Re-add setting requestBuf after seeking

added ReadStreamRange() method to efficiently read a range of data

.github/workflows/artifacts.yml

@@ -0,0 +1,46 @@
+name: Build Artifacts
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - "**.md"
+
+jobs:
+  build_artifacts:
+    name: Build Artifcats
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        goos:
+          - linux
+          - windows
+          - darwin
+        goarch:
+          - amd64
+          - arm64
+    steps:
+      - name: Set up Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: "^1.17"
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v2
+      - name: Get dependencies
+        run: go get ./...
+      - name: Build Client (${{ matrix.goos }}-${{ matrix.goarch }})
+        env:
+          GOOS: ${{ matrix.goos }}
+          GOARCH: ${{ matrix.goarch }}
+        run: go build -v -o ./bin/gowebdav-${{ matrix.goos }}-${{ matrix.goarch }} ./cmd/gowebdav/main.go
+      - name: Rename Windows Binary
+        if: ${{ matrix.goos == 'windows' }}
+        env:
+          FNAME: ./bin/gowebdav-${{ matrix.goos }}-${{ matrix.goarch }}
+        run: mv ${{ env.FNAME }} ${{ env.FNAME }}.exe
+      - name: Upload Artifcats
+        uses: actions/upload-artifact@v2
+        with:
+          name: ${{ matrix.goos }}-${{ matrix.goarch }}
+          path: ./bin/

.github/workflows/tests.yml

@@ -0,0 +1,30 @@
+name: Unit Tests
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - "*"
+    paths-ignore:
+      - "**.md"
+  pull_request:
+
+jobs:
+  unit_tests:
+    name: Unit Tests
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        goversion:
+          - "1.17"
+          - "1.16"
+    steps:
+      - name: Set up Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: ${{ matrix.goversion }}
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v2
+      - name: Get dependencies
+        run: go get ./...
+      - name: Run Unit Tests
+        run: go test -v -cover -race ./...

.gitignore

@@ -17,3 +17,5 @@
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
+
+.vscode/

README.md

@@ -167,7 +167,7 @@ included.
 * [func String(r io.Reader) string](#String)
 * [type Authenticator](#Authenticator)
 * [type BasicAuth](#BasicAuth)
-  * [func (b *BasicAuth) Authorize(c *Client, method string, path string)](#BasicAuth.Authorize)
+  * [func (b *BasicAuth) Authorize(req *http.Request, method string, path string)](#BasicAuth.Authorize)
   * [func (b *BasicAuth) Pass() string](#BasicAuth.Pass)
   * [func (b *BasicAuth) Type() string](#BasicAuth.Type)
   * [func (b *BasicAuth) User() string](#BasicAuth.User)
@@ -184,13 +184,14 @@ included.
   * [func (c *Client) RemoveAll(path string) error](#Client.RemoveAll)
   * [func (c *Client) Rename(oldpath, newpath string, overwrite bool) error](#Client.Rename)
   * [func (c *Client) SetHeader(key, value string)](#Client.SetHeader)
+  * [func (c *Client) SetInterceptor(interceptor func(method string, rq *http.Request))](#Client.SetInterceptor)
   * [func (c *Client) SetTimeout(timeout time.Duration)](#Client.SetTimeout)
   * [func (c *Client) SetTransport(transport http.RoundTripper)](#Client.SetTransport)
   * [func (c *Client) Stat(path string) (os.FileInfo, error)](#Client.Stat)
   * [func (c *Client) Write(path string, data []byte, _ os.FileMode) error](#Client.Write)
   * [func (c *Client) WriteStream(path string, stream io.Reader, _ os.FileMode) error](#Client.WriteStream)
 * [type DigestAuth](#DigestAuth)
-  * [func (d *DigestAuth) Authorize(c *Client, method string, path string)](#DigestAuth.Authorize)
+  * [func (d *DigestAuth) Authorize(req *http.Request, method string, path string)](#DigestAuth.Authorize)
   * [func (d *DigestAuth) Pass() string](#DigestAuth.Pass)
   * [func (d *DigestAuth) Type() string](#DigestAuth.Type)
   * [func (d *DigestAuth) User() string](#DigestAuth.User)
@@ -206,7 +207,7 @@ included.
   * [func (f File) String() string](#File.String)
   * [func (f File) Sys() interface{}](#File.Sys)
 * [type NoAuth](#NoAuth)
-  * [func (n *NoAuth) Authorize(c *Client, method string, path string)](#NoAuth.Authorize)
+  * [func (n *NoAuth) Authorize(req *http.Request, method string, path string)](#NoAuth.Authorize)
   * [func (n *NoAuth) Pass() string](#NoAuth.Pass)
   * [func (n *NoAuth) Type() string](#NoAuth.Type)
   * [func (n *NoAuth) User() string](#NoAuth.User)
@@ -254,18 +255,18 @@ func String(r io.Reader) string
 ```
 String pulls a string out of our io.Reader
 
-### <a name="Authenticator">type</a> [Authenticator](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=285:398#L24)
+### <a name="Authenticator">type</a> [Authenticator](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=381:500#L28)
 ``` go
 type Authenticator interface {
     Type() string
     User() string
     Pass() string
-    Authorize(*Client, string, string)
+    Authorize(*http.Request, string, string)
 }
 ```
 Authenticator stub
 
-### <a name="BasicAuth">type</a> [BasicAuth](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=94:145#L8)
+### <a name="BasicAuth">type</a> [BasicAuth](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=106:157#L9)
 ``` go
 type BasicAuth struct {
     // contains filtered or unexported fields
@@ -273,31 +274,31 @@ type BasicAuth struct {
 ```
 BasicAuth structure holds our credentials
 
-#### <a name="BasicAuth.Authorize">func</a> (\*BasicAuth) [Authorize](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=461:529#L29)
+#### <a name="BasicAuth.Authorize">func</a> (\*BasicAuth) [Authorize](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=473:549#L30)
 ``` go
-func (b *BasicAuth) Authorize(c *Client, method string, path string)
+func (b *BasicAuth) Authorize(req *http.Request, method string, path string)
 ```
 Authorize the current request
 
-#### <a name="BasicAuth.Pass">func</a> (\*BasicAuth) [Pass](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=376:409#L24)
+#### <a name="BasicAuth.Pass">func</a> (\*BasicAuth) [Pass](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=388:421#L25)
 ``` go
 func (b *BasicAuth) Pass() string
 ```
 Pass holds the BasicAuth password
 
-#### <a name="BasicAuth.Type">func</a> (\*BasicAuth) [Type](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=189:222#L14)
+#### <a name="BasicAuth.Type">func</a> (\*BasicAuth) [Type](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=201:234#L15)
 ``` go
 func (b *BasicAuth) Type() string
 ```
 Type identifies the BasicAuthenticator
 
-#### <a name="BasicAuth.User">func</a> (\*BasicAuth) [User](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=285:318#L19)
+#### <a name="BasicAuth.User">func</a> (\*BasicAuth) [User](https://github.com/studio-b12/gowebdav/blob/master/basicAuth.go?s=297:330#L20)
 ``` go
 func (b *BasicAuth) User() string
 ```
 User holds the BasicAuth username
 
-### <a name="Client">type</a> [Client](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=157:261#L16)
+### <a name="Client">type</a> [Client](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=165:357#L17)
 ``` go
 type Client struct {
     // contains filtered or unexported fields
@@ -305,103 +306,109 @@ type Client struct {
 ```
 Client defines our structure
 
-#### <a name="NewClient">func</a> [NewClient](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=902:946#L57)
+#### <a name="NewClient">func</a> [NewClient](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1012:1056#L61)
 ``` go
 func NewClient(uri, user, pw string) *Client
 ```
 NewClient creates a new instance of client
 
-#### <a name="Client.Connect">func</a> (\*Client) [Connect](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1516:1548#L77)
+#### <a name="Client.Connect">func</a> (\*Client) [Connect](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1836:1868#L86)
 ``` go
 func (c *Client) Connect() error
 ```
 Connect connects to our dav server
 
-#### <a name="Client.Copy">func</a> (\*Client) [Copy](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6376:6444#L303)
+#### <a name="Client.Copy">func</a> (\*Client) [Copy](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6695:6763#L312)
 ``` go
 func (c *Client) Copy(oldpath, newpath string, overwrite bool) error
 ```
 Copy copies a file from A to B
 
-#### <a name="Client.Mkdir">func</a> (\*Client) [Mkdir](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=5467:5523#L262)
+#### <a name="Client.Mkdir">func</a> (\*Client) [Mkdir](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=5786:5842#L271)
 ``` go
 func (c *Client) Mkdir(path string, _ os.FileMode) error
 ```
 Mkdir makes a directory
 
-#### <a name="Client.MkdirAll">func</a> (\*Client) [MkdirAll](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=5702:5761#L273)
+#### <a name="Client.MkdirAll">func</a> (\*Client) [MkdirAll](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6021:6080#L282)
 ``` go
 func (c *Client) MkdirAll(path string, _ os.FileMode) error
 ```
 MkdirAll like mkdir -p, but for webdav
 
-#### <a name="Client.Read">func</a> (\*Client) [Read](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6550:6600#L308)
+#### <a name="Client.Read">func</a> (\*Client) [Read](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6869:6919#L317)
 ``` go
 func (c *Client) Read(path string) ([]byte, error)
 ```
 Read reads the contents of a remote file
 
-#### <a name="Client.ReadDir">func</a> (\*Client) [ReadDir](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=2542:2602#L120)
+#### <a name="Client.ReadDir">func</a> (\*Client) [ReadDir](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=2862:2922#L129)
 ``` go
 func (c *Client) ReadDir(path string) ([]os.FileInfo, error)
 ```
 ReadDir reads the contents of a remote directory
 
-#### <a name="Client.ReadStream">func</a> (\*Client) [ReadStream](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6911:6974#L326)
+#### <a name="Client.ReadStream">func</a> (\*Client) [ReadStream](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=7230:7293#L335)
 ``` go
 func (c *Client) ReadStream(path string) (io.ReadCloser, error)
 ```
 ReadStream reads the stream for a given path
 
-#### <a name="Client.Remove">func</a> (\*Client) [Remove](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=4973:5015#L239)
+#### <a name="Client.Remove">func</a> (\*Client) [Remove](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=5292:5334#L248)
 ``` go
 func (c *Client) Remove(path string) error
 ```
 Remove removes a remote file
 
-#### <a name="Client.RemoveAll">func</a> (\*Client) [RemoveAll](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=5081:5126#L244)
+#### <a name="Client.RemoveAll">func</a> (\*Client) [RemoveAll](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=5400:5445#L253)
 ``` go
 func (c *Client) RemoveAll(path string) error
 ```
 RemoveAll removes remote files
 
-#### <a name="Client.Rename">func</a> (\*Client) [Rename](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6210:6280#L298)
+#### <a name="Client.Rename">func</a> (\*Client) [Rename](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=6529:6599#L307)
 ``` go
 func (c *Client) Rename(oldpath, newpath string, overwrite bool) error
 ```
 Rename moves a file from A to B
 
-#### <a name="Client.SetHeader">func</a> (\*Client) [SetHeader](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1099:1144#L62)
+#### <a name="Client.SetHeader">func</a> (\*Client) [SetHeader](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1228:1273#L66)
 ``` go
 func (c *Client) SetHeader(key, value string)
 ```
 SetHeader lets us set arbitrary headers for a given client
 
-#### <a name="Client.SetTimeout">func</a> (\*Client) [SetTimeout](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1244:1294#L67)
+#### <a name="Client.SetInterceptor">func</a> (\*Client) [SetInterceptor](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1380:1462#L71)
+``` go
+func (c *Client) SetInterceptor(interceptor func(method string, rq *http.Request))
+```
+SetInterceptor lets us set an arbitrary interceptor for a given client
+
+#### <a name="Client.SetTimeout">func</a> (\*Client) [SetTimeout](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1564:1614#L76)
 ``` go
 func (c *Client) SetTimeout(timeout time.Duration)
 ```
 SetTimeout exposes the ability to set a time limit for requests
 
-#### <a name="Client.SetTransport">func</a> (\*Client) [SetTransport](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1387:1445#L72)
+#### <a name="Client.SetTransport">func</a> (\*Client) [SetTransport](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=1707:1765#L81)
 ``` go
 func (c *Client) SetTransport(transport http.RoundTripper)
 ```
 SetTransport exposes the ability to define custom transports
 
-#### <a name="Client.Stat">func</a> (\*Client) [Stat](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=3929:3984#L187)
+#### <a name="Client.Stat">func</a> (\*Client) [Stat](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=4248:4303#L196)
 ``` go
 func (c *Client) Stat(path string) (os.FileInfo, error)
 ```
 Stat returns the file stats for a specified path
 
-#### <a name="Client.Write">func</a> (\*Client) [Write](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=7265:7334#L341)
+#### <a name="Client.Write">func</a> (\*Client) [Write](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=7584:7653#L350)
 ``` go
 func (c *Client) Write(path string, data []byte, _ os.FileMode) error
 ```
 Write writes data to a given path
 
-#### <a name="Client.WriteStream">func</a> (\*Client) [WriteStream](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=7690:7770#L364)
+#### <a name="Client.WriteStream">func</a> (\*Client) [WriteStream](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=8009:8089#L373)
 ``` go
 func (c *Client) WriteStream(path string, stream io.Reader, _ os.FileMode) error
 ```
@@ -415,9 +422,9 @@ type DigestAuth struct {
 ```
 DigestAuth structure holds our credentials
 
-#### <a name="DigestAuth.Authorize">func</a> (\*DigestAuth) [Authorize](https://github.com/studio-b12/gowebdav/blob/master/digestAuth.go?s=577:646#L36)
+#### <a name="DigestAuth.Authorize">func</a> (\*DigestAuth) [Authorize](https://github.com/studio-b12/gowebdav/blob/master/digestAuth.go?s=577:654#L36)
 ``` go
-func (d *DigestAuth) Authorize(c *Client, method string, path string)
+func (d *DigestAuth) Authorize(req *http.Request, method string, path string)
 ```
 Authorize the current request
 
@@ -507,7 +514,7 @@ func (f File) Sys() interface{}
 ```
 Sys ????
 
-### <a name="NoAuth">type</a> [NoAuth](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=442:490#L32)
+### <a name="NoAuth">type</a> [NoAuth](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=544:592#L36)
 ``` go
 type NoAuth struct {
     // contains filtered or unexported fields
@@ -515,25 +522,25 @@ type NoAuth struct {
 ```
 NoAuth structure holds our credentials
 
-#### <a name="NoAuth.Authorize">func</a> (\*NoAuth) [Authorize](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=785:850#L53)
+#### <a name="NoAuth.Authorize">func</a> (\*NoAuth) [Authorize](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=887:960#L57)
 ``` go
-func (n *NoAuth) Authorize(c *Client, method string, path string)
+func (n *NoAuth) Authorize(req *http.Request, method string, path string)
 ```
 Authorize the current request
 
-#### <a name="NoAuth.Pass">func</a> (\*NoAuth) [Pass](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=703:733#L48)
+#### <a name="NoAuth.Pass">func</a> (\*NoAuth) [Pass](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=805:835#L52)
 ``` go
 func (n *NoAuth) Pass() string
 ```
 Pass returns the current password
 
-#### <a name="NoAuth.Type">func</a> (\*NoAuth) [Type](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=529:559#L38)
+#### <a name="NoAuth.Type">func</a> (\*NoAuth) [Type](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=631:661#L42)
 ``` go
 func (n *NoAuth) Type() string
 ```
 Type identifies the authenticator
 
-#### <a name="NoAuth.User">func</a> (\*NoAuth) [User](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=615:645#L43)
+#### <a name="NoAuth.User">func</a> (\*NoAuth) [User](https://github.com/studio-b12/gowebdav/blob/master/client.go?s=717:747#L47)
 ``` go
 func (n *NoAuth) User() string
 ```

basicAuth.go

@@ -2,6 +2,7 @@ package gowebdav
 
 import (
 	"encoding/base64"
+	"net/http"
 )
 
 // BasicAuth structure holds our credentials
@@ -26,8 +27,8 @@ func (b *BasicAuth) Pass() string {
 }
 
 // Authorize the current request
-func (b *BasicAuth) Authorize(c *Client, method string, path string) {
+func (b *BasicAuth) Authorize(req *http.Request, method string, path string) {
 	a := b.user + ":" + b.pw
 	auth := "Basic " + base64.StdEncoding.EncodeToString([]byte(a))
-	c.headers.Set("Authorization", auth)
+	req.Header.Set("Authorization", auth)
 }

client.go

@@ -3,12 +3,14 @@ package gowebdav
 import (
 	"bytes"
 	"encoding/xml"
+	"fmt"
 	"io"
 	"net/http"
 	"net/url"
 	"os"
 	pathpkg "path"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -16,7 +18,10 @@ import (
 type Client struct {
 	root        string
 	headers     http.Header
+	interceptor func(method string, rq *http.Request)
 	c           *http.Client
+
+	authMutex sync.Mutex
 	auth      Authenticator
 }
 
@@ -25,7 +30,7 @@ type Authenticator interface {
 	Type() string
 	User() string
 	Pass() string
-	Authorize(*Client, string, string)
+	Authorize(*http.Request, string, string)
 }
 
 // NoAuth structure holds our credentials
@@ -50,12 +55,12 @@ func (n *NoAuth) Pass() string {
 }
 
 // Authorize the current request
-func (n *NoAuth) Authorize(c *Client, method string, path string) {
+func (n *NoAuth) Authorize(req *http.Request, method string, path string) {
 }
 
 // NewClient creates a new instance of client
 func NewClient(uri, user, pw string) *Client {
-	return &Client{FixSlash(uri), make(http.Header), &http.Client{}, &NoAuth{user, pw}}
+	return &Client{FixSlash(uri), make(http.Header), nil, &http.Client{}, sync.Mutex{}, &NoAuth{user, pw}}
 }
 
 // SetHeader lets us set arbitrary headers for a given client
@@ -63,6 +68,11 @@ func (c *Client) SetHeader(key, value string) {
 	c.headers.Add(key, value)
 }
 
+// SetInterceptor lets us set an arbitrary interceptor for a given client
+func (c *Client) SetInterceptor(interceptor func(method string, rq *http.Request)) {
+	c.interceptor = interceptor
+}
+
 // SetTimeout exposes the ability to set a time limit for requests
 func (c *Client) SetTimeout(timeout time.Duration) {
 	c.c.Timeout = timeout
@@ -135,7 +145,7 @@ func (c *Client) ReadDir(path string) ([]os.FileInfo, error) {
 
 		if p := getProps(r, "200"); p != nil {
 			f := new(File)
-			if ps, err := url.QueryUnescape(r.Href); err == nil {
+			if ps, err := url.PathUnescape(r.Href); err == nil {
 				f.name = pathpkg.Base(ps)
 			} else {
 				f.name = p.Name
@@ -337,6 +347,43 @@ func (c *Client) ReadStream(path string) (io.ReadCloser, error) {
 	return nil, newPathError("ReadStream", path, rs.StatusCode)
 }
 
+// ReadStreamRange reads the stream representing a subset of bytes for a given path,
+// utilizing HTTP Range Requests if the server supports it.
+// The range is expressed as offset from the start of the file and length, for example
+// offset=10, length=10 will return bytes 10 through 19.
+//
+// If the server does not support partial content requests and returns full content instead,
+// this function will emulate the behavior by skipping `offset` bytes and limiting the result
+// to `length`.
+func (c *Client) ReadStreamRange(path string, offset, length int64) (io.ReadCloser, error) {
+	rs, err := c.req("GET", path, nil, func(r *http.Request) {
+		r.Header.Add("Range", fmt.Sprintf("bytes=%v-%v", offset, offset+length-1))
+	})
+	if err != nil {
+		return nil, newPathErrorErr("ReadStreamRange", path, err)
+	}
+
+	if rs.StatusCode == http.StatusPartialContent {
+		// server supported partial content, return as-is.
+		return rs.Body, nil
+	}
+
+	// server returned success, but did not support partial content, so we have the whole
+	// stream in rs.Body
+	if rs.StatusCode == 200 {
+		// discard first 'offset' bytes.
+		if _, err := io.Copy(io.Discard, io.LimitReader(rs.Body, offset)); err != nil {
+			return nil, newPathErrorErr("ReadStreamRange", path, err)
+		}
+
+		// return a io.ReadCloser that is limited to `length` bytes.
+		return &limitedReadCloser{rs.Body, int(length)}, nil
+	}
+
+	rs.Body.Close()
+	return nil, newPathError("ReadStream", path, rs.StatusCode)
+}
+
 // Write writes data to a given path
 func (c *Client) Write(path string, data []byte, _ os.FileMode) error {
 	s := c.put(path, bytes.NewReader(data))

digestAuth.go

@@ -33,12 +33,12 @@ func (d *DigestAuth) Pass() string {
 }
 
 // Authorize the current request
-func (d *DigestAuth) Authorize(c *Client, method string, path string) {
+func (d *DigestAuth) Authorize(req *http.Request, method string, path string) {
 	d.digestParts["uri"] = path
 	d.digestParts["method"] = method
 	d.digestParts["username"] = d.user
 	d.digestParts["password"] = d.pw
-	c.headers.Set("Authorization", getDigestAuthorization(d.digestParts))
+	req.Header.Set("Authorization", getDigestAuthorization(d.digestParts))
 }
 
 func digestParts(resp *http.Response) map[string]string {

go.mod

@@ -0,0 +1,3 @@
+module github.com/studio-b12/gowebdav
+
+go 1.17

requests.go

@@ -10,58 +10,89 @@ import (
 )
 
 func (c *Client) req(method, path string, body io.Reader, intercept func(*http.Request)) (req *http.Response, err error) {
-	// Tee the body, because if authorization fails we will need to read from it again.
 	var r *http.Request
-	var ba bytes.Buffer
+	var retryBuf io.Reader
-	bb := io.TeeReader(body, &ba)
 
-	if body == nil {
+	if body != nil {
-		r, err = http.NewRequest(method, PathEscape(Join(c.root, path)), nil)
+		// Because Request#Do closes closable streams, Seeker#Seek
+		// will fail on retry because stream is already  closed.
+		// This inhibits the closing of the passed stream on passing
+		// it to the RoundTripper and closes the stream after we
+		// are done with the body content.
+		if cl, ok := body.(io.Closer); ok {
+			body = closeInhibitor{body}
+			defer cl.Close()
+		}
+		// If the authorization fails, we will need to restart reading
+		// from the passed body stream.
+		// When body is seekable, use seek to reset the streams
+		// cursor to the start.
+		// Otherwise, copy the stream into a buffer while uploading
+		// and use the buffers content on retry.
+		if sk, ok := body.(io.Seeker); ok {
+			if _, err = sk.Seek(0, io.SeekStart); err != nil {
+				return
+			}
+			retryBuf = body
 		} else {
-		r, err = http.NewRequest(method, PathEscape(Join(c.root, path)), bb)
+			buff := &bytes.Buffer{}
+			retryBuf = buff
+			body = io.TeeReader(body, buff)
+		}
+		r, err = http.NewRequest(method, PathEscape(Join(c.root, path)), body)
+	} else {
+		r, err = http.NewRequest(method, PathEscape(Join(c.root, path)), nil)
 	}
 
 	if err != nil {
 		return nil, err
 	}
 
-	c.auth.Authorize(c, method, path)
-
 	for k, vals := range c.headers {
 		for _, v := range vals {
 			r.Header.Add(k, v)
 		}
 	}
 
+	// make sure we read 'c.auth' only once since it will be substituted below
+	// and that is unsafe to do when multiple goroutines are running at the same time.
+	c.authMutex.Lock()
+	auth := c.auth
+	c.authMutex.Unlock()
+
+	auth.Authorize(r, method, path)
+
 	if intercept != nil {
 		intercept(r)
 	}
 
+	if c.interceptor != nil {
+		c.interceptor(method, r)
+	}
+
 	rs, err := c.c.Do(r)
 	if err != nil {
 		return nil, err
 	}
 
-	if rs.StatusCode == 401 && c.auth.Type() == "NoAuth" {
+	if rs.StatusCode == 401 && auth.Type() == "NoAuth" {
-
 		wwwAuthenticateHeader := strings.ToLower(rs.Header.Get("Www-Authenticate"))
 
 		if strings.Index(wwwAuthenticateHeader, "digest") > -1 {
-			c.auth = &DigestAuth{c.auth.User(), c.auth.Pass(), digestParts(rs)}
+			c.authMutex.Lock()
-
+			c.auth = &DigestAuth{auth.User(), auth.Pass(), digestParts(rs)}
+			c.authMutex.Unlock()
 		} else if strings.Index(wwwAuthenticateHeader, "basic") > -1 {
-			c.auth = &BasicAuth{c.auth.User(), c.auth.Pass()}
+			c.authMutex.Lock()
-
+			c.auth = &BasicAuth{auth.User(), auth.Pass()}
+			c.authMutex.Unlock()
 		} else {
 			return rs, newPathError("Authorize", c.root, rs.StatusCode)
 		}
 
-		if body == nil {
+		// retryBuf will be nil if body was nil initially so no check
-			return c.req(method, path, nil, intercept)
+		// for body == nil is required here.
-		} else {
+		return c.req(method, path, retryBuf, intercept)
-			return c.req(method, path, &ba, intercept)
-		}
-
 	} else if rs.StatusCode == 401 {
 		return rs, newPathError("Authorize", c.root, rs.StatusCode)
 	}
@@ -131,7 +162,9 @@ func (c *Client) doCopyMove(method string, oldpath string, newpath string, overw
 
 func (c *Client) copymove(method string, oldpath string, newpath string, overwrite bool) error {
 	s, data := c.doCopyMove(method, oldpath, newpath, overwrite)
+	if data != nil {
 		defer data.Close()
+	}
 
 	switch s {
 	case 201, 204:

utils.go

@@ -32,7 +32,7 @@ func newPathErrorErr(op string, path string, err error) error {
 	}
 }
 
-// PathEscape escapes all segemnts of a given path
+// PathEscape escapes all segments of a given path
 func PathEscape(path string) string {
 	s := strings.Split(path, "/")
 	for i, e := range s {
@@ -51,9 +51,10 @@ func FixSlash(s string) string {
 
 // FixSlashes appends and prepends a / if they are missing
 func FixSlashes(s string) string {
-	if s[0] != '/' {
+	if !strings.HasPrefix(s, "/") {
 		s = "/" + s
 	}
+
 	return FixSlash(s)
 }
 
@@ -107,3 +108,39 @@ func parseXML(data io.Reader, resp interface{}, parse func(resp interface{}) err
 	}
 	return nil
 }
+
+// limitedReadCloser wraps a io.ReadCloser and limits the number of bytes that can be read from it.
+type limitedReadCloser struct {
+	rc        io.ReadCloser
+	remaining int
+}
+
+func (l *limitedReadCloser) Read(buf []byte) (int, error) {
+	if l.remaining <= 0 {
+		return 0, io.EOF
+	}
+
+	if len(buf) > l.remaining {
+		buf = buf[0:l.remaining]
+	}
+
+	n, err := l.rc.Read(buf)
+	l.remaining -= n
+
+	return n, err
+}
+
+func (l *limitedReadCloser) Close() error {
+	return l.rc.Close()
+}
+
+// closeInhibitor implements io.Closer and
+// wraps a Reader. When Close() is performed
+// on it, it will simply be silently rejected.
+type closeInhibitor struct {
+	io.Reader
+}
+
+func (ci closeInhibitor) Close() error {
+	return nil
+}

utils_test.go

@@ -43,3 +43,25 @@ func TestEscapeURL(t *testing.T) {
 		t.Error("expected: " + ex + " got: " + u.String())
 	}
 }
+
+func TestFixSlashes(t *testing.T) {
+	expected := "/"
+
+	if got := FixSlashes(""); got != expected {
+		t.Errorf("expected: %q, got: %q", expected, got)
+	}
+
+	expected = "/path/"
+
+	if got := FixSlashes("path"); got != expected {
+		t.Errorf("expected: %q, got: %q", expected, got)
+	}
+
+	if got := FixSlashes("/path"); got != expected {
+		t.Errorf("expected: %q, got: %q", expected, got)
+	}
+
+	if got := FixSlashes("path/"); got != expected {
+		t.Errorf("expected: %q, got: %q", expected, got)
+	}
+}