adding get provider name support for chi router (#569)

Author: fardinabir

go.mod

@@ -3,6 +3,7 @@ module github.com/markbates/goth
 go 1.18
 
 require (
+	github.com/go-chi/chi/v5 v5.1.0
 	github.com/golang-jwt/jwt/v4 v4.2.0
 	github.com/gorilla/mux v1.6.2
 	github.com/gorilla/pat v0.0.0-20180118222023-199c85a7f6d1

go.sum

@@ -9,6 +9,8 @@ github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/decred/dcrd/crypto/blake256 v1.0.1/go.mod h1:2OfgNZ5wDpcsFmHmCK5gZTPcCXqlm2ArzUIkw9czNJo=
 github.com/decred/dcrd/dcrec/secp256k1/v4 v4.2.0 h1:8UrgZ3GkP4i/CLijOJx79Yu+etlyjdBU4sfcs2WYQMs=
 github.com/decred/dcrd/dcrec/secp256k1/v4 v4.2.0/go.mod h1:v57UDF4pDQJcEfFUCRop3lJL149eHGSe9Jvczhzjo/0=
+github.com/go-chi/chi/v5 v5.1.0 h1:acVI1TYaD+hhedDJ3r54HyA6sExp3HfXq7QWEEY/xMw=
+github.com/go-chi/chi/v5 v5.1.0/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
 github.com/goccy/go-json v0.10.2 h1:CrxCmQqYDkv1z7lO7Wbh2HN93uovUHgrECaO5ZrCXAU=
 github.com/goccy/go-json v0.10.2/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MGFi0w8I=
 github.com/golang-jwt/jwt/v4 v4.2.0 h1:besgBTC8w8HjP6NzQdxwKH9Z5oQMZ24ThTrHp3cZ8eU=

gothic/gothic.go

@@ -22,6 +22,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/go-chi/chi/v5"
 	"github.com/gorilla/mux"
 	"github.com/gorilla/sessions"
 	"github.com/markbates/goth"
@@ -282,6 +283,11 @@ func getProviderName(req *http.Request) (string, error) {
 		return p, nil
 	}
 
+	// try to get it from the url param "provider", when req is routed through 'chi'
+	if p := chi.URLParam(req, "provider"); p != "" {
+		return p, nil
+	}
+
 	// try to get it from the go-context's value of providerContextKey key
 	if p, ok := req.Context().Value(ProviderParamKey).(string); ok {
 		return p, nil