Best way to check if a URL is valid

Question

I want to use PHP to check  if string stored in  myoutput variable contains a valid link syntax or is it just a normal text  The function or solution  that I m looking for  should recognize all links formats including the ones with GET parameters   A solution  suggested on many sites  to actually query string  using CURL or file get contents   function  is not possible in my case and I would like to avoid it   I thought about regular expressions or another solution

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You can use this function  but its will return false if website offline     function isValidUrl  url         url   parse url  url       if   isset  url  host     return false      return   gethostbyname  url  host        url  host

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public function testing  Url           ch   curl init  Url       curl setopt  ch  CURLOPT TIMEOUT  5       curl setopt  ch  CURLOPT CONNECTTIMEOUT  5       curl setopt  ch  CURLOPT RETURNTRANSFER  true        data   curl exec  ch        httpcode   curl getinfo  ch  CURLINFO HTTP CODE       curl close  ch       if  httpcode  gt   200  amp  amp   httpcode  lt   301            this- gt output- gt set header  Access-Control-Allow-Origin                this- gt output- gt set content type  application json    utf-8             this- gt output- gt set status header 200            this- gt output- gt set output json encode  VALID URL   JSON PRETTY PRINT   JSON UNESCAPED UNICODE   JSON UNESCAPED SLASHES            return       else           this- gt output- gt set header  Access-Control-Allow-Origin                this- gt output- gt set content type  application json    utf-8             this- gt output- gt set status header 200            this- gt output- gt set output json encode  INVALID URL   JSON PRETTY PRINT   JSON UNESCAPED UNICODE   JSON UNESCAPED SLASHES            return

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Another way to check if given URL is valid is to try to access it  below function will fetch the headers from given URL  this will ensure that URL is valid AND web server is alive   function is url  url            response   array              Check if URL is empty         if  empty  url                  response   get headers  url                     return  bool in array  HTTP 1 1 200 OK    response  true     Array        0    gt  HTTP 1 1 200 OK       Date    gt  Sat  29 May 2004 12 28 14 GMT      Server    gt  Apache 1 3 27  Unix    Red-Hat Linux       Last-Modified    gt  Wed  08 Jan 2003 23 11 55 GMT      ETag    gt   3f80f-1b6-3e1cb03b       Accept-Ranges    gt  bytes      Content-Length    gt  438      Connection    gt  close      Content-Type    gt  text html

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Given issues with filter var   needing http     I use    is url   filter var  filename  FILTER VALIDATE URL     array key exists  scheme   parse url  filename

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function is url  uri       if preg match      http https         a-z0-9       -     1  a-z 0-9         a-z  2 5        0-9  1 5            i    uri          return  uri            else          return false

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Using filter var   will fail for urls with non-ascii chars  e g   http   pt wikipedia org wiki Guimar  es    The following function encode all non-ascii chars  e g  http   pt wikipedia org wiki Guimar C3 A3es  before calling filter var     Hope this helps someone    lt  php  function validate url  url         path   parse url  url  PHP URL PATH        encoded path   array map  urlencode   explode       path         url   str replace  path  implode       encoded path    url        return filter var  url  FILTER VALIDATE URL    true   false        example if  validate url  http   somedomain com some path file1 jpg          echo  NOT A URL     else       echo  IS A URL

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Here is the best tutorial I found over there    http   www w3schools com php filter validate url asp   lt  php  url    http   www qbaki com       Remove all illegal characters from a url  url   filter var  url  FILTER SANITIZE URL       Validate url if  filter var  url  FILTER VALIDATE URL      false    echo   url is a valid URL      else   echo   url is not a valid URL        gt    Possible  flags   FILTER FLAG SCHEME REQUIRED - URL must be RFC compliant  like http   example  FILTER FLAG HOST REQUIRED - URL must include host name  like http   www example com  FILTER FLAG PATH REQUIRED - URL must have a path after the domain name  like www example com example1   FILTER FLAG QUERY REQUIRED - URL must have a query string  like  example php name Peter amp age 37

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Personally I would like to use regular expression here  Bellow code perfectly worked for me    baseUrl       url          for my case https   www xrepeater com  posted url     home      Test with one by one    posted url      home    posted url     xrepeater com    posted url     www xrepeater com    posted url     http   www xrepeater com    posted url     https   www xrepeater com    posted url     https   xrepeater com services    posted url     xrepeater dev home test    posted url     home test       regularExpression       https  ftp               SCHEME Check  regularExpression       a-z0-9         amp      -      a-z0-9         amp      -             User and Pass Check  regularExpression       a-z0-9-        a-z  2 3        Host or IP Check  regularExpression         0-9  2 5         Port Check  regularExpression          a-z0-9    -                 Path Check  regularExpression         a-z  amp     -  a-z0-9    amp          -          GET Query String Check  regularExpression        a-z  -  a-z0-9     -          Anchor Check  if preg match     regularExpression  i    posted url          if preg match    http https    i   posted url              final url   preg replace    http      i   http      posted url              return      -    Match      final url            else               final url    http      posted url               return           Match      final url                   else        if  substr  posted url  0  1                          return           Not Match     final url   lt br gt    baseUrl  posted url            final url    baseUrl  posted url              else                return      -    Not Match     posted url   lt br gt    baseUrl      posted url            final url    baseUrl      final url

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if anyone is interested to use the cURL for validation  You can use the following code    lt  php  public function validationUrl  Url           if   Url    NULL               return  false                     ch   curl init  Url           curl setopt  ch  CURLOPT TIMEOUT  5           curl setopt  ch  CURLOPT CONNECTTIMEOUT  5           curl setopt  ch  CURLOPT RETURNTRANSFER  true            data   curl exec  ch            httpcode   curl getinfo  ch  CURLINFO HTTP CODE           curl close  ch           return   httpcode  gt   200  amp  amp   httpcode  lt  300    true   false

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Came across this article from 2012  It takes into account variables that may or may not be just plain URLs   The author of the article  David M  eller  provides this function that he says      could be worth wile  sic    along with some examples of filter var and its shortcomings          Modified version of  filter var          param  mixed  url Could be a URL or possibly much more      return bool     function validate url   url          url   trim   url         return             strpos   url   http           0    strpos   url   https           0    amp  amp          filter var               url              FILTER VALIDATE URL              FILTER FLAG SCHEME REQUIRED    FILTER FLAG HOST REQUIRED               false

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Actually    filter var  url  FILTER VALIDATE URL   doesn t work very well  When you type in a real url  it works but  it only checks for http    so if you type something like  http   weirtgcyaurbatc   it will still say it s real

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You can use a native Filter Validator  filter var  url  FILTER VALIDATE URL        Validates value as URL  according to    http   www faqs org rfcs rfc2396   optionally with required components  Beware a valid URL may not specify the HTTP protocol http    so further validation may be required to determine the URL uses an expected protocol  e g  ssh    or mailto   Note that the function will only find ASCII URLs to be valid  internationalized domain names  containing non-ASCII characters  will fail    Example   if  filter var  url  FILTER VALIDATE URL      FALSE        die  Not a valid URL

[php] Best way to check if a URL is valid

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