如何等待下一个POST请求

Question

So what I am trying to do is when the bot receives /uploadPhoto message it waits for the next message and checks if it contains photo. I have tried many different loops including do..while, if, while and other solutions. Now what I think is that I need to call the doPost function from the doPost function. Is there any way to do that?

Tried do..while, if, while and other loops.

function doPost(e){          

var contents = JSON.parse(e.postData.contents);
var id = contents.message.id;
var text = contents.message.text;

case "uploadPhoto":
sendText(id, "Upload a photo...");

        //endText(id, "Upload a photo to be displayed as your product%0AUsage: upload a photo with a caption /uploadPhoto");

        /**const zinutes_id = contents.message.message_id; 
        const zinutes_id_opa = zinutes_id + 1;
        while (true) {
          if (zinutes_id == zinutes_id_opa){
            if ("photo" in contents.message) {
              var photo = contents.message.photo[3].file_id;
              sendText(id, "okay " + photo);
              sendPhoto(id, photo);
              break;
            }
          }
        } */


       /**  if ("photo" in contents.message){
          var photo = contents.message.photo[3].file_id;
          sendText(id, "okay " + photo);
          sendPhoto(id, photo);
        } else {
          sendText(id, "Upload a photo!");
        }*/
        break;

}

1. Text /uploadPhoto to bot
2. Bot texts back "Upload a photo..."
3. Bot waits for the next message and parses its contents

EDIT:

This is what I managed to do:

doPost(e){
  if(contents.message.includes("photo")){
    var fotke = contents.message.photo[3].file_id;
  }


  if (checkLastCommand(id) == "uploadPhoto") {
    if (fotke !== "undefined") {
     // @ts-ignore
     sheet.getRange(searchUser(id),6).setValue(fotke);
     sendText(id, fotke);
     // @ts-ignore
     sheet.getRange(searchUser(id),7).clear();
    } else {
     sendText(id, "this is not a photo");
     // @ts-ignore
     sheet.getRange(searchUser(id),7).clear();
  } else if (firstChar === '/') {
     case "uploadPhoto":
         sendText(id, "Upload a photo...");
         sheet.getRange(searchUser(id), 7).setValue("uploadPhoto");
         break;
  }


}
function checkLastCommand(x) {
  // @ts-ignore
  var z = sheet.getRange(searchUser(x), 7).getValue(); 
  return z;
} 

Now it waits for the photo but for some reason it does not find photo in the POST request. I get "undefined" in the cell and the bot does not respond to photo but instead to /(command) with undefined

Answer 1

So apparently I came up with a solution.

if ("photo" in contents.message) {
   var fotke = contents.message.photo[3].file_id;
} else {
   var text = contents.message.text;
   var firstChar = text.substr(0,1);
}

The program did not want to read file_id of a sent photo because it kept on waiting for a text message.