WinHTTP proxy sample
This sample demonstrates how to use the WinHTTP API to determine the proxy for a particular URL. It uses the core functionality provided in WinHTTP for querying the proxy settings.
Both WinHttpGetProxyForUrl and WinHttpGetProxyForUrlEx are used in this sample. These functions implement 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. These functions can automatically discover the location of the PAC file on the local network.
This sample can be extended as needed for your application, using the proxy code from this sample as a starting point, to add additional functionality. For example, an application could add a per-URL proxy cache, awareness for network changes, a filter for bad proxies, or other desired functionality.
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Related topics
Windows HTTP Services (WinHTTP)
Related technologies
Windows HTTP Services (WinHTTP)
Operating system requirements
Client
Windows 8.1
Server
Windows Server 2012 R2
Build the sample
To build the sample using Visual Studio:
- Open Windows Explorer and navigate to the \cpp directory.
- Double-click the icon for the WinhttpProxySample.sln file to open the file in Visual Studio.
- In the Build menu, select Build Solution. The application will be built in the default \Debug or \Release directory.
Run the sample
To run the sample:
- Navigate to the directory that contains the new executable, using the command prompt.
- Type WinhttpProxySample.exe <url> at the command prompt.