@@ -49,6 +49,8 @@ class HTTPNode {
 	 * Adds a validation function that checks if the actual value of a parameter matches the expectation
 	 * @param paramIdx defines the ID of the parameter that should be checked (starts by 0)
 	 * @param validator the function (string -> bool) that checks if the parameter matches the expecatation
+	 * 
+	 * @see ValidatorFunctions.hpp if you need some predefined templates for functions
 	 */
 	void addURLParamValidator(uint8_t paramIdx, const HTTPValidationFunction * validator);
 
 
@@ -58,7 +58,10 @@ size_t HTTPRequest::readBytes(byte * buffer, size_t length) {
 		length = _remainingContent;
 	}
 
-	size_t bytesRead = _con->readBuffer(buffer, length);
+	size_t bytesRead = 0;
+	if (length > 0) {
+		_con->readBuffer(buffer, length);
+	}
 
 	if (_contentLengthSet) {
 		_remainingContent -= bytesRead;
 
@@ -0,0 +1,14 @@
+#include "ValidatorFunctions.hpp"
+
+namespace httpsserver {
+  bool validateNotEmpty(std::string s) {
+    return s!="";
+  }
+
+  bool validateUnsignedInteger(std::string s) {
+    for(size_t x = 0; x < s.size(); x++) {
+      if (s[x]<'0' || s[x]>'9') return false;
+    }
+    return true;
+  }
+}
@@ -0,0 +1,33 @@
+#ifndef SRC_VALIDATORFUNCTIONS_HPP_
+#define SRC_VALIDATORFUNCTIONS_HPP_
+
+#include <Arduino.h>
+#include <string>
+#undef max
+#undef min
+#include <functional>
+#include <memory>
+#include "HTTPValidator.hpp"
+#include "util.hpp"
+
+/**
+ * This file contains some validator functions that can be used to validate URL parameters.
+ * 
+ * They covor common cases like checking for integer, non-empty, ..., so the user of this library
+ * does not need to write them on his own.
+ */
+
+namespace httpsserver {
+
+  /** Checks that a string is not empty. */
+  bool validateNotEmpty(std::string s);
+
+  /**
+   * Checks that the value is a positive integer (combine it with newValidateUnsignedIntegerMax if
+   * you have constraints regarding the size of that number
+   */
+  bool validateUnsignedInteger(std::string s);
+
+}
+
+#endif
@@ -2,31 +2,41 @@
 
 namespace httpsserver {
 
-int parseInt(std::string s) {
-	int i = 0; // value
-	int m = 1; // multiplier
+uint32_t parseUInt(std::string s, uint32_t max) {
+	uint32_t i = 0; // value
 
 	// Check sign
 	size_t x = 0;
-	if (s[0]=='-') {
-
-		x = 1;
-	} else if (s[0]=='+') {
+	if (s[0]=='+') {
 		x = 1;
 	}
 
+	// We device max by 10, so we can check if we would exceed it by the next *10 multiplication
+	max/=10;
+
 	// Convert by base 10
 	for(; x < s.size(); x++) {
 		char c = s[x];
-		if (c >= '0' && c<='9') {
-			i = i*10 + (c-'0');
+		if (i < max) {
+			if (c >= '0' && c<='9') {
+				i = i*10 + (c-'0');
+			} else {
+				break;
+			}
 		} else {
-			break;
+			return max;
 		}
 	}
 
-	// Combine both.
-	return m*i;
+	return i;
+}
+
+int32_t parseInt(std::string s) {
+	uint32_t max = 0x7fffffff;
+	if (s[0]=='-') {
+		return -1 * parseUInt(s.substr(1,max));
+	}
+	return parseUInt(s,max);
 }
 
 std::string intToString(int i) {
 
@@ -8,7 +8,9 @@
 
 namespace httpsserver {
 
-int parseInt(std::string s);
+uint32_t parseUInt(std::string s, uint32_t max = 0xffffffff);
+
+int32_t parseInt(std::string s);
 
 std::string intToString(int i);