X-Page-Usage in response header

[sridharraman]

Hi

As per the Facebook Messenger documentation (https://developers.facebook.com/blog/post/2016/06/16/page-level-rate-limits/), the response header contains additional information:

The values for call_count, total_cputime and total_time are whole numbers representing the percentage used values for each of the metrics.

Is there any way of accessing these header values using this gem?

Thanks,
Sridhar

[jgorset]

Not yet, but I'd be happy to merge a pull requests that does that!

[cfurrow]

In my own testing, I've not seen this header, X-Page-Usage, come through yet in responses from Facebook to my webhook endpoint. I've not released my app/bot yet, so it's possible they do not send while the app is in development mode.

[cfurrow]

I looked for the X-Page-Usage headers when sending a message over the api, and receiving a response from Facebook, and that header was not present in the response. Not sure where they come into play.

Example headers from FB after sending a message successfully to Facebook's API:

{
  "access-control-allow-origin"=>["*"], 
  "pragma"=>["no-cache"], 
  "cache-control"=>["private, no-cache, no-store, must-revalidate"], 
  "facebook-api-version"=>["v2.11"], 
  "expires"=>["Sat, 01 Jan 2000 00:00:00 GMT"], 
  "x-fb-rev"=>["3659829"], 
  "content-type"=>["text/javascript; charset=UTF-8"], 
  "x-fb-trace-id"=>["snipped"], 
  "strict-transport-security"=>["max-age=15552000; preload"], 
  "x-fb-debug"=>["snipped characters"], 
  "date"=>["Tue, 20 Feb 2018 14:40:50 GMT"], 
  "connection"=>["close"], 
  "content-length"=>["85"]
}

[cfurrow]

Reading the FB docs, I now see why I'm not seeing that header yet:

If enough calls are being made on behalf of a page to be considered for rate limiting by our system, we return an X-Page-Usage HTTP header.

So if you are approaching that rate limit, THEN Facebook includes that header in the response. Rate limits are divided between app and Facebook pages:

• 200 calls per user, per hour, for apps
• A total of 4800 calls per daily engaged users. 24hr window slides and is updated every minute.

[jgorset]

Alright, cool, that makes sense!