[3.2.0] Errors observed in API Documents when using Markdown File

[athiththan11]

Description:

Add Document in the Documents section of the Publisher portal is not working when trying to upload a markdown file as API documentation. There were no error messages or alerts produced in the Publisher portal, but clicking the Add Document button twice or thrice produces the following trace in the carbon logs

[2020-08-15 16:31:03,120] ERROR - ApisApiServiceImpl Requested document 'How To' already exists
[2020-08-15 16:31:10,313] ERROR - DocumentIndexer No document associated to API
[2020-08-15 16:31:10,314] ERROR - DocumentIndexer Error while updating indexed document.
org.wso2.carbon.apimgt.api.APIManagementException: No document associated to API
	at org.wso2.carbon.apimgt.impl.indexing.indexer.DocumentIndexer.fetchDocumentContent_aroundBody4(DocumentIndexer.java:179) ~[org.wso2.carbon.apimgt.impl_6.7.192.jar:?]
	at org.wso2.carbon.apimgt.impl.indexing.indexer.DocumentIndexer.fetchDocumentContent(DocumentIndexer.java:163) ~[org.wso2.carbon.apimgt.impl_6.7.192.jar:?]
	at org.wso2.carbon.apimgt.impl.indexing.indexer.DocumentIndexer.getIndexedDocument_aroundBody0(DocumentIndexer.java:97) [org.wso2.carbon.apimgt.impl_6.7.192.jar:?]
	at org.wso2.carbon.apimgt.impl.indexing.indexer.DocumentIndexer.getIndexedDocument(DocumentIndexer.java:74) [org.wso2.carbon.apimgt.impl_6.7.192.jar:?]
	at org.wso2.carbon.registry.indexing.indexer.IndexDocumentCreator.getIndexDocument(IndexDocumentCreator.java:333) [org.wso2.carbon.registry.indexing_4.7.35.jar:?]
	at org.wso2.carbon.registry.indexing.indexer.IndexDocumentCreator.createIndexDocument(IndexDocumentCreator.java:96) [org.wso2.carbon.registry.indexing_4.7.35.jar:?]
	at org.wso2.carbon.registry.indexing.AsyncIndexer$IndexingTask.createIndexDocument(AsyncIndexer.java:245) [org.wso2.carbon.registry.indexing_4.7.35.jar:?]
	at org.wso2.carbon.registry.indexing.AsyncIndexer$IndexingTask.run(AsyncIndexer.java:210) [org.wso2.carbon.registry.indexing_4.7.35.jar:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_201]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_201]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_201]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_201]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201]

Then, press Cancel and reloading the Documents page throws the following NPE in the carbon logs

[2020-08-15 16:31:20,789] ERROR - GlobalThrowableMapper An unknown exception has been captured by the global exception mapper.
java.lang.NullPointerException: null
	at org.wso2.carbon.apimgt.impl.utils.APIUtil.getDocument_aroundBody404(APIUtil.java:6767) ~[org.wso2.carbon.apimgt.impl_6.7.192.jar:?]
	at org.wso2.carbon.apimgt.impl.utils.APIUtil.getDocument(APIUtil.java:6760) ~[org.wso2.carbon.apimgt.impl_6.7.192.jar:?]
	at org.wso2.carbon.apimgt.rest.api.publisher.v1.impl.ApisApiServiceImpl.apisApiIdDocumentsDocumentIdContentGet(ApisApiServiceImpl.java:1790) ~[classes/:?]
	at org.wso2.carbon.apimgt.rest.api.publisher.v1.ApisApi.apisApiIdDocumentsDocumentIdContentGet(ApisApi.java:250) ~[classes/:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_201]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_201]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_201]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_201]
	at org.apache.cxf.service.invoker.AbstractInvoker.performInvocation(AbstractInvoker.java:179) ~[cxf-core-3.2.8.jar:3.2.8]
	at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:96) ~[cxf-core-3.2.8.jar:3.2.8]
	at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:193) [cxf-rt-frontend-jaxrs-3.2.8.jar:3.2.8]
	at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:103) [cxf-rt-frontend-jaxrs-3.2.8.jar:3.2.8]
	at org.apache.cxf.interceptor.ServiceInvokerInterceptor$1.run(ServiceInvokerInterceptor.java:59) [cxf-core-3.2.8.jar:3.2.8]
	at org.apache.cxf.interceptor.ServiceInvokerInterceptor.handleMessage(ServiceInvokerInterceptor.java:96) [cxf-core-3.2.8.jar:3.2.8]
	at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:308) [cxf-core-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121) [cxf-core-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:267) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:234) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:208) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:160) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:216) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:301) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at org.apache.cxf.transport.servlet.AbstractHTTPServlet.doGet(AbstractHTTPServlet.java:225) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) [tomcat-servlet-api_9.0.31.wso2v1.jar:?]
	at org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:276) [cxf-rt-transports-http-3.2.8.jar:3.2.8]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat_9.0.31.wso2v1.jar:?]
	at org.wso2.carbon.identity.context.rewrite.valve.TenantContextRewriteValve.invoke(TenantContextRewriteValve.java:86) [org.wso2.carbon.identity.context.rewrite.valve_1.4.0.jar:?]
	at org.wso2.carbon.identity.authz.valve.AuthorizationValve.invoke(AuthorizationValve.java:110) [org.wso2.carbon.identity.authz.valve_1.4.0.jar:?]
	at org.wso2.carbon.identity.auth.valve.AuthenticationValve.invoke(AuthenticationValve.java:75) [org.wso2.carbon.identity.auth.valve_1.4.0.jar:?]
	at org.wso2.carbon.tomcat.ext.valves.CompositeValve.continueInvocation(CompositeValve.java:99) [org.wso2.carbon.tomcat.ext_4.6.0.jar:?]
	at org.wso2.carbon.tomcat.ext.valves.TomcatValveContainer.invokeValves(TomcatValveContainer.java:49) [org.wso2.carbon.tomcat.ext_4.6.0.jar:?]
	at org.wso2.carbon.tomcat.ext.valves.CompositeValve.invoke(CompositeValve.java:62) [org.wso2.carbon.tomcat.ext_4.6.0.jar:?]
	at org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:145) [org.wso2.carbon.tomcat.ext_4.6.0.jar:?]
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:688) [tomcat_9.0.31.wso2v1.jar:?]
	at org.wso2.carbon.tomcat.ext.valves.CarbonContextCreatorValve.invoke(CarbonContextCreatorValve.java:57) [org.wso2.carbon.tomcat.ext_4.6.0.jar:?]
	at org.wso2.carbon.tomcat.ext.valves.RequestCorrelationIdValve.invoke(RequestCorrelationIdValve.java:119) [org.wso2.carbon.tomcat.ext_4.6.0.jar:?]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:367) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1639) [tomcat_9.0.31.wso2v1.jar:?]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat_9.0.31.wso2v1.jar:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_201]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_201]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat_9.0.31.wso2v1.jar:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201]

Please find the attached Gif for reference on the flow followed (please find the high-quality recording here).

Steps to reproduce:

• Start the API Manager v3.2.0 - RC5
• Go to the Publisher portal and publish an API
• Go to the Documents section and add a new document
• Fill the form and upload a file with .md type
• Click on Add Document and check the carbon logs (Errors)
• Click on Cancel and refresh the page and check the carbon logs (NPE)

Affected Product Version:

• API Manager v3.2.0 - RC5

[hasuniea]

fixed the issue in uploading files: wso2/carbon-apimgt#9221

Apart from that, we don't support .md file formats in the source formats. Because we rely on the react dropzone library and it doesn't support the text/markdown content type. We will update the official docs accordingly with the supported content types.Please find the doc issue[1]

[1] . wso2/docs-apim#1765