Is there a way to have a Codeigniter controller re

问题:

I was wondering if there was a way for a controller to, instead of returning a string, or a view, return an image (be it JPG, PNG etc). For example, instead of ending with a $this->load->view('folder/special_view.php), I'd like to do something like $this->load->image('images/gorilla.png'), and have it so if my user were to go to that controller they would see an image as if they'd gone to a normal .png or jpeg. Can I set the headers so it expects a different MIME? Example code of this would be fantastic.

It would take forever for me to explain why I need this, but it involves bringing a premade CMS into codeigniter, and having it need certian things to be true. Thank you so much!

回答1:

sure you can, use this instead of $this->load->view()

$filename="/path/to/file.jpg"; //<-- specify the image  file
if(file_exists($filename)){ 
  $mime = mime_content_type($filename); //<-- detect file type
  header('Content-Length: '.filesize($filename)); //<-- sends filesize header
  header("Content-Type: $mime"); //<-- send mime-type header
  header('Content-Disposition: inline; filename="'.$filename.'";'); //<-- sends filename header
  readfile($filename); //<--reads and outputs the file onto the output buffer
  die(); //<--cleanup
  exit; //and exit
}

回答2:

This is not intended as One-upmanship, but pǝlɐɥʞ's suggestion is a pure PHP implementation that is not all that re-usable. You wanted to use the syntax $this->load->image('images/gorilla.png') so here is how you can.

Create /application/libraries/MY_Loader.php

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**
 * Loader Class
 *
 * Loads views and files
 *
 * @package     CodeIgniter
 * @subpackage  Libraries
 * @author      Phil Sturgeon
 * @category    Loader
 * @link        http://codeigniter.com/user_guide/libraries/loader.html
 */
class MY_Loader extends CI_Loader {

    function image($file_path, $mime_type_or_return = 'image/png')
    {
        $this->helper('file');

        $image_content = read_file($file_path);

        // Image was not found
        if($image_content === FALSE)
        {
            show_error('Image "'.$file_path.'" could not be found.');
            return FALSE;
        }

        // Return the image or output it?
        if($mime_type_or_return === TRUE)
        {
            return $image_content;
        }

        header('Content-Length: '.strlen($image_content)); // sends filesize header
        header('Content-Type: '.$mime_type_or_return); // send mime-type header
        header('Content-Disposition: inline; filename="'.basename($file_path).'";'); // sends filename header
        exit($image_content); // reads and outputs the file onto the output buffer
    }

There are a few ways you can use this:

Basic output (default is jpeg)

$this->load->image('/path/to/images/gorilla.png');

Send mime-type to use other image types

$this->load->image('/path/to/images/gorilla.jpg', 'image/jpeg');

Return the image

$image = $this->load->image('/path/to/images/gorilla.php', TRUE);

Just like $this->load->view, the 3rd parameter being set to TRUE means it will return instead of directly outputting.

Hope this helps :-)

回答3:

An easier way with automatic mime-type.

$this->load->helper('file');

$image_path = '/path/to/image/file';

$this->output->set_content_type(get_mime_by_extension($image_path));
$this->output->set_output(file_get_contents($image_path));

回答4:

About the Phil's code:

In CodeIgniter 2.0, today, there are a one change that have to be made in order to make it work:

• The library has to be in /application/core/MY_Loader.php

I like to remark a small typo about the library's explanation:

• There is a mistake in the header "Basic output (default is jpeg)" because in fact the default is .png

Another solutions to the problem are:

I've made a small code to make it work with the core codeIgniter libraries:

    $this->output->set_header("Content-Type: image/png");
    $this->load->file('../images/example.png');

Or using the Image Manipulation Library

    $config['image_library'] = "GD2";
    $config['source_image'] = "../images/example.png";
    $config['maintain_ratio'] = TRUE;
    $config['dynamic_output'] = TRUE;

    $this->load->library('image_lib', $config);
    $image = $this->image_lib->resize();

In both cases you get the same image you get from the source but in the output.

But for me, I liked more the extension to the core library :-)

Thank you very much Phil.

回答5:

If it fits your use case, simply redirecting to it is just fine. For example, tracking using images would be like:

// Do your logic here

redirect($image_path); // Or PHP's header location function

No need to change headers. Your use case may not fit this, but someone might find this useful ^_^

回答6:

I would do a

$computedImage = 'path/to/the/image.ext';
$this->load->helper('file');
$this->output->set_content_type(get_mime_by_extension($computedImage))->set_output(file_get_contents($computedImage));

If this helps. Cheers!

回答7:

This method works even if you have $config['compress_output'] set to TRUE

$filename="/path/to/file.jpg"; //<-- specify the image  file
if(file_exists($filename)){ 
  header('Content-Length: '.filesize($filename])); //<-- sends filesize header
  header('Content-Type: image/jpg'); //<-- send mime-type header
  header('Content-Disposition: inline; filename="'.$filename.'";'); //<-- sends filename     header
  $jpg = file_get_contents($filename); 
  $this->output->set_output($jpg);
}