save() call throws error if called after edit in case of huge model data

[mishaltripathi]

Hello,

I have custom command handler(model server) at backend which we are calling from model server edit() api from frontend side. This operation parses some huge input file and gets updated to model data. And we need to save the model file after this operation. Now when we try to call save() at below two places.

1. Calling save() once we get response from edit() api.
2. Calling save() during incremental update listener event.

Unfortunately the save action in both cases are failing and creating href links in model file and throws backend errors.

Working scenario:
If I am doing small data operation like adding couple of objects or editing them then save works fine in both scenario.

Do anyone have pointers how to save the model file after calling custom commands.

Thanks,
Mishal

[eneufeld]

Hi @mishaltripathi,
do you have a stacktrace of the failing save operation?

Best,
Eugen

[mishaltripathi]

Hi @eneufeld ,

Here, I am first doing a patch operation and then save. Below is the stacktrace of the operations. Though both operations can be seen as success but creates href in the model after save.

2023-07-26 23:11:53,051904000 [JettyServerThreadPool-19] INFO ProviderDefaults - PATCH /api/v2/models?modeluri=sample.extn&format=json-v2 -> Status: 200 (took 4069.1287 ms) 2023-07-26 23:11:58,257308000 [Thread-12] ERROR DefaultModelResourceManager - Could not load resource with URI: file:/home/mishal/workspace/sample.extn org.eclipse.emf.ecore.resource.impl.ResourceSetImpl$1DiagnosticWrappedException: org.xml.sax.SAXParseExceptionpublicId: file:/home/mishal/workspace/sample.extn; systemId: file:/home/mishal/workspace/sample.extn; lineNumber: 1; columnNumber: 1; Premature end of file. at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.handleDemandLoadException(ResourceSetImpl.java:319) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.demandLoadHelper(ResourceSetImpl.java:278) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.getResource(ResourceSetImpl.java:406) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.DefaultModelResourceManager.loadResource(DefaultModelResourceManager.java:324) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.DefaultModelResourceManager.basicCloseResource(DefaultModelResourceManager.java:453) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.DefaultModelResourceManager.closeResource(DefaultModelResourceManager.java:410) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.DefaultModelRepository.closeModel(DefaultModelRepository.java:157) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.watchers.ReconcilingStrategy$AlwaysReload.basicReconcileModel(ReconcilingStrategy.java:79) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.watchers.ReconcilingStrategy$AlwaysReload.lambda$0(ReconcilingStrategy.java:64) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.DefaultModelResourceManager.runResourceSetAction(DefaultModelResourceManager.java:781) [com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.DefaultModelRepository.runResourceSetAction(DefaultModelRepository.java:206) [com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.watchers.ReconcilingStrategy$AlwaysReload.reconcileModel(ReconcilingStrategy.java:63) [com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.watchers.AbstractModelWatcher.reconcile(AbstractModelWatcher.java:52) [com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.watchers.FileModelWatcher.handleEvent(FileModelWatcher.java:167) [com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emfcloud.modelserver.emf.common.watchers.FileModelWatcher.run(FileModelWatcher.java:129) [com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at java.lang.Thread.run(Thread.java:829) [?:?] Caused by: org.xml.sax.SAXParseException: Premature end of file. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:204) ~[?:?] at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:178) ~[?:?] at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:400) ~[?:?] at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327) ~[?:?] at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1465) ~[?:?] at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:1013) ~[?:?] at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605) ~[?:?] at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:534) ~[?:?] at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:888) ~[?:?] at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:824) ~[?:?] at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141) ~[?:?] at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1216) ~[?:?] at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:635) ~[?:?] at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:324) ~[?:?] at org.eclipse.emf.ecore.xmi.impl.XMLLoadImpl.load(XMLLoadImpl.java:175) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emf.ecore.xmi.impl.XMLResourceImpl.doLoad(XMLResourceImpl.java:261) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emf.ecore.resource.impl.ResourceImpl.load(ResourceImpl.java:1563) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emf.ecore.resource.impl.ResourceImpl.load(ResourceImpl.java:1342) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.demandLoad(ResourceSetImpl.java:259) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.demandLoadHelper(ResourceSetImpl.java:274) ~[com.example.modelserver-0.0.1-SNAPSHOT-standalone.jar:?] ... 14 more 2023-07-26 23:11:58,330093000 [JettyServerThreadPool-20] INFO ProviderDefaults - GET /api/v2/save?modeluri=sample.extn -> Status: 200 (took 221.92484 ms)

Thanks,
Mishal

[eneufeld]

Hi @mishaltripathi ,

so the stacktrace says: ERROR DefaultModelResourceManager - Could not load resource with URI: file:/home/mishal/workspace/sample.extn [...] file:/home/mishal/workspace/sample.extn; lineNumber: 1; columnNumber: 1; Premature end of file.
So it says the file you want to edit is not a valid xmi file. The reason being that it is empty.

Depending on your use case you can either create a file once using the ecore tools in eclipse and create a dynamic instance.

Or if you need to be able to create new files from your tool, you should add a command something like this to the client: https://github.com/eclipse-emfcloud/ecore-glsp/blob/6c0bab10dc1a2a0432514b8c1d93bbca00dea3df/client/packages/theia-ecore/src/node/model-server-client.ts#L26
and on the modelserver a handler:
https://github.com/eclipse-emfcloud/ecore-glsp/blob/6c0bab10dc1a2a0432514b8c1d93bbca00dea3df/server/org.eclipse.emfcloud.ecore.modelserver/src/main/java/org/eclipse/emfcloud/ecore/modelserver/EcoreModelServerRouting.java#L51
and the actual code:
https://github.com/eclipse-emfcloud/ecore-glsp/blob/6c0bab10dc1a2a0432514b8c1d93bbca00dea3df/server/org.eclipse.emfcloud.ecore.modelserver/src/main/java/org/eclipse/emfcloud/ecore/modelserver/EcoreModelResourceManager.java#L99

I hope this helps.

Best,
Eugen

[mishaltripathi]

Thanks @eneufeld for your suggestion. I will definitely check this.