Using Message GetFile()

[suntong]

Hi @eatmoreapple,

Do you have sample code how to use the func (*Message) GetFile and save it to disk please?

I assume it'll be another FAQ, and I don't know how you derive a file name for that GetFile. Thx!

[eatmoreapple]

请看示例

[eatmoreapple]

bot.MessageHandler = func(msg *openwechat.Message) {
        if msg.IsPicture() {
	        resp, err := msg.GetFile()
	        if err != nil {
		        // handle err here
		        return
	        }
	        defer resp.Body.Close()
	        file, _ := os.Create("test.png")
	        defer file.Close()
	        io.Copy(file, resp.Body)
        
        }
}

[eatmoreapple]

dispatcher := openwechat.NewMessageMatchDispatcher()
dispatcher.OnImage(func(ctx *openwechat.MessageContext) {
        resp, err := ctx.GetFile()
        if err != nil {
	        // handle err here
	        return
        }
        defer resp.Body.Close()
        file, _ := os.Create("test.png")
        defer file.Close()
        io.Copy(file, resp.Body)
})
bot.MessageHandler = openwechat.DispatchMessage(dispatcher)

[eatmoreapple]

filename似乎是拿不到的

[suntong]

filename似乎是拿不到的

OK, no way to derive a file name for that GetFile function, but how about from the message itself? If there is an attachment, say a .pdf file, the file name is carried within the message itself right?

For the unnamed cases, like pictures, or voices, I found from
wechaty/puppet-padlocal@d402f49
that wechaty's practice is to use message-${messageId}-image-${imageNameSuffix}.jpg, just I don't know how to translate those variables into openwechat (yet), and I'm also not sure if the code is correct, as the pictures can be in .jpg or, .png or even .gif format, and it seems that fix only names everything as .jpg.

Thanks

[eatmoreapple]

messageId 可以用 msg.MediaId拿到 ， 具体的文件类型你可以用 http.DetectContentType 这个方法来获取

[suntong]

Thanks a lot!

[eatmoreapple]

有些类型的文件是可以拿到文件名的

resp, err := msg.GetFile()
if err != nil {
fmt.Println(err)
      return
}
defer resp.Body.Close()
fmt.Println(resp.Header.Get("Content-Disposition"))
name := strings.Replace(resp.Header.Get("Content-Disposition"), "attachment; filename=", "", -1)
fmt.Println("name", name)
file, _ := os.Create(name)
defer file.Close()
io.Copy(file, resp.Body)

[suntong]

Love it bro. thx a lot!

[suntong]

I'll look into whether we can wrap up everything inside openwechat, instead of pushing all above to the client side...

[suntong]

collecting how to use http.DetectContentType:

//判断文件协议content-type,0表示xml,1表示
//alter:    ,by:   ,time:  ,#第几次修改
func DecideFile(body []byte) int {
	if http.DetectContentType(body) == "text/xml; charset=utf-8" {
		return 0
	} else if http.DetectContentType(body) == "text/plain; charset=utf-8" {
		return 1
	}
	return 3
}

func IsPDFFile(data []byte) (string, bool) {
	contentType := http.DetectContentType(data)
	if strings.Index(contentType, "application/pdf") != -1 {
		return contentType, true
	}
	return contentType, false
}

and with Headers["Content-Encoding"]

func (r *ResponseDetails) ConvertToResponseDetailsView() views.ResponseDetailsView {
	needsEncoding := false

	// Check headers for gzip
	contentEncodingValues := r.Headers["Content-Encoding"]
	if len(contentEncodingValues) > 0 {
		needsEncoding = true
	} else {
		mimeType := http.DetectContentType([]byte(r.Body))
		needsEncoding = true
		for _, v := range supportedMimeTypes {
			if strings.Contains(mimeType, v) {
				needsEncoding = false
				break
			}
		}
	}

	// If contains gzip, base64 encode
	body := r.Body
	if needsEncoding {
		body = base64.StdEncoding.EncodeToString([]byte(r.Body))
	}

	return views.ResponseDetailsView{Status: r.Status, Body: body, Headers: r.Headers, EncodedBody: needsEncoding}
}

and just in case need to further parse the ContentType, e.g., video/mp4, application/pdf etc --

• https://en.wikipedia.org/wiki/Media_type
• https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types

[eatmoreapple]

Media类型的文件可以直接用msg.FileName拿到文件名称