# MYSTERY: How to get access to the upstream algorithm from the client side?
**URL:** https://discourse.paraview.org/t/mystery-how-to-get-access-to-the-upstream-algorithm-from-the-client-side/15813
**Category:** Development
**Created:** [November 29, 2024, 7:31am UTC](https://discourse.paraview.org/t/mystery-how-to-get-access-to-the-upstream-algorithm-from-the-client-side/15813 "2024-11-29T07:31:11Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@joint](https://discourse.paraview.org/u/joint)
#### Post date: [November 29, 2024, 7:31am UTC](https://discourse.paraview.org/t/mystery-how-to-get-access-to-the-upstream-algorithm-from-the-client-side/15813/1 "2024-11-29T07:31:11Z")
Hello dear Paraview developers!
I have a question of great importance. How can one get access to the algorithm upstream to the current algorithm from the widget side?
I know about
```auto
filter = vtkSrcPrxyPtr::Take(vtkSMSourceProxy::SafeDownCast(proxyManager->NewProxy("filters", "ClientServerMoveData"))
```
instrument to get data output of the current algorithm on the client side. However, I can’t figure out how to get access to output of the upstream algorithms. All the proxies are SOURCE proxies, and seem not to have any input ports or so.
I can imagine accessing the necessary proxies from the Active Objects, but how to then figure out which algorithm is upstream to the current? I can make 1-10 algos and then attach 11th to the 5th for example, and if I use indices to get the previous for 11th, I would then get 10th and not 5th, which is indeed desirable?
Thank You great a lot!
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [November 29, 2024, 8:56am UTC](https://discourse.paraview.org/t/mystery-how-to-get-access-to-the-upstream-algorithm-from-the-client-side/15813/2 "2024-11-29T08:56:05Z")
> How can one get access to the algorithm upstream to the current algorithm from the widget side?
At pq level:
`pqPipelineFilter::getInput`
At SM level:
`vtkSMProxy::GetProducerProxy`