PHP uses regular expression matching to obtain the domain name in the URL

The parse_url () function is available on the PHP official website. The result is similar to the parse_url () function, which is implemented using regular expressions.

URI is the type of resources available on the Web-HTML documents, images, video clips, programs, etc.-are located by an Uniform Resource Identifier ("URI. Object group:

^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?12            3  4          5       6  7        8 9

The test code is as follows:

<? Php $ search = '~ ^ ([^ :/? #] + ):)? (// ([^ /? #] *)? ([^? #] *) (\? ([^ #] *)? (#(.*))?~ I '; $ url = 'HTTP: // www.bkjia.com/pub/ietf/uri/?gonn'?#url = trim ($ url); preg_match_all ($ search, $ url, $ rr ); printf ("<p> output URL data: </p> <pre> % s </pre> \ n", var_export ($ rr, TRUE )); /* the groups are as follows: $1 = http: $2 = http $3 = // www.bkjia.com $4 = www.bkjia.com $5 =/pub/ietf/uri/$6 = <undefined> $7 = <undefined> $8 = # gonn $9 = Gonn */?>

The above regular expression can get any part of the URL. The following code is simpler:

<? Php // obtain the host name preg_match ("/^ (http: \/) from the URL :\/\/)? ([^ \/] +)/I "," http://www.bkjia.com/index.html ", $ matches); $ host = $ matches [2]; // obtain the preg_match ("/[^ \. \/] + \. [^ \. \/] + $/", $ host, $ matches); echo" domain name is: {$ matches [0]} \ n ";?>