Cannot access session in Magento2

Question

I'm not able to access customer session in my block. Session does not return customer. Here is my code:

<?php
namespace YS\India\Block;

use Magento\Customer\Model\Session;
use Magento\Framework\View\Element\Template\Context;
use Magento\Framework\View\Element\Template;

class Header
extends Template
{
protected $session;
protected $customerRepository;

public function __construct(
    Context $context,
    Session $session,
    array $data = []
)
{
    $this->session = $session;

    parent::__construct($context, $data);
}

public function getBaseUrl(){
    return $this->_storeManager->getStore()->getBaseUrl();
}

public function isCustomerLogged(){
    return $this->session->isLoggedIn();
}

public function getLoggedCustomerName(){

    return $this->session->getCustomer()->getFirstname();
}
}

Then I created a test controller:

<?php

namespace YS\India\Controller\Auth;

use Magento\Framework\App\Action\Context;
use Magento\Customer\Model\Session;
use Magento\Customer\Controller\AbstractAccount;

class Test extends AbstractAccount
{ 
protected $session;

public function __construct(
    Context $context,
    Session $customerSession
)
{
    $this->session = $customerSession;
    parent::__construct($context);
}

public function execute()
{
    echo $this->session->isLoggedIn() ? "yes" : "no";

    echo "<br/>" . $this->session->getCustomer()->getFirstname();
}
}

This controller works fine and gives the first name.

Please help what is I'm missing in block

Thanks

Answer 1

cacheable=false in layout file did the trick.

<block class="YS\India\Block\Header" template="header/top_header.phtml" cacheable="false">

Answer 2

If you can't access session by instance of Magento\Customer\Model\Session Try instance Magento\Framework\App\Http\Context
Sample:

public function __construct(
    \Magento\Framework\App\Http\Context $httpContext
){
    $this->httpContext = $httpContext;
}

public function getCustomerSession()
{
    $this->httpContext->getValue(\Magento\Customer\Model\Context::CONTEXT_AUTH)->getSession();
}