[Question] How can I send the xlxs file as a http response without actually creating the file?

[cescoferraro]

I want to create a GET endpoint where the user downloads the xlxs file created with excelize.
How can I achive such thing without actually creating a FS file. The below works, but its far from ideal.

func GenerateExcel(w http.ResponseWriter, r *http.Request) {
	xlsx := excelize.NewFile()
	xlsx.NewSheet(2, "Sheet2")
	xlsx.SetCellValue("Sheet2", "A2", "Hello world.")
	xlsx.SetCellValue("Sheet1", "B2", 100)
	xlsx.SetActiveSheet(2)
	err := xlsx.SaveAs("./Workbook.xlsx")
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
	data, err := ioutil.ReadFile("./Workbook.xlsx")
	if err != nil {
		log.Fatal(err)
	}
	w.Header().Set("Content-Type", "application/octet-stream")
	w.Header().Set("Content-Disposition", "attachment; filename="+"Workbook.xlsx")
	w.Header().Set("Content-Transfer-Encoding", "binary")
	w.Header().Set("Expires", "0")
	http.ServeContent(w, r, "Workbook.xlxs", time.Now(), bytes.NewReader(data))
}

[xuri]

Thanks for your issue. http.ResponseWriter implements Write([]byte) (int, error), and the function Write provides function to write to an io.Writer.

func GenerateExcel(w http.ResponseWriter, r *http.Request) {
    xlsx := excelize.NewFile()
    xlsx.NewSheet("Sheet2")
    xlsx.SetCellValue("Sheet2", "A2", "Hello world.")
    xlsx.SetCellValue("Sheet1", "B2", 100)
    xlsx.SetActiveSheet(2)
    err := xlsx.SaveAs("./Workbook.xlsx")
    if err != nil {
        fmt.Println(err)
        return
    }
    w.Header().Set("Content-Type", "application/octet-stream")
    w.Header().Set("Content-Disposition", "attachment; filename="+"Workbook.xlsx")
    w.Header().Set("Content-Transfer-Encoding", "binary")
    w.Header().Set("Expires", "0")
    xlsx.Write(w)
}

[cescoferraro]

@xuri Thanks! I off work today. Will try this asap. Do I still need to xlxs.SaveAs?

[cescoferraro]

@xuri yeap that did it! There is no need to SaveAs, just Write(w) works. How about?

func (f *File) SendThroughHTTP(w http.ResponseWriter, filename string){
		w.Header().Set("Content-Type", "application/octet-stream")
		w.Header().Set("Content-Disposition", "attachment; filename="+filename+".xlsx")
		w.Header().Set("Content-Transfer-Encoding", "binary")
        f.Write(w)
}

[dolmen]

@cescoferraro That would add an unnecessary dependency of excelize on net/http.

[sourabhkheterpal]

@cescoferraro : as you mentioned in above comment, we can achieve it without calling saveAs function.

I have executed the above code after removing saveAs function. When i did HTTP request it give me Response in Binary format.

func GenerateExcel(w http.ResponseWriter, r *http.Request) {
    xlsx := excelize.NewFile()
    xlsx.NewSheet("Sheet2")
    xlsx.SetCellValue("Sheet2", "A2", "Hello world.")
    xlsx.SetCellValue("Sheet1", "B2", 100)
    xlsx.SetActiveSheet(2)
  
    w.Header().Set("Content-Type", "application/octet-stream")
    w.Header().Set("Content-Disposition", "attachment; filename="+"Workbook.xlsx")
    w.Header().Set("Content-Transfer-Encoding", "binary")
    w.Header().Set("Expires", "0")
    xlsx.Write(w)
}

How can i save it as file with xlsx extension after making http request?

Please let me know if you need more detail.

[pulpfree]

When saving the file directly to disk with xlsx.SaveAs("./Workbook.xlsx") the file opens properly and all is good. However when writing to http.ResponseWriter as shown in @sourabhkheterpal's example, the file, when saved, isn't recognized and I cannot open it with an xlsx compatible application like Numbers.

Now I'm using the github.com/awslabs/aws-lambda-go-api-proxy/handlerfunc library which uses the base64.StdEncoding.EncodeToString method to encode the body. Am I right in assuming this encoding is the problem?

[zsr228]

as you mentioned @xuri , use write function return file instream, the xlsx file downloaded , opening it isn't recognized and need to repair. can you tell me the problem?

[khawerrind]

Guys any solution for it?

[xuri]

@cescoferraro, @pulpfree, @zsspj12, @khawerrind The execlize now support to get bytes.Buffer from the saved file by WriteToBuffer(), and we can get io.Reader like this:

buf, _ := xlsx.WriteToBuffer()
strings.NewReader(buf.String())

Reference issue #127.