From 8001defa0c0d92835cd24ebd294ca1d604c780a7 Mon Sep 17 00:00:00 2001
From: demiangetman <demian.getman@gmail.com>
Date: Mon, 30 Sep 2019 18:57:54 +0300
Subject: [PATCH] Add custom file name support for media

---
 api.go      | 31 +++++++++++--------------------
 media.go    |  6 +++---
 sendable.go | 11 +++++++----
 3 files changed, 21 insertions(+), 27 deletions(-)

diff --git a/api.go b/api.go
index 0e472fb..c0c3a81 100644
--- a/api.go
+++ b/api.go
@@ -8,7 +8,6 @@ import (
 	"mime/multipart"
 	"net/http"
 	"os"
-	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -18,7 +17,7 @@ import (
 
 // Raw lets you call any method of Bot API manually.
 func (b *Bot) Raw(method string, payload interface{}) ([]byte, error) {
-	url := b.URL+ "/bot" + b.Token+"/"+ method
+	url := b.URL + "/bot" + b.Token + "/" + method
 
 	var buf bytes.Buffer
 	if err := json.NewEncoder(&buf).Encode(payload); err != nil {
@@ -31,6 +30,7 @@ func (b *Bot) Raw(method string, payload interface{}) ([]byte, error) {
 	}
 	resp.Close = true
 	defer resp.Body.Close()
+
 	json, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		return []byte{}, wrapSystem(err)
@@ -39,16 +39,11 @@ 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
+func addFileToWriter(writer *multipart.Writer,
+	filename, field string, file interface{}) error {
 
+	var reader io.Reader
 	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)
@@ -56,14 +51,12 @@ func addFileToWriter(writer *multipart.Writer, fieldName string, file interface{
 			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)
+		return errors.Errorf("File for field `%v` should be an io.ReadCloser or string", field)
 	}
 
-	part, err = writer.CreateFormFile(fieldName, filename)
+	part, err := writer.CreateFormFile(field, filename)
 	if err != nil {
 		return err
 	}
@@ -72,11 +65,9 @@ func addFileToWriter(writer *multipart.Writer, fieldName string, file interface{
 	return err
 }
 
-func (b *Bot) sendFiles(
-	method string,
-	files map[string]File,
+func (b *Bot) sendFiles(method string, files map[string]File,
 	params map[string]string) ([]byte, error) {
-	// ---
+
 	body := &bytes.Buffer{}
 	rawFiles := map[string]interface{}{}
 
@@ -102,7 +93,7 @@ func (b *Bot) sendFiles(
 	writer := multipart.NewWriter(body)
 
 	for field, file := range rawFiles {
-		if err := addFileToWriter(writer, field, file); err != nil {
+		if err := addFileToWriter(writer, params["file_name"], field, file); err != nil {
 			return nil, wrapSystem(err)
 		}
 	}
@@ -117,7 +108,7 @@ func (b *Bot) sendFiles(
 		return nil, wrapSystem(err)
 	}
 
-	url := b.URL+ "/bot" + b.Token+"/"+ method
+	url := b.URL + "/bot" + b.Token + "/" + method
 	req, err := http.NewRequest("POST", url, body)
 	if err != nil {
 		return nil, wrapSystem(err)
diff --git a/media.go b/media.go
index e7069b2..e336687 100644
--- a/media.go
+++ b/media.go
@@ -83,6 +83,7 @@ type Audio struct {
 	Title     string `json:"title,omitempty"`
 	Performer string `json:"performer,omitempty"`
 	MIME      string `json:"mime_type,omitempty"`
+	FileName  string `json:"file_name,omitempty"`
 }
 
 // MediaFile returns &Audio.File
@@ -95,13 +96,11 @@ func (a *Audio) MediaFile() *File {
 type Document struct {
 	File
 
-	// Original filename as defined by sender.
-	FileName string `json:"file_name"`
-
 	// (Optional)
 	Thumbnail *Photo `json:"thumb,omitempty"`
 	Caption   string `json:"caption,omitempty"`
 	MIME      string `json:"mime_type"`
+	FileName  string `json:"file_name,omitempty"`
 }
 
 // MediaFile returns &Document.File
@@ -123,6 +122,7 @@ type Video struct {
 	Thumbnail         *Photo `json:"thumb,omitempty"`
 	SupportsStreaming bool   `json:"supports_streaming,omitempty"`
 	MIME              string `json:"mime_type,omitempty"`
+	FileName          string `json:"file_name,omitempty"`
 }
 
 // MediaFile returns &Video.File
diff --git a/sendable.go b/sendable.go
index fb1801c..1650367 100644
--- a/sendable.go
+++ b/sendable.go
@@ -49,6 +49,7 @@ func (a *Audio) Send(b *Bot, to Recipient, opt *SendOptions) (*Message, error) {
 		"caption":   a.Caption,
 		"performer": a.Performer,
 		"title":     a.Title,
+		"file_name": a.FileName,
 	}
 
 	if a.Duration != 0 {
@@ -78,8 +79,9 @@ func (a *Audio) Send(b *Bot, to Recipient, opt *SendOptions) (*Message, error) {
 // Send delivers media through bot b to recipient.
 func (d *Document) Send(b *Bot, to Recipient, opt *SendOptions) (*Message, error) {
 	params := map[string]string{
-		"chat_id": to.Recipient(),
-		"caption": d.Caption,
+		"chat_id":   to.Recipient(),
+		"caption":   d.Caption,
+		"file_name": d.FileName,
 	}
 
 	if d.FileSize != 0 {
@@ -120,8 +122,9 @@ func (s *Sticker) Send(b *Bot, to Recipient, opt *SendOptions) (*Message, error)
 // Send delivers media through bot b to recipient.
 func (v *Video) Send(b *Bot, to Recipient, opt *SendOptions) (*Message, error) {
 	params := map[string]string{
-		"chat_id": to.Recipient(),
-		"caption": v.Caption,
+		"chat_id":   to.Recipient(),
+		"caption":   v.Caption,
+		"file_name": v.FileName,
 	}
 
 	if v.Duration != 0 {