require(vendor/autoload.php): failed to open stream: No such file or directory

Question

I have been porting my project to CodeIgniter4 from CodeIgniter3 for some time now. I am now at the stage where I would like to spew out some information in PDF. I used to use dompdf library in CI3 without any problems. I have hit a concrete wall in CI4.

I went through the step 1 to 4 as explained in this tutorial with the following deviations

In the app/Config/Autoload.php, I registered the dompdf service this way:

public $psr4 = [
    APP_NAMESPACE => APPPATH, // For custom app namespace
    'Config'      => APPPATH . 'Config',
    //'Dompdf'    => APPPATH . 'ThirdParty/dompdf/src',
    //not like this ^^^
    'Dompdf'      => APPPATH . 'ThirdParty/vendor/dompdf/dompdf/src', <-- like this
];

and my controller looks like this

<?php
namespace App\ThirdParty;
namespace App\Controllers;

use Dompdf\Dompdf;
use CodeIgniter\Controller;

class AjaxDomPDF extends Controller
{
  function htmlToPDF($view){
    $dompdf = new \Dompdf\Dompdf();
    $dompdf->loadHtml(view($view));
    $dompdf->setPaper('A4', 'landscape');
    $dompdf->render();
    $dompdf->stream();
  }
}

and my route entry in app/Config/Routes.php file is

$routes->get('generatePDF/(:segment)', 'AjaxDomPDF::htmlToPDF/$1');

With this arragement, I get the error

Class 'Dompdf\Cpdf' not found

I foraged and the best solution seemed to be this and therefore I edited my controller to like as follows

<?php
namespace App\ThirdParty;
namespace App\Controllers;

require 'vendor/autoload.php';
require 'vendor/dompdf/dompdf/lib/Cpdf.php';

use Dompdf\Dompdf;
// disable DOMPDF's internal autoloader if you are using Composer
define('DOMPDF_ENABLE_AUTOLOAD', false);
define("DOMPDF_ENABLE_REMOTE", true);

// include DOMPDF's default configuration
require_once 'vendor/dompdf/dompdf/dompdf_config.inc.php';

use CodeIgniter\Controller;

class AjaxDomPDF extends Controller
{
  function htmlToPDF($view){
    $dompdf = new \Dompdf\Dompdf();
    $dompdf->loadHtml(view($view));
    $dompdf->setPaper('A4', 'landscape');
    $dompdf->render();
    $dompdf->stream();
  }
}

With this I now get the error

require(vendor/autoload.php): failed to open stream: No such file or directory

I foraged and found this similar question but no answer there, so far, seem to address my problem.

Answer 1

If you run this command (composer require dompdf/dompdf) in the root directory of your Codeigniter site then you only need to change DomPdf path in the app/Config/Autoload.php file from APPPATH . 'ThirdParty/vendor/dompdf/dompdf/src' to '/vendor/dompdf/src' like this:

public $psr4 = [
    APP_NAMESPACE => APPPATH, // For custom app namespace
    'Config'      => APPPATH . 'Config',
    'Dompdf'    =>  '/vendor/dompdf/src',
];

Explanation: When you run a composer command the Composer create (or update the content if already exist) a vendor directory in the current directory (where you entered in command line before execute any composer command) and downloads the requirements into this directory.

UPDATE:

When you execute a composer command this create or update own vendor directory in current directory. So firstly you create a new CI4 project by Composer with following command: composer create-project codeigniter4/appstarter

---

Then the Composer also create a "config" directory to itself for the current environment that includes classmaps, PSR-4 autoloads, etc... Now in the vendor/composer directory there is a autoload_psr4.php file which generated when command executed. This file contains all of requirements (both of composer require <example> and found at "require"-block in composer.json file.

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Now in the /project-root-directory/vendor/composer/autoload_psr4.php file contains the Codeigniter namespace! After that -- because you wrote -- your Dompdf library and its requirements found in /project-root-directory/app/ThirdParty/vendor/. This is possible if you execute the next command inside the /app/ThirdParty/ directory: composer require dompdf/dompdf

And when appears the following question, you pressed n as No. No composer.json in current directory, do you want to use the one at /project-root-directory? [Y,n]?

Otherwise the Dompdf and its requirements installed into 1st-level vendor directory in project-root.

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When you execute the command above, in the app/ThirdParty/vendor/ directory contains only! the Dompdf and its requirements and nothing else therefore you can load the Codeigniter\Controller class with use CodeIgniter\Controller; but the use Dompdf\Dompdf; not working, because the Dompdf vendor directory is not same as Codeigniter framework vendor directory therefore can not communicate to each other.