BookStack/app/Http/Controllers/ImageController.php

<?php

namespace Oxbow\Http\Controllers;

use Illuminate\Filesystem\Filesystem as File;
use Illuminate\Http\Request;

use Oxbow\Http\Requests;
use Oxbow\Image;

class ImageController extends Controller
{
    protected $image;
    protected $file;

    /**
     * ImageController constructor.
     * @param Image $image
     * @param File $file
     */
    public function __construct(Image $image, File $file)
    {
        $this->image = $image;
        $this->file = $file;
    }

    /**
     * Returns an image from behind the public-facing application.
     * @param Request $request
     * @return \Illuminate\Http\Response
     */
    public function getImage(Request $request)
    {
        $cacheTime = 60*60*24;
        $path = storage_path() . '/' . $request->path();
        $modifiedTime = $this->file->lastModified($path);
        $eTag = md5($modifiedTime . $path);
        $headerLastModified = gmdate('r', $modifiedTime);
        $headerExpires = gmdate('r', $modifiedTime + $cacheTime);

        $headers = [
            'Last-Modified' => $headerLastModified,
            'Cache-Control' => 'must-revalidate',
            'Pragma' => 'public',
            'Expires' => $headerExpires,
            'Etag' => $eTag
        ];

        $browserModifiedSince = $request->header('If-Modified-Since');
        $browserNoneMatch = $request->header('If-None-Match');
        if($browserModifiedSince !== null && file_exists($path) && ($browserModifiedSince == $headerLastModified || $browserNoneMatch == $eTag)) {
            return response()->make('', 304, $headers);
        }

        if(file_exists($path)) {
            return response()->make(file_get_contents($path), 200, array_merge($headers, [
                'Content-Type' => $this->file->mimeType($path),
                'Content-Length' => filesize($path),
            ]));
        }
        abort(404);
    }

    /**
     * Handles image uploads for use on pages.
     * @param Request $request
     * @return \Illuminate\Http\JsonResponse
     */
    public function upload(Request $request)
    {
        $imageUpload = $request->file('file');
        $name = $imageUpload->getClientOriginalName();
        $imagePath = '/images/' . Date('Y-m-M') . '/';
        $storagePath = storage_path(). $imagePath;
        $fullPath = $storagePath . $name;
        while(file_exists($fullPath)) {
            $name = substr(sha1(rand()), 0, 3) . $name;
            $fullPath = $storagePath . $name;
        }
        $imageUpload->move($storagePath, $name);
        // Create and save image object
        $this->image->name = $name;
        $this->image->url = $imagePath . $name;
        $this->image->save();
        return response()->json(['link' => $this->image->url]);
    }


}