When REPORT_PERCENTAGE is set to 100%, the `report-uri` directive is not always included in the CSP header

[robhudson]

When the setting REPORT_PERCENTAGE is set to 100%, the report-uri should always be included in the Content Security Policy header. However, it has been observed that this is not true.

The current logic allows this issue to occur because when the randomly generated integer equals 100, the condition to include the report-uri is not met. Specifically, the check 100 < 100 evaluates to False, which results in the report-uri being omitted from the CSP header. This effectively means that even with REPORT_PERCENTAGE set to 100%, there is a scenario where the report-uri is not included, preventing the expected reporting of CSP violations.

        include_report_uri = random.randint(0, 100) < report_percentage
        if not include_report_uri:
            replace["report-uri"] = None

[crbunney]

I've also encountered this issue on 4.0b1. report-to in contrast behaves as expected and is added to the CSP policy header

[robhudson]

I've also encountered this issue on 4.0b1. report-to in contrast behaves as expected and is added to the CSP policy header

This is because the code only removes the report_uri directive and doesn't also remove report-to. Probably because report-to was added relatively recently and likely got missed here. I'd consider this to be a related bug.

The report-to directive requires a reporting endpoint as the value and is defined in a separate header. Are you defining that header elsewhere in some way? I just opened #235 to consider having django-csp set the reporting endpoints.