PHPMaster.com has a new tutorial for those interested in how to work with streams, he base resources behind working with things like files and remote connections.
Streams are resources provided by PHP that we often use transparently, but which can also be very powerful tools. By learning how to harness their power, we can take our applications to a higher level. [...] Every stream has a implementation wrapper which has the additional code necessary to handle the specific protocol or encoding. PHP provides some built-in wrappers and we can easily create and register custom ones. We can even modify or enhance the behavior of wrappers using contexts and filters.
They start by introducing two of the most commonly used streams - "file" and "http" as well as some of the wrappers that can be used to work with them. He also talks about the "php://" stream, a special instance that lets you access things like a temporary memory block and stdout/stdin. He finishes up the tutorial with a look at "contexts" - the parameters that can be used to modify the stream wrapper (like his HTTP example).