Adobe CEP Resources

CEP searches for extensions in three specific locations in a defined order. If multiple extensions share the same bundle ID, CEP follows specific versioning and modification rules to decide which one to load.

Extension Folder Types

1. Product extension folder: Used by host application installers. Path varies by product (e.g., ${PP}/CEP/extensions). Third-party extensions cannot be installed here.
2. System extension folder:
   • Windows (x64): C:\Program Files (x86)\Common Files\Adobe\CEP\extensions and C:\Program Files\Common Files\Adobe\CEP\extensions (since CEP 6.1)
   • macOS: /Library/Application Support/Adobe/CEP/extensions
3. Per-user extension folder:
   • Windows: C:\Users\<USERNAME>\AppData\Roaming\Adobe\CEP\extensions
   • macOS: ~/Library/Application Support/Adobe/CEP/extensions

Loading Priority Logic

CEP determines which extension to load using these rules:

1. Search Order: Product folder $\rightarrow$ System folder $\rightarrow$ Per-user folder.
2. Filtering: Extensions without a matching host application ID and version are ignored.
3. Version Conflict: If bundle IDs match, the one with the higher version is loaded.
4. Modification Date Conflict: If bundle IDs and versions match, the one with the latest manifest modification date is loaded.
5. Tie-breaker: If all the above match, the first one found is loaded.

Important Constraints

• Character Restriction: The character # is not allowed in extension folder paths on Windows or macOS because CEF treats it as a delimiter.

The HostList defines which Adobe applications and versions your extension supports.

Version Range Syntax

• Inclusive range: [15.0,15.9] supports version 15.0 up to and including 15.9.
• Exclusive range: [15.0,15.9) supports version 15.0 up to but not including 15.9.

Default vs. Per-Extension HostList

• Default HostList: Defined under <ExecutionEnvironment>. It applies to all extensions in the bundle.
• Per-Extension HostList: Defined under <DispatchInfoList> -> <Extension Id="...">. This overrides the default HostList for that specific extension.
• Note: Adding a HostList with no child nodes effectively disables that extension for all host applications.
• Warning: Do not use both HostList tags and the Host attribute in DispatchInfo tags; use HostList for new extensions.

<!-- Inclusive range example -->
<HostList>
    <Host Name="PHXS" Version="[15.0,15.9]"/>
    <Host Name="PHSP" Version="[15.0,15.9]"/>
</HostList>

<!-- Per-extension override example -->
<DispatchInfoList>
  <Extension Id="com.adobe.CEPHTMLTEST.Panel1">
    <HostList>
      <Host Name="PHXS" />
    </HostList>
  </Extension>
</DispatchInfoList>

CEP and Chromium use a multi-process architecture. Each CEP extension runs in its own CEP HTML Engine, which typically consists of three processes: one main/browser process, one renderer process, and one GPU process.

Process Naming:

• macOS: The main process is named CEPHtmlEngine. The renderer and GPU processes are named CEPHtmlEngine Helper.
• Windows: All three processes are named CEPHtmlEngine.exe.

Identifying Processes via Command Line: You can identify which extension a process belongs to by inspecting its command line parameters:

• Browser process: Does not contain the --type flag.
• Renderer process: Contains --type=renderer.
• GPU process: Contains --type=gpu-process.

How to check command line parameters:

• macOS: Run ps -ef | grep CEPHtmlEngine in a terminal.
• Windows: Use system tools to inspect the command line arguments of running programs.

CEP searches for extensions in a specific order:

1. Product extension folder
2. System extension folder
3. Per-user extension folder.

Conflict Resolution:

• Extensions must have an appropriate host application ID and version to be loaded.
• If multiple extensions share the same extension bundle ID:
  • The one with the higher version is loaded.
  • If versions are identical, the one with the latest manifest.xml modification date is loaded.
  • If modification dates are also identical, the first one found is loaded.

Installation Best Practices:

• Host application installers should use the product extension folder.
• Extensions installed via creative.adobe.com/addons should use the system or per-user extension folder.

Constraint: The character # is not allowed in extension folder paths on Windows or macOS because the Chromium Embedded Framework (CEF) treats it as a delimiter.

There is no direct way for ExtendScript to access the HTML extension's DOM. Instead, you must use CEP's event-based communication system using CSXSEvent and the PlugPlugExternalObject library.

1. ExtendScript Side: Dispatching an Event

First, create an instance of ExternalObject using the PlugPlugExternalObject library. Then, create and dispatch a CSXSEvent.

var externalObjectName = "PlugPlugExternalObject"; 
var mylib = new ExternalObject( "lib:" + externalObjectName );
var eventObj = new CSXSEvent(); 
eventObj.type="documentCreated"; 
eventObj.data="blahblah"; 
eventObj.dispatch();

2. HTML Extension Side: Listening for the Event

In your HTML extension, use CSInterface.addEventListener to listen for the specific event type dispatched by the host application.

var cs = new CSInterface();

cs.addEventListener("documentCreated", function(event){
  alert('Cool!' + event.data);
});

var extendScript = 'var externalObjectName = "PlugPlugExternalObject"; var mylib = new ExternalObject( "lib:" + externalObjectName ); app.document.add(); var eventObj = new CSXSEvent(); eventObj.type="documentCreated"; eventObj.data="blahblah"; eventObj.dispatch();'
cs.evalScript(extendScript);

CEP operates using several distinct execution contexts:

1. Browser Context: The default JavaScript context for the CEP browser engine. Accesses Browser objects and CEP's file system APIs.
2. Native Context: An extended context via the cep object, providing file system access through CSInterface.js.
3. Node Context: Enabled via the --enable-nodejs command line switch. It can operate in two modes:
   • Separate Context: Created without --mixed-context. The cep_node symbol is global across all frames, but Node.js globals (like process) are only available in the main frame. Modifications to cep_node in one frame are reflected in others.
   • Mixed Context: Created with --enable-nodejs and --mixed-context. The cep_node symbol is local to each frame (modifications do not propagate), and Node.js globals are available uniquely within every frame.
4. Host App Context: The context accessed via the evalscript API to interact with the host application.