redirect.go

Documentation: github.com/go-resty/resty/v2

     1  // Copyright (c) 2015-2021 Jeevanandam M (jeeva@myjeeva.com), All rights reserved.
     2  // resty source code and usage is governed by a MIT style
     3  // license that can be found in the LICENSE file.
     4  
     5  package resty
     6  
     7  import (
     8  	"errors"
     9  	"fmt"
    10  	"net"
    11  	"net/http"
    12  	"strings"
    13  )
    14  
    15  type (
    16  	// RedirectPolicy to regulate the redirects in the resty client.
    17  	// Objects implementing the RedirectPolicy interface can be registered as
    18  	//
    19  	// Apply function should return nil to continue the redirect jounery, otherwise
    20  	// return error to stop the redirect.
    21  	RedirectPolicy interface {
    22  		Apply(req *http.Request, via []*http.Request) error
    23  	}
    24  
    25  	// The RedirectPolicyFunc type is an adapter to allow the use of ordinary functions as RedirectPolicy.
    26  	// If f is a function with the appropriate signature, RedirectPolicyFunc(f) is a RedirectPolicy object that calls f.
    27  	RedirectPolicyFunc func(*http.Request, []*http.Request) error
    28  )
    29  
    30  // Apply calls f(req, via).
    31  func (f RedirectPolicyFunc) Apply(req *http.Request, via []*http.Request) error {
    32  	return f(req, via)
    33  }
    34  
    35  // NoRedirectPolicy is used to disable redirects in the HTTP client
    36  // 		resty.SetRedirectPolicy(NoRedirectPolicy())
    37  func NoRedirectPolicy() RedirectPolicy {
    38  	return RedirectPolicyFunc(func(req *http.Request, via []*http.Request) error {
    39  		return errors.New("auto redirect is disabled")
    40  	})
    41  }
    42  
    43  // FlexibleRedirectPolicy is convenient method to create No of redirect policy for HTTP client.
    44  // 		resty.SetRedirectPolicy(FlexibleRedirectPolicy(20))
    45  func FlexibleRedirectPolicy(noOfRedirect int) RedirectPolicy {
    46  	return RedirectPolicyFunc(func(req *http.Request, via []*http.Request) error {
    47  		if len(via) >= noOfRedirect {
    48  			return fmt.Errorf("stopped after %d redirects", noOfRedirect)
    49  		}
    50  		checkHostAndAddHeaders(req, via[0])
    51  		return nil
    52  	})
    53  }
    54  
    55  // DomainCheckRedirectPolicy is convenient method to define domain name redirect rule in resty client.
    56  // Redirect is allowed for only mentioned host in the policy.
    57  // 		resty.SetRedirectPolicy(DomainCheckRedirectPolicy("host1.com", "host2.org", "host3.net"))
    58  func DomainCheckRedirectPolicy(hostnames ...string) RedirectPolicy {
    59  	hosts := make(map[string]bool)
    60  	for _, h := range hostnames {
    61  		hosts[strings.ToLower(h)] = true
    62  	}
    63  
    64  	fn := RedirectPolicyFunc(func(req *http.Request, via []*http.Request) error {
    65  		if ok := hosts[getHostname(req.URL.Host)]; !ok {
    66  			return errors.New("redirect is not allowed as per DomainCheckRedirectPolicy")
    67  		}
    68  
    69  		return nil
    70  	})
    71  
    72  	return fn
    73  }
    74  
    75  //‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
    76  // Package Unexported methods
    77  //_______________________________________________________________________
    78  
    79  func getHostname(host string) (hostname string) {
    80  	if strings.Index(host, ":") > 0 {
    81  		host, _, _ = net.SplitHostPort(host)
    82  	}
    83  	hostname = strings.ToLower(host)
    84  	return
    85  }
    86  
    87  // By default Golang will not redirect request headers
    88  // after go throughing various discussion comments from thread
    89  // https://github.com/golang/go/issues/4800
    90  // Resty will add all the headers during a redirect for the same host
    91  func checkHostAndAddHeaders(cur *http.Request, pre *http.Request) {
    92  	curHostname := getHostname(cur.URL.Host)
    93  	preHostname := getHostname(pre.URL.Host)
    94  	if strings.EqualFold(curHostname, preHostname) {
    95  		for key, val := range pre.Header {
    96  			cur.Header[key] = val
    97  		}
    98  	} else { // only library User-Agent header is added
    99  		cur.Header.Set(hdrUserAgentKey, hdrUserAgentValue)
   100  	}
   101  }
   102
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