According to the log file, i only get the following message:
[INFO ] [inding.http.internal.HttpThingHandler] - Using the secure client for thing 'http:url:xpath_zamg'
[INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'xpath_zamg_location' changed from NULL to
It should work on HTML but only if it’s xhtml, meaning that it conforms to the XML standard. That means every open tag must have a closing tag and a few other similar requirements. Browsers are not as strict and will be happy to render a page that is missing such things.
But the header shows that the page is claiming to be XHTML so XPath shouldn’t have a problem with it.
Given the data is pulled by the HTTP binding, why not apply the transform there? If there is an error it will be more apparent there as I think the Profile fails silently.
Hi @rlkoshak , thank you for your feedback.
I’ve also read that XHTML should work with XPATH. You mean the XPATH command can be executed directly via the binding? I’ve tried this now and i’m one step further. But now the whole XHTML code is downloaded and the desired value is not selected.
That indicates that the actual xpath is not being found. I can’t explain why the online tester works and this does not. Often different programming languages will have slightly different behaviors. Perhaps Java works a little differently.
Hi @rlkoshak, thanks, then i will try another way…
I have now extracted the data via Python-script and BeautifulSoup and saved it in a file. Now i would like to import this output (file) using HTTP binding and output it using an item. In your opinion, is it better to save the data in a csv-file or in a txt-file? (only the values are listed one below the other) Unfortunately, i haven’t found much for OH3 - can i configure everything via the GUI or does a script have to be created for this?
I thought, i might be able to load the file via the binding and process the content in OH.
But what i actually want to do, i fetch the content of the website once an hour using a Python-script and save the content in a file. I store this file in a defined location, from which OH reads the content of the file and displays it in/with an item. For example, the content of the file looks like this:
Kitzbühel 767m 28.5° 29 % Südost, 13 km/h 29 km/h 0.0 mm 81 % 1002.3 hPa
Unfortunately, i don’t really know how to approach this matter. I can certainly look up the individual steps via the forum, but i don’t know what options there are in general and which of them are also useful for my project.
I am currently in the process of familiarizing myself with HABApp, so I would like to implement it in Python if possible.
Okay i understand, thanks for the explanation. And if i wanted to do everything with OH, how would that go about here? The rule engine HABApp is not so important to me now, if i could solve this via the internal rule engine, i would honestly prefer that. The only thing that matters to me is that i can do it with Python. The OH Python-binding has already been installed and also works.
You’ve done the hard part, getting the raw data into openHAB.
EDIT - the XPATH trouble is about namespace.
The returned webpage includes <html xmlns="http://www.w3.org/1999/xhtml" lang="de">
so all the enclosed html tags are in that namespace.
I had a play in a rule; XPath with "/html/head/title/text()"
returns nothing, because it searches for no-namespace tags. "/*[name()='html']/*[name()='head']/*[name()='title']/text()"
returns Tirol ZAMG from the <title>Tirol — ZAMG</title>
section, using namespace.
Thank you very much @rossko57 you gave me the right hint, now it works!
For all those who find it a little difficult to create the path, chrome has the option of displaying the XPATH path in the developer tools. You still have to modify the output a bit, but it makes the creation of the path a lot easier.
@boogie, are you able to able to provide any more details on what your final XPATH expression was here?
In the XHTML I am trying to parse through (from my old-ish Brother printer), the XPATH expression should ideally be something like:
The value that I want is the ‘50’. It is representative of my printer toner quantity remaining.
I have tried expanding out my XPATH string, something like: "/*[name()='html']/*[name()='body']/*[name()='div']/*[name()='div']/*[name(2)='div']/*[name(2)='div']/ … etc. but that did not seem to work.
The XPATH documentation does not provide any details on how to delve into duplicate tags on the same level of the tree, or how to retrieve properties of tags rather than the text contained within the tags…
There are lots of Xpath testers online where you can paste in the XML and experiment with Xpath expressions until you get it right. They are often also associated with a tutorial. https://codebeautify.org/Xpath-Tester is one but there are others.
It’s been too long since I’ve done Xpath to guess at the right syntax.