Add proxy support for `HTTPClient` and the editor

* Adds proxy related methods for `HTTPClient` and `HTTPRequest`
* Adds `network/http_proxy/{host,port}` editor settings
* Makes AssetLib and Export Template Manager proxy aware

core/io/http_client.cpp

@@ -77,9 +77,21 @@ Error HTTPClient::connect_to_host(const String &p_host, int p_port, bool p_ssl,
 
 	connection = tcp_connection;
 
-	if (conn_host.is_valid_ip_address()) {
+	if (ssl && https_proxy_port != -1) {
+		proxy_client.instance();
+		server_host = https_proxy_host;
+		server_port = https_proxy_port;
+	} else if (!ssl && http_proxy_port != -1) {
+		server_host = http_proxy_host;
+		server_port = http_proxy_port;
+	} else {
+		server_host = conn_host;
+		server_port = conn_port;
+	}
+
+	if (server_host.is_valid_ip_address()) {
 		// Host contains valid IP
-		Error err = tcp_connection->connect_to_host(IP_Address(conn_host), p_port);
+		Error err = tcp_connection->connect_to_host(IP_Address(server_host), server_port);
 		if (err) {
 			status = STATUS_CANT_CONNECT;
 			return err;
@@ -88,7 +100,7 @@ Error HTTPClient::connect_to_host(const String &p_host, int p_port, bool p_ssl,
 		status = STATUS_CONNECTING;
 	} else {
 		// Host contains hostname and needs to be resolved to IP
-		resolving = IP::get_singleton()->resolve_hostname_queue_item(conn_host);
+		resolving = IP::get_singleton()->resolve_hostname_queue_item(server_host);
 		status = STATUS_RESOLVING;
 	}
 
@@ -141,7 +153,12 @@ Error HTTPClient::request_raw(Method p_method, const String &p_url, const Vector
 	ERR_FAIL_COND_V(status != STATUS_CONNECTED, ERR_INVALID_PARAMETER);
 	ERR_FAIL_COND_V(connection.is_null(), ERR_INVALID_DATA);
 
-	String request = String(_methods[p_method]) + " " + p_url + " HTTP/1.1\r\n";
+	String uri = p_url;
+	if (!ssl && http_proxy_port != -1) {
+		uri = vformat("http://%s:%d%s", conn_host, conn_port, p_url);
+	}
+
+	String request = String(_methods[p_method]) + " " + uri + " HTTP/1.1\r\n";
 	bool add_host = true;
 	bool add_clen = p_body.size() > 0;
 	bool add_uagent = true;
@@ -214,7 +231,12 @@ Error HTTPClient::request(Method p_method, const String &p_url, const Vector<Str
 	ERR_FAIL_COND_V(status != STATUS_CONNECTED, ERR_INVALID_PARAMETER);
 	ERR_FAIL_COND_V(connection.is_null(), ERR_INVALID_DATA);
 
-	String request = String(_methods[p_method]) + " " + p_url + " HTTP/1.1\r\n";
+	String uri = p_url;
+	if (!ssl && http_proxy_port != -1) {
+		uri = vformat("http://%s:%d%s", conn_host, conn_port, p_url);
+	}
+
+	String request = String(_methods[p_method]) + " " + uri + " HTTP/1.1\r\n";
 	bool add_host = true;
 	bool add_uagent = true;
 	bool add_accept = true;
@@ -301,6 +323,7 @@ void HTTPClient::close() {
 	}
 
 	connection.unref();
+	proxy_client.unref();
 	status = STATUS_DISCONNECTED;
 	head_request = false;
 	if (resolving != IP::RESOLVER_INVALID_ID) {
@@ -337,7 +360,7 @@ Error HTTPClient::poll() {
 
 					Error err = ERR_BUG; // Should be at least one entry.
 					while (ip_candidates.size() > 0) {
-						err = tcp_connection->connect_to_host(ip_candidates.pop_front(), conn_port);
+						err = tcp_connection->connect_to_host(ip_candidates.pop_front(), server_port);
 						if (err == OK) {
 							break;
 						}
@@ -366,7 +389,48 @@ Error HTTPClient::poll() {
 					return OK;
 				} break;
 				case StreamPeerTCP::STATUS_CONNECTED: {
-					if (ssl) {
+					if (ssl && proxy_client.is_valid()) {
+						Error err = proxy_client->poll();
+						if (err == ERR_UNCONFIGURED) {
+							proxy_client->set_connection(tcp_connection);
+							const Vector<String> headers;
+							err = proxy_client->request(METHOD_CONNECT, vformat("%s:%d", conn_host, conn_port), headers);
+							if (err != OK) {
+								status = STATUS_CANT_CONNECT;
+								return err;
+							}
+						} else if (err != OK) {
+							status = STATUS_CANT_CONNECT;
+							return err;
+						}
+						switch (proxy_client->get_status()) {
+							case STATUS_REQUESTING: {
+								return OK;
+							} break;
+							case STATUS_BODY: {
+								proxy_client->read_response_body_chunk();
+								return OK;
+							} break;
+							case STATUS_CONNECTED: {
+								if (proxy_client->get_response_code() != RESPONSE_OK) {
+									status = STATUS_CANT_CONNECT;
+									return ERR_CANT_CONNECT;
+								}
+								proxy_client.unref();
+								return OK;
+							}
+							case STATUS_DISCONNECTED:
+							case STATUS_RESOLVING:
+							case STATUS_CONNECTING: {
+								status = STATUS_CANT_CONNECT;
+								ERR_FAIL_V(ERR_BUG);
+							} break;
+							default: {
+								status = STATUS_CANT_CONNECT;
+								return ERR_CANT_CONNECT;
+							} break;
+						}
+					} else if (ssl) {
 						Ref<StreamPeerSSL> ssl;
 						if (!handshaking) {
 							// Connect the StreamPeerSSL and start handshaking
@@ -416,7 +480,7 @@ Error HTTPClient::poll() {
 					Error err = ERR_CANT_CONNECT;
 					while (ip_candidates.size() > 0) {
 						tcp_connection->disconnect_from_host();
-						err = tcp_connection->connect_to_host(ip_candidates.pop_front(), conn_port);
+						err = tcp_connection->connect_to_host(ip_candidates.pop_front(), server_port);
 						if (err == OK) {
 							return OK;
 						}
@@ -756,6 +820,9 @@ HTTPClient::HTTPClient() {
 	status = STATUS_DISCONNECTED;
 	head_request = false;
 	conn_port = -1;
+	server_port = -1;
+	http_proxy_port = -1;
+	https_proxy_port = -1;
 	body_size = -1;
 	chunked = false;
 	body_left = 0;
@@ -775,6 +842,34 @@ HTTPClient::~HTTPClient() {
 
 #endif // #ifndef JAVASCRIPT_ENABLED
 
+void HTTPClient::set_http_proxy(const String &p_host, int p_port) {
+#ifdef JAVASCRIPT_ENABLED
+	WARN_PRINT("HTTP proxy feature is not available");
+#else
+	if (p_host.empty() || p_port == -1) {
+		http_proxy_host = "";
+		http_proxy_port = -1;
+	} else {
+		http_proxy_host = p_host;
+		http_proxy_port = p_port;
+	}
+#endif
+}
+
+void HTTPClient::set_https_proxy(const String &p_host, int p_port) {
+#ifdef JAVASCRIPT_ENABLED
+	WARN_PRINT("HTTPS proxy feature is not available");
+#else
+	if (p_host.empty() || p_port == -1) {
+		https_proxy_host = "";
+		https_proxy_port = -1;
+	} else {
+		https_proxy_host = p_host;
+		https_proxy_port = p_port;
+	}
+#endif
+}
+
 String HTTPClient::query_string_from_dict(const Dictionary &p_dict) {
 	String query = "";
 	Array keys = p_dict.keys();
@@ -860,6 +955,9 @@ void HTTPClient::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_status"), &HTTPClient::get_status);
 	ClassDB::bind_method(D_METHOD("poll"), &HTTPClient::poll);
 
+	ClassDB::bind_method(D_METHOD("set_http_proxy", "host", "port"), &HTTPClient::set_http_proxy);
+	ClassDB::bind_method(D_METHOD("set_https_proxy", "host", "port"), &HTTPClient::set_https_proxy);
+
 	ClassDB::bind_method(D_METHOD("query_string_from_dict", "fields"), &HTTPClient::query_string_from_dict);
 
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "blocking_mode_enabled"), "set_blocking_mode", "is_blocking_mode_enabled");

core/io/http_client.h

@@ -160,8 +160,14 @@ private:
 	Status status;
 	IP::ResolverID resolving;
 	Array ip_candidates;
-	int conn_port;
+	int conn_port; // Server to make requests to.
 	String conn_host;
+	int server_port; // Server to connect to (might be a proxy server).
+	String server_host;
+	int http_proxy_port; // Proxy server for http requests.
+	String http_proxy_host;
+	int https_proxy_port; // Proxy server for https requests.
+	String https_proxy_host;
 	bool ssl;
 	bool ssl_verify_host;
 	bool blocking;
@@ -180,6 +186,7 @@ private:
 
 	Ref<StreamPeerTCP> tcp_connection;
 	Ref<StreamPeer> connection;
+	Ref<HTTPClient> proxy_client;
 
 	int response_num;
 	Vector<String> response_headers;
@@ -227,6 +234,10 @@ public:
 
 	String query_string_from_dict(const Dictionary &p_dict);
 
+	// Use empty string or -1 to unset.
+	void set_http_proxy(const String &p_host, int p_port);
+	void set_https_proxy(const String &p_host, int p_port);
+
 	HTTPClient();
 	~HTTPClient();
 };

doc/classes/HTTPClient.xml

@@ -149,6 +149,24 @@
 				Sends the body data raw, as a byte array and does not encode it in any way.
 			</description>
 		</method>
+		<method name="set_http_proxy">
+			<return type="void" />
+			<argument index="0" name="host" type="String" />
+			<argument index="1" name="port" type="int" />
+			<description>
+				Sets the proxy server for HTTP requests.
+				The proxy server is unset if [code]host[/code] is empty or [code]port[/code] is -1.
+			</description>
+		</method>
+		<method name="set_https_proxy">
+			<return type="void" />
+			<argument index="0" name="host" type="String" />
+			<argument index="1" name="port" type="int" />
+			<description>
+				Sets the proxy server for HTTPS requests.
+				The proxy server is unset if [code]host[/code] is empty or [code]port[/code] is -1.
+			</description>
+		</method>
 	</methods>
 	<members>
 		<member name="blocking_mode_enabled" type="bool" setter="set_blocking_mode" getter="is_blocking_mode_enabled" default="false">

doc/classes/HTTPRequest.xml

@@ -121,6 +121,24 @@
 				Returns [constant OK] if request is successfully created. (Does not imply that the server has responded), [constant ERR_UNCONFIGURED] if not in the tree, [constant ERR_BUSY] if still processing previous request, [constant ERR_INVALID_PARAMETER] if given string is not a valid URL format, or [constant ERR_CANT_CONNECT] if not using thread and the [HTTPClient] cannot connect to host.
 			</description>
 		</method>
+		<method name="set_http_proxy">
+			<return type="void" />
+			<argument index="0" name="host" type="String" />
+			<argument index="1" name="port" type="int" />
+			<description>
+				Sets the proxy server for HTTP requests.
+				The proxy server is unset if [code]host[/code] is empty or [code]port[/code] is -1.
+			</description>
+		</method>
+		<method name="set_https_proxy">
+			<return type="void" />
+			<argument index="0" name="host" type="String" />
+			<argument index="1" name="port" type="int" />
+			<description>
+				Sets the proxy server for HTTPS requests.
+				The proxy server is unset if [code]host[/code] is empty or [code]port[/code] is -1.
+			</description>
+		</method>
 	</methods>
 	<members>
 		<member name="body_size_limit" type="int" setter="set_body_size_limit" getter="get_body_size_limit" default="-1">

editor/export_template_manager.cpp

@@ -150,6 +150,11 @@ void ExportTemplateManager::_download_template(const String &p_url, bool p_skip_
 	download_templates->set_download_file(EditorSettings::get_singleton()->get_cache_dir().plus_file("tmp_templates.tpz"));
 	download_templates->set_use_threads(true);
 
+	const String proxy_host = EDITOR_DEF("network/http_proxy/host", "");
+	const int proxy_port = EDITOR_DEF("network/http_proxy/port", -1);
+	download_templates->set_http_proxy(proxy_host, proxy_port);
+	download_templates->set_https_proxy(proxy_host, proxy_port);
+
 	Error err = download_templates->request(p_url);
 	if (err != OK) {
 		_set_current_progress_status(TTR("Error requesting URL:") + " " + p_url, true);

editor/plugins/asset_library_editor_plugin.cpp

@@ -37,6 +37,15 @@
 #include "editor/editor_settings.h"
 #include "editor/project_settings_editor.h"
 
+static inline void setup_http_request(HTTPRequest *request) {
+	request->set_use_threads(EDITOR_DEF("asset_library/use_threads", true));
+
+	const String proxy_host = EDITOR_DEF("network/http_proxy/host", "");
+	const int proxy_port = EDITOR_DEF("network/http_proxy/port", -1);
+	request->set_http_proxy(proxy_host, proxy_port);
+	request->set_https_proxy(proxy_host, proxy_port);
+}
+
 void EditorAssetLibraryItem::configure(const String &p_title, int p_asset_id, const String &p_category, int p_category_id, const String &p_author, int p_author_id, const String &p_cost) {
 	title->set_text(p_title);
 	asset_id = p_asset_id;
@@ -543,7 +552,7 @@ EditorAssetLibraryItemDownload::EditorAssetLibraryItemDownload() {
 	download = memnew(HTTPRequest);
 	add_child(download);
 	download->connect("request_completed", this, "_http_download_completed");
-	download->set_use_threads(EDITOR_DEF("asset_library/use_threads", true));
+	setup_http_request(download);
 
 	download_error = memnew(AcceptDialog);
 	add_child(download_error);
@@ -863,7 +872,7 @@ void EditorAssetLibrary::_request_image(ObjectID p_for, String p_image_url, Imag
 	iq.image_index = p_image_index;
 	iq.image_type = p_type;
 	iq.request = memnew(HTTPRequest);
-	iq.request->set_use_threads(EDITOR_DEF("asset_library/use_threads", true));
+	setup_http_request(iq.request);
 
 	iq.target = p_for;
 	iq.queue_id = ++last_queue_id;
@@ -1482,7 +1491,7 @@ EditorAssetLibrary::EditorAssetLibrary(bool p_templates_only) {
 
 	request = memnew(HTTPRequest);
 	add_child(request);
-	request->set_use_threads(EDITOR_DEF("asset_library/use_threads", true));
+	setup_http_request(request);
 	request->connect("request_completed", this, "_http_request_completed");
 
 	last_queue_id = 0;

scene/main/http_request.cpp

@@ -463,6 +463,14 @@ int HTTPRequest::get_body_size() const {
 	return body_len;
 }
 
+void HTTPRequest::set_http_proxy(const String &p_host, int p_port) {
+	client->set_http_proxy(p_host, p_port);
+}
+
+void HTTPRequest::set_https_proxy(const String &p_host, int p_port) {
+	client->set_https_proxy(p_host, p_port);
+}
+
 void HTTPRequest::set_timeout(int p_timeout) {
 	ERR_FAIL_COND(p_timeout < 0);
 	timeout = p_timeout;
@@ -508,6 +516,9 @@ void HTTPRequest::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_download_chunk_size"), &HTTPRequest::set_download_chunk_size);
 	ClassDB::bind_method(D_METHOD("get_download_chunk_size"), &HTTPRequest::get_download_chunk_size);
 
+	ClassDB::bind_method(D_METHOD("set_http_proxy", "host", "port"), &HTTPRequest::set_http_proxy);
+	ClassDB::bind_method(D_METHOD("set_https_proxy", "host", "port"), &HTTPRequest::set_https_proxy);
+
 	ClassDB::bind_method(D_METHOD("_timeout"), &HTTPRequest::_timeout);
 
 	ADD_PROPERTY(PropertyInfo(Variant::STRING, "download_file", PROPERTY_HINT_FILE), "set_download_file", "get_download_file");

scene/main/http_request.h

@@ -146,6 +146,10 @@ public:
 	int get_downloaded_bytes() const;
 	int get_body_size() const;
 
+	// Use empty string or -1 to unset.
+	void set_http_proxy(const String &p_host, int p_port);
+	void set_https_proxy(const String &p_host, int p_port);
+
 	HTTPRequest();
 	~HTTPRequest();
 };