@Jdlrobson - this is about applying the print styles to the PDFs, and then T171956: Allow PDF rendering to be triggered only by electron for single-article PDFs is about deploying them - do we need another task in-between? A spike maybe?

to be turned into a spike - How should the new print styles be applied to single-article PDFs?

We realised there are lots of things we need to work out for this before we implement

• How does this get impacted by the Vector feature flag?
• How should the new print styles be applied to single-article PDFs?
• Will styles be applied inside Electron or in a pre-processing step?

I think all these questions hinge on how we apply the styles.
https://en.wikipedia.org/api/rest_v1/#!/Page_content/get_page_pdf_title currently only takes a title parameter.

If we apply styles inside Electron, we'll need to send an additional parameter which would be either

• css - the css to apply to the pdf
• list of ResourceLoader module names - so the service could obtain styles from ResourceLoader
• a skin name - e.g. 'vector' that the service uses to retrieve the needed stylesheets

If we apply styles in PHP and create a <style> tag inside the HTML output, this becomes much easier.

I'm not worried about the Vector feature flag. The Vector print styles module is available even with the feature flag disabled.

Should we promote the existing feature flagged print styles

Yes. I'd hope we deploy this before the OCG roll out. It seems like an important precursor.

According to @bmansurov Electron already includes print styles for the skin so really the question is whether we need to roll out the new print styles before.

If we were to deploy the new print styles everywhere prior to launching Proton, then we can simply resolve this task as there'll be no work required. @ovasileva: Is this feasible?

/cc @bmansurov

In T171957#3585565, @phuedx wrote:

If we were to deploy the new print styles everywhere prior to launching Proton, then we can simply resolve this task as there'll be no work required. @ovasileva: Is this feasible?

/cc @bmansurov

I think that's possible, but depends on T169730: Define and implement instrumentation for printing on desktop web. If we can start gathering data this week, we would need approximately 2 weeks of data prior to deploying the print styles. That still leaves us on-schedule. What would be required if we deploy the print styles first?

In T171957#3587785, @ovasileva wrote:

I think that's possible, but depends on T169730: Define and implement instrumentation for printing on desktop web. If we can start gathering data this week, we would need approximately 2 weeks of data prior to deploying the print styles.

The size of that task makes this timeline unlikely.

What would be required if we deploy the print styles first?

Did you mean to ask "if we don't deploy the print styles first?"? If so, then that's what this task is asking.

>> What would be required if we deploy the print styles first?

Did you mean to ask "if we don't deploy the print styles first?"? If so, then that's what this task is asking.

No, I did mean if we deploy the print styles first. I think we can have a short lag between retiring OCG and deploying the new styles - there's no significant issues with the electron styles as of now. Anyhow, let me rephrase - if we close this task, what is the task we should open if working under the assumption that we are deploying the print styles first? Or is there nothing to be done?

In T171957#3591010, @ovasileva wrote:

Anyhow, let me rephrase - if we close this task, what is the task we should open if working under the assumption that we are deploying the print styles first? Or is there nothing to be done?

AFAIK there's nothing to be done. We discussed this during the last kick off ritual and that led to me writing T171957#3585565. @bmansurov: Is this correct?

Yes, that's correct. As long as the new print styles are the default, we don't need to do anything extra to get them applied to Electron rendered pages.

Ok, we can wait on this until we have the print styles out everywhere. However T171956: Allow PDF rendering to be triggered only by electron for single-article PDFs will not be blocked on print styles deployment.