DocumentationAEMAEM Screens Guide

Dispatcher Configurations for AEM Screens dispatcher-configurations-for-aem-screens

Last update: Thu May 09 2024 00:00:00 GMT+0000 (Coordinated Universal Time)

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Dispatcher is Adobe Experience Manager’s caching, or load-balancing tool, or both.

The following page provides the guidelines for configuring a Dispatcher for an AEM Screens project.

NOTE
If a Dispatcher is available, connections to the registration servlet can be prevented by filtering in the Dispatcher rules.
If there is no Dispatcher, disable the registration servlet in the OSGi components listing.

Before you configure Dispatcher for an AEM Screens project, have prior knowledge of Dispatcher.
See Configuring Dispatcher for more details.

Configuring Dispatcher for Manifest Version v2 configuring-dispatcher

IMPORTANT
The following Dispatcher configurations apply only to Manifest version v2. See Dispatcher Configurations for Manifest version v3 for Manifest version v3.

AEM Screens players or devices use an authenticated session to access the resources in the Publishing instances as well. When you have multiple publish instances, the requests should always go to the same Publishing instance so that the authenticated session is valid for all the requests coming from the AEM Screens players or devices.

Follow the steps below to configure the Dispatcher for an AEM Screens project.

Enabling Sticky Sessions enable-sticky-session

If you want to use multiple publish instances fronted by single Dispatcher, update the dispatcher.any file to enable stickiness.

/stickyConnections {
  /paths
  {
    "/"
  }
 }

If you have one publish instance fronted by one Dispatcher, enabling the stickiness at the Dispatcher does not help because the load balancer may send each request to Dispatcher. In this case, click Enable in Stickiness field to turn it on at your load balancer level, as shown in the figure below:

image

For example, if you are using AWS ALB, see Target groups for your Application Load Balancers for enabling stickiness at the ALB level. Enable the stickiness for one day.

Step 1: Configuring Client Headers step-configuring-client-headers

Add the following to /clientheaderssection:

X-Requested-With

X-SET-HEARTBEAT

X-REQUEST-COMMAND

Step 2: Configuring Screens Filters step-configure-screens-filters

To configure Screens filters, add the following to /filter.

## AEM Screens Filters
## # Login, Ping and Device Configurations
/0200 { /type "allow" /method "POST" /url "/libs/granite/core/content/login.validate/j_security_check" }
/0201 { /type "allow" /method "GET" /url "/libs/granite/csrf/token.json" }
/0202 { /type "allow" /method "GET" /url "/content/screens/svc.json" }
/0203 { /type "allow" /method "GET" /url "/content/screens/svc.ping.json" }
/0204 { /type "allow" /method "GET" /url "/content/screens/svc.config.json" }
## # Device Dashboard Configurations
/0210 { /type "allow" /method '(GET|POST)' /url "/home/users/screens/*/devices/*/profile_screens.preferences.json" }
/0211 { /type "allow" /method "POST" /url "/home/users/screens/*/devices/*/profile_screens.logs.json" }
/0212 { /type "allow" /method "POST" /url "/home/users/screens/*/devices/*/profile_screens.statusinfo.json" }
/0213 { /type "allow" /method "POST" /url "/home/users/screens/*/devices/*/profile_screens.screenshot.json" }
## # Content Configurations
/0220 { /type "allow" /method '(GET|HEAD)' /url "/content/screens/*" }
/0221 { /type "allow" /method '(GET|HEAD)' /url "/content/screens/*/jcr:content/*/offline-config_*.zip" }
/0222 { /type "allow" /method '(GET|HEAD)' /url '/var/contentsync/content/screens/.+/jcr:content/.+/offline-config_.*\.[0-9]+\.zip' }

Step 3: Disabling Dispatcher Cache step-disabling-dispatcher-cache

Disable Dispatcher caching for /content/screens path.

Screens players use authenticated sessions, so the Dispatcher does not cache any of the screens players requests for channels/assets.

To enable the cache for the assets so that the assets are served from the Dispatcher cache, do the following:

  • Add /allowAuthorization 1 in /cache section
  • Add the below rules to /rules section of /cache
/0000
    {
        /glob "*"
        /type "allow"
    }

/0001
    {
        # Disable Dispatcher Cache for Screens channels
        /glob "/content/screens/*.html"
        /type "deny"
    }

/0002
    {
    # Disable Dispatcher Cache for Screens offline manifests
    /glob "/content/screens/*.json"
    /type "deny"
    }

/0003
    { # Disable Dispatcher Cache for Screens devices json
    /glob "/home/users/screens/*.json"
    /type "deny"
    }

Configuring Dispatcher for Manifest Version v3 configuring-dispatcherv3

Make sure to allow these filters and cache rules in dispatchers fronting the Publishing instances for the functioning of Screens.

Pre-requisites for Manifest Version v3 prerequisites3

Follow these two prerequisites before configuring a Dispatcher (manifest version v3) for AEM Screens:

  • Make sure that you are using v3 manifests. Navigate to https://<server:port>/system/console/configMgr/com.adobe.cq.screens.offlinecontent.impl.ContentSyncCacheFeatureFlag and ensure that Enable ContentSync Cache is unchecked.

  • Make sure that the Dispatcher flush agent is configured at /etc/replication/agents.publish/dispatcher1useast1Agent in publish instance.

    image

    image

Filters filter-v3

## AEM Screens Filters
## # Login, Ping and Device Configurations
/0200 { /type "allow" /method "POST" /url "/libs/granite/core/content/login.validate/j_security_check" }
/0201 { /type "allow" /method "GET" /url "/libs/granite/csrf/token.json" }
/0202 { /type "allow" /method "GET" /url "/content/screens/svc.json" }
/0203 { /type "allow" /method "GET" /url "/content/screens/svc.ping.json" }
/0204 { /type "allow" /method "GET" /url "/content/screens/svc.config.json" }

## # Device Dashboard Configurations
/0210 { /type "allow" /method '(GET|POST)' /url "/home/users/screens/*/devices/*/profile_screens.preferences.json" }
/0211 { /type "allow" /method "POST" /url "/home/users/screens/*/devices/*/profile_screens.logs.json" }
/0212 { /type "allow" /method "POST" /url "/home/users/screens/*/devices/*/profile_screens.statusinfo.json" }
/0213 { /type "allow" /method "POST" /url "/home/users/screens/*/devices/*/profile_screens.screenshot.json" }

## # Content Configurations
/0220 { /type "allow" /method '(GET|HEAD)' /url "/content/screens/*" }
#/0221 { /type "allow" /method '(GET|HEAD)' /url "/content/experience-fragments/*" } ## uncomment this, if you're using experience-fragments
/0222 { /type "allow" /extension '(css|eot|gif|ico|jpeg|jpg|js|gif|pdf|png|svg|swf|ttf|woff|woff2|html|mp4|mov|m4v)' /path "/content/dam/*" } ## add any other formats required for your project here

## # Enable clientlibs proxy servlet
/0230 { /type "allow" /method "GET" /url "/etc.clientlibs/*" }

Cache Rules cache-rules-v3

  • Add /allowAuthorized "1" to /cache section in publish_farm.any.

  • All the AEM Screens players use an authenticated session to connect to AEM (author/publish). Out-of-the-box, a Dispatcher does not cache these URLs, so you should enable them.

  • Add statfileslevel "10" to /cache section in publish_farm.any
    This rule supports caching up to ten levels from the cache docroot and invalidate accordingly when content is published rather than invalidating everything. Feel free to change this level based on how deep your content structure is

  • Add the following to /invalidate section in publish_farm.any

    code language-none 
    /0003 {
    /glob "*.json"
    /type "allow"
}

  • Add the following rules to /rules section in /cache in publish_farm.any or in a file that is included from publish_farm.any:

    code language-none 
    ## Don't cache CSRF login tokens
/0001
    {
    /glob "/libs/granite/csrf/token.json"
    /type "deny"
    }
## Allow Dispatcher Cache for Screens channels
/0002
    {
        /glob "/content/screens/*.html"
        /type "allow"
    }
## Allow Dispatcher Cache for Screens offline manifests
/0003
    {
    /glob "/content/screens/*.manifest.json"
    /type "allow"
    }
## Allow Dispatcher Cache for Assets
/0004
    {

    /glob "/content/dam/*"
    /type "allow"
    }
## Disable Dispatcher Cache for Screens devices json
/0005
    {
    /glob "/home/users/screens/*.json"
    /type "deny"
    }
## Disable Dispatcher Cache for Screens svc json
/0006
    {
    /glob "/content/screens/svc.json"
    /type "deny"
    }

Add invalidation rule for segments.js invalidsegmentjs

If you are using targeted campaigns with AEM Screens, then the segments.js file served by the Dispatcher must be invalidated, as you add and publish new segments on AEM. Without this invalidation rule, new targeted campaigns do not work on the AEM Screens Player (it shows the default content instead).

  • Add an invalidation rule to /etc/httpd/conf.dispatcher.d/available_farms/999_ams_publish_farm.any. Here is the rule to add:
    /invalidate {
                        .
                        .
                        /0004 {
                               /glob "conf/<project-name>/settings/wcm/.js"
                               /type "allow"
                        }
                }
  • This rule ensures the segments.js file is invalidated and latest is fetched when modified.
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