How to properly encode Web API parameter in URL path?

Question

I have endpoint used to find book by book reference.

The book reference is string that can contain white-space and any kind of special characters, e.g. mybook, my book, my-book, my/book, book++

// GET api/books/reference/{reference}
[HttpGet("reference/{reference}")]
public ActionResult<BookItem> FindByReference(string reference)

This is what I get when testing:

GET api/books/reference/mybook
OK

GET api/books/reference/my book
OK

GET api/books/reference/my-book
OK

GET api/books/reference/my+book
404 Not found

GET api/books/reference/my/book
404 Not found

GET api/books/reference/book++
404 Not found

What is a proper way to encode this reference parameter IN THE URL PATH so that it gets properly resolved by routing? Is that even possible?

Thanks, but - weird - if I use `UrlEncode` on the `my book` I get the `my+book` which results in 404. — Dusan, Dec 27 '18 at 17:28
"api/books/reference/my book" seem to be wrong - I'd expect this to fail as space is not valid for path... As @JDB says the question is very strange - indeed Uri need to be constructed correctly first so testing invalid once is not really useful. Reading through RFC (or at least https://stackoverflow.com/questions/4669692/valid-characters-for-directory-part-of-a-url-for-short-links) could help with "valid" definition. — Alexei Levenkov, Dec 27 '18 at 17:32
You pass url as query parameter (since you've used UrlEncode)? That is even more confusing. Could you post some [MCVE] of your client side code and server side code that handles that query parameter to call your FindByReference method? (Normally one would use `new Uri("http://fooo/bar var").AbsoluteUri` for just url) — Alexei Levenkov, Dec 27 '18 at 17:36

score 0 · Accepted Answer · answered Jan 02 '19 at 10:52

The encoding of the URLs is the responsibility of the client calling the API, a client must supply a valid URL if it wants a proper response. If you encode your examples you will get:

GET api/books/reference/mybook

GET api/books/reference/my%20book

GET api/books/reference/my-book

GET api/books/reference/my%2Bbook

GET api/books/reference/my%2Fbook

GET api/books/reference/book%2B%2B

These should now work.

If you want help with the actual encoding you will have to edit your question with the client source code.

How to properly encode Web API parameter in URL path?

1 Answers1