EC
102
HTTPINFOCommon1xx InformationalHIGH confidence

Processing

Production Risk

Low. It serves as a helpful keep-alive signal for clients during long operations, preventing unnecessary timeouts.

What this means

This code indicates that the server has received and is processing the request, but no response is available yet. It is used to prevent the client from timing out while waiting for a long-running operation to complete.

Why it happens
  1. 1A client sends a request that is expected to take a significant amount of time, such as a complex database query or batch processing job.
  2. 2The server sends this interim response to assure the client that the request has not been lost or ignored.
  3. 3This is a WebDAV extension and is not part of the core HTTP standard.
How to reproduce

A client submits a WebDAV request that involves manipulating a large number of files on the server.

trigger — this will error
trigger — this will error
PROPFIND /container/ HTTP/1.1
Host: example.com
Depth: 1

expected output

HTTP/1.1 102 Processing

Fix

Keep the client connection alive during long WebDAV operations

Keep the client connection alive during long WebDAV operations
// Server-side: Node.js / Express — send 102 to prevent client timeout
app.post('/dav/batch', async (req, res) => {
  // Send 102 immediately to prevent the client timing out
  res.writeProcessing(); // writes "HTTP/1.1 102 Processing

"

  // Perform the long-running WebDAV operation
  const result = await performLongOperation(req.body);

  // Send the final response
  res.status(207).json(result);
});

Why this works

HTTP/1.1 clients may time out if no bytes arrive for an extended period. Sending '102 Processing' as an interim response resets the client's inactivity timer without committing to a final status. This is a WebDAV-specific extension (RFC 2518) — only use it for WebDAV endpoints or clients that explicitly support it.

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