80 lines
3.7 KiB
Markdown
80 lines
3.7 KiB
Markdown
---
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title: Pageview Time Experiment
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date: 2019-08-19
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---
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# Pageview Time Experiment
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My blog has a lot of content in a lot of diverse categories. In order to help me
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decide which kind of content I should publish next, I have created a very
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simple method to track pageview time and enabled it for all of my blogposts. I'll
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go into detail of how it works and potential risks of it below.
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The high level idea is that I want to be able to know what kind of content has
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people's attention for the longest amount of time. I am using the time people
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have the page open as a particularly terrible proxy for that value. I wanted to
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make this data anonymous, simplistic and (reasonably) public.
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## How It Works
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Here is how it works:
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When the page is loaded, a [javascript file records the start time](/static/js/pageview_timer.js).
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This then sets a [pagehide handler](https://developer.mozilla.org/en-US/docs/Web/API/Window/pagehide_event)
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to send a [navigator beacon](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/sendBeacon)
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containing the following data:
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- The path of the page being viewed
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- The start time
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- The end time recorded by the pagehide handler
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This information is asynchronously pushed to [`/api/pageview-timer`](https://github.com/Xe/site/blob/91d7214b341088edba7a37a83a753e75ed02d7ad/cmd/site/pageview.go)
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and added to an in-memory prometheus histogram. These histograms can be checked at
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[`/metrics`](/metrics). This data is not permanently logged.
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## Security Concerns
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I believe this data is anonymous, simplistic and public for the following reasons:
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I believe this data is anonymous because there is no way for me to correlate users
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to histogram entries, nor is there a way for me to view all of the raw histogram
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entries. This site records the bare minimum for what I need in order to make sure
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everything is functioning normally, and all data is stored in ephemeral in-memory
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containers as much as possible. This includes any logs that my service produces.
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I believe this data is simplistic because it only has a start time, a stop time
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and the path that is being looked at. This data doesn't take into account things
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like people leaving a page open for hours on end idly, and that could skew the
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numbers. The API endpoint is also fairly unprotected, meaning that falsified data
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could be submitted to it easily. I think that this is okay though.
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I believe this data is public because I have the percentile views of the histograms
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present on [`/metrics`](/metrics). I have no reason to hide this data, and I do not
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intend to use it for any moneymaking purposes (though I doubt it could be to begin
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with).
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I fully respect the [do not track](https://allaboutdnt.com) header and flag in browsers.
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If [`pageview_timer.js`](/static/js/pageview_timer.js) detects the presence of
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do not track in the browser, it stops running immediately and does not set the pagehide
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handler. If that somehow fails, the server looks for the presence of the `DNT` header
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set to `1` and instantly discards the data and replies with a 404.
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Like always, if you have any questions or concerns please reach out to me. I
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want to ensure that I am creating useful views into how people use my blog
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without violating people's rights to privacy.
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I intend to keep this up for at least a few weeks. If it doesn't have any practical
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benefit in that timespan, I will disable this and post a follow-up explaining how
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I believe it wasn't useful.
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Thanks and be well.
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---
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EDIT 2019-10-15: browsers disable this call from the context I am using and I don't
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really care enough to figure out how to fix it. This experiment is over. Thank you
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to everyone that participated. All data will be scrubbed and a followup will be
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posted soon.
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