PHP cURL: circumventing '#' denoting a file POST - php

Question

I'm trying to make a cURL post, and one of the parameters includes a string prefixed with the '#' symbol. Typically for a cURL post, the '#' means I'm trying post a file, but in this case, I just want to pass the string prefixed with '#'. Is there a way, or what is the best way to get around this?
Here's my params array:
$params = array(
'UserID' => $this->username,
'Password' => $this->password,
'Type' => $type,
'Symbol' => $symbol, // this will look something like #CH14
'Market' => '',
'Vendor' => '',
'Format' => 'JSN'
);
And here's how my cURL post is taking place (the url is irrelevant to the actual problem.):
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
// Return the transfer as a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
$response = curl_exec($ch);
if($response === FALSE)
{
$error = curl_error($ch);
$error_code = curl_errno($ch);
throw new Exception("CURL ERROR: #$error_code\n$error\n");
}
curl_close($ch);
return $response;
This works for everything I need it to do except when I need to pass it a symbol with an '#' in front. Any help would be greatly appreciated. Thanks.

Answer 1

According to the curl_setopt() manual entry:
CURLOPT_POSTFIELDS
The full data to post in a HTTP "POST" operation. To post a file, prepend a filename with # and use the full path. The filetype can be explicitly specified by following the filename with the type in the format ';type=mimetype'. This parameter can either be passed as a urlencoded string like 'para1=val1&para2=val2&...' or as an array with the field name as key and field data as value. If value is an array, the Content-Type header will be set to multipart/form-data. As of PHP 5.2.0, value must be an array if files are passed to this option with the # prefix. As of PHP 5.5.0, the # prefix is deprecated and files can be sent using CURLFile.
Hence, we can simply convert it to a string using http_build_query():
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($params));

Answer 2

Use http_build_query() to build the query string.
From the documentation for the function:
Generates a URL-encoded query string from the associative (or indexed) array provided.
As stated above, it will correctly encode all the special characters as required. It can be used as below:
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($params));
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