Improve API endpoint compatibility by preventing CORS preflight request. #17
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The `Content-Type` and `Referrer` headers cause browsers implementing CORS to send a preflight (`OPTION`) request. If we remove them, our `GET` requests will be "simple", and no longer trigger a preflight. Preventing the preflight and using a "simple" request makes it easier to work with endpoints that do not implement an `OPTIONS` response, but nevertheless do set `Access-Control-Allow-Origin` on the `GET` response. (Especially development environments.) We do not need `Content-Type` because our `GET` requests have no payload. Users requiring `Referrer` may add it explicitly with `<autocomplete :request-headers="...">`. https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS https://developer.mozilla.org/en-US/docs/Web/API/Request/referrerPolicy Tested on latest Chrome, Firefox and Safari. Should be fine back to June/July 2016 (Chrome 52, Firefox 47). Note, the MDN browser compat info for Request.referrerPolicy Safari seems incomplete: refererPolicy does work.
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The
Content-TypeandReferrerheaders cause browsers implementingCORS to send a preflight (
OPTION) request. If we remove them, ourGETrequests will be "simple", and no longer trigger a preflight.Preventing the preflight and using a "simple" request makes it easier to
work with endpoints that do not implement an
OPTIONSresponse, butnevertheless do set
Access-Control-Allow-Originon theGETresponse.(Especially development environments.)
We do not need
Content-Typebecause ourGETrequests have nopayload.
Users requiring
Referrermay add it explicitly with<autocomplete :request-headers="...">.https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
https://developer.mozilla.org/en-US/docs/Web/API/Request/referrerPolicy
Tested on latest Chrome, Firefox and Safari. Should be fine back to
June/July 2016 (Chrome 52, Firefox 47). Note, the MDN browser compat
info for Request.referrerPolicy Safari seems incomplete: refererPolicy
does work.