1// Copyright (c) 2015-2019 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 5package resty 6 7import ( 8 "errors" 9 "fmt" 10 "net" 11 "net/http" 12 "strings" 13) 14 15type ( 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). 31func (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()) 37func 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)) 45func 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 51 checkHostAndAddHeaders(req, via[0]) 52 53 return nil 54 }) 55} 56 57// DomainCheckRedirectPolicy is convenient method to define domain name redirect rule in resty client. 58// Redirect is allowed for only mentioned host in the policy. 59// resty.SetRedirectPolicy(DomainCheckRedirectPolicy("host1.com", "host2.org", "host3.net")) 60func DomainCheckRedirectPolicy(hostnames ...string) RedirectPolicy { 61 hosts := make(map[string]bool) 62 for _, h := range hostnames { 63 hosts[strings.ToLower(h)] = true 64 } 65 66 fn := RedirectPolicyFunc(func(req *http.Request, via []*http.Request) error { 67 if ok := hosts[getHostname(req.URL.Host)]; !ok { 68 return errors.New("redirect is not allowed as per DomainCheckRedirectPolicy") 69 } 70 71 return nil 72 }) 73 74 return fn 75} 76 77func getHostname(host string) (hostname string) { 78 if strings.Index(host, ":") > 0 { 79 host, _, _ = net.SplitHostPort(host) 80 } 81 hostname = strings.ToLower(host) 82 return 83} 84 85// By default Golang will not redirect request headers 86// after go throughing various discussion comments from thread 87// https://github.com/golang/go/issues/4800 88// go-resty will add all the headers during a redirect for the same host 89func checkHostAndAddHeaders(cur *http.Request, pre *http.Request) { 90 curHostname := getHostname(cur.URL.Host) 91 preHostname := getHostname(pre.URL.Host) 92 if strings.EqualFold(curHostname, preHostname) { 93 for key, val := range pre.Header { 94 cur.Header[key] = val 95 } 96 } else { // only library User-Agent header is added 97 cur.Header.Set(hdrUserAgentKey, fmt.Sprintf(hdrUserAgentValue, Version)) 98 } 99} 100