Simple blogging system written in Go https://goblog.app
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

199 lines
4.6 KiB

package main
import (
"bytes"
"context"
"encoding/base64"
"errors"
"html"
"io"
"log"
"net/url"
"path"
"strings"
"github.com/carlmjohnson/requests"
)
const ttsParameter = "tts"
func (a *goBlog) initTTS() {
if !a.ttsEnabled() {
return
}
createOrUpdate := func(p *post) {
// Automatically create audio for published section posts only
if !p.isPublishedSectionPost() {
return
}
// Check if there is already a tts audio file
if p.firstParameter(ttsParameter) != "" {
return
}
// Create TTS audio
err := a.createPostTTSAudio(p)
if err != nil {
log.Printf("create post audio for %s failed: %v", p.Path, err)
}
}
a.pPostHooks = append(a.pPostHooks, createOrUpdate)
a.pUpdateHooks = append(a.pUpdateHooks, createOrUpdate)
a.pDeleteHooks = append(a.pDeleteHooks, func(p *post) {
// Try to delete the audio file
_ = a.deletePostTTSAudio(p)
})
}
func (a *goBlog) ttsEnabled() bool {
tts := a.cfg.TTS
// Requires media storage as well
return tts != nil && tts.Enabled && tts.GoogleAPIKey != "" && a.mediaStorageEnabled()
}
func (a *goBlog) createPostTTSAudio(p *post) error {
// Get required values
lang := a.cfg.Blogs[p.Blog].Lang
if lang == "" {
lang = "en"
}
// Build SSML
var ssml strings.Builder
ssml.WriteString("<speak>")
ssml.WriteString(html.EscapeString(a.renderMdTitle(p.Title())))
ssml.WriteString("<break time=\"1s\"/>")
ssml.WriteString(html.EscapeString(cleanHTMLText(string(a.postHtml(p, false)))))
ssml.WriteString("</speak>")
// Generate audio
var audioBuffer bytes.Buffer
err := a.createTTSAudio(lang, ssml.String(), &audioBuffer)
if err != nil {
return err
}
// Save audio
audioReader := bytes.NewReader(audioBuffer.Bytes())
fileHash, err := getSHA256(audioReader)
if err != nil {
return err
}
loc, err := a.saveMediaFile(fileHash+".mp3", audioReader)
if err != nil {
return err
}
if loc == "" {
return errors.New("no media location for tts audio")
}
if old := p.firstParameter(ttsParameter); old != "" && old != loc {
// Already has tts audio, but with different location
// Try to delete the old audio file
_ = a.deletePostTTSAudio(p)
}
// Set post parameter
err = a.db.replacePostParam(p.Path, ttsParameter, []string{loc})
if err != nil {
return err
}
// Purge cache
a.cache.purge()
return nil
}
// Tries to delete the tts audio file, but doesn't remove the post parameter
func (a *goBlog) deletePostTTSAudio(p *post) bool {
// Check if post has tts audio
audio := p.firstParameter(ttsParameter)
if audio == "" {
return false
}
// Get filename and check if file is from the configured media storage
fileUrl, err := url.Parse(audio)
if err != nil {
// Failed to parse audio url
log.Println("failed to parse audio url:", err)
return false
}
fileName := path.Base(fileUrl.Path)
if a.getFullAddress(a.mediaFileLocation(fileName)) != audio {
// File is not from the configured media storage
return false
}
// Try to delete the audio file
err = a.deleteMediaFile(fileName)
if err != nil {
log.Println("failed to delete audio file:", err)
return false
}
return true
}
func (a *goBlog) createTTSAudio(lang, ssml string, w io.Writer) error {
// Check if Google Cloud TTS is enabled
gctts := a.cfg.TTS
if !gctts.Enabled || gctts.GoogleAPIKey == "" {
return errors.New("missing config for Google Cloud TTS")
}
// Check parameters
if lang == "" {
return errors.New("language not provided")
}
if ssml == "" {
return errors.New("empty text")
}
if w == nil {
return errors.New("writer not provided")
}
// Check max length
// TODO: Support longer texts by splitting into multiple requests
// if len(ssml) > 5000 {
// return errors.New("text is too long")
// }
// Create request body
body := map[string]interface{}{
"audioConfig": map[string]interface{}{
"audioEncoding": "MP3",
},
"input": map[string]interface{}{
"ssml": ssml,
},
"voice": map[string]interface{}{
"languageCode": lang,
},
}
// Do request
var response map[string]interface{}
err := requests.
URL("https://texttospeech.googleapis.com/v1beta1/text:synthesize").
Param("key", gctts.GoogleAPIKey).
Client(a.httpClient).
UserAgent(appUserAgent).
Post().
BodyJSON(body).
ToJSON(&response).
Fetch(context.Background())
if err != nil {
return errors.New("tts request failed: " + err.Error())
}
// Decode response
if encoded, ok := response["audioContent"]; ok {
if encodedStr, ok := encoded.(string); ok {
if audio, err := base64.StdEncoding.DecodeString(encodedStr); err == nil {
_, err := w.Write(audio)
return err
} else {
return err
}
}
}
return errors.New("no audio content")
}