Hello I’m reading the Sitepoint book PHP Master Cutting Edge Code. I’m currently reading about web services and they’re talking about using web proxies. Before I begin let me say that I understand the issues surrounding cross domain policies, what that means to browsers and why they limit the browsers etc. I also get what (at least in broad strokes) a proxy server is.
Here’s what’s not clear to me. Why do I need to setup a proxy script on my domain to access another third party service? For example if I want to connect to Flicker’s API I don’t have to create a proxy, I simply use xml-RPC calls and can connect to Flickr and get a response back. So why would I need a proxy?
Is a proxy used in cases where the third party site is not setup to receive calls from external websites? The book explains how to setup a proxy script on my local site, I’m just unsure why I need to do this.