Error encountered while using thymeleaf as email templating

[berinle]

Hi -
I am trying to use thymeleaf as the template engine for spring boot. I have followed this guide (http://www.thymeleaf.org/springmail.html) and the issue I am running into is that thymeleaf can't seem to resolve the variables set in org.thymeleaf.context.Context when I make the call to process the template.

I get errors like this...

org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "user" (email.html:7)
at org.thymeleaf.spring3.expression.SpelVariableExpressionEvaluator.evaluate(SpelVariableExpressionEvaluator.java:108)
at org.thymeleaf.standard.expression.VariableExpression.executeVariable(VariableExpression.java:116)
at org.thymeleaf.standard.expression.SimpleExpression.executeSimple(SimpleExpression.java:394)

....

I have the sample application here https://github.com/berinle/spring-boot-sample

It can be run by cloning the project and "cd" into it and run the following command: "./gradlew run" (without the quotes). Then open your browser and hit http://localhost:8080.

Click the "send email" button and you should see the error on the console.

Also a broader question is what is the best way to easily override the generated "templateEngine" bean created by @EnableAutoConfiguration?

On the "dev" branch of the same project above, I have configured the following beans...

@Bean
public ServletContextTemplateResolver webTemplateResolver() {
    ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver();
    templateResolver.setPrefix("templates/");
    templateResolver.setTemplateMode("HTML5");
    templateResolver.setSuffix(".html");
    templateResolver.setOrder(2);
    templateResolver.setCacheable(true);

    return templateResolver;
}

@Bean
public SpringTemplateEngine templateEngine(){
    SpringTemplateEngine templateEngine = new SpringTemplateEngine();
    templateEngine.addTemplateResolver(emailTemplateResolver());
    templateEngine.addTemplateResolver(webTemplateResolver());
    return templateEngine;
}

@Bean
public ThymeleafViewResolver thymeleafViewResolver(){
    ThymeleafViewResolver resolver = new ThymeleafViewResolver();
    resolver.setTemplateEngine(templateEngine());
    resolver.setCharacterEncoding("UTF-8");
    resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 20);
    return resolver;
}

But navigating to http://localhost:8080 after that configuration reports the following error...

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateInputException: Error resolving template "index", template might not exist or might not be accessible by any of the configured Template Resolvers
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:958)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:837)

....

[berinle]

Apparently, this is a bug with thymeleaf 2.0.17 in offline mode.

See:
http://forum.thymeleaf.org/Using-thymeleaf-as-email-templating-engine-with-Spring-Boot-td4026893.html
-- and --
thymeleaf/thymeleaf-spring#26

Bumping the version to 2.0.18 or higher resolved the issue.

Thanks!

PS: It will still be helpful to know how to override the default beans e.g. templateEngine defined by @EnableAutoConfiguration. The docs don't do a good job at explaining it. That was the second part this bug ticket.