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UserAgent

property UserAgent: string read;

Example​

procedure ScriptEvent(var Value: variant);
begin
  if Request <> nil then
    Value := Request.UserAgent
  else
    Value := '';
end;

Usage​

UserAgent returns Velox's selected optional User-Agent request-header text without identifying or attesting the client software.

Additional Technical Info​

UserAgent returns the first User-Agent value selected by Indy's request-header processing. It is an unparsed optional string and can contain multiple product/comment tokens. Velox does not validate grammar, identify a vendor/version, check a signature or compare it to TLS/network behavior.

Any caller can omit or spoof the field. Do not use it for authentication, authorisation, tenant selection or a permanent compatibility guarantee. If an API must adapt to a known client capability, prefer explicit versioned protocol negotiation and schema rather than fragile substring detection.

For diagnostics/analytics, length-bound the value and treat it as potentially identifying personal/device data. Avoid high-cardinality unsanitised metric labels and prevent control characters from reaching logs. Empty means no selected value; duplicate fields are not combined by this getter.

The property is read-only live request metadata with no behavior side effect. Test Request for nil.

External references

Created 2026-07-15