This adds h2 http support for the client api.
The public client api requires no changes, it will detect by
ALPN if the server can handle http/2, if so, it will use it.
Multiple client connections using the lws api will be mapped on
to the same single http/2 + tls socket using http/2 streams
that are serviced simultaneously where possible.
AG: unlike openssl, mbedtls does not load the system trust store.
So this change will make client tls operations that work OK on openssl fail on
mbedtls unless you provide the correct CA cert.
This allows lws to distinguish between untrusted CAs, hostname
mismatches, expired certificates.
NOTE: LCCSCF_ALLOW_SELFSIGNED actually allows for untrusted CAs, and
will also skip hostname verification. This is somewhat a limitiation of
the current lws verification process.
AG: improve error reporting up to the CLIENT_CONNECTION_ERROR argument
and add a note specific to mbedtls in the test client. Adapt the test
client to note the CA requirement if built with mbedTLS. Adapt the
minimal test clients to have the CAs available and use them if mbedTLS.
This adds an lws cmake option that builds all the minimal examples as part of lws,
it's useful for QA.
It adds a macro to examples that depend on a particular lws configuration to understand
they should just null out their project definition in builds where the lws configuration
requirement is not met, and we are building as part of lws.
It also adapts all the example library additions to select the just-built-but-not-yet-installed
library in the case it is built as part of lws. If built standalone, it now uses the cmake
platform-abstracted way to add the library requirement too.
Until now LWS_CALLBACK_CLOSED has served the same for
client and server connections. This introduces a new
LWS_CALLBACK_CLIENT_CLOSE which is sent on established
ws client connections, insread of LWS_CALLBACK_CLOSED.
LWS_CALLBACK_CLOSED continues to be sent when server
ws connections close.
This allows you to set a 404 handler URL on a vhost.
The necessary user code looks like...
info.error_document_404 = "/404.html";
... at vhost-creation time.
In the existing lws_return_http_status() api, if it sees
the vhost has an "error_document_404" path set and that
we are trying to report a 404, it changes the action
instead to a redirect to the error_document_404 path.
The redirect target is returned using 404 status code.
If the redirect target doesn't exist, then it falls back
to just reporting the simple canned 404.
