ESP8266 Community Forum

- Wed May 31, 2023 4:53 pm #96501 Hi to all, Im trying to understand the code used in the WebUpdate sketch (Im using arduino 1.18.19). In that code you will find this lines:

Code: Select allserver.on("/update", HTTP_POST, []() {
      server.sendHeader("Connection", "close");
      server.send(200, "text/plain", (Update.hasError()) ? "FAIL" : "OK");
      ESP.restart();
    }, []() {
      HTTPUpload& upload = server.upload();
      if (upload.status == UPLOAD_FILE_START) {
        Serial.setDebugOutput(true);
        WiFiUDP::stopAll();
        Serial.printf("Update: %s\n", upload.filename.c_str());
        uint32_t maxSketchSpace = (ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000;
        if (!Update.begin(maxSketchSpace)) { //start with max available size
          Update.printError(Serial);
        }
      } else if (upload.status == UPLOAD_FILE_WRITE) {
        if (Update.write(upload.buf, upload.currentSize) != upload.currentSize) {
          Update.printError(Serial);
        }
      } else if (upload.status == UPLOAD_FILE_END) {
        if (Update.end(true)) { //true to set the size to the current progress
          Serial.printf("Update Success: %u\nRebooting...\n", upload.totalSize);
        } else {
          Update.printError(Serial);
        }
        Serial.setDebugOutput(false);
      }
      yield();
    });


I don't understand what this flags needs to be checked :

Code: Select allupload.status == UPLOAD_FILE_START
upload.status == UPLOAD_FILE_WRITE
upload.status == UPLOAD_FILE_END


I don't understand what those lines do in the code. Why do I need to check those flags? If I upload the file the data will be stored in server.upload(). Why do I need to ask about those flags?
I guess this is more a question regarding how a server works and not related to the program, but tried to find information about this and I can't find 'till now anything similar to what I found in this code.
If any of you can point to some reference, will be appreciated.
I guess I just want to understand each part of the code to get the big picture on how this code woks and not just cut and paste the code.
Thanks
Gastón

- Thu Jun 01, 2023 2:39 am #96504 Data transfer is done is smaller pieces (which is common to all TCP/IP traffic, not only on an ESP/Arduino):

1. Start data transfer(UPLOAD_FILE_START)
2. Send x Bytes of data (UPLOAD_FILE_WRITE)
3. Repeat step 2 until all bytes are sent
4. Close data transfer (UPLOAD_FILE_END)

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.

- Thu Jun 01, 2023 5:10 am #96506 Thanks for your response!! Thanks