I strongly agree with this, and I would like to see it considered as a bug, not a feature request.

The problem is that, under some circumstances, the header() issued by Piwik will mess with the calling page's output, although I am still unsure why or how.

Note that the problem is the same whether the format is json, php or xml.

I would like to clarify. Using format=php, the calling page is rendered as text/plain. So far, using format=original is the only way I can get the result without it interfering with the calling context.

Considering that the result of the calls to header() will seriously disrupt the calling code, I believe that this issue should be considered a bug, not a feature request. Besides, it is now over 2 years old. Can anything be done about it?
Perhaps a quick mention in the documentation that "original" should be used when calling the API in PHP?

@LeCoyote

I made a change and now format=original will also set the text/plain header. This was to prevent potential sec issues with displaying raw content.

we'd like to fix this issue and allow to disable headers, unfortunately it's not trivial. There are dozens of calls to header() all over the codebase... (I just looked)

In your case maybe it is possible to call Piwik, before any output is sent to the client ?

@matt

This issue is about Piwik unexpectedly adding headers using the internal method. The format=original workaround is the only way to use the internal method without breaking stuff. I don't understand how disabling this workaround is a security fix. Now the internal method is truly broken.

Your suggestion of calling Piwik before output is sent won't help. It leaves Piwik in control of the Content-type. This means every page that calls Piwik using the internal method is sentenced to serve text/plain. I cannot figure out how it can be a workaround.

Also, this is still a bug, not a new feature. Piwik's documentation of Piwik_API_Request::process() clearly mentions that using format=original should return a PHP object, not display anything, which is basically what sending the Content-type header will do. If this is broken, please at least make it obvious in the documentation.

I never said it would be trivial. I did say however that this should be addressed as a bug and I still stand by that statement. Unexpectedly disrupting content flow without warning or documentation to that effect is not a missing feature: it's a bug.

Thanks for feedback. It's definitely a bug....

I think the solution is to wrap all header() call into a refactored method, that will not print the headers if we are not dispatching. similar fix to https://github.com/piwik/piwik/blob/bc2f9371b7174f397b06df2d5f71ea5bb50c6cfb/core/SettingsPiwik.php#L173

Piwik's documentation of Piwik_API_Request::process()
Btw maybe you can help with documentation. There is an "edit" link at the bottom of developer docs feel free to suggest improvements... Cheers!

About a year ago, you mentioned that it was "definitely a bug". I can also confirm that it is still present. Why is it now considered an enhancement?

@LeCoyote changed it back to Bug