Phalcon interview questions

Phalcon interview questions and answers

#1 What is Phalcon?

Phalcon is a free open source PHP framework based on MVC design pattern that is delivered to end users as a C -extension for the PHP language providing high performance and lower resource consumption.Phalcon is developed by Andres Gutierrez and written in Zephir/C.

#2 Which template engine Phalcon use?

Phalcon uses a powerful and fast templating engine called Volt.
Volt is an ultra-fast and designer-friendly templating language written in C for PHP. It provides you a set of helpers to write views in an easy way. Volt is highly integrated with other components of Phalcon, just as you can use it as a stand-alone component in your applications.
source (https://docs.phalconphp.com/en/3.0.0/reference/volt.html)

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#3 Explain Routing in Phalcon?

Routing in Phalcon Framework is managed by its Router component. Router components allow you to
define routes that are mapped to controllers or handlers that should receive the request from your application.A router simply parses a URI to determine this information. The router has two modes: MVC mode and match-only mode. The first mode is ideal for working with MVC applications.

#4 List some database related functions in Phalcon?

find(),findFirst(),query(),findFirstBy(),count(),save(),delete()
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#5 How to pass data from the controller to view in Phalcon?

The setVar() method is used to pass data from the controller to view template in Phalcon.


Usage:- $this->view->setVar("username", $user->username);

#6 How can you inject Services into a Volt Template?

If a service container (DI) is available for Volt, you can use the services by only accessing the name of the service in the template:


{# Inject the 'flash' service #}
<div id="messages">{{ flash.output() }}</div>

{# Inject the 'security' service #}


#7 Explain ODM in Phalcon?

ODM (Object-Document Mapper) offers a CRUD functionality, events, validations among other services in Phalcon.

#8 Explain directory structure of Phalcon Framework?

The root folder of Phalcon Php contains files and directories

  • App
    • Config
    • Controllers
    • Library
    • Migrations
    • Models
    • Views
  • Cache
  • Public
    • Css
    • files
    • img
    • js
    • temp
  • .htaccess
  • .htaccess
  • .htrouter.php
  • index.html

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#9 What is Zephir in Phalcon?

Zephir – Ze(nd Engine) Ph(p) I(nt)r(mediate) – is a high-level language that eases the creation and maintainability of extensions for PHP. Zephir extensions are exported to C code that can be compiled and optimized by major C compilers such as gcc/clang/vc++. Functionality is exposed to the PHP language

source (https://github.com/phalcon/zephir)

#10 List various type of Application Events in Phalcon?

Below is the list of Application Events in Phalcon.

Event NameTriggered
bootExecuted when the application handles its first request
beforeStartModuleBefore initialize a module, only when modules are registered
afterStartModuleAfter initializing a module, only when modules are registered
beforeHandleRequestBefore execute the dispatch loop
afterHandleRequestAfter execute the dispatch loop

#11 Explain MVC in Phalcon?

Phalcon offers the object-oriented classes, necessary to implement the Model, View, Controller architecture (often referred to as MVC) in your application. This design pattern is widely used by other web frameworks and desktop applications.

MVC benefits include:

  • Isolation of business logic from the user interface and the database layer.
  • Making it clear where different types of code belong for easier maintenance.

If you decide to use MVC, every request to your application resources will be managed by the MVC architecture. Phalcon classes are written in C language, offering a high-performance approach to this pattern in a PHP based application.

#12 List Database engines supported by Phalcon?

Phalcon uses PDO_ to connect to databases. The following database engines are supported:

  • Phalcon\Db\Adapter\Pdo\Mysql : Mysql
  • Phalcon\Db\Adapter\Pdo\Postgresql : Postgresql
  • Phalcon\Db\Adapter\Pdo\Sqlite : SQLite

#13 List basic features provided by Phalcon?

Below is the list of basic features provided by Phalcon PHP framework.

  • Low overhead
  • MVC & HMVC Pattern
  • Dependency Injection
  • Support for Rest
  • Autoloader
  • Router

#14 Explain Dependency Injection in Phalcon?

Phalcon is built upon a powerful yet easy to understand and use a pattern called Dependency Injection.

Phalcon’s Dependency injection initializes or define services once – and use them virtually anywhere throughout the application.

#15 How to read, write and delete sessions in Phalcon?

Phalcon session component provides object-oriented wrappers to access session data.
Below is usage guide to Read, Write and Delete sessions in Phalcon

Writing or Creating session in Phalcon

 $this->session->set("user-name", "Michael");

Reading or Retrieving session in Phalcon

 $this->session->get("user-name");

Deleting or Removing session in Phalcon

  $this->session->remove("user-name");
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