e; currentAction
                        def action = applicationContext.getBean(controllerClass.fullName).class.declaredFields.find { field -> field.name == currentAction }
//If action is found get the annotation else set it to null
                        annotation = action ? action.getAnnotation(RequiredSession) : null
                    }

//Check for the field in session whether the are null or not if any of the field is null loginFailed is true
                    boolean loginFailed = annotation ? (annotation.fields().any {session[it] == null}) : false

                    if (loginFailed) {

// If login is failed user redirected to on fail action and controller
                        redirect(action: annotation.onFailAction() , controller: annotation.onFailController())
                        return false;
                    }
                }
            }

        }
    }
}

And its all done. Now we just annotate our controller and actions accordingly.

@RequiredSession(exclude = ["registration", "joinProject"])
class UserController {
      def edit ={}
      def update = {}
      def list ={}
      def save ={}

      def registration ={}
      def joinProject = {}
}

In above example registration and joinProject action will bypass the session fields check.

@RequiredSession
class ItemController {
        def index={}
        def buy ={}
        def save ={}
}

All the action of above examples can be accessed only when user is logged in.

class HomeController {
      def index ={}
      def aboutUs={}
      @RequiredSession
      def dashboard = {}
}

Actions other than dashboard are public actions which can be accessed without login.

class UserController {
  @RequiredSession(fields = ["loggedInUserId"])
   def updatePassword = {

   }
}

For updating password user dont need to have some project into session so we specified the fields to be checked in session.

Hope it helps

## Uday Pratap Singh ##
uday@intelligrape.com
http://www.IntelliGrape.com/
http://in.linkedin.com/in/meudaypratap