How to post a photo to Telegram api?

[hououin_kyouma]

Hello, I am using ESP32-CAM board and trying to post a photo to Telegram api. I've tried to send a text message and take a picture. They are working. But I can not send a photo to api. It gives a response like below:

Code: [Select all] [Expand/Collapse]

1. I (6517) Sending sendMessage: Starting Taking Picture!
2. I (6517) Sending sendMessage: pic->len=7119
3. W (6527) Sending sendMessage: Iniciare
4. W (6527) Sending sendMessage: Enviare POST
5. I (8097) Sending sendMessage: HTTP POST Status = 400, content_length = 91
6. W (8107) Sending sendMessage: Desde Perform el output es: {"ok":false,"error_code":400,"description":"Bad Request: there is no photo in the request"}

GeSHi © Codebox Plus Extension

And here is my post a photo code below:

Code: [Select all] [Expand/Collapse]

1. static esp_err_t https_telegram_sendPicture_perform_post()
2. {
3. ESP_LOGI(TAG3, "Starting Taking Picture!");
4.  
5.     camera_fb_t *pic = esp_camera_fb_get();
6.  
7.     if (!pic)
8.     {
9.         ESP_LOGE(TAG3, "Camera capture failed");
10.  
11.         return ESP_FAIL;
12.     }
13.     else
14.     {
15.         ESP_LOGI(TAG3, "pic->len=%d", pic->len);
16.     }
17.  
18. char url[512] = "";
19.  
20.     char output_buffer[MAX_HTTP_OUTPUT_BUFFER] = {0};   // Buffer to store response of http request
21.     // char output_buffer[1024*10] = {0};   // Buffer to store response of http request
22.  
23.     esp_http_client_config_t config =
24.     {
25.         .url = "https://api.telegram.org",
26.         .transport_type = HTTP_TRANSPORT_OVER_SSL,
27.         .event_handler = _http_event_handler,
28.         .cert_pem = telegram_certificate_pem_start,
29.         .user_data = output_buffer,
30.     };
31.  
32.     //POST
33.     ESP_LOGW(TAG3, "Iniciare");
34.  
35.     esp_http_client_handle_t client = esp_http_client_init(&config)
36.  
37.     //Copy the url+TOKEN
38.     strcat(url, url_string);
39.     //Passing the method
40.     strcat(url, "/sendPhoto");
41.  
42.     esp_http_client_set_url(client, url);
43.  
44.     ESP_LOGW(TAG3, "Enviare POST");
45.  
46.     char post_data[1024*10] = "";
47.     sprintf(post_data,"{\"chat_id\":%s,\"photo\":%s}", chat_ID2, (const char *) pic->buf);
48.  
49.     esp_http_client_set_method(client, HTTP_METHOD_POST);
50.     esp_http_client_set_header(client, "Content-Type", "image/jpeg");
51.     esp_http_client_set_post_field(client, (const char*) post_data, strlen(post_data));
52.  
53.     esp_err_t err = esp_http_client_perform(client);
54.     if (err == ESP_OK)
55.     {
56.         ESP_LOGI(TAG3, "HTTP POST Status = %ld, content_length = %ld",
57.                 (long)esp_http_client_get_status_code(client),
58.                 (long)esp_http_client_get_content_length(client));
59.         ESP_LOGW(TAG3, "Desde Perform el output es: %s",output_buffer);
60.  
61.     }
62.     else
63.     {
64.         ESP_LOGE(TAG3, "HTTP POST request failed: %s", esp_err_to_name(err));
65.     }
66.  
67.     ESP_LOGW(TAG, "Limpiare");
68.     esp_http_client_close(client);
69.     esp_http_client_cleanup(client);
70.     ESP_LOGI(TAG3, "esp_get_free_heap_size: %lu", esp_get_free_heap_size ());
71.  
72.     esp_camera_fb_return(pic);
73.  
74.     return ESP_OK;
75. }

GeSHi © Codebox Plus Extension

I've stucked to the same error by days. Thanks for your attention.

[ESP_adokitkat]

Hello.

Are you sure you can just insert binary data as string into json string? According to Telegram bot API you should use multipart/form-data POST method.

[hououin_kyouma]

Hello. I've changed the 'image/jpeg' to 'multipart/form-data'.

Code: Select all

esp_http_client_set_header(client, "Content-Type", "multipart/form-data");

Even if I try to post with 'multipart/form-data' I got a response like below:

Code: Select all

I (8977) Sending sendMessage: Starting Taking Picture!
I (8987) Sending sendMessage: pic->len=8272
W (8997) Sending sendMessage: Iniciare
I (8997) Sending sendMessage: url string es: https://api.telegram.org/bot[token]/sendPhoto
W (9007) Sending sendMessage: Enviare POST
W (9017) HTTP_CLIENT Handler: El json es es: {"chat_id":1111111,"photo":����}
I (10877) Sending sendMessage: HTTP POST Status = 400, content_length = 0
W (10877) Sending sendMessage: Desde Perform el output es:
W (10877) HTTP_CLIENT Handler: Limpiare
I (10887) HTTP_CLIENT Handler: HTTP_EVENT_DISCONNECTED
I (10897) HTTP_CLIENT Handler: HTTP_EVENT_DISCONNECTED
I (10897) Sending sendMessage: esp_get_free_heap_size: 2125792
I (10907) HTTP_CLIENT Handler: Finish http example

What is {"photo":����} exactly mean? I can not insert binary data to json? And in this line:

Code: Select all

W (10877) Sending sendMessage: Desde Perform el output es:

It can not get any http response.

Thanks for your attention.

[ESP_adokitkat]

Hello. I've changed the 'image/jpeg' to 'multipart/form-data'.

Code: Select all

esp_http_client_set_header(client, "Content-Type", "multipart/form-data");

Even if I try to post with 'multipart/form-data' I got a response like below:

Code: Select all

I (8977) Sending sendMessage: Starting Taking Picture!
I (8987) Sending sendMessage: pic->len=8272
W (8997) Sending sendMessage: Iniciare
I (8997) Sending sendMessage: url string es: https://api.telegram.org/bot[token]/sendPhoto
W (9007) Sending sendMessage: Enviare POST
W (9017) HTTP_CLIENT Handler: El json es es: {"chat_id":1111111,"photo":����}
I (10877) Sending sendMessage: HTTP POST Status = 400, content_length = 0
W (10877) Sending sendMessage: Desde Perform el output es:
W (10877) HTTP_CLIENT Handler: Limpiare
I (10887) HTTP_CLIENT Handler: HTTP_EVENT_DISCONNECTED
I (10897) HTTP_CLIENT Handler: HTTP_EVENT_DISCONNECTED
I (10897) Sending sendMessage: esp_get_free_heap_size: 2125792
I (10907) HTTP_CLIENT Handler: Finish http example

What is {"photo":����} exactly mean? I can not insert binary data to json? And in this line:

Code: Select all

W (10877) Sending sendMessage: Desde Perform el output es:

It can not get any http response.

Thanks for your attention.

No, you cannot use JSON like that with "multipart/form-data" as well as embedding binary data into any other text data, including JSON.

I found some examples for you:
https://developer.mozilla.org/en-US/doc ... %20type%3A
https://stackoverflow.com/a/46150309
https://github.com/nopnop2002/esp-idf-m ... #L110-L147
https://stackoverflow.com/a/73937408

You need to construct HTTP POST request yourself and attach the data there. I am no expert on the matter though.

[hououin_kyouma]

Thanks a lot, after days finally I can post multipart/data-form