Use HTTP/2 only for HTTPS requests #497
Merged
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The previously used flag tried to upgrade any request to HTTP/2, by sending an
Upgrade: h2c
header. Some HTTP servers (such as PHP's built-in one, which I use for mocking HTTP requests) apparently cannot deal with it. Using theCURL_HTTP_VERSION_2TLS
flag instead makes Curl attempt an upgrade for HTTPS requests (e.g. to Stripe's API endpoint), but not for HTTP ones.See https://ec.haxx.se/http-http2.html and https://curl.haxx.se/libcurl/c/CURLOPT_HTTP_VERSION.html.
(Plus, see my previous comments in PR #494 which introduced this feature.)