Download from S3 bucket

[Dharanesh]

I've already written the esp self OTA code, and it functions well.
I now have to read and download a different file from Amazon S3 in order to flash it onto an AVR MCU that is attached to a UART. The locations of both firmwares are the same.

I am able to make the connection. I can't read this, however.

The code

Code: Untitled.cpp Select all

 

        int content_length = esp_http_client_get_content_length(client);

        ESP_LOGI("avr", "Content length: %d", content_length);

        if (content_length < 0)

        {

            ESP_LOGE("avr", "Failed to get content length");

        }

        int buffer_size = snprintf(NULL, 0, "%d", content_length);

        ESP_LOGI("avr", "Buffer size: %d", buffer_size);



        char *buffer = (char *)malloc(content_length);

        if (buffer == NULL)

        {

            ESP_LOGE("avr", "Failed to allocate memory for buffer");

        }

        else

        {

            // Convert the content_length to a string and store it in the buffer

            snprintf(buffer, buffer_size + 1, "%d", content_length+1);

            ESP_LOGI("avr", "Buffer: %s", buffer);

        }



        ESP_LOGI("avr","block 1");

        int data_read_total = 0;

        while (data_read_total <= content_length)

        {

            int data_read = esp_http_client_read(client, buffer, content_length);

            // int data_read = esp_http_client_read(client, buffer + data_read_total, content_length - data_read_total);

            ESP_LOGI("avr", "Data read: %d", data_read);

            if (data_read <= 0)

            {

                ESP_LOGE("avr", "Failed to read data");

                // break; // Exit the loop if reading fails

            }

            data_read_total += data_read;

        }

        buffer[content_length+1] = '\0'; // Null-terminate the buffer

        printf("Buffer: %s\n", buffer);



        ESP_LOGI("avr", "Data read: %d", data_read_total);



        free(buffer);

The Log

Code: Untitled.cpp Select all

I (69399) avr: HTTP_EVENT_ON_HEADER, key=Server, value=AmazonS3

I (69399) avr: HTTP_EVENT_ON_HEADER, key=Content-Length, value=27258

I (69889) avr: HTTP_EVENT_ON_FINISH

I (69889) avr: Content length: 27258

I (69899) avr: Buffer size: 5

I (69899) avr: Buffer: 27259

I (69899) avr: block 1

I (69909) avr: Data read: 0

E (69909) avr: Failed to read data

Buffer: 27259

I (69909) avr: Data read: 0

I have to read the bin file and load it into Spiff. After that, I have to read the contents of Spiff and transmit it to AVR, page by page.

[Sprite]

Code: Select all

int buffer_size = snprintf(NULL, 0, "%d", content_length);

Can you explain this line?

[Dharanesh]

Code: Select all

int buffer_size = snprintf(NULL, 0, "%d", content_length);

Can you explain this line?

While the buffer's argument is char in esp_http_client_read(esp_http_client_handle_t client, char *buffer, int len), the content_length is assigned to the buffer with that size since esp_http_client_get_content_length(client); returns int.


based on the content_length while allocating the buffer

[Sprite]

While the buffer's argument is char in esp_http_client_read(esp_http_client_handle_t client, char *buffer, int len), the content_length is assigned to the buffer with that size since esp_http_client_get_content_length(client); returns int.

based on the content_length while allocating the buffer

You're not doing an assignment, you're doing a snprintf. Why? (Also, you need to be clearer. 'is assigned to the buffer with that size' doesn't describe anything your C code does.)