How to Fix \'Bad Request: there is no photo in the request\' Error When Uploading Files to Telegram Bots in Go?

Uploading Files with POST Requests in Go for Telegram

In Go, you can upload files to Telegram bots using the http package. However, you encountered an error: "Bad Request: there is no photo in the request." This indicates that the file data is not included correctly in your request.

To resolve this issue, the following code can be used:

<code class="go">import (
    "bytes"
    "io"
    "mime/multipart"
    "net/http"
    "path/filepath"
)

// content is a struct which contains a file's name, its type and its data.
type content struct {
    fname string
    ftype string
    fdata []byte
}

func sendPostRequest(url string, files ...content) ([]byte, error) {
    var (
        buf = new(bytes.Buffer)
        w   = multipart.NewWriter(buf)
    )

    for _, f := range files {
        part, err := w.CreateFormFile(f.ftype, filepath.Base(f.fname))
        if err != nil {
            return []byte{}, err
        }

        _, err = part.Write(f.fdata)
        if err != nil {
            return []byte{}, err
        }
    }

    err := w.Close()
    if err != nil {
        return []byte{}, err
    }

    req, err := http.NewRequest("POST", url, buf)
    if err != nil {
        return []byte{}, err
    }
    req.Header.Add("Content-Type", w.FormDataContentType())

    client := &http.Client{}
    res, err := client.Do(req)
    if err != nil {
        return []byte{}, err
    }
    defer res.Body.Close()

    cnt, err := io.ReadAll(res.Body)
    if err != nil {
        return []byte{}, err
    }
    return cnt, nil
}</code>

This code uses the multipart package to create a multipart/form-data request containing the file data. The content struct represents a file with its name, type, and data. The sendPostRequest function takes a URL and a variable number of content objects, constructs the multipart request, sends it, and returns the response.

In your case, you can use this code to upload a file to a Telegram bot API:

<code class="go">func SendPostRequest(url string, filename string) []byte {
    file, err := os.Open(filename)
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    stat, err := file.Stat()
    if err != nil {
        log.Fatal(err)
    }

    fileData, err := ioutil.ReadAll(file)
    if err != nil {
        log.Fatal(err)
    }

    return sendPostRequest(url,
        content{filename, "photo/jpeg", fileData},
    )
}</code>

This code opens the file, reads its contents into a byte slice, and uses sendPostRequest to send the file to the API.

The above is the detailed content of How to Fix \'Bad Request: there is no photo in the request\' Error When Uploading Files to Telegram Bots in Go?. For more information, please follow other related articles on the PHP Chinese website!