issue regarding authentication from the coinbase using websocket(WS) in the vb6

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Websocket Authentication Failure on Coinbase Sandbox: Floating-Point Timestamp Issue

Summary

A VB6 client experienced an “Authentication Failed” error when connecting to Coinbase’s sandbox WebSocket. The connection succeeded, but authentication failed due to an unexpected timestamp format in the subscription message, violating Coinbase’s API requirements.

Root Cause

  • Coinbase’s authentication requires integer timestamps (whole seconds) in request signatures.
  • The application sent a floating-point timestamp (e.g., "timestamp": "1767952088.908") with fractional seconds.
  • The server rejected the authentication due to the invalid timestamp format.

Why This Happens in Real Systems

  1. Legacy system quirks: Older platforms like VB6 may default to floating-point time formats without explicit rounding.
  2. API misinterpretation: Engineers might assume WebSocket auth mirrors REST (where fractional seconds exist elsewhere), missing endpoint-specific rules.
  3. Documentation gaps: Sandbox-specific limitations (e.g., stricter time validation) can differ from production.

Real-World Impact

  • Users lose real-time trading data access for authenticated channels.
  • Automated trading strategies halt unexpectedly.
  • Connection closures disrupt order execution flows.

Example Code

' Incorrect: Floating-point timestamp
ts = UnixTimeUtcSeconds()  ' Returns fractional seconds

' Corrected: Truncated to integer
ts = Format$(Fix(UnixTimeUtcSeconds()), "0")

How Senior Engineers Fix It

  1. Verify timestamp requirements: Confirm API docs mandate integer timestamps.
  2. Enforce integer conversions: 
    ts = CStr(CLng(UnixTimeUtcSeconds()))  ' Force integer seconds
  3. Add validation tests: Compare timestamps against /users/self/verify responses.
  4. Standardize time libraries: Replace custom UnixTimeUtcSeconds() with integer-precise alternatives.

Why Juniors Miss It

  • Ambiguous errors: “Authentication Failed” messages lack specifics about timestamp formatting.
  • Sandbox nuances: Differences between sandbox/production behavior obscure root causes.
  • Legally ambiguous: Reliance on third-party SDKs/scripts without auditing for API changes.
  • Path-focused debugging: Validating HMAC logic but overlooking input format.