diff --git a/src/protocol/http/http.c b/src/protocol/http/http.c
index 9f42b21a..7461c736 100644
--- a/src/protocol/http/http.c
+++ b/src/protocol/http/http.c
@@ -350,10 +350,22 @@ add_url_to_http_string(struct string *header, struct uri *uri, uri_component_T c
 	 * before. We should probably encode all URLs as early as
 	 * possible, and possibly decode them back in protocol
 	 * backends. --pasky */
-	char *string = get_uri_string(uri, components);
-	char *data = string;
+	struct string encoded;
+	char *string;
+	char *data;
 
-	if (!string) return;
+	if (!init_string(&encoded)) {
+		return;
+	}
+	string = get_uri_string(uri, components);
+
+	if (!string) {
+		done_string(&encoded);
+		return;
+	}
+	encode_uri_string_percent(&encoded, string, -1);
+	mem_free(string);
+	data = encoded.source;
 
 	while (*data) {
 		int len = strcspn(data, " \t\r\n\\");
@@ -369,8 +381,7 @@ add_url_to_http_string(struct string *header, struct uri *uri, uri_component_T c
 
 		data	+= len;
 	}
-
-	mem_free(string);
+	done_string(&encoded);
 }
 
 /* Parse from @end - 1 to @start and set *@value to integer found.
diff --git a/src/protocol/uri.c b/src/protocol/uri.c
index 90d9df14..1e9c08c6 100644
--- a/src/protocol/uri.c
+++ b/src/protocol/uri.c
@@ -1422,6 +1422,29 @@ encode_uri_string(struct string *string, const char *name, int namelen,
 	}
 }
 
+void
+encode_uri_string_percent(struct string *string, const char *name, int namelen)
+{
+	char n[4];
+	const char *end;
+
+	n[0] = '%';
+	n[3] = '\0';
+
+	if (namelen < 0) namelen = strlen(name);
+
+	for (end = name + namelen; name < end; name++) {
+		if (safe_char(*name) || (*name == '/') || (*name == '%')) {
+			add_char_to_string(string, *name);
+		} else {
+			/* Hex it. */
+			n[1] = Hx((((int) *name) & 0xF0) >> 4);
+			n[2] = Hx(((int) *name) & 0xF);
+			add_bytes_to_string(string, n, sizeof(n) - 1);
+		}
+	}
+}
+
 void
 encode_win32_uri_string(struct string *string, char *name, int namelen)
 {
diff --git a/src/protocol/uri.h b/src/protocol/uri.h
index 837cd697..0337ae50 100644
--- a/src/protocol/uri.h
+++ b/src/protocol/uri.h
@@ -321,6 +321,8 @@ int get_uri_port(const struct uri *uri);
 void encode_uri_string(struct string *string, const char *name, int namelen,
 		       int convert_slashes);
 
+void encode_uri_string_percent(struct string *string, const char *name, int namelen);
+
 /* special version for Windows directory listing */
 void encode_win32_uri_string(struct string *string, char *name, int namelen);