Laravel验证文件数组

https://laravel.com/docs/5.4/validation

<?php

public function store(Request $request)
{
    $tasks_count = Task::count() ;
  
    if ( $tasks_count < 20  ) { 
        // dd( $request->all()  ) ;
        // dd($request->file('photos'));

        // VALIDATION RULES
        // 'sometimes' will make this field optional
      $this->validate( $request, [
            'task_title' => 'required',
          'task'       => 'required',
            'project_id' => 'required',
            'photos.*'     => 'sometimes|required|mimes:png,gif,jpeg,txt,pdf,doc'  // photos is an array
      ]) ;

        // dd($request->all() ) ;

        // First save Task Info
      $task = Task::create([
          'project_id' => $request->project_id,
          'task_title' => $request->task_title,
          'task'       => $request->task,
          'priority'   => $request->priority
      ]);

        // Then save files using the newly created ID above

        if ( $request->file('photos' ) != ''  ) { 
            foreach ($request->photos as $file) {
                // To Storage
                // $filename = $file->store(''); // /storage/app/taskfiles

                // To public/images
                $filename = $file->getClientOriginalName();
                $file->move('images',$filename);

                // Now create 
                TaskFiles::create([
                    'task_id' => $task->id, // then use the new available task->id  to store the filename to DB
                    'filename' => $filename
                ]);

            }
        }


      Session::flash('success', 'Task Created') ;
      return redirect()->route('task.show') ; 
    }
    
    else {
      Session::flash('info', 'Please delete some tasks, Demo max tasks: 20') ;
      return redirect()->route('task.show') ;	        
    }
/*
task  
--------------------------------------------------------------------
id  |  project_id  |  task_title  | task  |  priority  |  completed


task_file
---------------------------
id  |  task_id  |  filename

*/	   

    }