Mastodonに画像付きのトゥート（ツイート）する方法

Mastodon-APIに画像付きのトゥート（ツイート）する方法

気付き1：ヘッダーにユーザーエージェントがないと拒否される。
気付き2：配列をhttp_build_queryで変換するとパラメーターが文字化けになる。

<?php
class Mastodon
{
    const host = "mstdn.jp";
    const endpoint1  = "/api/v1/statuses";
    const endpoint2  = "/api/v1/media";

    public function toot($text){
        $data = array('file' => new CURLFile("/var/www/html/t_m/image.png", 'image/png', "image.png"));
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, "https://" . self::host . self::endpoint2);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
        curl_setopt($ch, CURLOPT_HTTPHEADER, ['User-Agent: ' . $_SERVER['HTTP_USER_AGENT'], 'Content-Type: multipart/form-data', 'Authorization: Bearer ' . MSTDN_ACCESSTOKEN]);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
        $response =   json_decode(@curl_exec($ch));
        curl_close($ch);
        if (isset($response->id)) {
            $postdata = [
                "visibility" => "public",
                "media_ids" => [$response->id],
                "status" => strip_tags($text),
            ];
            $data = json_encode($postdata);
            $ch = curl_init();
            curl_setopt($ch, CURLOPT_URL, "https://" . self::host . self::endpoint1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
            curl_setopt($ch, CURLOPT_HTTPHEADER, ['User-Agent: ' . $_SERVER['HTTP_USER_AGENT'], 'Content-Type: application/json', 'Authorization: Bearer ' . MSTDN_ACCESSTOKEN]);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
            $response =  @curl_exec($ch);
            curl_close($ch);
        }
    }
}