Hi Korhaai,
Depending upon your gateway version, v5/v5c or the v10 API Gateway, there are some choices.
1. For both v5/v5c and the API Gateway, your target url can be something like https://backendhost:port/url?X-Query-String=$(request.parameters.x-query-string). In this case the request query parameter value will be substituted into the target url
2. For the API Gateway only, in the invoke policy under "parameter control" select the "Allow list" radio button, and then specify x-query-string in the allow list and it will propagate just that query header. This list also supports regular expressions, so .* will allow all request query parameters to be propagated, ^x- will allow all request query parameters that start with an x-, etc.
Regards,
Steve
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Steve Linn
Senior Consulting I/T Specialist
IBM
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