cURL - Uploading string with a "+" will replace "+" with " " - c++

Question

Yeah weird title, I don't know what it should be.
I have a dll, and after a long time trying and finally figuring out how I could upload things to a webhook, it finally works. But, when I try to upload a string which contains a +, the + will be replaced with a " ".
Example:
Uploaded: FRvERUb9xgMlP4BS+bm+t+CLI6cG026vbtev2gSbBYM=
Received: FRvERUb9xgMlP4BS bm t CLI6cG026vbtev2gSbBYM=
I want to know how I can upload it so that the thing will also send the characters +.
The code for uploading:
void sendmsg() {
CURL* curl;
CURLcode res;
curl_global_init(CURL_GLOBAL_ALL);
curl = curl_easy_init();
if (curl) {
curl_easy_setopt(curl, CURLOPT_URL, "my webhook");
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "content=FRvERUb9xgMlP4BS+bm+t+CLI6cG026vbtev2gSbBYM=");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
curl_global_cleanup();
}

Answer 1

This POST is a normal application/x-www-form-urlencoded kind (and libcurl will set that Content-Type by default when this option is used), which is commonly used by HTML forms.
You can use curl_easy_escape to url-encode your data, if necessary. It returns a pointer to an encoded string that can be passed as postdata.
if (curl) {
curl_easy_setopt(curl, CURLOPT_URL, "my webhook");
char* content = curl_easy_escape(curl, "FRvERUb9xgMlP4BS+bm+t+CLI6cG026vbtev2gSbBYM=", 0);
if (content) {
curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS, ("content="s + content).c_str());
curl_free(content);
res = curl_easy_perform(curl);
}
curl_easy_cleanup(curl);
}