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: [Select all] [Expand/Collapse]

1.  
2.         int content_length = esp_http_client_get_content_length(client);
3.         ESP_LOGI("avr", "Content length: %d", content_length);
4.         if (content_length < 0)
5.         {
6.             ESP_LOGE("avr", "Failed to get content length");
7.         }
8.         int buffer_size = snprintf(NULL, 0, "%d", content_length);
9.         ESP_LOGI("avr", "Buffer size: %d", buffer_size);
10.  
11.         char *buffer = (char *)malloc(content_length);
12.         if (buffer == NULL)
13.         {
14.             ESP_LOGE("avr", "Failed to allocate memory for buffer");
15.         }
16.         else
17.         {
18.             // Convert the content_length to a string and store it in the buffer
19.             snprintf(buffer, buffer_size + 1, "%d", content_length+1);
20.             ESP_LOGI("avr", "Buffer: %s", buffer);
21.         }
22.  
23.         ESP_LOGI("avr","block 1");
24.         int data_read_total = 0;
25.         while (data_read_total <= content_length)
26.         {
27.             int data_read = esp_http_client_read(client, buffer, content_length);
28.             // int data_read = esp_http_client_read(client, buffer + data_read_total, content_length - data_read_total);
29.             ESP_LOGI("avr", "Data read: %d", data_read);
30.             if (data_read <= 0)
31.             {
32.                 ESP_LOGE("avr", "Failed to read data");
33.                 // break; // Exit the loop if reading fails
34.             }
35.             data_read_total += data_read;
36.         }
37.         buffer[content_length+1] = '\0'; // Null-terminate the buffer
38.         printf("Buffer: %s\n", buffer);
39.  
40.         ESP_LOGI("avr", "Data read: %d", data_read_total);
41.  
42.         free(buffer);

GeSHi © Codebox Plus Extension

The Log

Code: [Select all] [Expand/Collapse]

1. I (69399) avr: HTTP_EVENT_ON_HEADER, key=Server, value=AmazonS3
2. I (69399) avr: HTTP_EVENT_ON_HEADER, key=Content-Length, value=27258
3. I (69889) avr: HTTP_EVENT_ON_FINISH
4. I (69889) avr: Content length: 27258
5. I (69899) avr: Buffer size: 5
6. I (69899) avr: Buffer: 27259
7. I (69899) avr: block 1
8. I (69909) avr: Data read: 0
9. E (69909) avr: Failed to read data
10. Buffer: 27259
11. I (69909) avr: Data read: 0

GeSHi © Codebox Plus Extension

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.

[ESP_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

[ESP_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.)