fshttp: Add cookie support with cmdline switch --use-cookies

Cookies are handled by cookiejar in memory with fshttp module through
the entire session.

One useful scenario is, with HTTP storage system where index server
adds authentication cookie while redirecting to CDN for actual files.

Also, it can be helpful to reuse fshttp in other storage systems
requiring cookie.

fs/fshttp/http.go

@@ -7,12 +7,14 @@ import (
 	"crypto/tls"
 	"net"
 	"net/http"
+	"net/http/cookiejar"
 	"net/http/httputil"
 	"reflect"
 	"sync"
 	"time"
 
 	"github.com/ncw/rclone/fs"
+	"golang.org/x/net/publicsuffix"
 	"golang.org/x/time/rate"
 )
 
@@ -22,9 +24,10 @@ const (
 )
 
 var (
-	transport   http.RoundTripper
-	noTransport sync.Once
-	tpsBucket   *rate.Limiter // for limiting number of http transactions per second
+	transport    http.RoundTripper
+	noTransport  sync.Once
+	tpsBucket    *rate.Limiter // for limiting number of http transactions per second
+	cookieJar, _ = cookiejar.New(&cookiejar.Options{PublicSuffixList: publicsuffix.List})
 )
 
 // StartHTTPTokenBucket starts the token bucket if necessary
@@ -142,9 +145,13 @@ func NewTransport(ci *fs.ConfigInfo) http.RoundTripper {
 
 // NewClient returns an http.Client with the correct timeouts
 func NewClient(ci *fs.ConfigInfo) *http.Client {
-	return &http.Client{
+	transport := &http.Client{
 		Transport: NewTransport(ci),
 	}
+	if ci.Cookie {
+		transport.Jar = cookieJar
+	}
+	return transport
 }
 
 // Transport is a our http Transport which wraps an http.Transport