nmdc-telegramfrontend/contented.go

174 lines
5.2 KiB
Go

package main
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"io"
"log"
"mime"
"mime/multipart"
"net/http"
"net/textproto"
"time"
telegram "github.com/go-telegram-bot-api/telegram-bot-api"
filetype "gopkg.in/h2non/filetype.v1"
)
func (this *NTFServer) ContentedEnabled() bool {
return this.contentedMaxBytes > 0
}
func (this *NTFServer) ContentedUploadFromSync(main *telegram.File, thumbs *[]telegram.PhotoSize) (string, error) {
// If file fits under size limit, take it
if int64(main.FileSize) < this.contentedMaxBytes {
return this.ContentedUploadSync(main.FileID, int64(main.FileSize))
}
// Otherwise, we'll settle for the highest-res thumbnail we can take
if thumbs == nil || len(*thumbs) == 0 {
return "", errors.New("The file was too large for the image host server (and no smaller thumbnail is available)")
}
//
bestKnownIdx := -1
bestKnownMpx := int64(-1)
for idx, img := range *thumbs {
if int64(img.FileSize) > this.contentedMaxBytes {
continue // no good
}
// Highest total pixel count
mpx := int64(img.Width) * int64(img.Height)
if mpx > bestKnownMpx {
bestKnownIdx = idx
bestKnownMpx = mpx
}
}
if bestKnownIdx == -1 {
return "", errors.New("The file was too large for the image host server (and no smaller thumbnail is available)")
}
return this.ContentedUploadSync((*thumbs)[bestKnownIdx].FileID, int64((*thumbs)[bestKnownIdx].FileSize))
}
func (this *NTFServer) ContentedUploadSync(fileId string, expectSizeBytes int64) (string, error) {
// If file fits under size limit, take it
if expectSizeBytes > this.contentedMaxBytes {
return "", errors.New("The file was too large for the image host server (and no smaller thumbnail is available)")
}
// Prepare to download the file from telegram
url, err := this.bot.GetFileDirectURL(fileId)
if err != nil {
return "", fmt.Errorf("TelegramGetFileDirectURL: %s", err.Error())
}
if this.verbose {
log.Printf("Downloading telegram file %s", url)
}
resp, err := http.Get(url)
if err != nil {
return "", fmt.Errorf("HttpGet: %s", err.Error())
}
defer resp.Body.Close()
if this.verbose {
log.Printf("Downloaded telegram file response headers: %#v\n", resp.Header)
}
// Download
fileBuff := bytes.Buffer{}
_, err = io.CopyN(&fileBuff, resp.Body, expectSizeBytes) // CopyN asserts either err!=nil, or copiedBytes == expectSizeBytes. So we're safe
if err != nil {
return "", fmt.Errorf("CopyN: %s", err.Error())
}
// Determine a suitable pseudo-filename from the telegram content-type
// Telegram seems to always supply application/octet-stream
// If Telegram gives us something else, trust it; but otherwise, we can probably do better
fileName := fmt.Sprintf("telegram-upload-%d", time.Now().Unix())
fileContentType := resp.Header.Get("Content-Type") // is it blank? who knows?
if fileContentType == `application/octet-stream` || fileContentType == `` {
// Autodetect something better, if possible
if contentTypeMatches, err := filetype.Match(fileBuff.Bytes()); err == nil {
fileContentType = contentTypeMatches.MIME.Value
fileName += `.` + contentTypeMatches.Extension // no leading period
}
} else {
// We were supplied a good mime type, just need to find a good file extension
if fileExts, err := mime.ExtensionsByType(fileContentType); err == nil && len(fileExts) > 0 {
fileName += fileExts[0] // Just pick the first one. They all contain a leading period
}
}
// Contented uploads are in multipart mime format
uploadBody := bytes.Buffer{}
formValues := multipart.NewWriter(&uploadBody)
// Adapted from (mime/multipart)Writer.CreateFormFile to support a custom interior content type
multipartFileHeader := make(textproto.MIMEHeader)
multipartFileHeader.Set("Content-Disposition", fmt.Sprintf(`form-data; name="%s"; filename="%s"`, "f", fileName))
multipartFileHeader.Set("Content-Type", fileContentType)
filePart, err := formValues.CreatePart(multipartFileHeader)
if err != nil {
return "", err
}
_, err = io.CopyN(filePart, bytes.NewReader(fileBuff.Bytes()), expectSizeBytes)
if err != nil {
return "", err
}
// Upload
err = formValues.Close()
if err != nil {
return "", fmt.Errorf("Close: %s", err.Error())
}
req, err := http.NewRequest("POST", this.config.ContentedURL+"upload", &uploadBody)
if err != nil {
return "", err
}
req.Header.Set("Content-Type", formValues.FormDataContentType()) // it's "multipart/form-data; boundary=xxxx" with a magic string
uploadResp, err := http.DefaultClient.Do(req)
if err != nil {
return "", fmt.Errorf("Upload failed: %s", err.Error())
}
defer uploadResp.Body.Close()
// Read back the response from contented
// Should be a 200 error code, JSON content type, array of strings of shortcodes to the uploaded file(s)
if uploadResp.StatusCode != 200 {
return "", fmt.Errorf("Unexpected HTTP %d response back from file hosting server", uploadResp.StatusCode)
}
shortCodes := make([]string, 0, 1)
err = json.NewDecoder(uploadResp.Body).Decode(&shortCodes)
if err != nil {
return "", fmt.Errorf("Decoding response from file hosting server: %s", err.Error())
}
if len(shortCodes) != 1 || len(shortCodes[0]) == 0 {
return "", errors.New("Unexpected blank response back from file hosting server")
}
// DONE
return this.config.ContentedURL + "p/" + shortCodes[0], nil
}