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fix(oohelperd,netemx): construct equivalent HTTPTransports (#1464)
This diff modifies oohelperd and netemx to ensure we construct
equivalent HTTPTransports.
Let's show that this is actually the case.
Let's start from the HTTP/1.1 and HTTP2 transport.
This is what `oohelperd` does after this diff:
```Go
NewHTTPClient: func(logger model.Logger) model.HTTPClient {
// TODO(ooni/probe#2534): the NewHTTPTransportWithResolver has QUIRKS and
// we should evaluate whether we can avoid using it here
return NewHTTPClientWithTransportFactory(
logger,
netxlite.NewHTTPTransportWithResolver,
)
},
```
This is what `netemx` does after this diff:
```Go
handler.NewHTTPClient = func(logger model.Logger) model.HTTPClient {
return oohelperd.NewHTTPClientWithTransportFactory(
logger,
func(dl model.DebugLogger, r model.Resolver) model.HTTPTransport {
dialer := netx.NewDialerWithResolver(dl, r)
tlsDialer := netxlite.NewTLSDialer(dialer, netx.NewTLSHandshakerStdlib(dl))
// TODO(ooni/probe#2534): NewHTTPTransport is QUIRKY but
// we probably don't care about using a QUIRKY function here
return netxlite.NewHTTPTransport(dl, dialer, tlsDialer)
},
)
}
```
We're using the same (now public) `NewHTTPClientWithTransportFactory`
function. So, what remains to be done to reach a QED is to show that
this code called by `oohelperd`:
```Go
return NewHTTPClientWithTransportFactory(
logger,
netxlite.NewHTTPTransportWithResolver,
)
```
is equivalent to this code called by `netemx`:
```Go
func(dl model.DebugLogger, r model.Resolver) model.HTTPTransport {
dialer := netx.NewDialerWithResolver(dl, r)
tlsDialer := netxlite.NewTLSDialer(dialer, netx.NewTLSHandshakerStdlib(dl))
// TODO(ooni/probe#2534): NewHTTPTransport is QUIRKY but
// we probably don't care about using a QUIRKY function here
return netxlite.NewHTTPTransport(dl, dialer, tlsDialer)
},
```
This is evident if we expand `netxlite.NewHTTPTransportWithResolver`,
whose implementation is:
```Go
func NewHTTPTransportWithResolver(logger model.DebugLogger, reso model.Resolver) model.HTTPTransport {
dialer := NewDialerWithResolver(logger, reso)
thx := NewTLSHandshakerStdlib(logger)
tlsDialer := NewTLSDialer(dialer, thx)
return NewHTTPTransport(logger, dialer, tlsDialer)
}
```
in fact, the following lines of code called from `oohelperd`:
```Go
dialer := NewDialerWithResolver(logger, reso)
thx := NewTLSHandshakerStdlib(logger)
tlsDialer := NewTLSDialer(dialer, thx)
return NewHTTPTransport(logger, dialer, tlsDialer)
```
are equivalent to this `netemx` code:
```Go
dialer := netx.NewDialerWithResolver(dl, r)
tlsDialer := netxlite.NewTLSDialer(dialer, netx.NewTLSHandshakerStdlib(dl))
// TODO(ooni/probe#2534): NewHTTPTransport is QUIRKY but
// we probably don't care about using a QUIRKY function here
return netxlite.NewHTTPTransport(dl, dialer, tlsDialer)
```
Modulo the fact that `netemx` code is using methods of the
`*netxlite.Netx` structure rather than bare functions.
Let's now inspect how we construct HTTP3.
This is what `oohelperd` does:
```Go
NewHTTP3Client: func(logger model.Logger) model.HTTPClient {
return NewHTTPClientWithTransportFactory(
logger,
netxlite.NewHTTP3TransportWithResolver,
)
},
```
This is what `netemx` does:
```Go
handler.NewHTTP3Client = func(logger model.Logger) model.HTTPClient {
return oohelperd.NewHTTPClientWithTransportFactory(
logger,
func(dl model.DebugLogger, r model.Resolver) model.HTTPTransport {
qd := netx.NewQUICDialerWithResolver(netx.NewUDPListener(), dl, r)
return netxlite.NewHTTP3Transport(dl, qd, nil)
},
)
}
```
Because we're using the same `NewHTTPClientWithTransportFactory`
factory, we need to show that `oohelperd`'s
```Go
return NewHTTPClientWithTransportFactory(
logger,
netxlite.NewHTTP3TransportWithResolver,
)
```
is equivalent to `netemx`'s
```Go
return oohelperd.NewHTTPClientWithTransportFactory(
logger,
func(dl model.DebugLogger, r model.Resolver) model.HTTPTransport {
qd := netx.NewQUICDialerWithResolver(netx.NewUDPListener(), dl, r)
return netxlite.NewHTTP3Transport(dl, qd, nil)
},
)
```
To show that we need to expand `NewHTTP3TransportWithResolver`, which
reads:
```Go
func NewHTTP3TransportWithResolver(logger model.DebugLogger, reso model.Resolver) model.HTTPTransport {
qd := NewQUICDialerWithResolver(NewUDPListener(), logger, reso)
return NewHTTP3Transport(logger, qd, nil)
}
```
And then we can conclude that we're good because the code invoked by
`oohelperd`:
```Go
qd := NewQUICDialerWithResolver(NewUDPListener(), logger, reso)
return NewHTTP3Transport(logger, qd, nil)
```
is equivalent to the code invoked by `netemx`:
```Go
qd := netx.NewQUICDialerWithResolver(netx.NewUDPListener(), dl, r)
return netxlite.NewHTTP3Transport(dl, qd, nil)
```
modulo the fact that `netemx` is using methods defined by the `netx`
object.
Extracted from #1462.
Part of ooni/probe#2652.
Part of ooni/probe#1517.- Loading branch information
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