rest: add Parameters field to opts for adding URL parameters

rest/rest.go

@@ -10,6 +10,7 @@ import (
 	"io/ioutil"
 	"mime/multipart"
 	"net/http"
+	"net/url"
 	"sync"
 
 	"github.com/ncw/rclone/fs"
@@ -94,6 +95,7 @@ type Opts struct {
 	MultipartMetadataName string     // set the following 3 vars
 	MultipartContentName  string     // and Body and pass in request
 	MultipartFileName     string     // for multipart upload
+	Parameters            url.Values // any parameters for the final URL
 }
 
 // Copy creates a copy of the options
@@ -153,6 +155,9 @@ func (api *Client) Call(opts *Opts) (resp *http.Response, err error) {
 		}
 		url = api.rootURL + opts.Path
 	}
+	if opts.Parameters != nil && len(opts.Parameters) > 0 {
+		url += "?" + opts.Parameters.Encode()
+	}
 	req, err := http.NewRequest(opts.Method, url, opts.Body)
 	if err != nil {
 		return