Add File creation from io.Reader (fix #137)

Refactor sendFiles to accept Files

api.go

@@ -40,37 +40,78 @@ func (b *Bot) Raw(method string, payload interface{}) ([]byte, error) {
 	return json, nil
 }
 
+func addFileToWriter(writer *multipart.Writer, fieldName string, file interface{}) error {
+	var reader io.Reader
+	var part io.Writer
+	var err error
+	var filename string
+
+	if r, ok := file.(io.Reader); ok {
+		// Telegram requires fields to have a filename, otherwise
+		// `Bad Request: wrong URL host` would be returned
+		filename = "empty"
+		reader = r
+	} else if path, ok := file.(string); ok {
+		f, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+
+		reader = f
+		filename = filepath.Base(path)
+	} else {
+		return errors.Errorf("File for field `%v` should be an io.ReadCloser or string", fieldName)
+	}
+
+	part, err = writer.CreateFormFile(fieldName, filename)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.Copy(part, reader)
+	return err
+}
+
 func (b *Bot) sendFiles(
 	method string,
-	files map[string]string,
+	files map[string]File,
 	params map[string]string) ([]byte, error) {
 	// ---
 	body := &bytes.Buffer{}
-	writer := multipart.NewWriter(body)
+	rawFiles := map[string]interface{}{}
+
+	for name, f := range files {
+		switch {
+		case f.InCloud():
+			params[name] = f.FileID
+		case f.FileURL != "":
+			params[name] = f.FileURL
+		case f.OnDisk():
+			rawFiles[name] = f.FileLocal
+		case f.FileReader != nil:
+			rawFiles[name] = f.FileReader
+		default:
+			return nil, errors.Errorf("sendFiles: File for field %s doesn't exist", name)
+		}
+	}
 
-	for name, path := range files {
-		if err := func() error {
-			file, err := os.Open(path)
-			if err != nil {
-				return err
-			}
-			defer file.Close()
+	if len(rawFiles) == 0 {
+		return b.Raw(method, params)
+	}
 
-			part, err := writer.CreateFormFile(name, filepath.Base(path))
-			if err != nil {
-				return err
-			}
+	writer := multipart.NewWriter(body)
 
-			_, err = io.Copy(part, file)
-			return err
-		} (); err != nil {
+	for field, file := range rawFiles {
+		if err := addFileToWriter(writer, field, file); err != nil {
 			return nil, wrapSystem(err)
 		}
-
 	}
 
 	for field, value := range params {
-		writer.WriteField(field, value)
+		if err := writer.WriteField(field, value); err != nil {
+			return nil, wrapSystem(err)
+		}
 	}
 
 	if err := writer.Close(); err != nil {
@@ -109,20 +150,7 @@ func (b *Bot) sendObject(f *File, what string, params map[string]string) (*Messa
 		what = "video_note"
 	}
 
-	var respJSON []byte
-	var err error
-
-	if f.InCloud() {
-		params[what] = f.FileID
-		respJSON, err = b.Raw(sendWhat, params)
-	} else if f.FileURL != "" {
-		params[what] = f.FileURL
-		respJSON, err = b.Raw(sendWhat, params)
-	} else {
-		respJSON, err = b.sendFiles(sendWhat,
-			map[string]string{what: f.FileLocal}, params)
-	}
-
+	respJSON, err := b.sendFiles(sendWhat, map[string]File{what: *f}, params)
 	if err != nil {
 		return nil, err
 	}

bot.go

@@ -484,7 +484,7 @@ func (b *Bot) Send(to Recipient, what interface{}, options ...interface{}) (*Mes
 // From all existing options, it only supports telebot.Silent.
 func (b *Bot) SendAlbum(to Recipient, a Album, options ...interface{}) ([]Message, error) {
 	media := make([]string, len(a))
-	files := make(map[string]string)
+	files := make(map[string]File)
 
 	for i, x := range a {
 		var mediaRepr string
@@ -496,9 +496,9 @@ func (b *Bot) SendAlbum(to Recipient, a Album, options ...interface{}) ([]Messag
 			mediaRepr = f.FileID
 		} else if f.FileURL != "" {
 			mediaRepr = f.FileURL
-		} else if f.OnDisk() {
+		} else if f.OnDisk() || f.FileReader != nil {
 			mediaRepr = fmt.Sprintf("attach://%d", i)
-			files[strconv.Itoa(i)] = f.FileLocal
+			files[strconv.Itoa(i)] = *f
 		} else {
 			return nil, errors.Errorf(
 				"telebot: album entry #%d doesn't exist anywhere", i)
@@ -939,8 +939,7 @@ func (b *Bot) SetGroupPhoto(chat *Chat, p *Photo) error {
 		"chat_id": chat.Recipient(),
 	}
 
-	respJSON, err := b.sendFiles("setChatPhoto",
-		map[string]string{"photo": p.FileLocal}, params)
+	respJSON, err := b.sendFiles("setChatPhoto", map[string]File{"photo": p.File}, params)
 	if err != nil {
 		return err
 	}

file.go

@@ -1,6 +1,7 @@
 package telebot
 
 import (
+	"io"
 	"os"
 )
 
@@ -17,6 +18,9 @@ type File struct {
 
 	// file on the internet
 	FileURL string `json:"file_url"`
+
+	// file backed with io.Reader
+	FileReader io.Reader `json:"-"`
 }
 
 // FromDisk constructs a new local (on-disk) file object.
@@ -45,6 +49,19 @@ func FromURL(url string) File {
 	return File{FileURL: url}
 }
 
+// FromReader constructs a new file from io.Reader.
+//
+// Note, it returns File, not *File for a very good reason:
+// in telebot, File is pretty much an embeddable struct,
+// so upon uploading media you'll need to set embedded File
+// with something. NewFile() returning File makes it a one-liner.
+//
+//     photo := &tb.Photo{File: tb.FromReader(bytes.NewReader(...))}
+//
+func FromReader(reader io.Reader) File {
+	return File{FileReader: reader}
+}
+
 func (f *File) stealRef(g *File) {
 	if g.OnDisk() {
 		f.FileLocal = g.FileLocal

webhook.go

@@ -48,10 +48,11 @@ type registerResult struct {
 	Description string `json:"description"`
 }
 
-func (h *Webhook) getFiles() map[string]string {
-	m := make(map[string]string)
+func (h *Webhook) getFiles() map[string]File {
+	m := make(map[string]File)
+
 	if h.TLS != nil {
-		m["certificate"] = h.TLS.Cert
+		m["certificate"] = FromDisk(h.TLS.Cert)
 	}
 	// check if it is overwritten by an endpoint
 	if h.Endpoint != nil {
@@ -63,7 +64,7 @@ func (h *Webhook) getFiles() map[string]string {
 			delete(m, "certificate")
 		} else {
 			// someone configured a certificate
-			m["certificate"] = h.Endpoint.Cert
+			m["certificate"] = FromDisk(h.Endpoint.Cert)
 		}
 	}
 	return m