How do I check if a video exists on YouTube, using PHP?
Request the URLs with the HEAD method, like so:
HEAD /watch?v=p72I7g-RXpg HTTP/1.1
Host: www.youtube.com
HTTP/1.1 200 OK
[SNIP]
HEAD /watch?v=p72I7g-BOGUS HTTP/1.1
Host: www.youtube.com
HTTP/1.1 303 See Other
[SNIP]
Location: http://www.youtube.com/index?ytsession=pXHSDn5Mgc78t2_s7AwyMvu_Tvxn6szTJFAbsYz8KifV-OP20gt7FShXtE4gNYS9Cb7Eh55SgoeFznYK616MmFrT3Cecfu8BcNJ7cs8B6YPddHQSQFT7fSIXFHd5FmQBk299p9_YFCrEBBwTgtYhzKL-jYKPp2zZaACNnDkeZxCr9JEoNEDXyqLvgbB1w8zgOjJacI4iIS6_QvIdmdmLXz7EhBSl92O-qHOG9Rf1HNux_xrcB_xCAz3P3_KbryeQk_9JSRFgCWWgfwWMM3SjrE74-vkSDm5jVRE3ZlUI6bHLgVb7rcIPcg