Hi Tom, you are right. I changed the code that it returns the last value if record is None, and immediately Belchertown skin shows the value.
I considered your comments about dangers by comparing the timestamp of the last value with the actual time time.time(). If the value is too old an error is raised rather than a value returned. And I let the program complain to the log, that record is None. Skin with included GTS value <https://www.woellsdorf-wetter.de> Tom Keffer schrieb am Donnerstag, 18. Februar 2021 um 19:25:48 UTC+1: > That's one solution, but it has lots of dangers. The record could be hours > old. > > NB: if you want to do that, it's easy enough to code up a custom version > of get_scalar() that does this. If it detects a record of None, it gets the > latest record from the database, then calls weewx.xtypes.get_scalar() with > that. > > > On Thu, Feb 18, 2021 at 10:18 AM Karen K <kk44...@gmail.com> wrote: > >> Thank you for your extensive support! >> >> Could it be, that get_scalar() in other classes (especially in the basic >> ones) simply provide the last available value, if record is None? >> >> I could code it that way, but I am not sure, whether it is a good idea or >> not. >> >> Tom Keffer schrieb am Donnerstag, 18. Februar 2021 um 17:51:45 UTC+1: >> >>> Hi, Karen. Looks like you are making steady progress. >>> >>> This is a bug in the Belchertown skin that I alluded to in another >>> thread >>> <https://groups.google.com/g/weewx-user/c/fKVxr07vMuE/m/I-PdDb7vBgAJ>. >>> >>> In a convoluted way, the skin is asking for a value from xtypes using >>> the call >>> >>> xtype.get_scalar(obs_type, record, db_manager) >>> >>> >>> (Side note: the actual request is done through a getattr() query of a >>> weewx.tags.CurrentObj object). >>> >>> Unfortunately, the value for record as provided by the Belchertown skin >>> is None. In theory, the xtypes extension could look up the values it needs >>> from the database, but that would require knowing the time, but with >>> record equal to None, that's not possible either. >>> >>> The Belchertown skin needs to provide the current record. >>> >>> >>> >>> >>> >>> On Thu, Feb 18, 2021 at 8:39 AM Karen K <kk44...@gmail.com> wrote: >>> >>>> My XType extension is working in principle now. It calculates, and it >>>> delivers values, if there is $current.GTS, $latest.GTS, $day.GTS or >>>> $yesterday.GTS included in the skin definition. Also, images are >>>> generated showing the value over time. All is fine so far. >>>> >>>> Then I included the value in the Belchertown skin observation list. And >>>> I got an error message. It turned out, that it is possible that >>>> get_scalar() is called with *record is None*. From documentation I >>>> thought otherwise. That was confusing. >>>> >>>> As I included "if record is None: raise weewx.CannotCalculate(obs_type)" >>>> into get_scalar() no error message was logged any more. But no value >>>> was displayed in Belchertown skin. Again: if I include "$current.GTS" >>>> into the skin, the value is displayed. If I include the value in the >>>> observation list in skin.conf, it is not. I looked around and found out >>>> that Belchertown skin gets the value from calling >>>> weewx.tags.CurrentObj()within their special extension "belchertown.py" >>>> That seems to not include GTS value. >>>> >>>> So I am not sure what to do next. >>>> >>>> -- >>>> >>> You received this message because you are subscribed to the Google >>>> Groups "weewx-development" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to weewx-developm...@googlegroups.com. >>>> >>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/weewx-development/bf89f27d-abb4-4943-a2a9-e3ffbf1a8606n%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/weewx-development/bf89f27d-abb4-4943-a2a9-e3ffbf1a8606n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "weewx-development" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to weewx-developm...@googlegroups.com. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/weewx-development/4caf593c-5f43-4c21-bb44-37867f803e52n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/weewx-development/4caf593c-5f43-4c21-bb44-37867f803e52n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "weewx-development" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-development+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-development/d255d4cd-ca18-404d-a740-3a2b2264a719n%40googlegroups.com.
