List all available model attributes in Thymeleaf

Question

For debugging purposes I would like to list all model attributes available to my thymeleaf template while it is rendering.

Something like:

<table>
    <tr th:each="model : ${*}">
        <td th:text="${model}"></td>
    </tr>
</table>

But obviously that's nonsense, and I get a well-deserved error. (org.springframework.expression.spel.SpelParseException: EL1070E:(pos 0): Problem parsing left operand)

Is there a way of outputting such debug information? I'd settle even for some logging output.

Or, does Thymeleaf provide something similar to Struts 2's struts.devMode where it added a debug section at the bottom of the page listing all available properties?

score 46 · Accepted Answer · edited Jul 19 '18 at 11:54

46

Try this:

<table>
    <tr th:each="var : ${#vars}">
        <td th:text="${var.key}"></td>
        <td th:text="${var.value}"></td>
    </tr>
</table>

edited Jul 19 '18 at 11:54

Mahozad

18,032
13
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133

answered Oct 02 '15 at 13:56

the4dK

632
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4

Fantastic - this actually gives even more than I wanted: includes all of the spring beans available to the views, not just the models I've put in. Very useful information! – David Lavender Oct 05 '15 at 12:32
@the4dK you are a life saver! – Ali Jun 02 '17 at 02:43

score 43 · Answer 2 · edited Oct 19 '20 at 10:46

The accepted answer does not seem to work for Thymeleaf 3; here's an update. Please note that I'm using Spring; this might not work for non-Spring apps.

<table>
    <tr th:each="var : ${#vars.getVariableNames()}">
        <td th:text="${var}"></td>
        <td th:text="${#vars.getVariable(var)}"></td>
    </tr>
    <!-- 
        Adding these manually because they are considered special.
        see https://github.com/thymeleaf/thymeleaf/blob/thymeleaf-3.0.3.RELEASE/src/main/java/org/thymeleaf/context/WebEngineContext.java#L199
    -->
    <tr>
        <td>param</td>
        <td th:text="${#vars.getVariable('param')}"></td>
    </tr>
    <tr>
        <td>session</td>
        <td th:text="${#vars.getVariable('session')}"></td>
    </tr>
    <tr>
        <td>application</td>
        <td th:text="${#vars.getVariable('application')}"></td>
    </tr>
</table>

That said, what I've done is created a standalone Bean that makes things a bit prettier and dumps to logs instead of to HTML:

@Component
public class ThymeleafDumper {

    private Logger log = LoggerFactory.getLogger(ThymeleafDumper.class);

    public void dumpToLog(WebEngineContext ctx) {
        log.debug("Thymeleaf context: {}", formatThisUpNicely(ctx));
    }

    // ... etc
}

Where formatThisUpNicely can use ctx.getVariableNames(), put the results into a SortedMap, export to json, whatever. Don't forget those three 'special' variables!

Then expose an instance of it as a @ModelAttribute in a Controller or a ControllerAdvice:

@ControllerAdvice
public class SomeControllerAdvice {

    @Autowired
    private ThymeleafDumper thymeleafDumper;

    @ModelAttribute("dumper")
    public ThymeleafDumper dumper() {
        return this.thymeleafDumper;
    }
}

Then in my template run:

<div th:text="${dumper.dumpToLog(#vars)}"/>

Roy, I would have never, never, never figured out mav.addObject(Company.getCompany()) would become "string" displaying Tear Drop on the view even though it told me right here: In CompanyController.java mav model is {string=Tear Drop}. I can't wait to define some more fields. I bet they will be "string1...", at least until I figure out what I am supposed to be doing. Thank you so much 3 years later! ==> comments can only be edited for so many minutes. I had better learn to type faster. — Richard Bradley Smith, Feb 21 '20 at 01:01

score 5 · Answer 3 · answered Jul 26 '15 at 05:25

these are all the logging available configurations :

log4j.logger.org.thymeleaf=DEBUG
log4j.logger.org.thymeleaf.TemplateEngine.CONFIG=DEBUG
log4j.logger.org.thymeleaf.TemplateEngine.TIMER=DEBUG
log4j.logger.org.thymeleaf.TemplateEngine.cache.TEMPLATE_CACHE=DEBUG
log4j.logger.org.thymeleaf.TemplateEngine.cache.FRAGMENT_CACHE=DEBUG
log4j.logger.org.thymeleaf.TemplateEngine.cache.MESSAGE_CACHE=DEBUG
log4j.logger.org.thymeleaf.TemplateEngine.cache.EXPRESSION_CACHE=DEBUG

these will log all the thymeleaf actions. I hope it is helpful.

But beware, spring boot users! http://izeye.blogspot.com/2015/02/enable-orgthymeleaf-trace-log-in-spring.html — Roy Truelove, Feb 02 '17 at 21:49

score 2 · Answer 4 · answered Jul 09 '20 at 15:05

Thymeleaf 3.0: To put it short, try the following:

<table>
  <tr th:each="var : ${param.keySet()}">
    <td th:text="${var}"></td>
    <td th:text="${param.get(var)}"></td>
  </tr>
</table>

When a @Controller returns some value stored in a Spring Model, the values are actually stored as request parameters, which is accessible using: request.getParameter("paramName"); Thymeleaf provides a similar functionality: "Web context namespaces for request/session attributes", the syntax is as stated.

The Thymeleaf built-in ${param} kewords returns an WebRequestParamsVariablesMap extends VariablesMap<String,String[]> object, whose keySet() method returns a String[], which contains those variable names within a httprequest.

This is just outputting a blank table for me. – dbinott Oct 08 '22 at 14:04 — dbinott, Oct 08 '22 at 14:04

List all available model attributes in Thymeleaf

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