Double checking a bulk upload csv url

Hello, I am currently trying to get some data uploaded to ThingSpeak via an ESP32 with an SD card attached, using the bulk update csv API.

I have tried to get it correct to the example on this page https://uk.mathworks.com/help/thingspeak/bulkwritecsvdata.html

My url currently looks like this:

http://api.thingspeak.com/channels/2288289/bulk_update.csv?write_api_key=7DN763HM8PFKF4R0&time_format=absolute&updates=2000-00-00T00%3A0%3A0+0000%2C0%2C0%2C0%2C001

%2C%2C%2C%2C%2C0.000000%2C0.000000%2C%2C

(In this example all the values are zero because I am currently just testing but even with fake data it is not working)

The error is due to bad syntax

Please can someone help? Thanks in advance

[Christopher Stapels]

Are you using a GET request? Bulk update need a POST.

[Saul]

Full code here:

void uploadToThingSpeak() {

display.fillScreen(BLACK);
display.setCursor(0, 0);
display.setTextColor(CYAN);
display.print("Uploading data...");


while (dataFile.available()) {
    char line[100]; 
    readLine(dataFile).toCharArray(line, 100);
    Serial.println(line);
    Serial.println();
    
    char* arrline[12];
    // printcsvFields(line);
    getcsvFields(line, arrline);
    // for (int j=0; j<7; j++) {
        //   Serial.println(arrline[j]);
        // }
        // Serial.println();
        // std::string test = std::string("twenty") + arrline[1];
        // Serial.println(test.c_str());
        // Serial.println();
        //Create an HTTP client
        HTTPClient http;
        char key[] = {"/bulk_update.csv?write_api_key="};
        char time[] = {"&time_format=absolute&updates="};
        char comma[] = {"%2C"};
        //Create the ThingSpeak URL
        std::string url = std::string("http://api.thingspeak.com/channels/") + SECRET_CH_ID + key + SECRET_WRITE_APIKEY + time + arrline[0] + comma + arrline[1] + comma + arrline[2] + comma + arrline[3] + comma + arrline[6] + comma + comma + comma + comma + comma + arrline[4] + comma + arrline[5] + comma + comma;
        Serial.println(url.c_str());
        Serial.println();
        
        // Send the POST request
        http.begin(url.c_str());
        int httpCode = http.GET();
        if (httpCode == HTTP_CODE_OK) {
            Serial.println("Uploaded successfully");
            Serial.println();
            } else {
                Serial.println("Failed to upload");
                Serial.println();
                }
            http.end();
            
            // // can write any/all fields from lineord here, fields 8, 9 for this demo
                // ThingSpeak.setField(1, arrline[0]);
                // ThingSpeak.setField(2, arrline[1]);
                // ThingSpeak.setField(3, arrline[2]);
                // ThingSpeak.setField(4, arrline[3]);
                // ThingSpeak.setField(5, arrline[4]);
                // ThingSpeak.setField(6, arrline[5]);
                // ThingSpeak.setField(7, arrline[6]);
                // ThingSpeak.setField(8, arrline[7]);
                
                // // write to the ThingSpeak channel
                // int x = ThingSpeak.writeFields(SECRET_CH_ID, SECRET_WRITE_APIKEY);
                // if(x == 200) {
                    //   Serial.println("Channel update successful.");
                    //   Serial.println();
                    //   //short delay - test the limits allowed for this and number of lineords looped
                    //   // tests Feb 2022, 12s fails after first write, 15s works OK
                    //   delay(15000);
                    // }
                    // else {
                        //   Serial.println("Problem updating channel. HTTP error code " + String(x));
                        //   Serial.println();
                        //   return;
                    // }
                    }
                    display.setCursor(0, 3);
                    display.print("Upload Complete!");
                    delay(3000);
                    }

[Saul]

I am only using four data fields because the timestamp is separate in this case, same as the latitude/longitude (please correct me if I'm wrong).

I am not sure how to then access the timestamp and lat/lon for analysis - if someone could point me in the right direction for that as well it would be great.

[Christopher Stapels]

Have a look at this example to see a better way to generate a POST and do bulk updates on an ESP32.

I'm not sure what you mean about "using four data fields because the timestamp is separate in this case"

You can definitely post to all eight fields in a bulk update, have a look at the examples on the documentation page.

The ThingSpeak library parts in your code really threw me until I noticed they were all commented out. I suggest you clean up the code you post in a question to get best results if you get a chance. (remove sections you arent using)

Regarding the lat/lon question are you trying to understand how to read the lat lon data back from ThingSpeak? If so see the Read Data api, and condired the parameter 'location=true'

[Saul]

Thank you Christopher! I will look at this when I get a chance next week. Have a lovely weekend