Publicar en Linkedin desde Gmail

const author='NQxxxxxxx';  // Tu userId
const accessToken='AQUg-xxxxxxx'; // El accessToken, una cadena superlarga

const url = 'https://api.linkedin.com'
const label = 'Publicar en Linkedin';
const lifecycleState='PUBLISHED';
const visibility = 'PUBLIC';

function checkEmail() {
    try{
        unreadEmail()
    }catch(error){
      Logger.log(error)
    }
}

function unreadEmail() {
  const ts = GmailApp.search(`subject:${label} is:unread to:me from:me`);
  ts.forEach(t => {
    t.getMessages().forEach(m => {
      processEmail(m);
      m.markRead();
    });
  });
}

function processEmail(m) {

  const images = m.getAttachments();
  let medias = [];
  if( images ){
    images.forEach( (a)=>{ medias.push(uploadImage(a))} )
  }

  const body=html2text(m.getBody())

  var payload = {
    "author": "urn:li:person:"+author,
    "lifecycleState":lifecycleState,
    "visibility": {
      "com.linkedin.ugc.MemberNetworkVisibility":visibility
    },
    "specificContent":{
      "com.linkedin.ugc.ShareContent":{
        "shareCommentary":{
          "text": body
        },
        "shareMediaCategory" : medias.length ? "IMAGE" : "NONE",
        "media":medias
      }
    }
  };

  var options = {
    'method' : 'post',
    'contentType': 'application/json',
    'payload': JSON.stringify(payload),
    'headers': {
      'Authorization': `Bearer ${accessToken}`,
      'X-Restli-Protocol-Version': '2.0.0'
    }
  };
  Logger.log(options)
  const resp = UrlFetchApp.fetch(`${url}/v2/ugcPosts`, options);
  Logger.log(resp)
}

function html2text(body){
  const ret = `${body}`.replaceAll('<br>','\n')
          .replaceAll('</div>','\n')
          .replaceAll(/<[^>]+>/g, '')
          .replaceAll("&quot;",'"')
          .replaceAll("&quota",'á')
          .replaceAll("&quote",'é')
          .replaceAll("&quoti",'í')
          .replaceAll("&quoto",'ó')
          .replaceAll("&quotu",'ú')
  return ret;
}

function uploadImage(attachment) {

  var imgPayload = {
    "registerUploadRequest": {
        "recipes": [
            "urn:li:digitalmediaRecipe:feedshare-image"
        ],
        "owner": "urn:li:person:"+author,
        "serviceRelationships": [
            {
                "relationshipType": "OWNER",
                "identifier": "urn:li:userGeneratedContent"
            }
        ],
        "supportedUploadMechanism":[
          "SYNCHRONOUS_UPLOAD"
        ]
    }
  }
  var imgOptions = {
    'method' : 'post',
    'contentType': 'application/json',
    'payload': JSON.stringify(imgPayload),
    'headers': {
      'Authorization': `Bearer ${accessToken}`,
      'X-Restli-Protocol-Version': '2.0.0'
    }
  };
  const resp = UrlFetchApp.fetch(`${url}/v2/assets?action=registerUpload`, imgOptions);
  Logger.log(resp);

  const json = JSON.parse(resp)
  const uploadUrl = json.value.uploadMechanism["com.linkedin.digitalmedia.uploading.MediaUploadHttpRequest"].uploadUrl;
  const mediaId = json.value.asset;

  var optionsImage = {
    method : "put",
    payload : attachment.copyBlob(),
    headers:{
      'Authorization': `Bearer ${accessToken}`,
      'Accept':'*/*'
    }
  };
  Logger.log(uploadUrl)
  var respImage = UrlFetchApp.fetch(uploadUrl, optionsImage).getContentText();
  Logger.log(respImage)


  return {
    status:'READY',
    media: mediaId
  }

}