Add support for client side caching and revalidation (HTTP If-Modified-Since, must-revalidate and 304 Not Modified)

12 files changed, 79 insertions, 37 deletions

diff --git a/project2/cgi/cgiAppEngine.cpp b/project2/cgi/cgiAppEngine.cpp
index cc7a3aa..d9948e4 100644
--- a/project2/cgi/cgiAppEngine.cpp
+++ b/project2/cgi/cgiAppEngine.cpp
@@ -1,5 +1,6 @@
 #include <pch.hpp>
 #include "cgiAppEngine.h"
+#include "cgiResult.h"
 #include <cgicc/Cgicc.h>
 #include <cgicc/HTTPHeader.h>
 #include "cgiEnvironment.h"
@@ -41,39 +42,6 @@ CgiApplicationEngine::env() const
 	return _env;
 }
 
-class CgiResult : public TransformChainLink {
-	public:
-		CgiResult(CgiApplicationEngine::HttpHeaderPtr & h, std::ostream & s, const std::string & e) :
-			header(h),
-			stream(s),
-			encoding(e) {
-		}
-		CgiApplicationEngine::HttpHeaderPtr header;
-		std::ostream & stream;
-		const std::string encoding;
-};
-
-class WritableToCgiResult : public TransformImpl<WritableContent, CgiResult> {
-	public:
-		void transform(const WritableContent * wc, CgiResult * cr) const {
-			cr->header->addHeader("Content-Type", Glib::ustring::compose("%1; charset=%2", wc->getContentType(), cr->encoding));
-			cr->header->render(cr->stream);
-			wc->writeTo(cr->stream, cr->encoding);
-		}
-};
-DECLARE_TRANSFORM(WritableToCgiResult);
-
-class StaticToCgiResult : public TransformImpl<StaticContent, CgiResult> {
-	public:
-		void transform(const StaticContent * sc, CgiResult * cr) const {
-			cr->header->addHeader("Content-Type", Glib::ustring::compose("%1; charset=%2", sc->getContentType(), sc->getEncoding()));
-			cr->header->addHeader("Content-Length", Glib::ustring::compose("%1", sc->getSizeInBytes()));
-			cr->header->render(cr->stream);
-			sc->writeTo(cr->stream);
-		}
-};
-DECLARE_TRANSFORM(StaticToCgiResult);
-
 TransformSourcePtr
 finalTransformSource(TransformSourcePtr ts)
 {
diff --git a/project2/cgi/cgiEnvironment.cpp b/project2/cgi/cgiEnvironment.cpp
index a5d4af2..725199b 100644
--- a/project2/cgi/cgiEnvironment.cpp
+++ b/project2/cgi/cgiEnvironment.cpp
@@ -6,6 +6,7 @@
 #include <map>
 #include <cgicc/Cgicc.h>
 #include <glibmm/regex.h>
+#include <curl/curl.h>
 
 std::vector<std::string>
 makeVector(const boost::filesystem::path & y)
@@ -113,6 +114,11 @@ CgiEnvironment::platform() const
 	return hpi->derivedPlatform();
 }
 
+time_t
+CgiEnvironment::getRequestModifiedSince() const
+{
+	return curl_getdate(cgienv->getenv("HTTP_IF_MODIFIED_SINCE").c_str(), NULL);
+}
 
 Glib::ustring
 CgiEnvironment::getParamUri(unsigned int p) const
diff --git a/project2/cgi/cgiEnvironment.h b/project2/cgi/cgiEnvironment.h
index be6732c..5aded69 100644
--- a/project2/cgi/cgiEnvironment.h
+++ b/project2/cgi/cgiEnvironment.h
@@ -37,6 +37,7 @@ class CgiEnvironment : public Environment {
 		std::string getScriptName() const;
 		std::string getRedirectURL() const;
 		std::string getRequestMethod() const;
+		time_t getRequestModifiedSince() const;
 		std::string getCookieValue(const std::string & name) const;
 
 		void setCGICC(const cgicc::Cgicc *, const CgiEnvInput * cgienv);
diff --git a/project2/cgi/cgiResult.h b/project2/cgi/cgiResult.h
new file mode 100644
index 0000000..35165c8
--- /dev/null
+++ b/project2/cgi/cgiResult.h
@@ -0,0 +1,20 @@
+#ifndef CGIRESULT_H
+#define CGIRESULT_H
+
+#include "transform.h"
+#include "cgiAppEngine.h"
+
+class CgiResult : public TransformChainLink {
+	public:
+		CgiResult(CgiApplicationEngine::HttpHeaderPtr & h, std::ostream & s, const std::string & e) :
+			header(h),
+			stream(s),
+			encoding(e) {
+		}
+		CgiApplicationEngine::HttpHeaderPtr header;
+		std::ostream & stream;
+		const std::string encoding;
+};
+
+#endif
+
diff --git a/project2/cgi/cgiResultStatic.cpp b/project2/cgi/cgiResultStatic.cpp
new file mode 100644
index 0000000..542212e
--- /dev/null
+++ b/project2/cgi/cgiResultStatic.cpp
@@ -0,0 +1,22 @@
+#include <pch.hpp>
+#include <time.h>
+#include "cgiResult.h"
+
+class StaticToCgiResult : public TransformImpl<StaticContent, CgiResult> {
+	public:
+		void transform(const StaticContent * sc, CgiResult * cr) const {
+			cr->header->addHeader("Content-Type", Glib::ustring::compose("%1; charset=%2", sc->getContentType(), sc->getEncoding()));
+			cr->header->addHeader("Content-Length", Glib::ustring::compose("%1", sc->getSizeInBytes()));
+			char buf[100];
+			struct tm stm;
+			time_t mtime = sc->getModifiedTime();
+			gmtime_r(&mtime, &stm);
+			strftime(buf, sizeof(buf), "%a, %d %b %Y %T %z", &stm);
+			cr->header->addHeader("Last-Modified", buf);
+			cr->header->addHeader("Cache-Control", "must-revalidate");
+			cr->header->render(cr->stream);
+			sc->writeTo(cr->stream);
+		}
+};
+DECLARE_TRANSFORM(StaticToCgiResult);
+
diff --git a/project2/cgi/cgiResultWritable.cpp b/project2/cgi/cgiResultWritable.cpp
new file mode 100644
index 0000000..ea17d3b
--- /dev/null
+++ b/project2/cgi/cgiResultWritable.cpp
@@ -0,0 +1,14 @@
+#include <pch.hpp>
+#include "cgiResult.h"
+
+class WritableToCgiResult : public TransformImpl<WritableContent, CgiResult> {
+	public:
+		void transform(const WritableContent * wc, CgiResult * cr) const {
+			cr->header->addHeader("Content-Type", Glib::ustring::compose("%1; charset=%2", wc->getContentType(), cr->encoding));
+			cr->header->addHeader("Cache-control", "no-cache");
+			cr->header->render(cr->stream);
+			wc->writeTo(cr->stream, cr->encoding);
+		}
+};
+DECLARE_TRANSFORM(WritableToCgiResult);
+
diff --git a/project2/cgi/cgiStageCacheHit.cpp b/project2/cgi/cgiStageCacheHit.cpp
index 8d854b6..d398e8f 100644
--- a/project2/cgi/cgiStageCacheHit.cpp
+++ b/project2/cgi/cgiStageCacheHit.cpp
@@ -20,8 +20,6 @@ CgiApplicationEngine::CacheHitStage::run()
 CgiApplicationEngine::HttpHeaderPtr
 CgiApplicationEngine::CacheHitStage::getHeader() const
 {
-	Project2HttpHeader * header = new Project2HttpHeader("200 OK");
-	header->addHeader("Cache-control", "no-cache");
-	return HttpHeaderPtr(header);
+	return HttpHeaderPtr(new Project2HttpHeader("200 OK"));
 }
 
diff --git a/project2/cgi/cgiStagePresent.cpp b/project2/cgi/cgiStagePresent.cpp
index b6bb11e..d997e1d 100644
--- a/project2/cgi/cgiStagePresent.cpp
+++ b/project2/cgi/cgiStagePresent.cpp
@@ -22,8 +22,13 @@ CgiApplicationEngine::PresentStage::run()
 {
 	runChecks();
 	PresenterCaches backFill;
+	time_t reqMS = this->env()->getRequestModifiedSince();
 	BOOST_FOREACH(const PresenterCachePtr & pc, caches) {
 		if (pc->check(root->script->modifiedTime())) {
+			if (reqMS >= pc->getModifiedTime()) {
+				header = HttpHeaderPtr(new Project2HttpHeader("304 Not Modified"));
+				return NextStage(NULL, this, NULL, NULL);
+			}
 			CacheHitStage * chs = new CacheHitStage(root, pc);
 			chs->caches = backFill;
 			return NextStage(NULL, chs, pc, NULL);
@@ -63,7 +68,6 @@ CgiApplicationEngine::ResponseStage::ResponseStage(ScriptNodePtr r) :
 CgiApplicationEngine::HttpHeaderPtr
 CgiApplicationEngine::PresentStage::getHeader() const
 {
-	header->addHeader("Cache-control", "no-cache");
 	return header;
 }
 
diff --git a/project2/cgi/testCgi.cpp b/project2/cgi/testCgi.cpp
index 8a4ccb6..fb480a4 100644
--- a/project2/cgi/testCgi.cpp
+++ b/project2/cgi/testCgi.cpp
@@ -56,6 +56,7 @@ class TestInput : public cgicc::CgiInput, public CgiEnvInput {
 				TESTOPT("HTTP_REFERER", "", "Referrer")
 				TESTOPT("HTTP_COOKIE", "", "Cookie")
 				TESTOPT("HTTPS", "No", "HTTPS?")
+				TESTOPT("HTTP_IF_MODIFIED_SINCE", "", "Client cached copy timestamp")
 				("runCount", Options::value(&runCount, 1), "Repeat run this many times")
 				;
 			FileOptions fo(".testCgi.settings");
diff --git a/project2/common/presenterCache.h b/project2/common/presenterCache.h
index 63ff9f0..891535c 100644
--- a/project2/common/presenterCache.h
+++ b/project2/common/presenterCache.h
@@ -9,6 +9,7 @@ class PresenterCache : public SourceObject, public virtual TransformSource, publ
 	public:
 		PresenterCache(ScriptNodePtr);
 		virtual bool check(time_t scriptMtime) const = 0;
+		virtual time_t getModifiedTime() const = 0;
 
 		virtual std::ostream & writeCache(const std::string & ct, const std::string & encoding) = 0;
 		virtual void flushCache();
diff --git a/project2/common/transform.h b/project2/common/transform.h
index 973f4f0..2061374 100644
--- a/project2/common/transform.h
+++ b/project2/common/transform.h
@@ -82,6 +82,7 @@ class StaticContent {
 	public:
 		virtual Glib::ustring getContentType() const = 0;
 		virtual Glib::ustring getEncoding() const = 0;
+		virtual time_t getModifiedTime() const = 0;
 		virtual size_t getSizeInBytes() const = 0;
 		virtual void writeTo(std::ostream &) const = 0;
 };
diff --git a/project2/files/presenterCache.cpp b/project2/files/presenterCache.cpp
index 9c8ace2..d475824 100644
--- a/project2/files/presenterCache.cpp
+++ b/project2/files/presenterCache.cpp
@@ -93,6 +93,12 @@ class FilePresenterCache : public PresenterCache, public StaticContent, public S
 		{
 			return getXAttr("user.content-type");
 		}
+		time_t getModifiedTime() const
+		{
+			struct stat st;
+			safesys<CacheFileXAttr>(-1, fstat(*myCache, &st));
+			return st.st_mtime;
+		}
 		Glib::ustring getXAttr(const char * attr) const
 		{
 			char buf[BUFSIZ];