iphone programmatically read proxy settings

I'm looking at adding proxy support to my iphone svn client. When you set up a system wide vpn in the iphone settings you can add a global proxy. Is it possible for external apps to read this informatio开发者_开发知识库n through the api?

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Apple has created a sample application for this purpose, called CFProxySupportTool.

CFProxySupportTool shows how to use the CFProxySupport APIs to determine whether a network connection should pass through a proxy; this is useful if you're not using Apple's high-level networking APIs (like CFNetwork and the Foundation URL loading system) but still want to interpret the system-supplied proxy settings.

It's currently available at https://developer.apple.com/library/mac/#samplecode/CFProxySupportTool/Introduction/Intro.html

The code isn't exactly terse (more than 1000 lines), and is written in plain C. You can also look at the source code of ASIHTTPRequest's startRequest function, which seems to be based on CFProxySupportTool.

Here's a start:

systemProxySettings = [(NSDictionary *) CFNetworkCopySystemProxySettings() autorelease];

proxies = [(NSArray *) CFNetworkCopyProxiesForURL((CFURLRef) URL, (CFDictionaryRef) systemProxySettings) autorelease];

if (!proxies.count)
  return;

firstProxySettings = [proxies objectAtIndex:0];

if (nil != (pacScriptURL = [firstProxySettings objectForKey:(NSString *)kCFProxyAutoConfigurationURLKey]))
  {
    CFErrorRef cfErrorRef = NULL;
    NSError *nsError = nil;
    NSString *script;

    script = [NSString stringWithContentsOfURL:pacScriptURL
                                  usedEncoding:NULL
                                         error:&nsError];

    if (nsError)
      return;

    proxies = [(NSArray *) CFNetworkCopyProxiesForAutoConfigurationScript((CFStringRef) script, (CFURLRef) URL, &cfErrorRef) autorelease];

    if (cfErrorRef || !proxies.count)
      return;

    firstProxySettings = [proxies objectAtIndex:0];
  }

/* Now use `firstProxySettings' */

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A Swift 4 version (special thanks to mortehu for providing the initial example).

//Shown this way for clarity, you may not want to waste cycles in your production code
if let url = URL(string: "https://someurloutthere.com") {
    let systemProxySettings = CFNetworkCopySystemProxySettings()?.takeUnretainedValue() ?? [:] as CFDictionary
    let proxiesForTargetUrl = CFNetworkCopyProxiesForURL(url as CFURL, systemProxySettings).takeUnretainedValue() as? [[AnyHashable: Any]] ?? []

    for proxy in proxiesForTargetUrl {
        print("Proxy: \(String(describing: proxy))")
        //Print the proxy type
        print("Proxy Type: \(String(describing: proxy[kCFProxyTypeKey]))")
        //There different proxy value keys depending on the type, this is an example of getting the proxy config script if the type is kCFProxyTypeAutoConfigurationURL.  If the proxy type were kCFProxyTypeSOCKS you would want to access the SOCKS property keys to see/get the SOCKS proxy values 
        print("Proxy Autoconfig script URL: \(String(describing: proxy[kCFProxyAutoConfigurationURLKey]))"
    }
}

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Have you investigated using something like ASIHttpRequest, see the section in the how to document describing proxy support.

At the very least the source code should contain some helpful guidance.

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Take a look at the CFProxySupport API, in particular CFNetworkCopyProxiesForURL() will let you read the proxies that are needed to get to a particular URL.