gobackend-qingma/service/file_service.go

package service

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"mime/multipart"
	"net/http"
	"strings"
)

type FileService struct{}
type innerFileMeta struct {
	Count     int    `json:"count"`
	Fid       string `json:"fid"`
	Url       string `json:"url"`
	PublicUrl string `json:"publicUrl"`
}

const FILE_SERVER_URL = "http://localhost:9333"

func (fsrv *FileService) Upload(fileReader io.Reader) (interface{}, error) {
	res, err := http.Post(FILE_SERVER_URL+"/dir/assign", "application/x-www-form-urlencoded", nil)
	if err != nil {
		return "", err
	}
	defer res.Body.Close()
	buf, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return "", err
	}
	var metaf = &innerFileMeta{}
	err = json.Unmarshal(buf, metaf)
	if err != nil {
		return "", err
	}
	var purl = "http://" + metaf.PublicUrl + "/" + metaf.Fid
	request, err := newfileUploadRequest(purl, nil, "file", "test.jpg", fileReader)
	//rbytes, _ := httputil.DumpRequest(request, true)
	if err != nil {
		return "", err
	}
	client := &http.Client{}
	resp, err := client.Do(request)
	if err != nil {
		return "", err
	} else {
		//body := &bytes.Buffer{}
		//_, err := body.ReadFrom(resp.Body)
		resp.Body.Close()
		return metaf, nil
	}

}

type fileLocation struct {
	PublicUrl string `json:"publicUrl"`
	Url       string `json:"url"`
}

type fileLookupResponse struct {
	Locations []fileLocation `json:"locations"`
}

func (fsrv *FileService) GetImage(fid string) (interface{}, error) {
	fidParts := strings.Split(fid, ",")
	if len(fidParts) != 2 {
		return nil, errors.New("wrong file id")
	}
	resp, err := http.Get(fmt.Sprintf("%s/dir/lookup?volumeId=%s", FILE_SERVER_URL, fidParts[0]))
	if err != nil {
		return nil, err
	}
	je := json.NewDecoder(resp.Body)
	fr := fileLookupResponse{}
	err = je.Decode(&fr)
	resp.Body.Close()
	if err != nil {
		return nil, err
	}
	return fmt.Sprintf("http://%s/%s", fr.Locations[0].PublicUrl, fid), nil
	//fr.Locations[0].PublicUrl
}

// Creates a new file upload http request with optional extra params
func newfileUploadRequest(uri string, params map[string]string, paramName, fileName string, fileReader io.Reader) (*http.Request, error) {
	body := &bytes.Buffer{}
	writer := multipart.NewWriter(body)
	part, err := writer.CreateFormFile(paramName, fileName)
	if err != nil {
		return nil, err
	}
	_, err = io.Copy(part, fileReader)
	if err != nil {
		return nil, err
	}

	if params != nil {
		for key, val := range params {
			_ = writer.WriteField(key, val)
		}
	}
	err = writer.Close()
	if err != nil {
		return nil, err
	}

	req, err := http.NewRequest("POST", uri, body)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", writer.FormDataContentType())
	return req, nil
}