Re: Proxy Problem with CFNetwork
Re: Proxy Problem with CFNetwork
- Subject: Re: Proxy Problem with CFNetwork
- From: Becky Willrich <email@hidden>
- Date: Wed, 29 Oct 2003 11:21:39 -0800
I'm creating an CFHTTPMessageRef using CFHTTPMessageCreateRequest()
passing in my https url and POST for the method. I then set some
headers and call CFReadStreamCreateForHTTPRequest to create a stream.
Once I have the stream, here's how I'm setting the proxy settings:
CFDictionaryRef theProxyDict = SCDynamicStoreCopyProxies(NULL);
if (theProxyDict != NULL) {
CFReadStreamSetProperty(my_stream, kCFStreamPropertyHTTPProxy,
theProxyDict);
}
This should work; your code is correct. This is also more or less what
Safari does; an interesting test would be to make sure that Safari can
reach the given URL, and that Safari is in fact talking through the
proxy (is not connecting directly to the server). If Safari works, you
can fairly safely assume there's a bug somewhere in your code. If
Safari does not work, the bug is in CFNetwork. In that case, make sure
you're on 10.2.6 or later (some bugs in this area were fixed for
10.2.6), then please let us know.
Then I do a CFReadStreamOpen(my_stream), but it does not make the
connection to the proxy server.
The opening of a socket to the proxy may not occur promptly upon
calling CFReadStreamOpen() - it takes some time to look up the DNS
entry for the proxy, for instance. If you've waited a few seconds and
still don't have a connection, though, that's a problem. Also, nothing
will progress unless you somehow give the stream computational time.
There are 3 ways to do that, depending on your overall threading model.
First and best, set yourself up for event -driven control of the
stream by setting yourself as the client on the stream, then schedule
the stream on a run loop, then run that run loop. Second, for a
polling model, call CFReadStreamHasBytesAvailable() periodically - that
will give the stream time to advance the state of the underlying
connection. Third, for a blocking model, just call CFReadStreamRead();
that call blocks (advancing the internal state of the stream and
underlying connection) until bytes become available.
I verified that the Dictionary that is returned from
SCDynamicStoreCopyProxies() does in fact have a key for the HTTPS
proxy host and port.
Check also that the HTTPSProxyEnabled key is either absent or set to
"1". Finally, verify that the proxy exception list is empty or the URL
you're downloading doesn't match the exception list.
I also tried setting the proxy settings using the following code as
well with no better luck:
CFStringRef proxyHostRef = CFStringCreateWithCString(NULL, (const
char *)&proxyHost, kCFStringEncodingMacRoman);
CFReadStreamSetProperty(my_stream, kCFStreamPropertyHTTPSProxyHost,
proxyHostRef);
SInt32 proxyPortFull = proxyPort;
CFNumberRef proxyPortRef = CFNumberCreate(NULL, kCFNumberSInt32Type,
&proxyPortFull);
CFReadStreamSetProperty(my_stream, kCFStreamPropertyHTTPSProxyPort,
proxyPortRef);
This will not work; CFNetwork expect a full dictionary under the
property kCFStreamPropertyHTTPProxy.
I even tried creating a whole new Dictionary, by pulling out the
ProxyHost and ProxyPort key/value pair from the dictionary returned by
SCDynamicStoreCopyProxies() and then using the newly created
dictionary to set the proxy property, but that did not work either.
This also should have worked.
I don't understand why this is not working like it is described in the
documentation. Am I doing anything wrong here? Anyone have some
sample code that does this?
Take a look at /Developer/Examples/Networking/URLLoad; it has a panel
that allows the user to configure the proxy. You can look at it to see
how it passes the proxy info down to the stream, then uses the stream.
It doesn't show just grabbing the proxy dictionary from
SystemConfiguration, but it looks like you are doing that part
correctly.
Hope that helps,
REW
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