Imagines in musca Sedeo

In omni fere applicatione telae quae imaginibus utitur, opus est ut parva harum imaginum exemplaria crearentur et saepe plures formae adiectis imaginibus exstant.
Novas addit rationes ad applicationem exsistens etiam aliquos dolores causat. Hinc labor;

negotium

In indice requisitorum ineamus:

• Imagines aliquas formatorum musca additas generare sine additione functionis in applicatione aliquo tempore in applicatione existentiae introducendo;
• Imagines adiectae in omni petitione generari non oportet;
• Facultatem inactivare additional imagines non specificatarum formarum generandi.

Ultimum punctum exponam, quia primo puncto leviter contradicit. Si generationem quarumlibet imaginum apertam facimus, possibilitas est oppugnationis in situ generando multas petitiones ad imaginem resize in infinitos formas, ut haec vulnerabilitas claudenda sit.

nginx institutionem configuratione

Ad praedicta requisita solvenda opus est sequentis moduli nginx copiae:

• ngx_http_image_filter_module — resipiscendis imaginibus;
• ngx_http_proxy_module — caching for;
• ngx_http_secure_link_module — contra spam tueri;

modules ngx_http_image_filter_module и ngx_http_secure_link_module per defaltam non installantur, quare ad institutionem configurationis spectaculi definiri debent nginx:

phoinix@phoinix-work:~/src/nginx-0.8.29
$ ./configure --with-http_secure_link_module --with-http_image_filter_module


nginx configuratione

Unam novam addimus ad exercitum nostrum configuratione Location et parametri cache generalis:

...
    proxy_cache_path /www/myprojects/cache levels=1:2 keys_zone=image-preview:10m;
...
    server {
...
        location ~ ^/preview/([cir])/(.+) {
        # Тип операции
            set                         $oper $1;
        # Параметры изображения и путь к файлу
            set                         $remn $2;
        # Проксируем на отдельный хост
            proxy_pass                  http://myproject.ru:81/$oper/$remn;
            proxy_intercept_errors      on;
            error_page                  404 = /preview/404;
        # Кеширование
            proxy_cache                 image-preview;
            proxy_cache_key             "$host$document_uri";
        # 200 ответы кешируем на 1 день
            proxy_cache_valid           200 1d;
        # остальные ответы кешируем на 1 минуту
            proxy_cache_valid           any 1m;
        }
        
        # Возвращаем ошибку
        location = /preview/404 {
            internal;
            default_type                image/gif;
            alias                       /www/myprojects/image/noimage.gif;
        }
...
    }
...


Addimus etiam novam hospitem ad config;

server {
    server_name                     myproject.ru;
    listen                          81;

    access_log                      /www/myproject.ru/logs/nginx.preview.access_log;
    error_log                       /www/myproject.ru/logs/nginx.preview.error_log info;

    # Указываем секретное слово для md5
    secure_link_secret              secret;

    # Ошибки отправляем она отдельный location
    error_page                      403 404 415 500 502 503 504 = @404;

    # location Для фильтра size
    location ~ ^/i/[^/]+/(.+) {
        
        # грязный хак от Игоря Сысоева *
        alias                       /www/myproject.ru/images/$1;
        try_files                   "" @404;
    
        # Проверяем правильность ссылки и md5
        if ($secure_link = "") { return 404; }
        
        # Используем соответсвующий фильтр
        image_filter                size;
    }

    # По аналогии остальные location для других фильтров
    location ~ ^/c/[^/]+/(d+|-)x(d+|-)/(.+) {
        set                         $width  $1;
        set                         $height $2;
        
        alias                       /www/myproject.ru/images/$3;
        try_files                   "" @404;
    
        if ($secure_link = "") { return 404; }
    
        image_filter                crop  $width  $height;
    }
    
    location ~ ^/r/[^/]+/(d+|-)x(d+|-)/(.+) {
        set                         $width  $1;
        set                         $height $2;

        alias                       /www/myproject.ru/images/$3;
        try_files                   "" @404;

        if ($secure_link = "") { return 404; }

        image_filter                resize  $width  $height;
    }

    location @404 { return 404; }
}


Quam ob rem imagines additae obtineri possunt utentes nexus sequentes:

• myproject.ru/preview/i[md5]/[path_to_image]
• myproject.ru/preview/c[md5]/[size]/[path_to_image]
• myproject.ru/preview/r[md5]/[size]/[path_to_image]

* try_files " - sensitivo ad spatia et characteres Russian, sic ego cum fusum facere alias.

Uti in telam applicationem

Ad applicationis ambitum textus, sequenti modo facere potes (Perl);

sub proxy_image {
    use Digest::MD5     qw /md5_hex/;
    my %params = @_;
    my $filter = {
                    size    => 'i',
                    resize  => 'r',
                    crop    => 'c'            
                  }->{$params{filter}} || 'r';
    my $path = ($filter ne 'i' ?
                    ( $params{height} || '_' ) . 'x' . ( $params{width} || '_' ) . '/' :
                    ()
               ) . $params{source};
    my $md5 = md5_hex( $path . 'secret' );
    $path = '/preview/' . $filter . '/' . $md5 . '/' . $path;
    return $path;
}

my $preview_path = &proxy_image(
                    source  => 'image1.jpg',
                    height  => 100,
                    width   => 100,
                    filter  => 'resize'
                );


Etsi etiam commendare calculandum moles Preview.

pectis rastris,

Cum delendo imaginem originalem, Praevius naturaliter, non delebitur e cella donec cella infirmata sit, et in casu nostro, Praevius potest esse per diem post deletionem, sed hoc maximum tempus est.

original

Source: www.habr.com