How to specify the content-type in XSLT Transformations

Setup, Configuration and Use Items & Sitemaps
1

I have been using the following item definition to access weather information

Number bayern3_wetter_temperature_today_min “Min Temperature heute [%.1f °C]” // {http="<[Bayern3:600000:XSLT(bayern3_temp_min_today.xsl)]"}

in config file I have defined

http:Bayern3.url=http://www.br.de/wettervorhersage/services/rest/weatherdata/81825
http:Bayern3.updateInterval=3600000

This was working for many weeks but since a couple of days I am observing that the server seems to provide the information in json format which cannot be processed with my xsl transformation file.

Therefore I would like to specify the content-type when requesting the server.
Does anyone know the syntax to extend the item defintion?
I guess I have to add some extentions in {} in the config file but I am lost on the syntax.

the related curl would be
curl -i
-H “Accept: application/xml” -H “Content-Type: application/xml” http://www.br.de/wettervorhersage/services/rest/weatherdata/81825/

so maybe the following syntax in config

http:Bayern3.url=http://www.br.de/wettervorhersage/services/rest/weatherdata/81825{Accept=application/xml&Content-Type=application/xml}
could be something in the direction …

or maybe in items.
Number bayern3_wetter_temperature_today_min “Min Temperature heute [%.1f °C]” // {http="<[Bayern3{Accept=application/xml&Content-Type=application/xml}:600000:XSLT(bayern3_temp_min_today.xsl)]"}

2

That URL returns XML when I access it with a browser.

3

yes, in a browser it does but openhab does not. This is what I am receiving as an error.

2016-05-30 06:23:45.195 [ERROR] [.i.s.XsltTransformationService] - transformation throws exception
javax.xml.transform.TransformerException: javax.xml.transform.TransformerException: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: Content ist nicht zulässig in Prolog.
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(Unknown Source) ~[na:1.8.0_91]
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(Unknown Source) ~[na:1.8.0_91]
at org.openhab.core.transform.internal.service.XsltTransformationService.transform(XsltTransformationService.java:83) ~[na:na]
at org.openhab.binding.http.internal.HttpBinding.execute(HttpBinding.java:182) [bundlefile:na]
at org.openhab.core.binding.AbstractActiveBinding$BindingActiveService.execute(AbstractActiveBinding.java:156) [org.openhab.core_1.8.0.jar:na]
at org.openhab.core.service.AbstractActiveService$RefreshThread.run(AbstractActiveService.java:173) [org.openhab.core_1.8.0.jar:na]
Caused by: javax.xml.transform.TransformerException: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: Content ist nicht zulässig in Prolog.
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getDOM(Unknown Source) ~[na:1.8.0_91]
… 6 common frames omitted
Caused by: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: Content ist nicht zulässig in Prolog.
at com.sun.org.apache.xalan.internal.xsltc.dom.XSLTCDTMManager.getDTM(Unknown Source) ~[na:1.8.0_91]
at com.sun.org.apache.xalan.internal.xsltc.dom.XSLTCDTMManager.getDTM(Unknown Source) ~[na:1.8.0_91]
… 7 common frames omitted
2016-05-30 06:23:45.244 [ERROR] [.o.b.http.internal.HttpBinding] - transformation throws exception [transformation=XSLT(bayern3_date_today.xsl), response={“day”:[{“date”:1464559200000,“temperatureMin”:{“value”:“13”,“Unit”:“°C”},“temperatureMax”:{“value”:“20”,“Unit”:“°C”},“windSpeedMax”:{“value”:“20”,“direction”:null,“directionshort”:null,“Unit”:“km/h”},“windSpeedGuestMax”:{“value”:“37”,“direction”:null,“directionshort”:null,“Unit”:“km/h”}},{“date”:1464645600000,“temperatureMin”:{“value”:“12”,“Unit”:“°C”},“temperatureMax”:{“value”:“20”,“Unit”:“°C”},“windSpeedMax”:{“value”:“9”,“direction”:null,“directionshort”:null,“Unit”:“km/h”},“windSpeedGuestMax”:{“value”:“22”,“direction”:null,“directionshort”:null,“Unit”:“km/h”}}]}]
org.openhab.core.transform.TransformationException: transformation throws exception
at org.openhab.core.transform.internal.service.XsltTransformationService.transform(XsltTransformationService.java:86) ~[na:na]
at org.openhab.binding.http.internal.HttpBinding.execute(HttpBinding.java:182) ~[na:na]
at org.openhab.core.binding.AbstractActiveBinding$BindingActiveService.execute(AbstractActiveBinding.java:156) [org.openhab.core_1.8.0.jar:na]
at org.openhab.core.service.AbstractActiveService$RefreshThread.run(AbstractActiveService.java:173) [org.openhab.core_1.8.0.jar:na]
Caused by: javax.xml.transform.TransformerException: javax.xml.transform.TransformerException: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: Content ist nicht zulässig in Prolog.

4

If I removed the part of the item binding quoted above, it worked for me and returned XML to openHAB (1.8.3).

HTH,

Steve

5

Hi Steve,
Thanks for trying. Does not work here.
I tried to only leave {Accept=application/xml} but not successful.
regards
Martin

6

Here’s my exact test item definition. I’m not extracting anything from the XML so the item content is the entire XML content.

String HttpTest { http="<[http://www.br.de/wettervorhersage/services/rest/weatherdata/81825/{Accept=application/xml}:30000:REGEX((.*))]" }

Log:

2016-05-31 05:35:17.548 [DEBUG] [.o.b.http.internal.HttpBinding] - item 'HttpTest' is about to be refreshed now
2016-05-31 05:35:18.374 [DEBUG] [.o.b.http.internal.HttpBinding] - transformed response is '<?xml version="1.0" encoding="UTF-8" standalone="yes"?><weatherdata><day><date>2016-05-31T00:00:00+02:00</date><temperatureMin><value>11</value><Unit>°C</Unit></temperatureMin><temperatureMax><value>19</value><Unit>°C</Unit></temperatureMax><windSpeedMax><value>11</value><Unit>km/h</Unit></windSpeedMax><windSpeedGuestMax><value>22</value><Unit>km/h</Unit></windSpeedGuestMax></day><day><date>2016-06-01T00:00:00+02:00</date><temperatureMin><value>13</value><Unit>°C</Unit></temperatureMin><temperatureMax><value>18</value><Unit>°C</Unit></temperatureMax><windSpeedMax><value>19</value><Unit>km/h</Unit></windSpeedMax><windSpeedGuestMax><value>37</value><Unit>km/h</Unit></windSpeedGuestMax></day></weatherdata>'
2016-05-31 05:35:18.391 [INFO ] [runtime.busevents             ] - HttpTest state updated to <?xml version="1.0" encoding="UTF-8" standalone="yes"?><weatherdata><day><date>2016-05-31T00:00:00+02:00</date><temperatureMin><value>11</value><Unit>°C</Unit></temperatureMin><temperatureMax><value>19</value><Unit>°C</Unit></temperatureMax><windSpeedMax><value>11</value><Unit>km/h</Unit></windSpeedMax><windSpeedGuestMax><value>22</value><Unit>km/h</Unit></windSpeedGuestMax></day><day><date>2016-06-01T00:00:00+02:00</date><temperatureMin><value>13</value><Unit>°C</Unit></temperatureMin><temperatureMax><value>18</value><Unit>°C</Unit></temperatureMax><windSpeedMax><value>19</value><Unit>km/h</Unit></windSpeedMax><windSpeedGuestMax><value>37</value><Unit>km/h</Unit></windSpeedGuestMax></day></weatherdata>
7

Thanks Steve for taking the time.
Really appreciate this!!

It seems that your solution having the url direct in the item defintion avoiding the cached approach did the trick.Still unclear for me, because the cached approach worked for some time.

8

I’ve taken another look at the source code for the http binding and I think that the problem with the caching was that the headers must be specified in http:Bayern3.url rather than in the item binding.

9

Thanks again.
I will try this out aswell.