--- a/src/HTTPHandler.h	Thu Apr 21 00:22:02 2022 +0200
+++ b/src/HTTPHandler.h	Thu Apr 21 00:57:30 2022 +0200
@@ -40,6 +40,7 @@
 
 #include "Configuration.h"
 #include "HTTPClient.h"
+#include "Hex.h"
 
 namespace relpipe {
 namespace tr {
@@ -129,26 +130,6 @@
 		return convertor.from_bytes(buffer);
 	}
 
-	relpipe::common::type::StringX bodyToText(const std::string& body, bool* validEncoding = nullptr) {
-		try {
-			if (validEncoding) *validEncoding = true;
-			// TODO: use encoding from the HTTP response headers instead of the constant one?
-			return convertor.from_bytes(body);
-		} catch (...) {
-			if (validEncoding) *validEncoding = false;
-			std::stringstream filtered;
-			for (char ch : body) filtered << (ch >= ' ' && ch < 127 ? ch : '.');
-			return convertor.from_bytes(filtered.str());
-		}
-	}
-
-	relpipe::common::type::StringX bodyToHex(const std::string& body) {
-		std::stringstream hex;
-		hex << std::hex << std::setfill('0') << std::hex;
-		for (size_t i = 0, size = body.size(); i < size; i++) hex << std::setw(2) << (0xff & body[i]);
-		return convertor.from_bytes(hex.str());
-	}
-
 public:
 
 	HTTPHandler(shared_ptr<relpipe::writer::RelationalWriter> relationalWriter, Configuration configuration) : relationalWriter(relationalWriter), configuration(configuration) {
@@ -211,8 +192,10 @@
 		if (attributeName == L"id") requestId = value;
 		else if (attributeName == L"url") request.url = convertor.to_bytes(value);
 		else if (attributeName == L"method") request.method = parseMethod(value);
-		else if (attributeName == L"text") request.body = convertor.to_bytes(value);
-		else if (attributeName == L"data") request.body = "TODO: read binary data: " + convertor.to_bytes(value); // TODO: read hex/binary request body
+		else if (attributeName == L"text" && value.size()) request.body = convertor.to_bytes(value);
+		else if (attributeName == L"data" && value.size()) request.body = Hex::fromHex(value).str();
+		else if (attributeName == L"text"); // keep empty or value from 'data'
+		else if (attributeName == L"data"); // keep empty or value from 'text'
 		else if (isHeaderAttribute(attributeName)) appendRequestHeader(fetchHeaderName(attributeName), value);
 		else throw std::invalid_argument("Unsupported attribute in the header relation: " + convertor.to_bytes(attributeName + L" = " + value));
 
@@ -248,8 +231,8 @@
 			bool validText = false;
 			relationalWriter->writeAttribute(requestId);
 			relationalWriter->writeAttribute(convertor.from_bytes(request.url));
-			relationalWriter->writeAttribute(bodyToText(body, &validText));
-			relationalWriter->writeAttribute(bodyToHex(body)); // TODO: return as an octet-string (when supported) instead of hexadecimal
+			relationalWriter->writeAttribute(Hex::toTxt(body, &validText));
+			relationalWriter->writeAttribute(Hex::toHex(body)); // TODO: return as an octet-string (when supported) instead of hexadecimal
 			relationalWriter->writeAttribute(&validText, typeid (validText));
 			relationalWriter->writeAttribute(&responseCode, typeid (responseCode));
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Hex.h	Thu Apr 21 00:57:30 2022 +0200
@@ -0,0 +1,85 @@
+/**
+ * Relational pipes
+ * Copyright © 2022 František Kučera (Frantovo.cz, GlobalCode.info)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <iomanip>
+#include <iostream>
+#include <sstream>
+#include <vector>
+#include <stdexcept>
+
+namespace relpipe {
+namespace tr {
+namespace http {
+
+class Hex {
+private:
+
+	Hex() {
+	}
+
+	static char fromHex(wchar_t ch) {
+		if (L'0' <= ch && ch <= L'9') return ch - L'0';
+		else if (L'a' <= ch && ch <= L'f') return ch - L'a' + 10;
+		else throw std::invalid_argument("Unable to decode hexadeximal string.");
+	}
+
+public:
+
+	static std::stringstream fromHex(const std::wstring& hex) {
+		std::stringstream octets;
+
+		char octet = 0;
+
+		for (size_t i = 0, limit = hex.size(); i < limit; i++) {
+			if (i % 2 == 0) {
+				octet = fromHex(hex[i]) << 4;
+			} else {
+				octet += fromHex(hex[i]);
+				octets.put(octet);
+			}
+		}
+
+		return octets;
+	}
+
+	static std::wstring toHex(const std::string& octets) {
+		std::wstring_convert < codecvt_utf8<wchar_t>> convertor; // TODO: do not create converter each time
+		std::stringstream hex;
+		hex << std::hex << std::setfill('0') << std::hex;
+		for (size_t i = 0, size = octets.size(); i < size; i++) hex << std::setw(2) << (0xff & octets[i]);
+		return convertor.from_bytes(hex.str());
+	}
+
+	static std::wstring toTxt(const std::string& octets, bool* validEncoding = nullptr) {
+		std::wstring_convert < codecvt_utf8<wchar_t>> convertor; // TODO: do not create converter each time
+		try {
+			if (validEncoding) *validEncoding = true;
+			// TODO: use encoding from the HTTP response headers instead of the constant one?
+			return convertor.from_bytes(octets);
+		} catch (...) {
+			if (validEncoding) *validEncoding = false;
+			std::stringstream filtered;
+			for (char ch : octets) filtered << (ch >= ' ' && ch < 127 ? ch : '.');
+			return convertor.from_bytes(filtered.str());
+		}
+	}
+};
+
+}
+}
+}