我需要检查用户可以上传的横幅是否存在动态填充的图像，如果用户没有上传横幅图片，那么我想显示其他内容，例如默认图片。
这是我展示的图片横幅。
@foreach ($flyer->bannerPhotos as $photo)
<img src="/travel/{{ $photo->thumbnail_path }}" alt="{{ $flyer->owner->username }}" data-id="{{ $photo->id }}" id="Banner-image">
@endforeach
我尝试过“file_exists”，如果$ photo ==''，则显示其他内容，但它不起作用。您是否知道如何做到这一点？
***********编辑************
TravelFlyerController.php（缩短）
<?php
namespace App\Http\Controllers;
use App\User;
use App\Flyer;
use App\FlyerPhoto;
use App\FlyerBanner;
use App\Http\Requests;
use Illuminate\Http\Request;
use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Auth;
use App\Http\Requests\FlyerPhotoRequest;
use App\Http\Requests\FlyerBannerRequest;
use App\Http\Requests\TravelFlyersRequest;
class TravelFlyersController extends Controller {
/**
* Add banner photo to a flyer.
*
* @param $title
* @param FlyerBannerRequest $request
*/
public function addBannerPhoto($title, FlyerBannerRequest $request) {
// create a new photo instance from a file upload
$photo = FlyerBanner::fromFile($request->file('photo'))->upload();
// Set Flyer::LocatedAt() in (Flyer.php Model)
// = to the title, and add the banner photo.
// -- Find the flyer and add the banner photo.
Flyer::LocatedAt($title)->addBannerPhoto($photo);
}
FlyerBanner.php模型：
<?php
namespace App;
use Image;
use Illuminate\Database\Eloquent\Model;
use Symfony\Component\HttpFoundation\File;
use Symfony\Component\HttpFoundation\File\UploadedFile;
class FlyerBanner extends Model {
/**
* @var string
*/
protected $table = "flyer_banner";
/**
* @var array
*/
protected $fillable = ['name', 'path', 'thumbnail_path'];
/**
* @var
*/
protected $file;
/**
* @var
*/
protected $name;
/**
* A banner photo belongs to a flyer.
*
* @return \Illuminate\Database\Eloquent\Relations\BelongsTo
*/
public function flyer() {
return $this->belongsTo('App\Flyer');
}
/**
* Make a new instance from an uploaded file.
*
* @param UploadedFile $file
* @return static
*/
public static function fromFile(UploadedFile $file) {
// Make new instance of photo.
$photo = new static;
// Assign the Uploaded file to the $file object.
$photo->file = $file;
// Set $photo to the fill properties, which are
// the name, path, and thumbnail path of a photo.
$photo->fill([
'name' => $photo->setFileName(),
'path' => $photo->filePath(),
'thumbnail_path' => $photo->thumbnailPath()
]);
// return the photo
return $photo;
}
/**
* Get the banner photos base directory.
*/
public function baseDir() {
return 'src/public/FlyerBanner/photos';
}
/**
* Get the name and extension of the banner photo.
*
* @return string
*/
public function setFileName() {
// Get the file name original name
// and encrypt it with sha1
$hash = sha1 (
$this->file->getClientOriginalName()
);
// Get the extension of the photo.
$extension = $this->file->getClientOriginalExtension();
// Then set name = merge those together.
return $this->name = "{$hash}.{$extension}";
}
/**
* Return the full file path of the banner photo, with the name.
*
* @return string
*/
public function filePath() {
return $this->baseDir() . '/' . $this->name;
// Ex: 'BannerPhoto/photos/foo.jpg'
}
/**
* Return the full file thumbnail path of the banner photo, with the name.
*
* @return string
*/
public function thumbnailPath() {
return $this->baseDir() . '/tn-' . $this->name;
// Ex: 'BannerPhoto/photos/tn-foo.jpg'
}
/**
* Upload the file to the proper directory.
*
* @return $this
*/
public function upload() {
// move a file to the base directory with the file name.
$this->file->move($this->baseDir(), $this->name);
// Make the thumbnail.
$this->makeThumbnail();
return $this;
}
/**
* Function to make the actual thumbnail.
* -- make and save reference the Image intervention library, not Eloquent. --
*/
protected function makeThumbnail() {
Image::make($this->filePath())
->fit(2000, 800)
//->resize(null, 400, function ($constraint) {
// $constraint->aspectRatio();
// $constraint->upsize();
//})
->save($this->thumbnailPath());
}
/**
* Delete the banner photo path and thumbnail path in DB.
* Access the delete function in FlyerController@destroyBannerPhoto method
*/
public function delete() {
$image = $this->path;
$thumbnail_image = $this->thumbnail_path;
\File::delete([
$image,
$thumbnail_image
]);
parent::delete();
}
}
宣传单照片横幅上传表格：
<form action="/travel/{{ $flyer->title }}/banner" method="post" class="dropzone" id="addBannerForm" enctype="multipart/form-data">
{{ csrf_field() }}
</form>
我的路线：
Route::group(['middleware' => ['web']], function () {
/** Resource Route For Travel Flyers */
Route::resource('travelflyers', 'TravelFlyersController');
/** Show a Flyer. **/
Route::get('{title}', 'TravelFlyersController@show');
/** Add a photo banner to a flyer **/
Route::post('{title}/banner', 'TravelFlyersController@addBannerPhoto');
/** Delete Flyer Banner photo **/
Route::delete('photo/{id}', [
'uses' => '\App\Http\Controllers\TravelFlyersController@destroyBannerPhoto',
'as' => 'flyer.delete.banner',
]);
});
答案 0 :(得分：2)
Blade也有一个默认的is_null简写，您也可以使用<img src="travel/{{ $photo->thumbnail_path or 'path/to/default.jpg'}}" >
答案 1 :(得分：2)
在一个简单的行
中File::exists($imagePath)?true:false;
这是用来： \照亮\文件系统\文件系统
记得添加命名空间：
使用文件;
答案 2 :(得分：1)
在你的模型中你应该能够做到这一点;
public function getThumbnailPathAttribute($val){
return is_null($val)?"default/path.png":$val;
}
答案 3 :(得分：0)
如果您的Photo模型与Flyer有bannerPhotos关系，则可以在Photo模型中添加以下访问者：
public function getLocationAttribute($val) {
if ($this->thumbnail_path) {
return '/travel/'. $this->thumbnail_path;
}
return '/some/other/location/with/default/photo.jpg');
}
现在在您的Blade文件中，您可以执行以下操作：
@foreach ($flyer->bannerPhotos as $photo)
<img src="{{ $photo->location }}" alt="{{ $flyer->owner->username }}" data-id="{{ $photo->id }}" id="Banner-image">
@endforeach