From 328f8930e80068bf0b04411f5ca2b1e4702f8515 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Fri, 8 Feb 2019 21:13:13 +0000
Subject: Properly generic parameter extraction

---
 icespider/core/ihttpRequest.cpp | 48 ++++++-----------------------------------
 icespider/core/ihttpRequest.h   | 47 +++++++++++++++++++++++++++++++++++-----
 2 files changed, 48 insertions(+), 47 deletions(-)

diff --git a/icespider/core/ihttpRequest.cpp b/icespider/core/ihttpRequest.cpp
index aaa0c26..b8d866a 100644
--- a/icespider/core/ihttpRequest.cpp
+++ b/icespider/core/ihttpRequest.cpp
@@ -103,8 +103,8 @@ namespace IceSpider {
 		}
 	}
 
-	const std::string &
-	IHttpRequest::getURLParam(unsigned int idx) const
+	OptionalString
+	IHttpRequest::getURLParam(const unsigned int & idx) const
 	{
 		auto & url = getRequestPath();
 		if (idx >= url.size()) {
@@ -170,45 +170,9 @@ namespace IceSpider {
 		s.second->Serialize(mp);
 	}
 
-	std::optional<std::string>
-	operator!(const std::optional<std::string_view> & sv)
-	{
-		// TODO: Fix this mess (only required if operation requires std::string)
-		if (sv) return { std::string(*sv) };
-		return {};
-	}
-
-#define getParams(T) \
-	template<> T IHttpRequest::getURLParam<T>(unsigned int idx) const { \
-		return wrapLexicalCast<T>(getURLParam(idx)); } \
-	template<> std::optional<T> IHttpRequest::getQueryStringParam<T>(const std::string_view & key) const { \
-		return optionalLexicalCast<T>(getQueryStringParam(key)); } \
-	template<> std::optional<T> IHttpRequest::getCookieParam<T>(const std::string_view & key) const { \
-		return optionalLexicalCast<T>(getCookieParam(key)); } \
-	template<> std::optional<T> IHttpRequest::getHeaderParam<T>(const std::string_view & key) const { \
-		return optionalLexicalCast<T>(getHeaderParam(key)); }
-	template<> std::string_view IHttpRequest::getURLParam<std::string_view>(unsigned int idx) const {
-		return getURLParam(idx); }
-	template<> OptionalString IHttpRequest::getQueryStringParam<std::string_view>(const std::string_view & key) const { \
-		return getQueryStringParam(key); }
-	template<> OptionalString IHttpRequest::getCookieParam<std::string_view>(const std::string_view & key) const { \
-		return getCookieParam(key); }
-	template<> OptionalString IHttpRequest::getHeaderParam<std::string_view>(const std::string_view & key) const { \
-		return getHeaderParam(key); }
-	template<> std::string IHttpRequest::getURLParam<std::string>(unsigned int idx) const {
-		return getURLParam(idx); }
-	template<> std::optional<std::string> IHttpRequest::getQueryStringParam<std::string>(const std::string_view & key) const { \
-		return !getQueryStringParam(key); }
-	template<> std::optional<std::string> IHttpRequest::getCookieParam<std::string>(const std::string_view & key) const { \
-		return !getCookieParam(key); }
-	template<> std::optional<std::string> IHttpRequest::getHeaderParam<std::string>(const std::string_view & key) const { \
-		return !getHeaderParam(key); }
-
-	getParams(bool);
-	getParams(Ice::Short);
-	getParams(Ice::Int);
-	getParams(Ice::Long);
-	getParams(Ice::Float);
-	getParams(Ice::Double);
+	static_assert(std::is_convertible<OptionalString::value_type, std::string_view>::value);
+	static_assert(!std::is_convertible<OptionalString::value_type, std::string>::value);
+	static_assert(std::is_constructible<OptionalString::value_type, std::string>::value);
 }
 
+
diff --git a/icespider/core/ihttpRequest.h b/icespider/core/ihttpRequest.h
index 5471209..fb56efb 100644
--- a/icespider/core/ihttpRequest.h
+++ b/icespider/core/ihttpRequest.h
@@ -9,6 +9,7 @@
 #include <slicer/slicer.h>
 #include <Ice/Optional.h>
 #include <boost/lexical_cast.hpp>
+#include "exceptions.h"
 
 namespace IceSpider {
 	class Core;
@@ -27,7 +28,7 @@ namespace IceSpider {
 			virtual PathElements & getRequestPath() = 0;
 			virtual HttpMethod getRequestMethod() const = 0;
 
-			const std::string & getURLParam(unsigned int) const;
+			OptionalString getURLParam(const unsigned int &) const;
 			virtual OptionalString getQueryStringParam(const std::string_view &) const = 0;
 			virtual OptionalString getHeaderParam(const std::string_view &) const = 0;
 			virtual OptionalString getCookieParam(const std::string_view &) const = 0;
@@ -41,8 +42,35 @@ namespace IceSpider {
 
 			virtual std::ostream & dump(std::ostream & s) const = 0;
 
+			template<typename T, typename K>
+			inline
+			std::optional<T> getFrom(const K & key, OptionalString (IHttpRequest::*src)(const K &) const) const
+			{
+				if (auto v = (this->*src)(key)) {
+					if constexpr (std::is_convertible<std::string_view, T>::value) {
+						return *v;
+					}
+					else if constexpr (std::is_constructible<std::string_view, T>::value) {
+						return T(*v);
+					}
+					else {
+						try {
+							return boost::lexical_cast<T>(*v);
+						}
+						catch (const boost::bad_lexical_cast & e) {
+							throw Http400_BadRequest();
+						}
+					}
+				}
+				else {	
+					return std::nullopt;
+				}
+			}
 			template<typename T>
-			T getURLParam(unsigned int) const;
+			T getURLParam(unsigned int n) const
+			{
+				return *getFrom<T, unsigned int>(n, &IHttpRequest::getURLParam);
+			}
 			template<typename T>
 			std::optional<T> getBody() const
 			{
@@ -79,11 +107,20 @@ namespace IceSpider {
 				}
 			}
 			template<typename T>
-			std::optional<T> getQueryStringParam(const std::string_view & key) const;
+			std::optional<T> getQueryStringParam(const std::string_view & key) const
+			{
+				return getFrom<T, std::string_view>(key, &IHttpRequest::getQueryStringParam);
+			}
 			template<typename T>
-			std::optional<T> getHeaderParam(const std::string_view & key) const;
+			std::optional<T> getHeaderParam(const std::string_view & key) const
+			{
+				return getFrom<T, std::string_view>(key, &IHttpRequest::getHeaderParam);
+			}
 			template<typename T>
-			std::optional<T> getCookieParam(const std::string_view & key) const;
+			std::optional<T> getCookieParam(const std::string_view & key) const
+			{
+				return getFrom<T, std::string_view>(key, &IHttpRequest::getCookieParam);
+			}
 			virtual void response(short, const std::string_view &) const = 0;
 			template<typename T>
 			void response(const IRouteHandler * route, const T & t) const
-- 
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