HttpCache active but yii debuger has executed database queries

[brouckaertd]

Hi,

Is it normal behavior when the HttpCache is active the Yii Debugger still indicates Yii executed database queries?

The behaviors method in my controller looks like:

public function behaviors()

    {

        return [

            'verbs' => [

                'class' => VerbFilter::className(),

                'actions' => [

                    'delete' => ['POST'],

                ],

            ],

            [

                'class' => 'yii\filters\HttpCache',

                'only' => ['view'],

                'lastModified' => function ($action, $params) {

                    $q = new \yii\db\Query();

                    return strtotime($q->from('Extension')->where(['id' => $_GET['id']]) ->max('UpdatedAt'));

                },

//            'etagSeed' => function ($action, $params) {

//                return // generate ETag seed here

//            }

            ],

        ];

    }

When I navigate to my view page the HTTP status is 304, which is as expected.

Image -> image.prntscr.com/image/f59787f6db0a46a2ac01b2b27faf9e7b.png

But I would expect that the Yii Debugger won’t execute a Database Query, while he still executes all queries.

Image -> image.prntscr.com/image/44f2dccf41854523bb9c43f8060c4014.png

| Q | A

| ---------------- | —

| Yii version | 2.0.10

| PHP version | 5.6.25

| Operating system | Windows 10

|Apache | Apache/2.4.23 (Win64) PHP/5.6.25

[patrickm (Yiiframework)]

HttpCache is only client-side. If the request comes in, Yii deals with it without caching.

You might want page-caching: http://www.yiiframework.com/doc-2.0/guide-caching-page.html

[brouckaertd]

At the moment it doesn’t seems logic to me.

If this post is correct (source: http://stackoverflow.com/a/20978279/1080372)

When the browser puts something in its cache, it also stores the Last-Modified or ETag header from the server.

The browser then sends a request with the If-Modified-Since or If-None-Match header, telling the server to send a 304 if the content still has that date or ETag.

The server needs some way of calculating a date-modified or ETag for each version of each resource; this typically comes from the filesystem or a separate database column.

As the server knows when to return a HTTP status 304 (Not Modified), why does he still deals with the request?

The website in development won’t have a huge amount of users, nearly a handful users on a day.

So page caching won’t improve the performance drastically.

I hope my conclusion about page caching is correct?

[samdark (Alexander Makarov)]

You may be getting a cached response along with Yii Debugger output. Check if there’s actual query made.

[brouckaertd]

Hi,

Indeed!

It must be caching.

Did my tests again with ‘Neor Profile SQL’

When pressing ‘F5’ on the page, Yii executes two queries.

When pressing ‘SHIFT’ + ‘F5’ all database queries are executed.

Thanks!

The caching mechanism works as expected.