Invalid JSON input on handlebars is not reported properly.

[dirkbolte]

Proposal

See thread https://wiremock-community.slack.com/archives/C03N1E6HFPY/p1703250590706619 .

When an input JSON is empty, this results in a HandlebarsException, which is converted into the following response.

{
    "cause1": "java.lang.IllegalArgumentException: json string can not be null or empty",
    "servlet": "com.github.tomakehurst.wiremock.servlet.WireMockHandlerDispatchingServlet-4af6839c",
    "cause0": "com.github.jknack.handlebars.HandlebarsException: inline@35c3c400:1:2: java.lang.IllegalArgumentException: json string can not be null or empty\n    inline@35c3c400:1:2",
    "message": "com.github.jknack.handlebars.HandlebarsException: inline@35c3c400:1:2: java.lang.IllegalArgumentException: json string can not be null or empty\n    inline@35c3c400:1:2",
    "url": "/test",
    "status": "500"
}

I would have expected

wiremock/src/main/java/com/github/tomakehurst/wiremock/extension/responsetemplating/helpers/HandlebarsJsonPathHelper.java

Line 55 in b3874f0

} catch (InvalidJsonException e) {

to have caught the issue but it seems like the actual exception is different (breakpoint isn't hit).

Reproduction steps

• Create response templating which uses handlebars (e.g. a POST)
• add handlebars code: {{jsonPath (defaultIfEmpty request.body '{}') '$.doesNotExist' }}
• do a request without a body

Expected behavior:

• handleError is executed.

Actual:

• the error is encoded in the response.

References

See thread https://wiremock-community.slack.com/archives/C03N1E6HFPY/p1703250590706619 .

[dirkbolte]

Found that the code already had some precautions for a null body - would suggest to use the same approach for empty string.

[G-Basak]

@dirkbolte Is this issue good to close?

[dirkbolte]

Yes