Saturday, August 22, 2020

Content Preview/Review Solution in AEM/AMS

 This tutorial explains the approach to define a preview solution for AEM(Adobe Experience Manager)/AMS(Adobe Managed Server) platform to preview the content through Author instance before activating the content to publishers.

Some of the options to enable the preview options are

  1. Share the author URL with wcmmode=disabled, this requires the reviewer should be on-boarded into the Author environment to carry the review
  2. Enable an additional preview(publish) instance, establish the workflow to send the content to the preview server for review/approval before publishing the content to live, the reviewer can use the dedicated review URL to review the content. This approach needs an additional server license to review the content.
  3. Move the content to stage servers for review, the workflow can be established to move the content to a Stage environment for review, this approach has some restriction from AMS to move the content from Production to Stage servers through the workflow. This approach can be used for on-premise setup, refer the following URL for more details — https://www.albinsblog.com/2018/02/approach-to-implement-content-preview-in-adobe-experience-manager.html#.X0FhqOhKjb0

Let us now see an alternative simple approach to enable the content review solution in AEM

Content in an AEM Author instance is accessible with a special query string parameter that disables the AEM authoring user interface — ?wcmmode=disabled.

Additionally, by configuring a read-only user account within AEM with an explicit password set, the default single sign-on (“SSO”) behavior that redirects regular users to SAML for authentication is bypassed when sending those credentials via a standard HTTP Authorization header.

Combining these facts, a reverse proxy configuration using CloudFront can be set up within an AWS account to provide a lightweight, scalable review
solution with affordable CloudFront data transfer costs.

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Cloudfront Configuration

As a first step, let us create the required configurations for CloudFront — the AMS managed CloudFront instance can’t be used to enable these configurations, the custom CloudFront should be used.

Create two distinct AWS Lambda@Edge functions(Node JS) to be fired on the viewer request and origin request events

AEM-Preview-Solution

config.js

"use strict";module.exports = {
authUser: "reviewuser",
authPass: "reviewuser!",
aemUser: "reviewaemuser",
aemPass: "reviewaemuser!",
aemAuthorDisableParam: "wcmmode=disabled"
};

origin-request-handler

When a request hits this CloudFront request, the origin request Lambda script to append the ?wcmmode=disabled query string parameter to the end of the URL (merging with any existing parameters) before forwarding to the origin(AEM Author).

Additionally, ensures the HTTP Authorization header with AEM preview user is added before the origin request;

"use strict";const config = require("./config.js");exports.handler = (event, context, callback) => {
const cfRequest = event.Records[0].cf.request;
// Reject root requests
if (cfRequest.uri === "/") {
callback(null, {
status: "400",
body: "Invalid preview URL."
});
return;
}
// Disable authoring mode
cfRequest.querystring += (cfRequest.querystring === "" ? "" : "&") + config.aemAuthorDisableParam;
// Set authorization header
cfRequest.headers["authorization"] = [
{
key: "Authorization",
value:
`Basic ${new Buffer(`${config.aemUser}:${config.aemPass}`).toString("base64")}`
}
];
// Send back
callback(null, cfRequest);
};
AEM-Preview-Solution

viewer-request-handler

Sets an Authorization header when the viewer request event is fired, ensuring the content at this preview hostname is protected by a standard HTTP Basic Authentication prompt — users prompted with basic authentication to access the preview domain.

"use strict";const config = require("./config.js");exports.handler = (event, context, callback) => {
const cfRequest = event.Records[0].cf.request;
// Construct the auth string
const authString =
`Basic ${new Buffer(`${config.authUser}:${config.authPass}`).toString("base64")}`;
// Add auth header
if (
typeof cfRequest.headers.authorization === "undefined" ||
cfRequest.headers.authorization[0].value !== authString
) {
const response = {
status: "401",
statusDescription: "Unauthorized",
body: "Unauthorized",
headers: {
"www-authenticate": [{ key: "WWW-Authenticate", value: "Basic" }]
}
};
callback(null, response);
return;
}
// Continue request processing if authentication passed
callback(null, cfRequest);
};
AEM-Preview-Solution

Configure a new CloudFront distribution with the below settings:

General

  • The alternative domain name (CNAMEs): preview-example.com
  • Add a custom SSL certificate corresponding to the above hostname
    Origin

Origin

  • Origin domain name: author-prod-example.com(the author domain name, this domain will be used CloudFront to connect to author server)
  • Origin protocol policy: HTTPS Only

Behavior

  • Origin protocol policy: HTTPS Only
  • Viewer Protocol Policy: Redirect HTTP to HTTPS
  • Allowed HTTP methods: GET, HEAD, OPTIONS, PUT, POST, PATCH, DELETE(enable the minimum required options)
  • Cache based on selected request headers: Whitelist
  • Whitelist: Authorization, Host
  • Minimum TTL, Maximum TTL, Default TTL: all set to 60 — CloudFront caches the request for a configurable duration (60 seconds, currently), to avoid applying an unnecessary load to the Author instance;
  • Forward cookies: None
  • Compress objects automatically: Yes
  • Lambda function associations:
    Origin request: point to the ARN of the origin-request-handler
    Viewer request: point to the ARN of the viewer-request-handler
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Point a new DNS hostname preview-author.example.com(CNAME) to a new AWS CloudFront distribution through DNS Zone manager(e.g xxxxxxxxx.cloudfront.net).

preview-author.example.com CNAME xxxxxxxxx.cloudfront.net

AEM Configuration

Create a preview user in the Author instance with read-only access to the appropriate content/DAM and an explicit password set- reviewaemuser/reviewaemuser!(Please validate with Adobe before implementing this solution if there is any licensing issue with this common user, my understanding is there should not be any impact)

The Author instance is configured with this preview hostname as an additional VHOST in author-vhosts.any — author-vhosts.any, this file enable the supported vhosts for author-farm.any, also disable the http to https redirect in the default.vhost for the specific domain, even though the preview URL is enabled through https the SSL forward related headers will not be sent to the Dispatcher e.g “X-Forwarded-Proto”

default.vhost

RewriteEngine on
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteCond %{HTTP_HOST} !^preview-author.example.com$
RewriteCond %{REQUEST_URI} !^/dispatcher/invalidate.cache
RewriteRule !/eagle/check https://%{SERVER_NAME}%{REQUEST_URI} [L,R]

author-vhosts.any

"author-prod-example.com"
"preview-author.example.com"

AEM renders the page in the Author instance with the AEM authoring user interface disabled, effectively producing HTML markup identical to the output of the Publish instance once activated

Now the configurations are ready, Web publishers can construct a URL similar to the below, reflecting a page location within AEM, and circulate this to any user needing to preview the currently-authored content before it is activated live to the public-facing website. This URL is accessible with complete content path, but behind the credentials provided(reviewaemuser/reviewaemuser!). https://preview-author.example.com/content/test/us/en/home.html

Sunday, August 16, 2020

Sling Content Distribution in AEM (Part 3) — Sync Distribution | Sync Content between Publishers in AEM as a Cloud Service

This tutorial is the continuation of earlier tutorials on Sling Content Distribution in AEM, refer the following URL for part 1 and part 2 tutorials.

This tutorial is created based on AEM as Cloud Service Local Author and Publish instances. The social user sync module is removed from AEM as Cloud due to that some additional configurations required to enable the sync distribution between publishers.

I am using the OSGi system console to enable the required configurations for the demo, use run mode specific OGGI configurations while implementing content distribution in the project.

In this tutorial let us see the details on Sling Sync Distribution on AEM.

Sync Distribution — Definition

  • Sync distribution allows modifications made on one publish instance to be synchronized with other publish instances in the farm of publish instances via author instance
  • The modifications automatically synchronized across the publish instances in the farm and are not created on the author.
  • That is done by the author pulling the content from source instance(publish) and distribute it to the other publish instances on the farm.
  • Sling distribution only sends the modification data to non-originating publish instances, eliminating unnecessary traffic
  • The author pulls resources from n publish instances and push them to n-1 publish instances in the farm.
sling-sync-distribution-aem

This will helps us to sync the data generated in n publish instances to (n-1) publish instances other than the source publish instance in a farm through Author instance as a coordinator but without creating the content in Author.

Sync Distribution — Configurations

sling-sync-distribution-aem

Configure a local importer, agent-based exporter and a “queue” agent on all the publish instances

org.apache.sling.distribution.packaging.impl.importer.LocalDistributionPackageImporterFactory-sync.json

name=“sync”

org.apache.sling.distribution.agent.impl.QueueDistributionAgentFactory-pubsync.json

name=”pubsync

org.apache.sling.distribution.packaging.impl.exporter.AgentDistributionPackageExporterFactory-pubsync.json

name=”pubsync”

Configure a “sync distribution” agent on the author(coordinator instance)

org.apache.sling.distribution.agent.impl.SyncDistributionAgentFactory

name=“distribution-sync”

packageExporter.endpoints — pointing to the URL of the exporter on publish instance, configure the endpoints of all the publishers in the farm

packageImporter.endpoints — pointing to the URL of the importer on publish instance, configure the endpoints of all the publishers in the farm

Sync Distribution — Demo

  • Configure Authorized User
  • Adobe Granite Distribution — Encrypted Password Transport Secret Provider
  • Configure Queue agent and importer on Publisher
  • Configure Sync Distribution Agent on Author
  • Enable Triggers — Scheduled/JCREvent
  • Test — CURL/Triggers

Let us now see how to use the sync distribution to sync the content modifications between publish instances through Author instance(Coordinator) without creating the modifications in Author instance. The sync distribution can be used to sync any data between the farm of publishers.

Configure Authorized User

Create a new user with name — “usersync-admin” and add this user to the administrator group

Follow the amove steps in all the publish instances

Adobe Granite Distribution — Encrypted Password Transport Secret Provider

Once the authorized user is configured in all the publishers, enable Encrypted Password Transport Secret Provider in Author instance, this user will be used to sync the content between Author and Publish instances.

Access http://localhost:4502/system/console/configMgr

Create new configuration for factory “Adobe Granite Distribution — Encrypted Password Transport Secret Provider

name=”distributionsync-publishuser”

username=”usersync-admin”

encryptedPassword= <encryptedPassword for usersync-admin> — Encrypt the password through http://localhost:4502/system/console/crypto

Follow the below steps before encrypting the password to sync the hmac and master files from Author to all the publish instances.

  • Find the bundle Id in Author for com.adobe.granite.crypto.file, for example, 36 by navigating to /system/console/bundles/com.adobe.granite.crypto.file to see the Id.
  • Navigate to /crx-quickstart/launchpad/felix/bundle<Id>/data in the Author file system.
  • Copy the two files: hmac and master from the Author instance to the publish instances.
  • Restart the com.adobe.granite.crypto bundle or the complete Publish instances.

Configure importer, exporter and Queue agent on Publishers

Configure a queue agent that places the changes into the queues, an exporter that exports packages from the queue agent and importer that imports packages from the queue agent.

Access http://localhost:4503/system/console/configMgr

Create new configuration for factory “Apache Sling Distribution Agent — Queue Agents Factory”

Enter a name =“pubsync”
Title=“pubsync”
Check=“Enabled”
Service Name=Service name is optional, if required create a service user with the required permission
Change the log level if required
Allowed Roots=Add the root paths the agent is responsible for distribution e.g required multiple root paths can be configured ) e.g. [/content/we-retail/us]

sling-sync-distribution-aem

Now the Queue Agent factory is enabled, the agent can be managed through Tools — Deployments — Distribution

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Let us now configure a local importer

Access http://localhost:4503/system/console/configMgr

Create new configuration for factory “Apache Sling Distribution Importer — Local Package Importer Factory”

name=”sync”

sling-sync-distribution-aem

Let us now configure an agent-based exporter

Access http://localhost:4503/system/console/configMgr

Create new configuration for factory “Apache Sling Distribution Exporter — Agent Based Package Exporter

name=”pubsync”
agent.target=”(name=pubsync)”

sling-sync-distribution-aem

Repeat the above(configuring Queue agent, importer, and exporter)steps on other publishers in the farm

Configure Sync Distribution Agent on Author

Configure a Sync Distribution Agent in Author that will PULL the content from publishers(exporters) endpoints based on the configuration and distribute the content to the publishers other than the source.

Access http://localhost:4502/system/console/configMgr

Create new configuration for factory “Apache Sling Distribution Agent — Sync Agents Factory”

Enter a name=“distribution-sync”
Title =“distribution-sync”
Check “Enabled”
Service Name=Service name is optional, if required create a service user with the required permission
Change the log level if required
packageExporter.endpoints=[“http://localhost:4503/libs/sling/distribution/services/exporters/pubsync","http://localhost:4505/libs/sling/distribution/services/exporters/pubsync"]
packageImporter.endpoints=[“http://localhost:4503/libs/sling/distribution/services/importers/sync","http://localhost:4505/libs/sling/distribution/services/importers/sync"]
transportSecretProvider.target = (name=distributionsync-publishuser)

sling-sync-distribution-aem
sling-sync-distribution-aem

Now the Distribution Agent factory is enabled, the agent can be managed through Tools — Deployments — Distribution

sling-sync-distribution-aem

Now the initial configurations are ready, let us test the sync distribution scenario through curl commands

Modify some content under /content/wknd/us node in publish1

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Execute the below curl commands

On Publish1 — the publisher where the content is modified

curl -u admin:admin http://localhost:4503/libs/sling/distribution/services/agents/pubsync -d “action=ADD” -d “path=/content/wknd/us/en/jcr:content”

Now the content is queued to the publish1 distribution queue

On Author

curl -u admin:admin http://localhost:4502/libs/sling/distribution/services/agents/distribution-sync -d “action=PULL”

Now the content is pulled by Author and distributed to the publishers other than source, the content modifications are not created in Author.

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Let us now see how to automate the sync distribution through triggers

Configure a JCR Event Trigger in Publishers

Configure a JCR Event Trigger in Publishers — repeat the below steps to all the publishers, to add the JCR changes under the configured path to the Distribution queue

Access http://localhost:4502/system/console/configMgr

Create new configuration for factory “Apache Sling Distribution Trigger — Jcr Event Triggers Factory”

Enter name =“pubsync-trigger”
The path for which the changes are distributed=“/content/wknd/us”
serviceName=service name to access the content e.g distributionservice
Use deep distribution =Enable this if want to distribute the subtree of the configured node on any events

sling-sync-distribution-aem

Create a system user with name distributionservice and provide the required privileges to access the content, I am providing full access for the demo

Register a Server User Mapping for “Apache Sling Service User Mapper Service Amendment”

org.apache.sling.distribution.core:distributionservice=distributionservice

sling-sync-distribution-aem

Now link the trigger to the “Apache Sling Distribution Agent — Queue Agents Factory” configured with the name “pubsync” in the earlier step, Triggers — (name=pubsync-trigger)

sling-sync-distribution-aem

Configure a Scheduled Event Trigger in Author

Configure a Scheduled Event Trigger in Author to pull the content from publishers Queue and distribute the content to the publishers other than the source.

Access http://localhost:4502/system/console/configMgr

Create new configuration for factory “Apache Sling Distribution Trigger — Scheduled Triggers Factory”

Enter name =“pubsync-trigger”
Distribution Type=“PULL”
Distributed Path= the path to be distributed periodically e.g. “/content/wknd/us”
serviceName = service name to access the content e.g distributionservice
Interval in Seconds =the number of seconds between distribution requests. Default 30 seconds

sling-sync-distribution-aem

Create a system user with name distributionservice and provide the required privileges to access the content, I am providing full access for the demo

Register a Server User Mapping for “Apache Sling Service User Mapper Service Amendment”

org.apache.sling.distribution.core:distributionservice=distributionservice

sling-sync-distribution-aem

Now link the trigger to the “Apache Sling Distribution Agent — Sync Agents Factory” configured with the name “distribution-sync” in the earlier step, Triggers — (name=pubsync-trigger)

sling-sync-distribution-aem

Now the content modification from the publisher1 under /content/wknd/us node will be synced to the publishers other than the source(publisher1)on every 30 second

This concludes the sync distribution configuration between publishers through the author instance as a coordinator, the content changes from the publishers are pulled by the author and distributed to all the publishers other than the source. We can configure multiple publisher endpoints in the Author sync agent to pull and distribute the content changes. The triggers can be configured in Author and Publishers to completely automate the sync distribution of the contents.