Cannot send a response more than once per chrome.extension.onRequest listener per document

[Alon Bar-Lev]

Hello,

I am getting the above message, don't know exactly why, and how to
overcome this. I could not find any relevant reference.

The scenario is as follows: extension1 needs to acquire information
from a content script of extension2.
Because extension1 cannot directly call the content of extension2 the
path is extension1::background->extension2::background->extension2::content.

The funny thing is that it seems to be working... but I don't like
getting errors.

I appreciate any help!
Alon Bar-Lev.

So what I am doing is the following:

extension2::content
---
chrome.extension.onRequest.addListener(
function(request, sender, sendResponse) {
var p = request.parameters;
handle(p);
sendResponse({parameters: p});
}
);
---

extension2::background
---
chrome.extension.onRequestExternal.addListener(
function(request, sender, sendResponse) {
chrome.tabs.sendRequest(
request.tabId,
request,
sendResponse
);
}
);
---

extension1::background
---
(function(details) {
chrome.extension.sendRequest(
extId,
{
tabId: details.tabId,
frameId: details.frameId,
parameters: details.parameters
},
function(response) {
handle(response);
}
);
})(details);
---

[Matt Perry]

Where do the errors show up? In the page containing extension2::content, I assume? The error happens when you try to call sendResponse multiple times for the same message. This can happen if you have multiple onRequest listeners in a single document (e.g. if you have 2 content scripts injected into the same document, and both have an onRequest listener). The problem is that only one of their responses is actually sent.

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[Devin]

onRequest/sendResponse is ONLY intended for one time messages. For long lived connections you need to use ports with connect/onConnec described here.

[Alon Bar-Lev]

Hello Matt,

Thank you for your response.
Actually, I see this at the extension2::background page.
So I cannot have two listeners at background...
Strange limitation... I thought the concept of "addListener()" is to
allow publish subscriber model.

Thank you so much!
Alon.

[Alon Bar-Lev]

Hello Devin,

I had a problem with ports, as there it is difficult to correlate
between request and response. It made the code much more complicated.
So I preferred the sendRequese approach.

Thank you,
Alon.

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[Abraham Williams]

You can have as many listeners as you but but the API design is request:response. Once the request is satisfied with a response there is no longer an open request waiting for a response.

Abraham
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On Tue, May 15, 2012 at 11:41 AM, Alon Bar-Lev <alon....@gmail.com> wrote:

background