Using passwordless code (taken from API) in frontend - fusionauth

Question

Any suggestions on how to use the passwordless code (taken from API endpoint "/api/passwordless/start") and use it to redirect the user in frontend?
I thought this will work but it did not:
Request code from API endpoint "/api/passwordless/start"
Reply from API endpoint: "JriRpuGHmecXAD2qRB3_s-Ud4jMKxmtuD57bfYAjYn4"
Open/redirect to URL: http://localhost:9011/oauth2/passwordless/JriRpuGHmecXAD2qRB3_s-Ud4jMKxmtuD57bfYAjYn4?tenantId=57810835-47f7-683f-02ed-420592eface2
Instead I get this error:
Jan 23, 2020 9:21:27.276 AM ERROR io.fusionauth.app.primeframework.error.ExceptionExceptionHandler - An unhandled exception was thrown
java.lang.NullPointerException: null
at io.fusionauth.app.action.oauth2.BaseOAuthAction.handleInteractiveLoginResponse(BaseOAuthAction.java:391)
at io.fusionauth.app.action.oauth2.PasswordlessAction.authenticateAuthorizationGrant(PasswordlessAction.java:135)
at io.fusionauth.app.action.oauth2.PasswordlessAction.get(PasswordlessAction.java:50)
at sun.reflect.GeneratedMethodAccessor90.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.primeframework.mvc.util.ReflectionUtils.invoke(ReflectionUtils.java:414)
at org.primeframework.mvc.action.DefaultActionInvocationWorkflow.execute(DefaultActionInvocationWorkflow.java:79)
at org.primeframework.mvc.action.DefaultActionInvocationWorkflow.perform(DefaultActionInvocationWorkflow.java:62)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.validation.DefaultValidationWorkflow.perform(DefaultValidationWorkflow.java:47)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.security.DefaultSecurityWorkflow.perform(DefaultSecurityWorkflow.java:60)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.parameter.DefaultPostParameterWorkflow.perform(DefaultPostParameterWorkflow.java:50)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.content.DefaultContentWorkflow.perform(DefaultContentWorkflow.java:52)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.parameter.DefaultParameterWorkflow.perform(DefaultParameterWorkflow.java:57)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.parameter.DefaultURIParameterWorkflow.perform(DefaultURIParameterWorkflow.java:102)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.scope.DefaultScopeRetrievalWorkflow.perform(DefaultScopeRetrievalWorkflow.java:58)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.message.DefaultMessageWorkflow.perform(DefaultMessageWorkflow.java:45)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at io.fusionauth.app.primeframework.FrontEndTenantWorkflow.perform(FrontEndTenantWorkflow.java:76)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.action.DefaultActionMappingWorkflow.perform(DefaultActionMappingWorkflow.java:126)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.workflow.StaticResourceWorkflow.perform(StaticResourceWorkflow.java:97)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.parameter.RequestBodyWorkflow.perform(RequestBodyWorkflow.java:89)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at org.primeframework.mvc.security.DefaultSavedRequestWorkflow.perform(DefaultSavedRequestWorkflow.java:57)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at io.fusionauth.app.primeframework.CORSFilter.handleNonCORS(CORSFilter.java:291)
at io.fusionauth.app.primeframework.CORSFilter.doFilter(CORSFilter.java:252)
at io.fusionauth.app.primeframework.CORSRequestWorkflow.perform(CORSRequestWorkflow.java:48)
at org.primeframework.mvc.workflow.SubWorkflowChain.continueWorkflow(SubWorkflowChain.java:43)
at io.fusionauth.app.primeframework.FusionAuthMVCWorkflow.perform(FusionAuthMVCWorkflow.java:88)
at org.primeframework.mvc.workflow.DefaultWorkflowChain.continueWorkflow(DefaultWorkflowChain.java:44)
at org.primeframework.mvc.servlet.FilterWorkflowChain.continueWorkflow(FilterWorkflowChain.java:50)
at org.primeframework.mvc.servlet.PrimeFilter.doFilter(PrimeFilter.java:84)
at com.inversoft.maintenance.servlet.MaintenanceModePrimeFilter.doFilter(MaintenanceModePrimeFilter.java:59)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.inversoft.servlet.UTF8Filter.doFilter(UTF8Filter.java:27)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:798)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:808)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Note: The passwordless login sent over email is working.

Answer 1

It turns out that the "/api/passwordless/start" request needs more parameters for this use-case.
#robotdan:
"If you want to use the start API and then complete it via the front end OAuth endpoints (is this because you want to use something other than email for the transport?) , you may have to add some state to the the request.
At a minimum, you’d need to pass client_id, redirect_uri and tenanId (and their values( on the Start API request in the state parameter.
https://fusionauth.io/docs/v1/tech/apis/passwordless#start-passwordless-login
The easier way to do all of this is is to initiate it from the OAuth login page and then we build all of the state into the request in order to complete it via OAuth."
Thanks #robotdan