[wp-trac] [WordPress Trac] #43116: wp_footer actions being applied to output when the Content-Type header is set to "application/pdf"

[WordPress Trac]

#43116: wp_footer actions being applied to output when the Content-Type header is
set to "application/pdf"
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 Reporter:  jdgregson     |      Owner:
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  General       |    Version:  4.9.2
 Severity:  normal        |   Keywords:
  Focuses:                |
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 We encountered an issue trying to download some PDFs through index.php
 using Gravity Forms. I believe this issue should be fixed in WordPress
 Core rather than the Gravity Forms plugin.

 When a PDF downloaded through index.php contains a </body> tag (which is
 valid inside [https://en.wikipedia.org/wiki/XFA XFA] forms in the PDF),
 WordPress sees the tag and inserts the code which was added to the
 wp_footer hook, completely breaking the PDF.

 I have downloaded the PDF using wget and can see that the "Content-Type"
 header is set to "application/pdf".

 I suggest that the wp_footer hook (and probably all hooks) check to see if
 the Content-Type is something other than the default "text/html" and avoid
 executing if so.

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Ticket URL: <https://core.trac.wordpress.org/ticket/43116>
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