C++ cUrl send an image buff to telegram bot via api - c++

Question

I'm trying to send an image buff with cUrl to the telegram API using c++. Just to know I' m developing on Windows 10.
Here is all I have done.
First I send a photo from my hard drive using curl from terminal using this command:
curl -s -X POST "https://api.telegram.org/bottoken/sendPhoto" -F chat_id=id -F photo="#D:/a.jpg"
On the telegram chat I receive the photo with this command meanwhile on the console in which I did the cUrl request I have a response like this:
{"ok":true,"result":{"message_id":2398,"from":{"id":id,"is_bot":true,"first_name":"botname","username":"stuff"},"chat":{"id":chatid,"first_name":"userdata","username":"userdata","type":"private"},"date":1588929212,"photo":[{"file_id":"reallylongfileid","file_unique_id":"shorterid","file_size":26307,"width":240,"height":320}]}}
If I import this request using the Import tab and selecting raw text in Postman and execute it I have this response:
{
"ok": false,
"error_code": 400,
"description": "Bad Request: wrong HTTP URL specified"
}
If I try to use the postman generated code:
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
// I added CURLOPT_VERBOSE
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
curl_easy_setopt(curl, CURLOPT_URL, "https://api.telegram.org/bottoken/sendPhoto");
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
curl_easy_setopt(curl, CURLOPT_DEFAULT_PROTOCOL, "https");
struct curl_slist *headers = NULL;
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_mime *mime;
curl_mimepart *part;
mime = curl_mime_init(curl);
part = curl_mime_addpart(mime);
curl_mime_name(part, "chat_id");
curl_mime_data(part, "mychatid", CURL_ZERO_TERMINATED);
part = curl_mime_addpart(mime);
curl_mime_name(part, "photo");
curl_mime_data(part, "#D:/a.jpg", CURL_ZERO_TERMINATED);
curl_easy_setopt(curl, CURLOPT_MIMEPOST, mime);
res = curl_easy_perform(curl);
curl_mime_free(mime);
}
curl_easy_cleanup(curl);
I have this response on the console:
* Trying 149.154.167.220...
* TCP_NODELAY set
* Connected to api.telegram.org (149.154.167.220) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* SSL certificate problem: self signed certificate in certificate chain
* Closing connection 0
So I added this option to the code I wrote before:
curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
and the new response is:
* Trying 149.154.167.220...
* TCP_NODELAY set
* Connected to api.telegram.org (149.154.167.220) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
* subject: OU=Domain Control Validated; CN=api.telegram.org
* start date: Mar 24 13:48:17 2020 GMT
* expire date: May 23 16:17:38 2022 GMT
* subjectAltName: host "api.telegram.org" matched cert's "api.telegram.org"
* issuer: C=US; ST=Arizona; L=Scottsdale; O=GoDaddy.com, Inc.; OU=http://certs.godaddy.com/repository/; CN=Go Daddy Secure Certificate Authority - G2
* SSL certificate verify result: self signed certificate in certificate chain (19), continuing anyway.
> POST /botmybottoken/sendPhoto HTTP/1.1
Host: api.telegram.org
Accept: */*
Content-Length: 254
Content-Type: multipart/form-data; boundary=------------------------9b6fc10336ea9470
* We are completely uploaded and fine
* old SSL session ID is stale, removing
< HTTP/1.1 400 Bad Request
< Server: nginx/1.16.1
< Date: Fri, 08 May 2020 09:25:10 GMT
< Content-Type: application/json
< Content-Length: 83
< Connection: keep-alive
< Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
< Access-Control-Allow-Origin: *
< Access-Control-Expose-Headers: Content-Length,Content-Type,Date,Server,Connection
<
{"ok":false,"error_code":400,"description":"Bad Request: wrong HTTP URL specified"}* Connection #0 to host api.telegram.org left intact
* Closing connection 0
If I try to send this image buffer:
cv::Mat img(260, 301, CV_8UC3, cv::Scalar(0, 0, 0));
std::vector<uchar> buff;
std::vector<int> param(2);
param[0] = cv::IMWRITE_JPEG_QUALITY;
param[1] = 80;
cv::imencode(".jpg", img, buff, param);
std::string strImg((char*)buff.data(), buff.size());
And if I modify the request code only from this:
curl_mime_data(part, "#D:/a.jpg", CURL_ZERO_TERMINATED);
To this:
curl_mime_data(part, strImg.data(), strImg.size());
I have this response in the console:
* Trying 149.154.167.220...
* TCP_NODELAY set
* Connected to api.telegram.org (149.154.167.220) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
* subject: OU=Domain Control Validated; CN=api.telegram.org
* start date: Mar 24 13:48:17 2020 GMT
* expire date: May 23 16:17:38 2022 GMT
* subjectAltName: host "api.telegram.org" matched cert's "api.telegram.org"
* issuer: C=US; ST=Arizona; L=Scottsdale; O=GoDaddy.com, Inc.; OU=http://certs.godaddy.com/repository/; CN=Go Daddy Secure Certificate Authority - G2
* SSL certificate verify result: self signed certificate in certificate chain (19), continuing anyway.
> POST /botmybottoken/sendPhoto HTTP/1.1
Host: api.telegram.org
Accept: */*
Content-Length: 2164
Content-Type: multipart/form-data; boundary=------------------------f5bde0e2e0ef8114
Expect: 100-continue
* old SSL session ID is stale, removing
< HTTP/1.1 100 Continue
* We are completely uploaded and fine
< HTTP/1.1 400 Bad Request
< Server: nginx/1.16.1
< Date: Fri, 08 May 2020 09:30:34 GMT
< Content-Type: application/json
< Content-Length: 128
< Connection: keep-alive
< Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
< Access-Control-Allow-Origin: *
< Access-Control-Expose-Headers: Content-Length,Content-Type,Date,Server,Connection
<
{"ok":false,"error_code":400,"description":"Bad Request: wrong remote file identifier specified: Wrong character in the string"}* Connection #0 to host api.telegram.org left intact
* Closing connection 0
I don't want to use any c++ telegram bot library because I have just to send a Message or a photo.
I' m able to send a message with cUrl code.
With photos, I have some problems.
Because I have to do this two simple actions I prefer to use only cUrl and nothing else.
I need help cause I'm not understanding what's wrong.
I know I write a lot but I wish this could help you to understand everything better and faster.
Thank you!

Answer 1

int sendTelegramPhoto(string chat_id, string path_to_photo, string caption = NULL){
CURL *curl;
CURLcode response;
curl_global_init(CURL_GLOBAL_ALL);
curl = curl_easy_init();
if (curl)
{
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
curl_easy_setopt(curl, CURLOPT_POST, 1);
curl_easy_setopt(curl, CURLOPT_URL, "https://api.telegram.org/bottoken/sendPhoto");
curl_easy_setopt(curl, CURLOPT_DEFAULT_PROTOCOL, "https");
struct curl_slist *headers = NULL;
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_slist_append(headers, "Content-Type: multipart/form-data");
curl_slist_append(headers, "charset=utf-8");
curl_mime *mime;
curl_mimepart *part;
mime = curl_mime_init(curl);
part = curl_mime_addpart(mime);
curl_mime_name(part, "chat_id");
curl_mime_data(part, chat_id.c_str(), CURL_ZERO_TERMINATED);
part = curl_mime_addpart(mime);
curl_mime_name(part, "photo");
curl_mime_filedata(part, path_to_photo.c_str());
curl_mime_type(part, "image/jpeg");
part = curl_mime_addpart(mime);
curl_mime_name(part, "caption");
curl_mime_data(part, caption.c_str().c_str(), CURL_ZERO_TERMINATED);
curl_easy_setopt(curl, CURLOPT_MIMEPOST, mime);
response = curl_easy_perform(curl);
curl_mime_free(mime);
curl_slist_free_all(headers);
}
curl_easy_cleanup(curl);
return 0;
}

Answer 2

cv::Mat img(260, 301, CV_8UC3, cv::Scalar(0, 0, 0));
std::vector<uchar> buff;
std::vector<int> param(2);
param[0] = cv::IMWRITE_JPEG_QUALITY;
param[1] = 80;
cv::imencode(".jpg", img, buff, param);
std::string strImg((char*)buff.data(), buff.size());
CURLcode ret;
CURL* hnd;
curl_mime* mime1;
curl_mimepart* part1;
mime1 = NULL;
hnd = curl_easy_init();
curl_easy_setopt(hnd, CURLOPT_BUFFERSIZE, 102400L);
curl_easy_setopt(hnd, CURLOPT_URL, "https://api.telegram.org/bottoken/sendPhoto");
curl_easy_setopt(hnd, CURLOPT_NOPROGRESS, 1L);
mime1 = curl_mime_init(hnd);
part1 = curl_mime_addpart(mime1);
curl_mime_data(part1, "mychatid", CURL_ZERO_TERMINATED);
curl_mime_name(part1, "chat_id");
part1 = curl_mime_addpart(mime1);
curl_mime_data(part1, strImg.data(), strImg.size());
curl_mime_filename(part1, "myimage.jpg");
curl_mime_name(part1, "photo");
curl_easy_setopt(hnd, CURLOPT_MIMEPOST, mime1);
curl_easy_setopt(hnd, CURLOPT_USERAGENT, "curl/7.87.0-DEV");
curl_easy_setopt(hnd, CURLOPT_MAXREDIRS, 50L);
curl_easy_setopt(hnd, CURLOPT_CUSTOMREQUEST, "POST");
curl_easy_setopt(hnd, CURLOPT_FTP_SKIP_PASV_IP, 1L);
curl_easy_setopt(hnd, CURLOPT_TCP_KEEPALIVE, 1L);
ret = curl_easy_perform(hnd);
...