WooCommerce CSV Exports Are Silently Broken with S3 Uploads

Ben Word 2026-03-24

If you use WooCommerce with S3 Uploads, your analytics exports might be quietly failing and not sending any emails, despite Action Scheduler saying the job was complete.

From Analytics > Revenue, you click the Download button. The network tab shows the POST to /wc-analytics/reports/revenue/export with a payload:

{
  "report_args": {
    "interval": "day",
    "orderby": "date",
    "order": "desc",
    "page": 1,
    "per_page": 25,
    "after": "2025-01-01T00:00:00",
    "before": "2025-12-31T23:59:59"
  },
  "email": true
}

The response includes an export_id and a status link:

{
  "message": "Your report file is being generated.",
  "export_id": "12312312312312",
  "_links": {
    "status": [
      {
        "href": "https://example.com/wp-json/wc-analytics/reports/revenue/export/12312312312312/status"
      }
    ]
  }
}

But then no email is sent.

Checking WooCommerce > Status > Scheduled Actions, the woocommerce_admin_report_export batch jobs show “Complete.” The woocommerce_admin_email_report_download_link action ran and everything looks healthy in the admin.

Since the email never arrived, we dug into the export status endpoint code and found that when percent_complete reaches 100, it constructs a download_url from the export ID and report type. Using the export ID from the Scheduled Actions args, we manually hit:

/wp-admin/?action=woocommerce_admin_download_report_csv&filename=wc-revenue-report-export-12312312312312

A CSV downloaded, but with only headers:

Date,Orders,"Gross sales",Returns,Coupons,"Net sales",Taxes,Shipping,"Total sales"

Why it’s silent

WooCommerce’s batch exporter writes CSV data in WC_CSV_Batch_Exporter::write_csv_data(). The file operations use @fopen and @file_put_contents with silenced errors. When the write fails, no exception is thrown, nothing is logged, and the Action Scheduler job just “completes” with zero data written.

What’s happening

write_csv_data() opens the CSV file with fopen mode a+ (read + append):

$fopen_mode = apply_filters( 'woocommerce_csv_exporter_fopen_mode', 'a+' );
$fp = fopen( $this->get_file_path(), $fopen_mode );

When you’re running S3 Uploads, wp_upload_dir() returns an s3:// path. The S3 stream wrapper only supports r, w, a, and x — the + variants require seekable streams, which S3 objects aren’t. So fopen fails, $fp is false, and the data is never written.

When we tried generating the export via WP-CLI, the errors were no longer silenced:

PHP Warning: Mode not supported: a+. Use one 'r', 'w', 'a', or 'x'.
  in /var/www/public/app/mu-plugins/s3-uploads/inc/class-stream-wrapper.php on line 985

PHP Warning: fopen(s3://bucket/uploads/woocommerce_uploads/reports/wc-revenue-report-export.csv):
  Failed to open stream: "S3_Uploads\Stream_Wrapper::stream_open" call failed
  in /var/www/public/app/plugins/woocommerce/includes/export/abstract-wc-csv-batch-exporter.php on line 151

Fixing the CSV generation

WooCommerce added a hook in 6.8.0 via woocommerce/woocommerce#33652 that defaults to a+.

To fix the CSV generation, you’ll have to add a filter that overrides this to a, which is S3-compatible:

add_filter('woocommerce_csv_exporter_fopen_mode', fn () => 'a');

If you’re routing uploads through any S3 stream wrapper, you’re affected by this. The exports will always produce headers-only files with no data rows and the email is never sent.

Issue submitted to WooCommerce: https://github.com/woocommerce/woocommerce/issues/63835