Add support for HTTP response codes to wp_send_json_error(), wp_send_json_success(), and wp_send_json

[johnbillion]

wp_send_json_error() is the JSON-encoded equivalent of wp_die(). It should therefore support the sending of an HTTP response code in a similar way so a more appropriate response code can be set for error conditions. Currently, the response code needs to be set manually, otherwise it defaults to 200.

[ocean90]

#36261 was marked as a duplicate.

[stephenharris]

Adds support for a 'status_code' parameter to wp_send_json(_error|_success)

[stephenharris]

Alternative patch for allowing a header status to be set

[johnbillion]

In 38422:

Formatting: Add a parameter to wp_send_json_error(), wp_send_json_success(), and wp_send_json() for specifying the HTTP response code.

Defaults to 200 in all cases, but can be used, for example, to return a 403 when using wp_send_json_error().

Fixes #35666
Props stephenharris

[westonruter]

In 38478:

Customize: Use new $status_code parameter for wp_send_json_error() instead of calling status_header() separately.

Props johnbillion.
See #35666.
Fixes #37897.

[westonruter]

I've found a defect with the changes here. Namely, if status_header() was being called previously to wp_send_json(), then the default $status_header of 200 would clobber the status_header() that was first set. In other words, this breaks backwards compatibility.

On a related note, I also found that _ajax_wp_die_handler was clobbering the status_header() call if output buffering is on (since headers_sent() would be false). See 35666.3.diff​.

[johnbillion]

Good catch.

[johnbillion]

In 38576:

Formatting: Don't send an HTTP status code in wp_send_json() by default. This avoids clobbering an HTTP status code that may have been set prior to calling this function.

Props westonruter
See #35666

[johnbillion]

The output buffering issue needs a bit more testing I think.

[stevenkword]

@johnbillion -- Do you think you'd like to take a stab at the refresh, or would you like some fresh eyes on this?

[stevenkword]

Refresh after Changeset 38576

[stevenkword]

Patch 35666.4.diff​ updated after 38576, but still needs testing on the output buffering.

[johnbillion]

35666.2.diff​ tackles this by always telling wp_die() not to set an HTTP status code header.

With output buffering on, this means a status set by wp_send_json() doesn't get clobbered. With output buffering off, the functionality doesn't change because headers_sent() in _ajax_wp_die_handler() is always true (due to the JSON echoed in wp_send_json()) so the status header doesn't get set anyway.

@westonruter Wanna give this a whirl?

[westonruter]

@johnbillion works for me!

[johnbillion]

In 38956:

Formatting: Don't overwrite the status header for Ajax responses that use output buffering or otherwise set their headers early.

Fixes #35666