blocks|key|1536785|text|下面是我在Ant中用来从ANT_OPTS获取代理主机IP或主机名的正则表达式。它用于获取代理IP，以便我可以在为派生的JVM配置代理之前运行Ant+"isreachable“测试。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1536786|%5E.*-Dhttp\.proxyHost=(\w{1,}\.\w{1,}\.\w{1,}\.*\w{0,})\s.*$|code-block|syntax|javascript|1536787|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a regex that I used in Ant to obtain a proxy host IP or hostname out of ANT_OPTS. This was used to obtain the proxy IP so that I could run an Ant "isreachable" test before configuring a proxy for a forked JVM. 

<pre><code>^.*-Dhttp\.proxyHost=(\w{1,}\.\w{1,}\.\w{1,}\.*\w{0,})\s.*$
</code></pre>

blocks|key|1536842|text|我似乎不能编辑顶部的帖子，所以我会在这里添加我的答案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1536843|对于主机名-简单的答案，在这里的egrep示例--+http:+//www.linuxinsight.com/how_to_grep_for_ip_addresses_using_the_gnu_egrep_utility.html|1536844|egrep+'([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}'|code-block|syntax|javascript|1536845|尽管这种情况不考虑第一个二进制八位数中的值0，以及大于254+(ip地址)或255+(网络掩码)的值。也许一个额外的if语句会有所帮助。|1536846|至于合法的dns主机名，如果你只检查internet主机名(而不是intranet)，我写了以下代码，shell/php的混合，但它应该适用于任何正则表达式。|1536847|首先转到ietf网站，下载并解析合法一级域名列表：|1536848|tld=$(curl+-s+http://data.iana.org/TLD/tlds-alpha-by-domain.txt+%7C++sed+1d++%7C+cut+-f1+-d'-'+%7C+tr+'\n'+'%7C'+%7C+sed+'s/$.*$./\1/')
echo+"($tld)"|1536849|这将为您提供一段很好的re代码，用于检查顶级域名的合法性，如.com+.org或.ca|1536850|然后根据此处的指导原则添加表达式的第一部分--+http:+//www.domainit.com/support/faq.mhtml?category=Domain_FAQ&question=9+(任何字母数字组合和'-‘符号，破折号不应位于八位字节的开头或结尾。|1536851|(([a-z0-9]%2B%7C([a-z0-9]%2B[-]%2B[a-z0-9]%2B))[.])%2B|1536852|然后将它们放在一起(PHP+preg_match示例)：|1536853|$pattern+=+'/%5E(([a-z0-9]%2B%7C([a-z0-9]%2B[-]%2B[a-z0-9]%2B))[.])%2B(AC%7CAD%7CAE%7CAERO%7CAF%7CAG%7CAI%7CAL%7CAM%7CAN%7CAO%7CAQ%7CAR%7CARPA%7CAS%7CASIA%7CAT%7CAU%7CAW%7CAX%7CAZ%7CBA%7CBB%7CBD%7CBE%7CBF%7CBG%7CBH%7CBI%7CBIZ%7CBJ%7CBM%7CBN%7CBO%7CBR%7CBS%7CBT%7CBV%7CBW%7CBY%7CBZ%7CCA%7CCAT%7CCC%7CCD%7CCF%7CCG%7CCH%7CCI%7CCK%7CCL%7CCM%7CCN%7CCO%7CCOM%7CCOOP%7CCR%7CCU%7CCV%7CCX%7CCY%7CCZ%7CDE%7CDJ%7CDK%7CDM%7CDO%7CDZ%7CEC%7CEDU%7CEE%7CEG%7CER%7CES%7CET%7CEU%7CFI%7CFJ%7CFK%7CFM%7CFO%7CFR%7CGA%7CGB%7CGD%7CGE%7CGF%7CGG%7CGH%7CGI%7CGL%7CGM%7CGN%7CGOV%7CGP%7CGQ%7CGR%7CGS%7CGT%7CGU%7CGW%7CGY%7CHK%7CHM%7CHN%7CHR%7CHT%7CHU%7CID%7CIE%7CIL%7CIM%7CIN%7CINFO%7CINT%7CIO%7CIQ%7CIR%7CIS%7CIT%7CJE%7CJM%7CJO%7CJOBS%7CJP%7CKE%7CKG%7CKH%7CKI%7CKM%7CKN%7CKP%7CKR%7CKW%7CKY%7CKZ%7CLA%7CLB%7CLC%7CLI%7CLK%7CLR%7CLS%7CLT%7CLU%7CLV%7CLY%7CMA%7CMC%7CMD%7CME%7CMG%7CMH%7CMIL%7CMK%7CML%7CMM%7CMN%7CMO%7CMOBI%7CMP%7CMQ%7CMR%7CMS%7CMT%7CMU%7CMUSEUM%7CMV%7CMW%7CMX%7CMY%7CMZ%7CNA%7CNAME%7CNC%7CNE%7CNET%7CNF%7CNG%7CNI%7CNL%7CNO%7CNP%7CNR%7CNU%7CNZ%7COM%7CORG%7CPA%7CPE%7CPF%7CPG%7CPH%7CPK%7CPL%7CPM%7CPN%7CPR%7CPRO%7CPS%7CPT%7CPW%7CPY%7CQA%7CRE%7CRO%7CRS%7CRU%7CRW%7CSA%7CSB%7CSC%7CSD%7CSE%7CSG%7CSH%7CSI%7CSJ%7CSK%7CSL%7CSM%7CSN%7CSO%7CSR%7CST%7CSU%7CSV%7CSY%7CSZ%7CTC%7CTD%7CTEL%7CTF%7CTG%7CTH%7CTJ%7CTK%7CTL%7CTM%7CTN%7CTO%7CTP%7CTR%7CTRAVEL%7CTT%7CTV%7CTW%7CTZ%7CUA%7CUG%7CUK%7CUS%7CUY%7CUZ%7CVA%7CVC%7CVE%7CVG%7CVI%7CVN%7CVU%7CWF%7CWS%7CXN%7CXN%7CXN%7CXN%7CXN%7CXN%7CXN%7CXN%7CXN%7CXN%7CXN%7CYE%7CYT%7CYU%7CZA%7CZM%7CZW)[.]?$/i';

++++if+(preg_match,+$pattern,+$matching_string){
++++...+do+stuff
++++}|1536854|您可能还想添加一个if语句来检查您检查的字符串是否短于256个字符--+http://www.ops.ietf.org/lists/namedroppers/namedroppers.2003/msg00964.html|offset|length|1536855|entityMap|0|LINK|mutability|MUTABLE|url|http://www.ops.ietf.org/lists/namedroppers/namedroppers.2003/msg00964.html^0|0|0|0|0|0|0|0|0|0|0|0|0|10|22|0|0^^$0|@$1|2|3|4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1D|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1E|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|1F|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|1G|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1H|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|1I|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|1J|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1K|8|@]|9|@]|A|$]]|$1|U|3|V|5|F|7|1L|8|@]|9|@]|A|$G|H]]|$1|W|3|X|5|6|7|1M|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|F|7|1N|8|@]|9|@]|A|$G|H]]|$1|10|3|11|5|6|7|1O|8|@]|9|@$12|1P|13|1Q|1|1R]]|A|$]]|$1|14|3|-4|5|6|7|1S|8|@]|9|@]|A|$]]]|15|$16|$5|17|18|19|A|$1A|1B]]]]

I don't seem to be able to edit the top post, so I'll add my answer here.

For hostname - easy answer, on egrep example here -- http: //www.linuxinsight.com/how_to_grep_for_ip_addresses_using_the_gnu_egrep_utility.html

<pre><code>egrep '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}'
</code></pre>

Though the case doesn't account for values like 0 in the fist octet, and values greater than 254 (ip addres) or 255 (netmask). Maybe an additional if statement would help.

As for legal dns hostname, provided that you are checking for internet hostnames only (and not intranet), I wrote the following snipped, a mix of shell/php but it should be applicable as any regular expression.

first go to ietf website, download and parse a list of legal level 1 domain names:

<pre><code>tld=$(curl -s http://data.iana.org/TLD/tlds-alpha-by-domain.txt | sed 1d | cut -f1 -d'-' | tr '\n' '|' | sed 's/$.*$./\1/')
echo "($tld)"
</code></pre>

That should give you a nice piece of re code that checks for legality of top domain name, like .com .org or .ca

Then add first part of the expression according to guidelines found here -- http: //www.domainit.com/support/faq.mhtml?category=Domain_FAQ&amp;question=9 (any alphanumeric combination and '-' symbol, dash should not be in the beginning or end of an octet.

<pre><code>(([a-z0-9]+|([a-z0-9]+[-]+[a-z0-9]+))[.])+
</code></pre>

Then put it all together (PHP preg_match example):

<pre><code>$pattern = '/^(([a-z0-9]+|([a-z0-9]+[-]+[a-z0-9]+))[.])+(AC|AD|AE|AERO|AF|AG|AI|AL|AM|AN|AO|AQ|AR|ARPA|AS|ASIA|AT|AU|AW|AX|AZ|BA|BB|BD|BE|BF|BG|BH|BI|BIZ|BJ|BM|BN|BO|BR|BS|BT|BV|BW|BY|BZ|CA|CAT|CC|CD|CF|CG|CH|CI|CK|CL|CM|CN|CO|COM|COOP|CR|CU|CV|CX|CY|CZ|DE|DJ|DK|DM|DO|DZ|EC|EDU|EE|EG|ER|ES|ET|EU|FI|FJ|FK|FM|FO|FR|GA|GB|GD|GE|GF|GG|GH|GI|GL|GM|GN|GOV|GP|GQ|GR|GS|GT|GU|GW|GY|HK|HM|HN|HR|HT|HU|ID|IE|IL|IM|IN|INFO|INT|IO|IQ|IR|IS|IT|JE|JM|JO|JOBS|JP|KE|KG|KH|KI|KM|KN|KP|KR|KW|KY|KZ|LA|LB|LC|LI|LK|LR|LS|LT|LU|LV|LY|MA|MC|MD|ME|MG|MH|MIL|MK|ML|MM|MN|MO|MOBI|MP|MQ|MR|MS|MT|MU|MUSEUM|MV|MW|MX|MY|MZ|NA|NAME|NC|NE|NET|NF|NG|NI|NL|NO|NP|NR|NU|NZ|OM|ORG|PA|PE|PF|PG|PH|PK|PL|PM|PN|PR|PRO|PS|PT|PW|PY|QA|RE|RO|RS|RU|RW|SA|SB|SC|SD|SE|SG|SH|SI|SJ|SK|SL|SM|SN|SO|SR|ST|SU|SV|SY|SZ|TC|TD|TEL|TF|TG|TH|TJ|TK|TL|TM|TN|TO|TP|TR|TRAVEL|TT|TV|TW|TZ|UA|UG|UK|US|UY|UZ|VA|VC|VE|VG|VI|VN|VU|WF|WS|XN|XN|XN|XN|XN|XN|XN|XN|XN|XN|XN|YE|YT|YU|ZA|ZM|ZW)[.]?$/i';

 if (preg_match, $pattern, $matching_string){
 ... do stuff
 }
</code></pre>

You may also want to add an if statement to check that string that you checking is shorter than 256 characters -- <a href="http://www.ops.ietf.org/lists/namedroppers/namedroppers.2003/msg00964.html" rel="noreferrer">http://www.ops.ietf.org/lists/namedroppers/namedroppers.2003/msg00964.html</a>

blocks|key|1751835|text|def+isValidHostname(hostname):

++++if+len(hostname)+>+255:
++++++++return+False
++++if+hostname[-1:]+==+".":
++++++++hostname+=+hostname[:-1]+++#+strip+exactly+one+dot+from+the+right,
+++++++++++++++++++++++++++++++++++#++if+present
++++allowed+=+re.compile("(?!-)[A-Z\d-]{1,63}(?<!-)$",+re.IGNORECASE)
++++return+all(allowed.match(x)+for+x+in+hostname.split("."))|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1751836|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>def isValidHostname(hostname):

 if len(hostname) &gt; 255:
 return False
 if hostname[-1:] == ".":
 hostname = hostname[:-1] # strip exactly one dot from the right,
 # if present
 allowed = re.compile("(?!-)[A-Z\d-]{1,63}(?&lt;!-)$", re.IGNORECASE)
 return all(allowed.match(x) for x in hostname.split("."))
</code></pre>

blocks|key|1751880|text|正在检查主机名，如...mywebsite.co.in、thangaraj.name、18thangaraj.in、thangaraj106.in等|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1751881|[a-z\d%2B].*?\\.\w{2,4}$|code-block|syntax|javascript|1751882|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Checking for host names like... mywebsite.co.in, thangaraj.name, 18thangaraj.in, thangaraj106.in etc.,

<pre><code>[a-z\d+].*?\\.\w{2,4}$
</code></pre>

blocks|key|1536956|text|我认为这是最好的Ip验证正则表达式。请检查一次！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1536957|%5E(([01]?[0-9]?[0-9]%7C2([0-4][0-9]%7C5[0-5]))\.){3}([01]?[0-9]?[0-9]%7C2([0-4][0-9]%7C5[0-5]))$|code-block|syntax|javascript|1536958|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I think this is the best Ip validation regex. please check it once!!! 

<pre><code>^(([01]?[0-9]?[0-9]|2([0-4][0-9]|5[0-5]))\.){3}([01]?[0-9]?[0-9]|2([0-4][0-9]|5[0-5]))$
</code></pre>

blocks|key|1536966|text|这个怎么样？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1536967|([0-9]{1,3}\.){3}[0-9]{1,3}|code-block|syntax|javascript|1536968|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

how about this?

<pre><code>([0-9]{1,3}\.){3}[0-9]{1,3}
</code></pre>

blocks|key|1751938|text|/%5E(?:[a-zA-Z0-9]%2B%7C[a-zA-Z0-9][-a-zA-Z0-9]%2B[a-zA-Z0-9])(?:\.[a-zA-Z0-9]%2B%7C[a-zA-Z0-9][-a-zA-Z0-9]%2B[a-zA-Z0-9])?$/|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1751939|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

blocks|key|1751950|text|"%5E((\\d{1,2}%7C1\\d{2}%7C2[0-4]\\d%7C25[0-5])\.){3}(\\d{1,2}%7C1\\d{2}%7C2[0-4]\\d%7C25[0-5])$"|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1751951|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

blocks|key|1751972|text|这适用于有效的IP地址：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1751973|regex+=+'%5E([0-9]%7C[1-9][0-9]%7C[1][0-9][0-9]%7C[2][0-5][0-5])[.]([0-9]%7C[1-9][0-9]%7C[1][0-9][0-9]%7C[2][0-5][0-5])[.]([0-9]%7C[1-9][0-9]%7C[1][0-9][0-9]%7C[2][0-5][0-5])[.]([0-9]%7C[1-9][0-9]%7C[1][0-9][0-9]%7C[2][0-5][0-5])$'|code-block|syntax|javascript|1751974|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This works for valid IP addresses:

<pre><code>regex = '^([0-9]|[1-9][0-9]|[1][0-9][0-9]|[2][0-5][0-5])[.]([0-9]|[1-9][0-9]|[1][0-9][0-9]|[2][0-5][0-5])[.]([0-9]|[1-9][0-9]|[1][0-9][0-9]|[2][0-5][0-5])[.]([0-9]|[1-9][0-9]|[1][0-9][0-9]|[2][0-5][0-5])$'
</code></pre>

blocks|key|1751986|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1751987|((2[0-4]\d%7C25[0-5]%7C[01]?\d\d?)\.){3}(2[0-4]\d%7C25[0-5]%7C[01]?\d\d?)|code-block|syntax|javascript|1751988|它在我的情况下是有效的。|1751989|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

try this:

<pre><code>((2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?)
</code></pre>

it works in my case.

blocks|key|1752332|text|我想到了这个简单的正则表达式匹配模式，用于IP地址匹配\d%2B.\d%2B|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1752333|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I thought about this simple regex matching pattern for IP address matching
\d+[.]\d+[.]\d+[.]\d+

blocks|key|1537397|text|在php上：filter_var(gethostbyname($dns),+FILTER_VALIDATE_IP)+==+true+?+'ip'+:+'not+ip'|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1537398|entityMap^0|6|25|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

on php: <code>filter_var(gethostbyname($dns), FILTER_VALIDATE_IP) == true ? 'ip' : 'not ip'</code>

blocks|key|1537406|text|>>>+my_hostname+=+"testhostn.ame"
>>>+print+bool(re.match("%5E(([a-zA-Z]%7C[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]%7C[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$",+my_hostname))
True
>>>+my_hostname+=+"testhostn....ame"
>>>+print+bool(re.match("%5E(([a-zA-Z]%7C[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]%7C[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$",+my_hostname))
False
>>>+my_hostname+=+"testhostn.A.ame"
>>>+print+bool(re.match("%5E(([a-zA-Z]%7C[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]%7C[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$",+my_hostname))
True|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1537407|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&gt;&gt;&gt; my_hostname = "testhostn.ame"
&gt;&gt;&gt; print bool(re.match("^(([a-zA-Z]|[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]|[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$", my_hostname))
True
&gt;&gt;&gt; my_hostname = "testhostn....ame"
&gt;&gt;&gt; print bool(re.match("^(([a-zA-Z]|[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]|[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$", my_hostname))
False
&gt;&gt;&gt; my_hostname = "testhostn.A.ame"
&gt;&gt;&gt; print bool(re.match("^(([a-zA-Z]|[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]|[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$", my_hostname))
True
</code></pre>

blocks|key|1537472|text|新的网络框架具有结构IPv4Address和结构IPv6Address的错误初始化器，它们可以非常容易地处理IP地址部分。在使用正则表达式的IPv6中，使用所有的缩写规则很难做到这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1537473|不幸的是，我没有一个优雅的主机名答案。|1537474|请注意，Network+framework是最新的，因此它可能会迫使您针对最新的操作系统版本进行编译。|1537475|import+Network
let+tests+=+["192.168.4.4","fkjhwojfw","192.168.4.4.4","2620:3","2620::33"]

for+test+in+tests+{
++++if+let+_+=+IPv4Address(test)+{
++++++++debugPrint("\(test)+is+valid+ipv4+address")
++++}+else+if+let+_+=+IPv6Address(test)+{
++++++++debugPrint("\(test)+is+valid+ipv6+address")
++++}+else+{
++++++++debugPrint("\(test)+is+not+a+valid+IP+address")
++++}
}

output:
"192.168.4.4+is+valid+ipv4+address"
"fkjhwojfw+is+not+a+valid+IP+address"
"192.168.4.4.4+is+not+a+valid+IP+address"
"2620:3+is+not+a+valid+IP+address"
"2620::33+is+valid+ipv6+address"|code-block|syntax|javascript|1537476|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

The new Network framework has failable initializers for struct IPv4Address and struct IPv6Address which handle the IP address portion very easily. Doing this in IPv6 with a regex is tough with all the shortening rules.

Unfortunately I don't have an elegant answer for hostname.

Note that Network framework is recent, so it may force you to compile for recent OS versions.

<pre><code>import Network
let tests = ["192.168.4.4","fkjhwojfw","192.168.4.4.4","2620:3","2620::33"]

for test in tests {
 if let _ = IPv4Address(test) {
 debugPrint("\(test) is valid ipv4 address")
 } else if let _ = IPv6Address(test) {
 debugPrint("\(test) is valid ipv6 address")
 } else {
 debugPrint("\(test) is not a valid IP address")
 }
}

output:
"192.168.4.4 is valid ipv4 address"
"fkjhwojfw is not a valid IP address"
"192.168.4.4.4 is not a valid IP address"
"2620:3 is not a valid IP address"
"2620::33 is valid ipv6 address"
</code></pre>

Does anyone have a regular expression handy that will match any legal DNS hostname or IP address?

It's easy to write one that works 95% of the time, but I'm hoping to get something that's well tested to exactly match the latest RFC specs for DNS hostnames.

Regular expression to match DNS hostname or IP Address?

有没有人手边有一个正则表达式，可以匹配任何合法的DNS主机名或IP地址？编写一个在95%的时间内都能正常工作的程序是很容易的，但我希望得到一些经过良好测试的东西，以便与DNS主机名的最新RFC规范完全匹配。

问匹配DNS主机名或IP地址的正则表达式？
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