group send failed. telegram api bot, sendMediaGroup function - php

Question

in function input $files = $_FILES
Don't get what Telegram wants from me.
It says: "{"ok":false,"error_code":400,"description":"Bad Request: group send failed"}". HIELPLEAS!
function sendMediaGroup($files)
{
$url = "https://api.telegram.org/bot" . $this->token . "/" . __FUNCTION__;
$media = [];
$ch = curl_init();
$type = "photo";
$caption = "";
foreach ($files as $file)
{
$media[] = [
'type' => $type,
'media' => $file['tmp_name'],
'caption' => $caption
];
}
$disable_notification = false;
$reply_to_message_id = null;
$parameters = [
'chat_id' => $this->chat_id,
'media' => json_encode($media),
'disable_notification' => $disable_notification,
'reply_to_message_id' => $reply_to_message_id,
];
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type:multipart/form-data"));
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $parameters);
return $output = curl_exec($ch);
}

Answer 1

In order for Telegram to create a media group from photo URL in the Internet, a file link you pass as media attribute value must be accessible by Telegram's servers. Sometimes it is not the case and sendMediaGroup API call fails with the cryptic error message Bad Request: group send failed. In this case you can try another approach to send photos, e.g. in text field using sendMessage method or go to #webpagebot and send him a link to your file - this will update preview for the link and you will be able to send that link inside of the media group.
Note to moderators: this answer does not 100% targets original question, but link to this question pops up in first ten while searching using words from the caption.

Answer 2

You should name your files and attach files to the request according their name. So change your code like this:
function sendMediaGroup($files)
{
$url = "https://api.telegram.org/bot" . $this->token . "/" . __FUNCTION__;
$media = [];
$ch = curl_init();
$type = "photo";
$caption = "";
$parameters = array();
foreach ($files as $file)
{
$media[] = [
'type' => $type,
'media' => "attach://" . $file['tmp_name'],
'caption' => $caption
];
$parameters[] = [
$file['tmp_name'] => $file
];
}
$disable_notification = false;
$reply_to_message_id = null;
$parameters[] = [
'chat_id' => $this->chat_id,
'media' => json_encode($media),
'disable_notification' => $disable_notification,
'reply_to_message_id' => $reply_to_message_id,
];
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type:multipart/form-data"));
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $parameters);
return $output = curl_exec($ch);
}

Answer 3

If you are setting URL for media, you URL should work on :80 or :443 port. For example: https:examplesite.com/image1.jpg is OK, https:examplesite.com:8443/image1.jpg is not OK!