package upload

// Author: Yun
// Version: 2023年6月29日13:45:10
// Description: 向一个URL上传服务器本地文件

import (
	"bytes"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"os"
)

// 表单上传
func FormUpload(url, filePath string) ([]byte, error) {
	// 文件上传
	bodyBuf := bytes.NewBufferString("")
	bodyWriter := multipart.NewWriter(bodyBuf)
	_, err := bodyWriter.CreateFormFile("file", filePath)
	if err != nil {
		return nil, err
	}
	fh, err := os.Open(filePath)
	if err != nil {
		return nil, err
	}
	boundary := bodyWriter.Boundary()
	closeBuf := bytes.NewBufferString(fmt.Sprintf("\r\n--%s--\r\n", boundary))

	requestReader := io.MultiReader(bodyBuf, fh, closeBuf)
	fi, err := fh.Stat()
	if err != nil {
		return nil, err
	}
	req, err := http.NewRequest("POST", url, requestReader)
	if err != nil {
		return nil, err
	}
	req.Header.Add("Content-Type", "multipart/form-data; boundary="+boundary)
	req.ContentLength = fi.Size() + int64(bodyBuf.Len()) + int64(closeBuf.Len())

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer res.Body.Close()
	return io.ReadAll(res.Body)
}