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 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")) 58func 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 79func 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 91func 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