wp-includes/rest-api/class-wp-rest-request.php:668Parses the JSON parameters.
true|WP_Error protected function parse_json_params() { if ( $this->parsed_json ) { return true; } $this->parsed_json = true; // Check that we actually got JSON. if ( ! $this->is_json_content_type() ) { return true; } $body = $this->get_body(); if ( empty( $body ) ) { return true; } $params = json_decode( $body, true ); /* * Check for a parsing error. */ if ( null === $params && JSON_ERROR_NONE !== json_last_error() ) { // Ensure subsequent calls receive error instance. $this->parsed_json = false; $error_data = array( 'status' => WP_Http::BAD_REQUEST, 'json_error_code' => json_last_error(), 'json_error_message' => json_last_error_msg(), ); return new WP_Error( 'rest_invalid_json', __( 'Invalid JSON body passed.' ), $error_data ); } $this->params['JSON'] = $params; return true; }Introduced in 4.4.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api/class-wp-rest-request.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.