Re: Sling Model Exporter: Prevent serializing of a ResourceResolver
Hi Radu,
In general I agree, that it is too easy to leak implementation details
here. Maybe I can use these mixins in the first way to write a lot of WARN
messages in such a case, plus the option not to serialize them (by default
turned off, so serializing them nevertheless).
But my priority is not the prevention of these leaks, but rather mitigating
the.risk of breaking the serialization process. In that case I did not
experience issues with serializing the list of resources.
Jörg
Am Di., 27. Juni 2023 um 19:12 Uhr schrieb Radu Cotescu :
> Hi Jörg,
>
> I think you would have the same problem with that model given the other
> property, namely that list of resources.
>
> Unfortunately I don’t see an easy way out other than documenting this
> aspect and advising developers to avoid exposing implementation details.
> Whatever you’d change in the implementation to prevent this, it would be at
> least a behaviour change, potentially causing regressions similar to
> https://xkcd.com/1172/.
>
> Regards,
> Radu
>
> On Tue, 27 Jun 2023 at 18:35, Jörg Hoh
> wrote:
>
> > HI Stefan,
> >
> > I agree, but:
> >
> > I don't have control over the code, which causes the ResourceResolver to
> be
> > serialized. Also I cannot enforce, that such code is NOT written and
> > deployed (there are too many ways to make it wrong). Also because it
> > currently works, I would have to counter the "but it worked yesterday,
> and
> > I did not change anything since then" argument, in case it fails with an
> > exception like above.
> >
> > So I have to find another way to prevent the ResourceResolver from being
> > serialized ...
> >
> > Jörg
> >
> >
> >
> > Am Di., 27. Juni 2023 um 13:38 Uhr schrieb Stefan Seifert
> > :
> >
> > > well, using lombok with such a result is a bad idea. there should not
> be
> > a
> > > getResolver() method, this is an implementation detail and no getter
> > should
> > > be provided for it.
> > >
> > > so to put it another way: good that the serialization fails, so you can
> > > fix the calls to not add a getResolver() method!
> > >
> > > stefan
> > >
> > > p.s. i'm not a fan of lombok in general and have no experience with it,
> > > but I assume it can be configured to not expose the resolver.
> > >
> > > > -Original Message-
> > > > From: Jörg Hoh
> > > > Sent: Tuesday, June 27, 2023 1:28 PM
> > > > To: Sling Developers List
> > > > Subject: Sling Model Exporter: Prevent serializing of a
> > ResourceResolver
> > > >
> > > > Hi,
> > > >
> > > > Assuming this Sling Model (using Lombok's @Getter annotation)
> > > >
> > > > @Getter
> > > > @Model(
> > > > adaptables = { SlingHttpServletRequest.class },
> > > > adapters = { MyModel.class, ComponentExporter.class },
> > > > resourceType = MyModel.RESOURCE_TYPE) @Exporter(
> > > > name = ExporterConstants.SLING_MODEL_EXPORTER_NAME,
> > > > extensions = ExporterConstants.SLING_MODEL_EXTENSION)
> > > > public class MyModel implements ComponentExporter {
> > > >
> > > > static final String RESOURCE_TYPE =
> "myapp/components/mymodel";
> > > >
> > > > @Inject
> > > > private ResourceResolver resolver;
> > > >
> > > > @ChildResource
> > > > private List items;
> > > >
> > > > }
> > > >
> > > > When it this model is serialized via SlingModelExporter / Jackson,
> the
> > > > resolver field is also exported via the created getResolver())
> method.
> > > >
> > > > But serializing that does not always work:
> > > >
> > > > org.apache.sling.models.factory.ExportException:
> > > > com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
> > > > serializer found for class
> > > > com.day.cq.wcm.core.impl.policies.ContentPolicyManagerImpl and no
> > > > properties discovered to create BeanSerializer (to avoid exception,
> > > > disable
> > > > SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain:
> > > > com.myapp.PageImpl[":items"]> [...] > com.myapp.MyModel["resolver"]
> > > >
> > >org.apache.sling.resourceresolver.impl.ResourceResolverImpl["propertyM
Re: Sling Model Exporter: Prevent serializing of a ResourceResolver
Could you do something like [1] and [2] and just write out JSON null or
some other value that makes sense? That would avoid trying to serialize the
ResourceResolver (and potentially Resource as well), at the expense of a
remaining null. There also may be other features of the StdSerializer [3]
that can be used to prevent the field from being written at all, but I am
not familiar enough with it to say if it is possible or not.
[1]:
https://github.com/adobe/aem-core-wcm-components/blob/main/bundles/core/src/main/java/com/adobe/cq/wcm/core/components/internal/jackson/PageModuleProvider.java
[2]:
https://github.com/adobe/aem-core-wcm-components/blob/main/bundles/core/src/main/java/com/adobe/cq/wcm/core/components/internal/jackson/PageSerializer.java
[3]:
https://fasterxml.github.io/jackson-databind/javadoc/2.8/com/fasterxml/jackson/databind/ser/std/StdSerializer.html
//Paul
On Tue, Jun 27, 2023 at 12:11 PM Radu Cotescu wrote:
> Hi Jörg,
>
> I think you would have the same problem with that model given the other
> property, namely that list of resources.
>
> Unfortunately I don’t see an easy way out other than documenting this
> aspect and advising developers to avoid exposing implementation details.
> Whatever you’d change in the implementation to prevent this, it would be at
> least a behaviour change, potentially causing regressions similar to
> https://xkcd.com/1172/.
>
> Regards,
> Radu
>
> On Tue, 27 Jun 2023 at 18:35, Jörg Hoh
> wrote:
>
> > HI Stefan,
> >
> > I agree, but:
> >
> > I don't have control over the code, which causes the ResourceResolver to
> be
> > serialized. Also I cannot enforce, that such code is NOT written and
> > deployed (there are too many ways to make it wrong). Also because it
> > currently works, I would have to counter the "but it worked yesterday,
> and
> > I did not change anything since then" argument, in case it fails with an
> > exception like above.
> >
> > So I have to find another way to prevent the ResourceResolver from being
> > serialized ...
> >
> > Jörg
> >
> >
> >
> > Am Di., 27. Juni 2023 um 13:38 Uhr schrieb Stefan Seifert
> > :
> >
> > > well, using lombok with such a result is a bad idea. there should not
> be
> > a
> > > getResolver() method, this is an implementation detail and no getter
> > should
> > > be provided for it.
> > >
> > > so to put it another way: good that the serialization fails, so you can
> > > fix the calls to not add a getResolver() method!
> > >
> > > stefan
> > >
> > > p.s. i'm not a fan of lombok in general and have no experience with it,
> > > but I assume it can be configured to not expose the resolver.
> > >
> > > > -Original Message-
> > > > From: Jörg Hoh
> > > > Sent: Tuesday, June 27, 2023 1:28 PM
> > > > To: Sling Developers List
> > > > Subject: Sling Model Exporter: Prevent serializing of a
> > ResourceResolver
> > > >
> > > > Hi,
> > > >
> > > > Assuming this Sling Model (using Lombok's @Getter annotation)
> > > >
> > > > @Getter
> > > > @Model(
> > > > adaptables = { SlingHttpServletRequest.class },
> > > > adapters = { MyModel.class, ComponentExporter.class },
> > > > resourceType = MyModel.RESOURCE_TYPE) @Exporter(
> > > > name = ExporterConstants.SLING_MODEL_EXPORTER_NAME,
> > > > extensions = ExporterConstants.SLING_MODEL_EXTENSION)
> > > > public class MyModel implements ComponentExporter {
> > > >
> > > > static final String RESOURCE_TYPE =
> "myapp/components/mymodel";
> > > >
> > > > @Inject
> > > > private ResourceResolver resolver;
> > > >
> > > > @ChildResource
> > > > private List items;
> > > >
> > > > }
> > > >
> > > > When it this model is serialized via SlingModelExporter / Jackson,
> the
> > > > resolver field is also exported via the created getResolver())
> method.
> > > >
> > > > But serializing that does not always work:
> > > >
> > > > org.apache.sling.models.factory.ExportException:
> > > > com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
> > > > serializer found for class
> > > > com.day.cq.wcm.core.impl.policies.ContentPolicyManagerImpl and no
> > > > properties discover
Re: Sling Model Exporter: Prevent serializing of a ResourceResolver
Hi Jörg,
I think you would have the same problem with that model given the other
property, namely that list of resources.
Unfortunately I don’t see an easy way out other than documenting this
aspect and advising developers to avoid exposing implementation details.
Whatever you’d change in the implementation to prevent this, it would be at
least a behaviour change, potentially causing regressions similar to
https://xkcd.com/1172/.
Regards,
Radu
On Tue, 27 Jun 2023 at 18:35, Jörg Hoh
wrote:
> HI Stefan,
>
> I agree, but:
>
> I don't have control over the code, which causes the ResourceResolver to be
> serialized. Also I cannot enforce, that such code is NOT written and
> deployed (there are too many ways to make it wrong). Also because it
> currently works, I would have to counter the "but it worked yesterday, and
> I did not change anything since then" argument, in case it fails with an
> exception like above.
>
> So I have to find another way to prevent the ResourceResolver from being
> serialized ...
>
> Jörg
>
>
>
> Am Di., 27. Juni 2023 um 13:38 Uhr schrieb Stefan Seifert
> :
>
> > well, using lombok with such a result is a bad idea. there should not be
> a
> > getResolver() method, this is an implementation detail and no getter
> should
> > be provided for it.
> >
> > so to put it another way: good that the serialization fails, so you can
> > fix the calls to not add a getResolver() method!
> >
> > stefan
> >
> > p.s. i'm not a fan of lombok in general and have no experience with it,
> > but I assume it can be configured to not expose the resolver.
> >
> > > -----Original Message-
> > > From: Jörg Hoh
> > > Sent: Tuesday, June 27, 2023 1:28 PM
> > > To: Sling Developers List
> > > Subject: Sling Model Exporter: Prevent serializing of a
> ResourceResolver
> > >
> > > Hi,
> > >
> > > Assuming this Sling Model (using Lombok's @Getter annotation)
> > >
> > > @Getter
> > > @Model(
> > > adaptables = { SlingHttpServletRequest.class },
> > > adapters = { MyModel.class, ComponentExporter.class },
> > > resourceType = MyModel.RESOURCE_TYPE) @Exporter(
> > > name = ExporterConstants.SLING_MODEL_EXPORTER_NAME,
> > > extensions = ExporterConstants.SLING_MODEL_EXTENSION)
> > > public class MyModel implements ComponentExporter {
> > >
> > > static final String RESOURCE_TYPE = "myapp/components/mymodel";
> > >
> > > @Inject
> > > private ResourceResolver resolver;
> > >
> > > @ChildResource
> > > private List items;
> > >
> > > }
> > >
> > > When it this model is serialized via SlingModelExporter / Jackson, the
> > > resolver field is also exported via the created getResolver()) method.
> > >
> > > But serializing that does not always work:
> > >
> > > org.apache.sling.models.factory.ExportException:
> > > com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
> > > serializer found for class
> > > com.day.cq.wcm.core.impl.policies.ContentPolicyManagerImpl and no
> > > properties discovered to create BeanSerializer (to avoid exception,
> > > disable
> > > SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain:
> > > com.myapp.PageImpl[":items"]> [...] > com.myapp.MyModel["resolver"]
> > >
> >org.apache.sling.resourceresolver.impl.ResourceResolverImpl["propertyMa
> > > >p"]
> > >
> >java.util.HashMap["com.day.cq.wcm.core.impl.policies.ContentPolicyAdapt
> > > >erFactory.ContentPolicy"])
> > > at
> > >
> >
> org.apache.sling.models.jacksonexporter.impl.JacksonExporter.export(Jackso
> > > nExporter.java:138)
> > > [org.apache.sling.models.jacksonexporter:1.1.2]
> > > at
> > >
> >
> org.apache.sling.models.impl.ModelAdapterFactory.exportModel(ModelAdapterF
> > > actory.java:1333)
> > > [org.apache.sling.models.impl:1.5.4]
> > >
> > >
> > > I don't want to check each class I want to add to the propertyMap if it
> > > can be serialized or not; and a more serious problem is that
> serializing
> > > the resourceResolver and it's properyMap can leak a lot of information,
> > > which should be not get public.
> > >
> > > Do you see a way to prevent serialization of the ResourceResolver (and
> > > potentially other types as well) without touching the model classes?
> > >
> > > Jörg
> > >
> > > --
> > > Cheers,
> > > Jörg Hoh,
> > >
> > > https://cqdump.joerghoh.de
> > > Twitter: @joerghoh
> >
>
>
> --
> Cheers,
> Jörg Hoh,
>
> https://cqdump.joerghoh.de
> Twitter: @joerghoh
>
Re: Sling Model Exporter: Prevent serializing of a ResourceResolver
Hm, I think that Jackson Mixins [1] could work here.
[1] https://github.com/FasterXML/jackson-docs/wiki/JacksonMixInAnnotations
Am Di., 27. Juni 2023 um 13:28 Uhr schrieb Jörg Hoh :
> Hi,
>
> Assuming this Sling Model (using Lombok's @Getter annotation)
>
> @Getter
> @Model(
> adaptables = { SlingHttpServletRequest.class },
> adapters = { MyModel.class, ComponentExporter.class },
> resourceType = MyModel.RESOURCE_TYPE)
> @Exporter(
> name = ExporterConstants.SLING_MODEL_EXPORTER_NAME,
> extensions = ExporterConstants.SLING_MODEL_EXTENSION)
> public class MyModel implements ComponentExporter {
>
> static final String RESOURCE_TYPE = "myapp/components/mymodel";
>
> @Inject
> private ResourceResolver resolver;
>
> @ChildResource
> private List items;
>
> }
>
> When it this model is serialized via SlingModelExporter / Jackson, the
> resolver field is also exported via the created getResolver()) method.
>
> But serializing that does not always work:
>
> org.apache.sling.models.factory.ExportException:
> com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
> serializer found for class
> com.day.cq.wcm.core.impl.policies.ContentPolicyManagerImpl and no
> properties discovered to create BeanSerializer (to avoid exception, disable
> SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain:
> com.myapp.PageImpl[":items"]> [...] > com.myapp.MyModel["resolver"]
> >org.apache.sling.resourceresolver.impl.ResourceResolverImpl["propertyMap"]
> >java.util.HashMap["com.day.cq.wcm.core.impl.policies.ContentPolicyAdapterFactory.ContentPolicy"])
> at
> org.apache.sling.models.jacksonexporter.impl.JacksonExporter.export(JacksonExporter.java:138)
> [org.apache.sling.models.jacksonexporter:1.1.2]
> at
> org.apache.sling.models.impl.ModelAdapterFactory.exportModel(ModelAdapterFactory.java:1333)
> [org.apache.sling.models.impl:1.5.4]
>
>
> I don't want to check each class I want to add to the propertyMap if it
> can be serialized or not; and a more serious problem is that serializing
> the resourceResolver and it's properyMap can leak a lot of information,
> which should be not get public.
>
> Do you see a way to prevent serialization of the ResourceResolver (and
> potentially other types as well) without touching the model classes?
>
> Jörg
>
> --
> Cheers,
> Jörg Hoh,
>
> https://cqdump.joerghoh.de
> Twitter: @joerghoh
>
--
Cheers,
Jörg Hoh,
https://cqdump.joerghoh.de
Twitter: @joerghoh
Re: Sling Model Exporter: Prevent serializing of a ResourceResolver
HI Stefan,
I agree, but:
I don't have control over the code, which causes the ResourceResolver to be
serialized. Also I cannot enforce, that such code is NOT written and
deployed (there are too many ways to make it wrong). Also because it
currently works, I would have to counter the "but it worked yesterday, and
I did not change anything since then" argument, in case it fails with an
exception like above.
So I have to find another way to prevent the ResourceResolver from being
serialized ...
Jörg
Am Di., 27. Juni 2023 um 13:38 Uhr schrieb Stefan Seifert
:
> well, using lombok with such a result is a bad idea. there should not be a
> getResolver() method, this is an implementation detail and no getter should
> be provided for it.
>
> so to put it another way: good that the serialization fails, so you can
> fix the calls to not add a getResolver() method!
>
> stefan
>
> p.s. i'm not a fan of lombok in general and have no experience with it,
> but I assume it can be configured to not expose the resolver.
>
> > -Original Message-
> > From: Jörg Hoh
> > Sent: Tuesday, June 27, 2023 1:28 PM
> > To: Sling Developers List
> > Subject: Sling Model Exporter: Prevent serializing of a ResourceResolver
> >
> > Hi,
> >
> > Assuming this Sling Model (using Lombok's @Getter annotation)
> >
> > @Getter
> > @Model(
> > adaptables = { SlingHttpServletRequest.class },
> > adapters = { MyModel.class, ComponentExporter.class },
> > resourceType = MyModel.RESOURCE_TYPE) @Exporter(
> > name = ExporterConstants.SLING_MODEL_EXPORTER_NAME,
> > extensions = ExporterConstants.SLING_MODEL_EXTENSION)
> > public class MyModel implements ComponentExporter {
> >
> > static final String RESOURCE_TYPE = "myapp/components/mymodel";
> >
> > @Inject
> > private ResourceResolver resolver;
> >
> > @ChildResource
> > private List items;
> >
> > }
> >
> > When it this model is serialized via SlingModelExporter / Jackson, the
> > resolver field is also exported via the created getResolver()) method.
> >
> > But serializing that does not always work:
> >
> > org.apache.sling.models.factory.ExportException:
> > com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
> > serializer found for class
> > com.day.cq.wcm.core.impl.policies.ContentPolicyManagerImpl and no
> > properties discovered to create BeanSerializer (to avoid exception,
> > disable
> > SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain:
> > com.myapp.PageImpl[":items"]> [...] > com.myapp.MyModel["resolver"]
> > >org.apache.sling.resourceresolver.impl.ResourceResolverImpl["propertyMa
> > >p"]
> > >java.util.HashMap["com.day.cq.wcm.core.impl.policies.ContentPolicyAdapt
> > >erFactory.ContentPolicy"])
> > at
> >
> org.apache.sling.models.jacksonexporter.impl.JacksonExporter.export(Jackso
> > nExporter.java:138)
> > [org.apache.sling.models.jacksonexporter:1.1.2]
> > at
> >
> org.apache.sling.models.impl.ModelAdapterFactory.exportModel(ModelAdapterF
> > actory.java:1333)
> > [org.apache.sling.models.impl:1.5.4]
> >
> >
> > I don't want to check each class I want to add to the propertyMap if it
> > can be serialized or not; and a more serious problem is that serializing
> > the resourceResolver and it's properyMap can leak a lot of information,
> > which should be not get public.
> >
> > Do you see a way to prevent serialization of the ResourceResolver (and
> > potentially other types as well) without touching the model classes?
> >
> > Jörg
> >
> > --
> > Cheers,
> > Jörg Hoh,
> >
> > https://cqdump.joerghoh.de
> > Twitter: @joerghoh
>
--
Cheers,
Jörg Hoh,
https://cqdump.joerghoh.de
Twitter: @joerghoh
RE: Sling Model Exporter: Prevent serializing of a ResourceResolver
well, using lombok with such a result is a bad idea. there should not be a
getResolver() method, this is an implementation detail and no getter should be
provided for it.
so to put it another way: good that the serialization fails, so you can fix the
calls to not add a getResolver() method!
stefan
p.s. i'm not a fan of lombok in general and have no experience with it, but I
assume it can be configured to not expose the resolver.
> -Original Message-
> From: Jörg Hoh
> Sent: Tuesday, June 27, 2023 1:28 PM
> To: Sling Developers List
> Subject: Sling Model Exporter: Prevent serializing of a ResourceResolver
>
> Hi,
>
> Assuming this Sling Model (using Lombok's @Getter annotation)
>
> @Getter
> @Model(
> adaptables = { SlingHttpServletRequest.class },
> adapters = { MyModel.class, ComponentExporter.class },
> resourceType = MyModel.RESOURCE_TYPE) @Exporter(
> name = ExporterConstants.SLING_MODEL_EXPORTER_NAME,
> extensions = ExporterConstants.SLING_MODEL_EXTENSION)
> public class MyModel implements ComponentExporter {
>
> static final String RESOURCE_TYPE = "myapp/components/mymodel";
>
> @Inject
> private ResourceResolver resolver;
>
> @ChildResource
> private List items;
>
> }
>
> When it this model is serialized via SlingModelExporter / Jackson, the
> resolver field is also exported via the created getResolver()) method.
>
> But serializing that does not always work:
>
> org.apache.sling.models.factory.ExportException:
> com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
> serializer found for class
> com.day.cq.wcm.core.impl.policies.ContentPolicyManagerImpl and no
> properties discovered to create BeanSerializer (to avoid exception,
> disable
> SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain:
> com.myapp.PageImpl[":items"]> [...] > com.myapp.MyModel["resolver"]
> >org.apache.sling.resourceresolver.impl.ResourceResolverImpl["propertyMa
> >p"]
> >java.util.HashMap["com.day.cq.wcm.core.impl.policies.ContentPolicyAdapt
> >erFactory.ContentPolicy"])
> at
> org.apache.sling.models.jacksonexporter.impl.JacksonExporter.export(Jackso
> nExporter.java:138)
> [org.apache.sling.models.jacksonexporter:1.1.2]
> at
> org.apache.sling.models.impl.ModelAdapterFactory.exportModel(ModelAdapterF
> actory.java:1333)
> [org.apache.sling.models.impl:1.5.4]
>
>
> I don't want to check each class I want to add to the propertyMap if it
> can be serialized or not; and a more serious problem is that serializing
> the resourceResolver and it's properyMap can leak a lot of information,
> which should be not get public.
>
> Do you see a way to prevent serialization of the ResourceResolver (and
> potentially other types as well) without touching the model classes?
>
> Jörg
>
> --
> Cheers,
> Jörg Hoh,
>
> https://cqdump.joerghoh.de
> Twitter: @joerghoh
Sling Model Exporter: Prevent serializing of a ResourceResolver
Hi,
Assuming this Sling Model (using Lombok's @Getter annotation)
@Getter
@Model(
adaptables = { SlingHttpServletRequest.class },
adapters = { MyModel.class, ComponentExporter.class },
resourceType = MyModel.RESOURCE_TYPE)
@Exporter(
name = ExporterConstants.SLING_MODEL_EXPORTER_NAME,
extensions = ExporterConstants.SLING_MODEL_EXTENSION)
public class MyModel implements ComponentExporter {
static final String RESOURCE_TYPE = "myapp/components/mymodel";
@Inject
private ResourceResolver resolver;
@ChildResource
private List items;
}
When it this model is serialized via SlingModelExporter / Jackson, the
resolver field is also exported via the created getResolver()) method.
But serializing that does not always work:
org.apache.sling.models.factory.ExportException:
com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
serializer found for class
com.day.cq.wcm.core.impl.policies.ContentPolicyManagerImpl and no
properties discovered to create BeanSerializer (to avoid exception, disable
SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain:
com.myapp.PageImpl[":items"]> [...] > com.myapp.MyModel["resolver"]
>org.apache.sling.resourceresolver.impl.ResourceResolverImpl["propertyMap"]
>java.util.HashMap["com.day.cq.wcm.core.impl.policies.ContentPolicyAdapterFactory.ContentPolicy"])
at
org.apache.sling.models.jacksonexporter.impl.JacksonExporter.export(JacksonExporter.java:138)
[org.apache.sling.models.jacksonexporter:1.1.2]
at
org.apache.sling.models.impl.ModelAdapterFactory.exportModel(ModelAdapterFactory.java:1333)
[org.apache.sling.models.impl:1.5.4]
I don't want to check each class I want to add to the propertyMap if it can
be serialized or not; and a more serious problem is that serializing the
resourceResolver and it's properyMap can leak a lot of information, which
should be not get public.
Do you see a way to prevent serialization of the ResourceResolver (and
potentially other types as well) without touching the model classes?
Jörg
--
Cheers,
Jörg Hoh,
https://cqdump.joerghoh.de
Twitter: @joerghoh
