email.blade.php

@if ($crud->hasAccess('email'))
  <a href="{{ url($crud->route.'/'.$entry->getKey().'/email') }}" class="btn btn-sm btn-link"><i class="la la-envelope"></i> Email</a>
@endif

email_form.blade.php

@extends(backpack_view('blank'))
@php
$defaultBreadcrumbs = [
    trans('backpack::crud.admin') => url(config('backpack.base.route_prefix'), 'dashboard'),
    $crud->entity_name_plural => url($crud->route),
    'Email' => false,
];
// if breadcrumbs aren't defined in the CrudController, use the default breadcrumbs
$breadcrumbs = $breadcrumbs ?? $defaultBreadcrumbs;
@endphp
@section('header')
    <section class="container-fluid">
        <h2>
            <span class="text-capitalize">Send Email</span>
            <small>Sending email to {!! $entry->name !!}.</small>
            @if ($crud->hasAccess('list'))
                <small>
                    <a href="{{ url($crud->route) }}" class="d-print-none font-sm">
                        <i
                            class="la la-angle-double-{{ config('backpack.base.html_direction') == 'rtl' ? 'right' : 'left' }}"></i>
                        {{ trans('backpack::crud.back_to_all') }}
                        <span>{{ $crud->entity_name_plural }}</span>
                    </a>
                </small>
            @endif
        </h2>
    </section>
@endsection

@section('content')
    <div class="row">
        <div class="col-md-8 bold-labels">
            @if ($errors->any())
                <div class="alert alert-danger pb-0">
                    <ul class="list-unstyled">
                        @foreach ($errors->all() as $error)
                            <li><i class="la la-info-circle"></i> {{ $error }}</li>
                        @endforeach
                    </ul>
                </div>
            @endif
            <form method="post" action="">
                @csrf
                <div class="card">
                    <div class="card-body row">
                        <div class="form-group col-md-4">
                            <label>From</label>
                            <input type="text" name="from" value="{{ old('from',env('MAIL_FROM_ADDRESS')) }}" class="form-control @error('from') is-invalid @enderror">
                                @error('from')
                                <div class="invalid-feedback d-block">{{ $message }}</div>
                                @enderror
                        </div>
                        <div class="form-group col-md-4">
                            <label>To</label>
                            <input type="text" name="to" value="{{ $entry->email }}" readonly="readonly" disabled="disabled" class="form-control">
                        </div>
                        <div class="form-group col-md-4">
                            <label>Reply To</label>
                            <input type="text" name="reply_to" value="{{ old('reply_to',backpack_user()->email) }}" class="form-control @error('reply_to') is-invalid @enderror">
                                @error('reply_to')
                                <div class="invalid-feedback d-block">{{ $message }}</div>
                                @enderror
                        </div>
                        <div class="form-group col-sm-12">
                            <label>Subject</label>
                            <input type="text" name="subject" value="{{ old('subject') }}" class="form-control @error('subject') is-invalid @enderror">
                                @error('subject')
                                <div class="invalid-feedback d-block">{{ $message }}</div>
                                @enderror
                        </div>
                        <div class="form-group col-sm-12">
                            <label>Message</label>
                            <textarea name="message" class="form-control @error('message') is-invalid @enderror">{{ old('message') }}</textarea>
                            @error('message')
                            <div class="invalid-feedback d-block">{{ $message }}</div>
                            @enderror
                        </div>
                    </div>
                </div>
                <div class="d-none" id="parentLoadedAssets">[]</div>
                <div id="saveActions" class="form-group">
                    <input type="hidden" name="_save_action" value="send_email">
                    <button type="submit" class="btn btn-success">
                        <span class="la la-save" role="presentation" aria-hidden="true"></span> &nbsp;
                        <span data-value="send_email">Send Email</span>
                    </button>
                    <div class="btn-group" role="group">
                    </div>
                    <a href="{{ url($crud->route) }}" class="btn btn-default"><span class="la la-ban"></span>
                        &nbsp;Cancel</a>
                </div>
            </form>
        </div>
    </div>
@endsection

EmailOperation.php

<?php

namespace App\Http\Controllers\Admin\Operations;

use Illuminate\Support\Facades\Route;
use Illuminate\Support\Facades\Mail;
use Illuminate\Http\Request;
use Exception;
use Validator;
use Alert;

trait EmailOperation
{
    /**
     * Define which routes are needed for this operation.
     *
     * @param string $segment    Name of the current entity (singular). Used as first URL segment.
     * @param string $routeName  Prefix of the route name.
     * @param string $controller Name of the current CrudController.
     */
    protected function setupEmailRoutes($segment, $routeName, $controller)
    {
        Route::get($segment . '/{id}/email', [
            'as'        => $routeName . '.email',
            'uses'      => $controller . '@email',
            'operation' => 'email',
        ]);

        Route::post($segment . '/{id}/email', [
            'as'        => $routeName . '.email-send',
            'uses'      => $controller . '@postEmailForm',
            'operation' => 'email',
        ]);
    }

    /**
     * Add the default settings, buttons, etc that this operation needs.
     */
    protected function setupEmailDefaults()
    {
        $this->crud->allowAccess('email');

        $this->crud->operation('email', function () {
            $this->crud->loadDefaultOperationSettingsFromConfig();
        });

        $this->crud->operation('list', function () {
            // $this->crud->addButton('top', 'email', 'view', 'crud::buttons.email');
            $this->crud->addButton('line', 'email', 'view', 'crud::buttons.email');
        });
    }

    /**
     * Show the view for performing the operation.
     *
     * @return Response
     */
    public function email()
    {
        $this->crud->hasAccessOrFail('email');

        // prepare the fields you need to show
        $this->data['crud'] = $this->crud;
        $this->data['title'] = $this->crud->getTitle() ?? 'email ' . $this->crud->entity_name;
        $this->data['entry'] = $this->crud->getCurrentEntry();
        // load the view
        return view("crud::operations.email_form", $this->data);
    }

    public function postEmailForm(Request $request)
    {
        // run validation
        $validator = Validator::make($request->all(), [
            'from' => 'required|email',
            'reply_to' => 'nullable|email',
            'subject' => 'required',
            'message' => 'required'
        ]);
        if ($validator->fails())
            return redirect()->back()->withErrors($validator)->withInput();
        $entry = $this->crud->getCurrentEntry();
        try {
            // send the actual email
            Mail::raw($request['message'], function ($message) use ($entry, $request) {
                $message->from($request->from);
                $message->replyTo($request->reply_to);
                $message->to($entry->email, $entry->name);
                $message->subject($request['subject']);
            });

            Alert::success('Mail Sent')->flash();

            return redirect(url($this->crud->route));
        } catch (Exception $e) {
            // show a bubble with the error message
            Alert::error("Error, " . $e->getMessage())->flash();

            return redirect()->back()->withInput();
        }
    }
}