host.go

Documentation: github.com/aws/smithy-go/transport/http

     1  package http
     2  
     3  import (
     4  	"fmt"
     5  	"net"
     6  	"strconv"
     7  	"strings"
     8  )
     9  
    10  // ValidateEndpointHost validates that the host string passed in is a valid RFC
    11  // 3986 host. Returns error if the host is not valid.
    12  func ValidateEndpointHost(host string) error {
    13  	var errors strings.Builder
    14  	var hostname string
    15  	var port string
    16  	var err error
    17  
    18  	if strings.Contains(host, ":") {
    19  		hostname, port, err = net.SplitHostPort(host)
    20  		if err != nil {
    21  			errors.WriteString(fmt.Sprintf("\n endpoint %v, failed to parse, got ", host))
    22  			errors.WriteString(err.Error())
    23  		}
    24  
    25  		if !ValidPortNumber(port) {
    26  			errors.WriteString(fmt.Sprintf("port number should be in range [0-65535], got %v", port))
    27  		}
    28  	} else {
    29  		hostname = host
    30  	}
    31  
    32  	labels := strings.Split(hostname, ".")
    33  	for i, label := range labels {
    34  		if i == len(labels)-1 && len(label) == 0 {
    35  			// Allow trailing dot for FQDN hosts.
    36  			continue
    37  		}
    38  
    39  		if !ValidHostLabel(label) {
    40  			errors.WriteString("\nendpoint host domain labels must match \"[a-zA-Z0-9-]{1,63}\", but found: ")
    41  			errors.WriteString(label)
    42  		}
    43  	}
    44  
    45  	if len(hostname) == 0 && len(port) != 0 {
    46  		errors.WriteString("\nendpoint host with port must not be empty")
    47  	}
    48  
    49  	if len(hostname) > 255 {
    50  		errors.WriteString(fmt.Sprintf("\nendpoint host must be less than 255 characters, but was %d", len(hostname)))
    51  	}
    52  
    53  	if len(errors.String()) > 0 {
    54  		return fmt.Errorf("invalid endpoint host%s", errors.String())
    55  	}
    56  	return nil
    57  }
    58  
    59  // ValidPortNumber returns whether the port is valid RFC 3986 port.
    60  func ValidPortNumber(port string) bool {
    61  	i, err := strconv.Atoi(port)
    62  	if err != nil {
    63  		return false
    64  	}
    65  
    66  	if i < 0 || i > 65535 {
    67  		return false
    68  	}
    69  	return true
    70  }
    71  
    72  // ValidHostLabel returns whether the label is a valid RFC 3986 host abel.
    73  func ValidHostLabel(label string) bool {
    74  	if l := len(label); l == 0 || l > 63 {
    75  		return false
    76  	}
    77  	for _, r := range label {
    78  		switch {
    79  		case r >= '0' && r <= '9':
    80  		case r >= 'A' && r <= 'Z':
    81  		case r >= 'a' && r <= 'z':
    82  		case r == '-':
    83  		default:
    84  			return false
    85  		}
    86  	}
    87  
    88  	return true
    89  }
    90
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