Unable to expand() template link #169

[mdomasevicius]

Given

ControllerLinkBuilderFactory linkBuilderFactory = new ControllerLinkBuilderFactory();
linkBuilderFactory.setUriComponentsContributors(singletonList(new HateoasPageableHandlerMethodArgumentResolver()));

@GetMapping("/deals")
    CollectionResource<DealResource> findDeals(
        @RequestParam(required = false) String title,
        @RequestParam(value = "category_id", required = false) Long categoryId,
        @RequestParam(value = "tags[]", required = false) String[] tags,
        @PageableDefault(sort = "position", direction = ASC) Pageable pageable)

When:

Link next = linkBuilderFactory.linkTo(methodOn(MobileVoucherDealsController.class)
                .findDeals(title, categoryId, tags, pageable.next())).withRel("next");

Then: Link: http://localhost:8080/deals?page=1&size=1&sort=position,asc{&title,category_id,tags[]}

When: From #535

Just expand the Link without handing any parameters into the method and you should get a plain URI in turn.

next.expand(TemplateVariables.NONE);

Then:

Illegal character in query at index 59: http://localhost:8080/deals?page=1&size=1&sort=position,asc{&title,category_id,tags[]}

---

I tried expanding links in the same manner like http://localhost:8080/deals{/id} and it works resulting in http://localhost:8080/deals but not with template being after URL request params

[odrotbohm]

What's the reason you use tags[] as the variable name? We use the declared name in the template and according to the URI template spec, square brackets are not allowed in variable names. That's why the template fails to detect the placeholders in general and then the expansion fails.

[mdomasevicius]

Some iOS libraries:

• https://github.com/Alamofire/Alamofire
• https://github.com/Moya/Moya

When sending HTTP requests automatically serialize an array of params in this case tags to tags[]. Since we did not find any guidelines for REST about conventions regarding such case, decided and agreed with API consumers to leave it like this reasoning it would improve readability.