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docs/inter_extension_communication.md

+# Status
+
+Proposal
+
+# Overview
+
+Proposed API for communication between different extensions.  There are three parts, the actual APIs exposed to extensions, a change to the manifest to declare communication permissions, and a change to the event firing behavior

[Bons, 2015/08/20 20:16:50]

delete

+
+Original proposal and discussion took place in this thread:
+http://groups.google.com/group/chromium-extensions/browse_thread/thread/c2667325d17d2b56
+
+
+# API
+
+```
+chrome.extension:
+
+// Open a channel to another extension with the provided ID.
+// If the ID is unspecified, the channel is opened to the calling
+// extension and a chrome.extension.onConnect event is fired.
+// Otherwise if no extension with the provided ID exists, nothing happens. 
+// Otherwise the chrome.extension.onConnectExternal event is fired 
+// to all components of the extension with the provided ID.
+//
+// The channel can optionally be named. This name will be sent along 
+// with the onConnectExternal event 
+Port connect([string ID], [{[string name]}])
+
+// Fired when another extension opens a channel to this extension via 
+// chrome.extension.connectExternal(). 
+// If a channelName was provided, it is accessible via port.name. 
+Event onConnectExternal(Object port) 
+```
+```
+chrome.extension.Port:
+  Object sender:
+    Object tab; // if the sender were a tab
+    String id;  // ID of the sending extension.
+```
+
+# Event behavior
+
+## Problem
+
+The order in which the scripts within different background pages are executed is not defined, which is entirely reasonable, but it means that doing the obvious thing:
+```
+<script> 
+var port = chrome.extension.connectExternal('abcdef..'); 
+</script> 
+```
+would work unreliably depending on the exact order in which the background pages get loaded, the event handlers get registered, and the events are fired.
+
+A parallel issue exists for an extension that tries to open connections to itself using onConnect events
+
+## Proposed Solution
+
+The following language be added to the Events spec (http://dev.chromium.org/developers/design-documents/extensions/events ):
+
+Events for an extension are enqueued until the background page for an extension, if there is one, is loaded.