Avoid using chunked encoding for HTTPServerResponse.writeJsonBody by …

…default. Fixes #619.

source/vibe/db/redis/redis.d

@@ -841,6 +841,7 @@ private final class RedisConnection {
 	{
 		static if (is(ARG == string)) return arg.length;
 		else {
+			import vibe.internal.rangeutil;
 			long length;
 			auto rangeCnt = RangeCounter(&length);
 			rangeCnt.formattedWrite("%s", arg);
@@ -849,18 +850,6 @@ private final class RedisConnection {
 	}
 }
 
-private struct RangeCounter {
-	import std.utf;
-	long* length;
-
-	this(long* _captureLength) {
-		length = _captureLength;
-	}
-
-	void put(dchar ch) { *length += codeLength!char(ch); }
-	void put(string str) { *length += str.length; }
-}
-
 private void _request_void(ARGS...)(RedisConnection conn, string command, ARGS args)
 {
 	import vibe.stream.wrapper;

source/vibe/http/server.d

@@ -815,7 +815,7 @@ final class HTTPServerResponse : HTTPResponse {
 	}
 
 	/// Writes a JSON message with the specified status
-	void writeJsonBody(T)(T data, int status = HTTPStatus.OK, string content_type = "application/json; charset=UTF-8")
+	void writeJsonBody(T)(T data, int status = HTTPStatus.OK, string content_type = "application/json; charset=UTF-8", bool allow_chunked = false)
 	{
 		import std.traits;
 		import vibe.stream.wrapper;
@@ -826,6 +826,16 @@ final class HTTPServerResponse : HTTPResponse {
 
 		statusCode = status;
 		headers["Content-Type"] = content_type;
+
+		// set an explicit content-length field if chunked encoding is not allowed
+		if (!allow_chunked) {
+			import vibe.internal.rangeutil;
+			long length = 0;
+			auto counter = RangeCounter(&length);
+			serializeToJson(counter, data);
+			headers["Content-Length"] = formatAlloc(m_requestAlloc, "%d", length);
+		}
+
 		auto rng = StreamOutputRange(bodyWriter);
 		serializeToJson(&rng, data);
 	}

source/vibe/internal/rangeutil.d

@@ -0,0 +1,13 @@
+module vibe.internal.rangeutil;
+
+struct RangeCounter {
+	import std.utf;
+	long* length;
+
+	this(long* _captureLength) {
+		length = _captureLength;
+	}
+
+	void put(dchar ch) { *length += codeLength!char(ch); }
+	void put(string str) { *length += str.length; }
+}