Mock MVC / RequestBuilder should handle Accept-Language header appropriately [SPR-15209]

[spring-projects-issues]

Chris DaMour opened SPR-15209 and commented

we index all our data by locale, and we have an edge service normalize the accept-language request header for the given request.

I was trying to test this with mock mvc using the default boot locale resolver that just uses accept-language request header, but it did not work as expected.

This appears to be because MockHttpServletRequestBuilder and MockHttpServletRequest do not interpret the Accept-Language header at any point when implementing getLocale(). Since getLocale() is kind of fundamental to java servlet & AcceptHeaderLocaleResolver depends on this fundamentalness since it doesn't actually check the Accept-Language header directly, i think the mockers should be a little more knowledgeable about such a header.

however, I'm not sure if these are intentionally dumb. at some point the special handling of the Content-Type request header was removed from MockHttpServletRequest and that is a very similar case.

I'm not super comfortable with relying on locale() in my mock builder as it's not really verifying the incoming accept-language header is what's being respected.

If there's some direction i should follow i'd submit a PR

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Affects: 4.3.6

Issue Links:

• AcceptHeaderLocaleResolver should allow to define a default Locale [SPR-14312] #18884 AcceptHeaderLocaleResolver should allow to define a default Locale
• MockHttpServletResponse.setLocale(Locale) should set HttpHeaders.CONTENT_LANGUAGE header [SPR-16311] #20858 MockHttpServletResponse.setLocale(Locale) should set HttpHeaders.CONTENT_LANGUAGE header
• MockHttpServletResponse doesn't propagate Content-Language response header [SPR-17284] #21817 MockHttpServletResponse doesn't propagate Content-Language response header
• MockHttpServletRequest changes Accept-Language header values [SPR-17566] #22098 MockHttpServletRequest changes Accept-Language header values
• Update Cookie headers in MockHttpServletRequest and Response [SPR-15225] #19790 Update Cookie headers in MockHttpServletRequest and Response

[spring-projects-issues]

Rossen Stoyanchev commented

So you're currently setting the Accept-Language header in your tests? I'm wondering why not just use the locale methods on MockHttpServletRequestBuilder? We could add special handling for the Accept-Language header. That would be merely a convenience, it doesn't add value from an integration testing perspective since it's not the Servlet container parsing the headers.

[spring-projects-issues]

Chris DaMour commented

i do have tests with locale...but then anything that calls getHeader("accept-language") doesn't sync up
as mentioned in description:

I'm not super comfortable with relying on locale() in my mock builder as it's not really verifying the incoming accept-language header is what's being respected.

[spring-projects-issues]

Rossen Stoyanchev commented

Right I see it now. AcceptHeaderLocaleResolver relies on request.getLocale() but in 4.3 there was an extra check added for the presence of Accept-Language.