request Archives - Gullele's Corner

Add batch/multiple posts to Facebook Page – Graph API

facebook graph API batch request usage

If you have or managing any facebook page, chances are you might be using faebook’s graph API. It comes with lots of flavors of languages like Java, PHP, Javascript.

Ok you know about that, this post is not about that. If you want to see how to make a post to facebook through graph API, look at this post https://gullele.com/using-facebook-api-post-articles-php/

This post is about making multiple posts to Facebook page.

Why would I need batch requests

Imagine you have 20 blog articles you want to post to facebook. If you are not using batch, then it means you are sending 20 post requests to facebook. And as you can imaging it is easy to hit the limit easily. Facebook will stop you from bombarding their site.

When you are using batch, you have only one request, holding all 20 posts. Yup, that is it. One request vs 20. Now you know why you have to use that.

How to send multiple blog posts or other posts to Facebook page at once

If you follow the above link I referenced, you will have an idea on how single post is doing. I will just continue on that example class and will add just one more method to handle batch request.

The main idea is, each blog or whatever post has to be an object of Request. And you will send all those requests wrapped in one and send it.


	/**
	 * Send batch request to FB than a single one
	 * @param $post_data
	 */
	private function batchPost(array $post_data, $token)
	{
		/*
		 * In the case of the batch request, each has to be an object of request. And all those can be 
		 * send as one big request.
		 */
		$batch_response = [];
		$requests = [];
		foreach ($post_data as $id => $data) {
			$requests[$id] = $this->facebook->request('POST', '/me/feed', $data);
		}

		$batch_response = $this->facebook->sendBatchRequest($requests, $token);

		return $batch_response;
	}

In the above example, the method will be accepting $post_data as a parameter. If a post example is considered, a single $data will look like


$data = [
			'link' => "https://gullele.com/link-goes-here",
			'message'=>"how to make batch request in facebook api",
			'title'=>"Making Multiple Requests in Facebook",
			'description' => 'In this article I will show you how you can make multiple blog posts to Facebook page with one single request.',
		];

Then the line with $this->facebook->request will create a request object and add it as part of request array. Also mind the $id, each should have unique key in the $request array.

Then Facebook will send you back the response with post id and other lots of information that you might want to keep it for later reference like to get metrics on the post – how many likes, impressions, shares.. which will help you to improve in the long run.

Let me know if you have any questions or other methods.

JSF App slow with JPA connection

If you are working on Java Persistence API JPA on tomcat or any other web server this would be happening if you have multiple threads going off for connections.

The rule of thumb shall be to have one EntityManagerFactory and get EntityManagers out of it. Hence we would have one factory but multiple products that would take care of closing and managing them selves.

What are the signs:

1. Do you instantiate Persistence.createEntityManagerFactory(“name”) from multiple places?
2. What do you see on Process when you run

ps -aux | grep tomcat

Do you see multiple instances

If either or both of the above have yes, then here is the solution.

The first thing have single instance of ManagerFactory


package com.enderase.persistence;

import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

/**
* Singlton implementation for EntityManagerFactory
*
* @author Kaleb Woldearegay<kaleb@gullele.com>
*/
public class HibernateUtil {
private static final EntityManagerFactory entityManagerFactory;

static {
try {
entityManagerFactory = Persistence.createEntityManagerFactory("jpa");
} catch (Throwable exception) {
//log your error here
throw new ExceptionInInitializerError(exception);
}
}

public static EntityManagerFactory getEntityManager() {
return entityManagerFactory;
}
}

Then make sure you are taking care of the instances of the EntityManagers that are created from the factory using

EntityManagerFactory entityManagerFactory = HibernateUtil.getEntityManager();
EntityManager em = entityManagerFactory.createEntityManager();

Make sure to close them appropriately after using them

This should pretty much take care of the problem

Adding session bean to to requested bean using annotation JSF

One major part on JSF would separation of concerns even for beans. As a rule of thumb beans related to model are session beans and those which have actions to be taken care of are requested one.

So, In this particular scenario we would have two beans. Basically we don’t want to include any logic inside the session bean, rather we would add session bean as a member variable to request bean.

Lets take a simple registration process.

The requested bean which will be responsible for actions would look like

package com.enderase.beans;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.RequestScoped;

import com.enderase.model.Contractor;

@ManagedBean
@RequestScoped
public class ActionListeners implements Serializable{
	
	@ManagedProperty(value="#{contractorBean.contractor}")
	private Contractor contractor;
	
	public void setContractor(Contractor contractor){
		this.contractor = contractor;
	}
	
	public Contractor getContractor() {
		return this.contractor;
	}
	
	private static final long serialVersionUID = 1L;
	
	
	/**
	 * Action handler for Contractor save.
	 * @return String, next
	 */
	public String registerContractor() {
		Contractor contractor = this.contractor;
		if (contractor != null) {
			try {
				FileWriter fileWriter = new FileWriter("/tmp/name.note");
				BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
				bufferedWriter.write("Name "+contractor.getName()+" Email "+contractor.getEmail()
						+contractor.getState());
				bufferedWriter.close();
			} catch (Exception ex) {
				//log the exception here
			}
		}
		return "navigated";
	}
}

So the key thing here would be the @ManagedProperty part.
That would inject the session bean into the request bean without creating any instance of it.

*Don’t for get to add getter and setter for the session bean you are adding otherwise you would get an error.

The session bean would be a simple holder of model

package com.enderase.beans;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

import com.enderase.model.Contractor;

@ManagedBean
@SessionScoped
public class ContractorBean {
	
	private Contractor contractor;
	
	public ContractorBean() {
		this.contractor = new Contractor();
	}
	public Contractor getContractor(){
		return this.contractor;
	}
	
	public void setContractor(Contractor contractor){
		this.contractor = contractor;
	}
}

Where the contractor would be a simple POJO file

Component ID id:compid has already been found in the view JSF error

This error is quite explanatory in JSF.

I got once in a while when I work with dynamic generation of the components.

If you have this, the most common cause of this error would be you are trying to attach the an html component from your bean again.

Especially, if you have session scoped managed bean and you are attaching dynamically elements, may be one of your methods has already attached the component to the view (like the grid you are using for your component) and the other method is trying to attach it again.

If that is the case you might need to check the existence of the component in the grid (or any component you are using) before attaching it.

Also: see how to add session bean to request