add client Copy method

Author: rpdg

client.go

@@ -285,7 +285,7 @@ func (c *VercelBlobClient) List(options ListCommandOptions) (*ListBlobResult, er
 // be used to later download the blob.
 func (c *VercelBlobClient) Put(pathname string, body io.Reader, options PutCommandOptions) (*PutBlobPutResult, error) {
 
-	if pathname == "" {
+	if len(pathname) == 0 {
 		return nil, NewInvalidInputError("pathname")
 	}
 
@@ -418,6 +418,59 @@ func (c *VercelBlobClient) Delete(urlPath string) error {
 	return nil
 }
 
+func (c *VercelBlobClient) Copy(fromUrl, toPath string, options PutCommandOptions) (*PutBlobPutResult, error) {
+	if len(fromUrl) == 0 {
+		return nil, NewInvalidInputError("fromUrl")
+	}
+
+	if len(toPath) == 0 {
+		return nil, NewInvalidInputError("toPath")
+	}
+
+	apiUrl := c.getAPIURL(toPath)
+
+	req, err := http.NewRequest(http.MethodPut, apiUrl, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	req.URL.Query().Add("fromUrl", fromUrl)
+
+	c.addAPIVersionHeader(req)
+	err = c.addAuthorizationHeader(req, "put", toPath)
+	if err != nil {
+		return nil, err
+	}
+
+	if !options.AddRandomSuffix {
+		req.Header.Set("X-Add-Random-Suffix", "0")
+	}
+	if options.ContentType != "" {
+		req.Header.Set("X-Content-Type", options.ContentType)
+	}
+	if options.CacheControlMaxAge > 0 {
+		req.Header.Set("X-Cache-Control-Max-Age", strconv.FormatUint(options.CacheControlMaxAge, 10))
+	}
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, c.handleError(resp)
+	}
+
+	var result PutBlobPutResult
+	if err = json.NewDecoder(resp.Body).Decode(&result); err != nil {
+		return nil, err
+	}
+
+	return &result, nil
+}
+
 // Download a blob from the blob store
 //
 // # Arguments

client_test.go

@@ -2,7 +2,8 @@ package vercel_blob
 
 import (
 	"fmt"
-	"strings"
+	"io"
+	"os"
 	"testing"
 )
 
@@ -19,12 +20,14 @@ func Test_CountFiles(t *testing.T) {
 
 func Test_PutWithRandomSuffix(t *testing.T) {
 	client := NewVercelBlobClient()
+	f, _ := os.Open("a.png")
+	defer f.Close()
 	file1, err := client.Put(
-		"vercel_blob_unittest/a.txt",
-		strings.NewReader("test body"),
+		"vercel_blob_unittest/a.png",
+		io.Reader(f),
 		PutCommandOptions{
 			AddRandomSuffix: true,
-			ContentType:     "text/plain",
+			//ContentType:     "multipart/form-data",
 		})
 	if err != nil {
 		t.Error(err)
@@ -34,6 +37,20 @@ func Test_PutWithRandomSuffix(t *testing.T) {
 	}
 }
 
+func Test_Copy(t *testing.T) {
+	//https://fetegzn4vw3t5yqf.public.blob.vercel-storage.com/vercel_blob_unittest/a.txt
+	client := NewVercelBlobClient()
+	res, err := client.Copy("https://fetegzn4vw3t5yqf.public.blob.vercel-storage.com/vercel_blob_unittest/a.txt",
+		"vercel_blob_unittest/B.txt",
+		PutCommandOptions{})
+	if err != nil {
+		t.Error(err)
+		return
+	} else {
+		fmt.Println(res.URL)
+	}
+}
+
 func Test_Partial_Download(t *testing.T) {
 	client := NewVercelBlobClient()
 	bytes, err := client.Download("vercel_blob_unittest/a.txt",