/// This function implements the Web Proxy Auto-Discovery (WPAD) protocol for automatically configuring the proxy settings for an HTTP request. The WPAD protocol downloads a Proxy Auto-Configuration (PAC) file, which is a script that identifies the proxy server to use for a given target URL. PAC files are typically deployed by the IT department within a corporate network environment. The URL of the PAC file can either be specified explicitly or WinHttpGetProxyForUrl can be instructed to automatically discover the location of the PAC file on the local network.

public static extern bool WinHttpGetProxyForUrl(IntPtr hSession, string lpcwszUrl, ref WINHTTP_AUTOPROXY_OPTIONS pAutoProxyOptions, ref WINHTTP_PROXY_INFO pProxyInfo);

Declare Function WinHttpGetProxyForUrl Lib "winhttp.dll" (TODO) As TODO

ERROR_WINHTTP_AUTO_PROXY_SERVICE_ERROR - Returned by WinHttpGetProxyForUrl when a proxy for the specified URL cannot be located.

This function implements the Web Proxy Auto-Discovery (WPAD) protocol for automatically configuring the proxy settings for an HTTP request. The WPAD protocol downloads a Proxy Auto-Configuration (PAC) file, which is a script that identifies the proxy server to use for a given target URL. PAC files are typically deployed by the IT department within a corporate network environment. The URL of the PAC file can either be specified explicitly or WinHttpGetProxyForUrl can be instructed to automatically discover the location of the PAC file on the local network.

WinHttpGetProxyForUrl supports only ECMAScript-based PAC files.

WinHttpGetProxyForUrl must be called on a per-URL basis, because the PAC file can return a different proxy server for different URLs. This is useful because the PAC file enables an IT department to implement proxy server load balancing by mapping (hashing) the target URL (specified by the lpcwszUrl parameter) to a certain proxy in a proxy server array.

WinHttpGetProxyForUrl caches the autoproxy URL and the autoproxy script when auto-discovery is specified in the dwFlags member of the pAutoProxyOptions structure. For more information, see Autoproxy Cache.