PHP5.3 Tumblr API Post

define("CONSUMER_KEY", '');
define("CONSUMER_SECRET", '');
define("OAUTH_TOKEN", '');
define("OAUTH_SECRET", '');

function oauth_gen($method, $url, $iparams, &$headers) {

$iparams['oauth_consumer_key'] = CONSUMER_KEY;
$iparams['oauth_nonce'] = strval(time());
$iparams['oauth_signature_method'] = 'HMAC-SHA1';
$iparams['oauth_timestamp'] = strval(time());
$iparams['oauth_token'] = OAUTH_TOKEN;
$iparams['oauth_version'] = '1.0';
$iparams['oauth_signature'] = oauth_sig($method, $url, $iparams);
print $iparams['oauth_signature'];
$oauth_header = array();
foreach($iparams as $key => $value) {
if (strpos($key, "oauth") !== false) {
$oauth_header []= $key ."=".$value;
}
}
$oauth_header = "OAuth ". implode(",", $oauth_header);
$headers["Authorization"] = $oauth_header;
}

function oauth_sig($method, $uri, $params) {

$parts []= $method;
$parts []= rawurlencode($uri);

$iparams = array();
ksort($params);
foreach($params as $key => $data) {
if(is_array($data)) {
$count = 0;
foreach($data as $val) {
$n = $key . "[". $count . "]";
$iparams []= $n . "=" . rawurlencode($val);
$count++;
}
} else {
$iparams[]= rawurlencode($key) . "=" .rawurlencode($data);
}
}
$parts []= rawurlencode(implode("&", $iparams));
$sig = implode("&", $parts);
return base64_encode(hash_hmac('sha1', $sig, CONSUMER_SECRET.
"&". OAUTH_SECRET, true));
}

$headers = array("Host" => "http://api.tumblr.com/",
"Content-type" => "application/x-www-form-urlencoded", "Expect" => "");

############ Configuration ############
$params = array(
"data" => array(
file_get_contents("test.jpg"),
),
"type" => "photo",
"link" => "http://a-hadaka.jp/",
"caption" => "PHPからPost"
);
$blogname = "ahadaka.tumblr.com";
#######################################

oauth_gen("POST", "http://api.tumblr.com/v2/blog/$blogname/post", $params, $headers);

$ch = curl_init();
curl_setopt($ch, CURLOPT_USERAGENT, "PHP Uploader Tumblr v1.0");
curl_setopt($ch, CURLOPT_URL, "http://api.tumblr.com/v2/blog/$blogname/post");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1 );

curl_setopt($ch, CURLOPT_HTTPHEADER, array(
"Authorization: " . $headers['Authorization'],
"Content-type: " . $headers["Content-type"],
"Expect: ")
);

$params = http_build_query($params);

curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $params);