<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Gunnar,<div class=""><br class=""></div><div class="">I haven’t looked into process chaining, but this question was just raised recently:</div><div class=""><br class=""></div><div class=""><a href="https://lists.osgeo.org/pipermail/pywps-dev/2018-December/001363.html" class="">https://lists.osgeo.org/pipermail/pywps-dev/2018-December/001363.html</a></div><div class=""><br class=""></div><div class="">Here is in addition a description of how a process chain can be done:</div><div class=""><a href="http://geoprocessing.info/wpsdoc/Concepts#chaining" class="">http://geoprocessing.info/wpsdoc/Concepts#chaining</a></div><div class=""><br class=""></div><div class="">I’m not sure how your code and your chain works (the gitlab link is not public). A comment from my side would be, that your “worker” process should not know that it is part of a process chain.</div><div class=""><br class=""></div><div class="">Cheers,</div><div class="">Carsten<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 12 Dec 2018, at 6:34 pm, <a href="mailto:gunnar.stroeer@yahoo.de" class="">gunnar.stroeer@yahoo.de</a> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Hi Everybody,<br class=""><br class="">I currently develop some processes for a masterthesis using PyWPS v4 as implementation. Mostly it works fine for single processes, as well with QGIS as client. However I stucked when it comes to chaining.<br class=""><br class="">Normally in single processes I use "in_file = request.inputs['in_geom'][0].file" for read in some complex GML geometry. In cases I wanna use the same process in a chain the code above doesn't work anymore because the input is the same as the output of the prior process. Therefore "in_file = request.inputs['in_geom'][0].file" additionally gets all the XML code of the prior response - and the process crashed.<br class=""><br class="">To handle this I use "import lxml" to parse the response XML looking for the "xlink:href" attribute value with the referenced GML output file of the first process. It works for the process in a chain, only. Whether the process is used in a chain or not I could handle in the process code, like a case distinction. Therefor I have to parse XML all the time again and again... and it makes me feel that I use PyWPS in a wrong way.<br class=""><br class="">I also could use "RawDataOutput", but this is obviously a bad solution for large data inputs/outputs.<br class=""><br class="">Is there any method to handle the described problem without writing too much code just to get know whether the process is used in a chain or not? Or is there something completely wrong what I'm doing?<br class=""><br class=""><a href="https://gitlab.com/hadlaskard/integration-of-wps-in-local-sdi/blob/master/processes/proc_buffer.py" class="">https://gitlab.com/hadlaskard/integration-of-wps-in-local-sdi/blob/master/processes/proc_buffer.py</a><br class=""><br class="">Thanks,<br class="">Gunnar<br class="">_______________________________________________<br class="">pywps-dev mailing list<br class="">pywps-dev@lists.osgeo.org<br class="">https://lists.osgeo.org/mailman/listinfo/pywps-dev</div></div></blockquote></div><br class=""></div></body></html>