Add support for multipart/form-data to HTTPFetch for server announcing

src/clientmedia.cpp

@@ -266,7 +266,7 @@ void ClientMediaDownloader::initialStep(Client *client)
 			fetchrequest.request_id = m_httpfetch_next_id; // == i
 			fetchrequest.timeout = m_httpfetch_timeout;
 			fetchrequest.connect_timeout = m_httpfetch_timeout;
-			fetchrequest.post_fields = required_hash_set;
+			fetchrequest.post_data = required_hash_set;
 			fetchrequest.extra_headers.push_back(
 				"Content-Type: application/octet-stream");
 			httpfetch_async(fetchrequest);

src/httpfetch.cpp

@@ -46,6 +46,7 @@ HTTPFetchRequest::HTTPFetchRequest()
 	request_id = 0;
 	timeout = g_settings->getS32("curl_timeout");
 	connect_timeout = timeout;
+	multipart = false;
 
 	useragent = std::string("Minetest/") + minetest_version_hash + " (" + porting::get_sysinfo() + ")";
 }
@@ -184,6 +185,7 @@ struct HTTPFetchOngoing
 	std::ostringstream oss;
 	char *post_fields;
 	struct curl_slist *httpheader;
+	curl_httppost *post;
 
 	HTTPFetchOngoing(HTTPFetchRequest request_, CurlHandlePool *pool_):
 		pool(pool_),
@@ -192,7 +194,8 @@ struct HTTPFetchOngoing
 		request(request_),
 		result(request_),
 		oss(std::ios::binary),
-		httpheader(NULL)
+		httpheader(NULL),
+		post(NULL)
 	{
 		curl = pool->alloc();
 		if (curl != NULL) {
@@ -239,19 +242,53 @@ struct HTTPFetchOngoing
 						httpfetch_writefunction);
 				curl_easy_setopt(curl, CURLOPT_WRITEDATA, &oss);
 			}
+
 			// Set POST (or GET) data
 			if (request.post_fields.empty()) {
 				curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
+			} else if (request.multipart) {
+				curl_httppost *last = NULL;
+				for (std::map<std::string, std::string>::iterator it =
+							request.post_fields.begin();
+						it != request.post_fields.end();
+						++it) {
+					curl_formadd(&post, &last,
+							CURLFORM_NAMELENGTH, it->first.size(),
+							CURLFORM_PTRNAME, it->first.c_str(),
+							CURLFORM_CONTENTSLENGTH, it->second.size(),
+							CURLFORM_PTRCONTENTS, it->second.c_str(),
+							CURLFORM_END);
 				}
-			else {
-				curl_easy_setopt(curl, CURLOPT_POST, 1);
-				curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
-						request.post_fields.size());
-				curl_easy_setopt(curl, CURLOPT_POSTFIELDS,
-						request.post_fields.c_str());
+				curl_easy_setopt(curl, CURLOPT_HTTPPOST, post);
 				// request.post_fields must now *never* be
+				// modified until CURLOPT_HTTPPOST is cleared
+			} else {
+				curl_easy_setopt(curl, CURLOPT_POST, 1);
+				if (request.post_data.empty()) {
+					std::string str;
+					for (std::map<std::string, std::string>::iterator it =
+								request.post_fields.begin();
+							it != request.post_fields.end();
+							++it) {
+						if (str != "")
+							str += "&";
+						str += urlencode(it->first);
+						str += "=";
+						str += urlencode(it->second);
+					}
+					curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
+							str.size());
+					curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS,
+							str.c_str());
+				} else {
+					curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
+							request.post_data.size());
+					curl_easy_setopt(curl, CURLOPT_POSTFIELDS,
+							request.post_data.c_str());
+					// request.post_data must now *never* be
 					// modified until CURLOPT_POSTFIELDS is cleared
 				}
+			}
 			// Set additional HTTP headers
 			for (size_t i = 0; i < request.extra_headers.size(); ++i) {
 				httpheader = curl_slist_append(
@@ -333,6 +370,10 @@ struct HTTPFetchOngoing
 			curl_easy_setopt(curl, CURLOPT_HTTPHEADER, NULL);
 			curl_slist_free_all(httpheader);
 		}
+		if (post != NULL) {
+			curl_easy_setopt(curl, CURLOPT_HTTPPOST, NULL);
+			curl_formfree(post);
+		}
 
 		// Store the cURL handle for reuse
 		pool->free(curl);

src/httpfetch.h

@@ -22,6 +22,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include <string>
 #include <vector>
+#include <map>
 #include "config.h"
 
 // Can be used in place of "caller" in asynchronous transfers to discard result
@@ -47,10 +48,16 @@ struct HTTPFetchRequest
 	// Timeout for the connection phase, in milliseconds
 	long connect_timeout;
 
-	// POST data (should be application/x-www-form-urlencoded
-	// unless a Content-Type header is specified in extra_headers)
+	// Indicates if this is multipart/form-data or
+	// application/x-www-form-urlencoded.  POST-only.
+	bool multipart;
+
+	// POST fields.  Fields are escaped properly.
 	// If this is empty a GET request is done instead.
-	std::string post_fields;
+	std::map<std::string, std::string> post_fields;
+
+	// Raw POST data, overrides post_fields.
+	std::string post_data;
 
 	// If not empty, should contain entries such as "Accept: text/html"
 	std::vector<std::string> extra_headers;

src/serverlist.cpp

@@ -230,11 +230,8 @@ void sendAnnounce(std::string action, const std::vector<std::string> & clients_n
 	Json::FastWriter writer;
 	HTTPFetchRequest fetchrequest;
 	fetchrequest.url = g_settings->get("serverlist_url") + std::string("/announce");
-	std::string query = std::string("json=") + urlencode(writer.write(server));
-	if (query.size() < 1000)
-		fetchrequest.url += "?" + query;
-	else
-		fetchrequest.post_fields = query;
+	fetchrequest.post_fields["json"] = writer.write(server);
+	fetchrequest.multipart = true;
 	httpfetch_async(fetchrequest);
 }
 #endif