github.com/prebid/prebid-server/v2@v2.18.0/util/httputil/httputil.go (about)

     1  package httputil
     2  
     3  import (
     4  	"net"
     5  	"net/http"
     6  	"strings"
     7  
     8  	"github.com/prebid/prebid-server/v2/util/iputil"
     9  )
    10  
    11  var (
    12  	trueClientIP  = http.CanonicalHeaderKey("True-Client-IP")
    13  	xForwardedFor = http.CanonicalHeaderKey("X-Forwarded-For")
    14  	xRealIP       = http.CanonicalHeaderKey("X-Real-IP")
    15  )
    16  
    17  type ContentEncoding string
    18  
    19  const (
    20  	ContentEncodingGZIP ContentEncoding = "gzip"
    21  )
    22  
    23  func (k ContentEncoding) Normalize() ContentEncoding {
    24  	return ContentEncoding(strings.ToLower(string(k)))
    25  }
    26  
    27  // FindIP returns the first ip address found in the http request matching the predicate v.
    28  func FindIP(r *http.Request, v iputil.IPValidator) (net.IP, iputil.IPVersion) {
    29  	if ip, ver := findTrueClientIP(r, v); ip != nil {
    30  		return ip, ver
    31  	}
    32  
    33  	if ip, ver := findForwardedFor(r, v); ip != nil {
    34  		return ip, ver
    35  	}
    36  
    37  	if ip, ver := findRealIP(r, v); ip != nil {
    38  		return ip, ver
    39  	}
    40  
    41  	if ip, ver := findRemoteAddr(r, v); ip != nil {
    42  		return ip, ver
    43  	}
    44  
    45  	return nil, iputil.IPvUnknown
    46  }
    47  
    48  func findTrueClientIP(r *http.Request, v iputil.IPValidator) (net.IP, iputil.IPVersion) {
    49  	if value := r.Header.Get(trueClientIP); value != "" {
    50  		value = strings.TrimSpace(value)
    51  		if ip, ver := iputil.ParseIP(value); ip != nil && v.IsValid(ip, ver) {
    52  			return ip, ver
    53  		}
    54  	}
    55  	return nil, iputil.IPvUnknown
    56  }
    57  
    58  func findForwardedFor(r *http.Request, v iputil.IPValidator) (net.IP, iputil.IPVersion) {
    59  	if value := r.Header.Get(xForwardedFor); value != "" {
    60  		for _, p := range strings.Split(value, ",") {
    61  			p = strings.TrimSpace(p)
    62  			if ip, ver := iputil.ParseIP(p); ip != nil && v.IsValid(ip, ver) {
    63  				return ip, ver
    64  			}
    65  		}
    66  	}
    67  	return nil, iputil.IPvUnknown
    68  }
    69  
    70  func findRealIP(r *http.Request, v iputil.IPValidator) (net.IP, iputil.IPVersion) {
    71  	if value := r.Header.Get(xRealIP); value != "" {
    72  		value = strings.TrimSpace(value)
    73  		if ip, ver := iputil.ParseIP(value); ip != nil && v.IsValid(ip, ver) {
    74  			return ip, ver
    75  		}
    76  	}
    77  	return nil, iputil.IPvUnknown
    78  }
    79  
    80  func findRemoteAddr(r *http.Request, v iputil.IPValidator) (net.IP, iputil.IPVersion) {
    81  	if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
    82  		if ip, ver := iputil.ParseIP(host); ip != nil && v.IsValid(ip, ver) {
    83  			return ip, ver
    84  		}
    85  	}
    86  	return nil, iputil.IPvUnknown
    87  }