spring social version 1.0.3: Why i've Field or property 'name' cannot be found on null error

Question

I use Spring Social 1.0.3 to add "Sign In with Facebook" and "Sign In with Twitter" on my login page. Here my login view page :

login view :

 <form action="<c:url value="/connect/twitter" />" method="POST">
  <p><button type="submit"><img src="<c:url value="/resources/images/social/twitter/sign-in-with-twitter-d.png" />"/>
    </button></p>
</form>

  <form action="<c:url value="/connect/facebook" />" method="POST">
  <p><button type="submit"><img src="<c:url value="/resources/images/social/facebook/sign-in-with-facebook.png" />"/>
    </button></p>
</form>

Spring social xml configuration:

<context:property-placeholder location="classpath:application.properties" />

    <bean id="connectionFactoryLocator" 
      class="org.springframework.social.connect.support.ConnectionFactoryRegistry">
    <property name="connectionFactories">
        <list>
            <bean class="org.springframework.social.twitter.connect.TwitterConnectionFactory">
                <constructor-arg value="${twitter.consumerKey}" />
                <constructor-arg value="${twitter.consumerSecret}" />               
            </bean>
            <bean class="org.springframework.social.facebook.connect.FacebookConnectionFactory">
                <constructor-arg value="${facebook.clientId}" />
                <constructor-arg value="${facebook.clientSecret}" />                
            </bean>
        </list>
    </property>
</bean>

<bean id="usersConnectionRepository" 
      class="org.springframework.social.connect.jdbc.JdbcUsersConnectionRepository">
    <constructor-arg ref="dataSource" />
    <constructor-arg ref="connectionFactoryLocator" />
    <constructor-arg ref="textEncryptor" />
</bean>

<bean id="connectionRepository" factory-method="createConnectionRepository" 
      factory-bean="usersConnectionRepository" scope="request">
    <constructor-arg value="#{request.userPrincipal.name}" />
    <aop:scoped-proxy proxy-target-class="false" />
</bean>

 <bean id="textEncryptor" class="org.springframework.security.crypto.encrypt.Encryptors" 
                factory-method="noOpText">

        </bean>

<bean class="org.springframework.social.connect.web.ConnectController">
    <!-- relies on by-type autowiring for the constructor-args -->
    <property name="applicationUrl" value="${application.url}" />
</bean>
</beans>

application properties file:

#Facebook
facebook.clientId=ideletetherealvalue
facebook.clientSecret=ideletetherealvalue

#Twitter
twitter.consumerKey=ideletetherealvalue
twitter.consumerSecret=ideletetherealvalue

application.url=http://localhost:8080/myapp

The url application http://localhost:8080/myapp is authorized in facebook application.

When i click on "Sign In with Twitter" or "Sign In with Facebook", i am redirect to Twitter or Facebook to submit my login and password.

1.Twitter when i submit my credentials then another page ask me to allow the application I allow the application and then i get the following error :

DEBUG [org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver] [] http-bio-8080-exec-10 Resolving exception from handler [public java.lang.String org.springframework.social.connect.web.ConnectController.connectionStatus(java.lang.String,org.springframework.web.context.request.NativeWebRequest,org.springframework.ui.Model)]: org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E:(pos 0): Field or property 'name' cannot be found on null
    DEBUG [org.springframework.web.servlet.DispatcherServlet] [] http-bio-8080-exec-10 Could not complete request
    org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E:(pos 0): Field or property 'name' cannot be found on null


The complete error is here http://pastebin.com/hyRicyFu

2.Facebook when i submit my credentials then i get the following error:

org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E:(pos 0): Field or property 'name' cannot be found on null
DEBUG [org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver] [] http-bio-8080-exec-2 Resolving exception from handler [public java.lang.String org.springframework.social.connect.web.ConnectController.connectionStatus(java.lang.String,org.springframework.web.context.request.NativeWebRequest,org.springframework.ui.Model)]: org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E:(pos 0): Field or property 'name' cannot be found on null
DEBUG [org.springframework.web.servlet.DispatcherServlet] [] http-bio-8080-exec-2 Could not complete request
org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1007E:(pos 0): Field or property 'name' cannot be found on null

The complete error is here http://pastebin.com/hyRicyFu

Questions: According to what i understand this error comes from

<bean id="connectionRepository" factory-method="createConnectionRepository" 
      factory-bean="usersConnectionRepository" scope="request">
    <constructor-arg value="#{request.userPrincipal.name}" />
    <aop:scoped-proxy proxy-target-class="false" />
</bean>

error message : Field or property 'name' cannot be found on null

I need some confirmation : a- Have i to create in database a user when the user submit ? Which controller i have to extend ? If someone has an example it will help

b- If i am wrong, what's happening , why i am getting the error ?

Answer 1

Yes, you are correct - the problem is with that configuration.

<bean id="connectionRepository" factory-method="createConnectionRepository" 
      factory-bean="usersConnectionRepository" scope="request">
    <constructor-arg value="#{request.userPrincipal.name}" />
    <aop:scoped-proxy proxy-target-class="false" />
</bean>

The above creates a connection repository with the argument to the constructor as request.userPrincipal.name - this would only work if your user was already signed in (this is trying to instantiate a per-request repository for the principal user - so needs an ID for that repository to be tied to).

Check the docs specifically for handling social signin: http://docs.spring.io/spring-social/docs/1.0.3.RELEASE/reference/html/signin.html

You will see there is a different approach altogether for social sign-up (vs signed in users integrating with social 3rd parties)