Write sha1 hashes onto presenter cache files and validate client caches with them via etag

9 files changed, 77 insertions, 11 deletions

diff --git a/project2/cgi/cgiEnvironment.cpp b/project2/cgi/cgiEnvironment.cpp
index 725199b..af99f0d 100644
--- a/project2/cgi/cgiEnvironment.cpp
+++ b/project2/cgi/cgiEnvironment.cpp
@@ -1,5 +1,6 @@
 #include <pch.hpp>
 #include <boost/version.hpp>
+#include <boost/algorithm/string.hpp>
 #include "cgiEnvironment.h"
 #include "appEngine.h"
 #include "exceptions.h"
@@ -114,6 +115,15 @@ CgiEnvironment::platform() const
 	return hpi->derivedPlatform();
 }
 
+CgiEnvironment::ETags
+CgiEnvironment::getRequestETags() const
+{
+	const std::string e = cgienv->getenv("HTTP_IF_NONE_MATCH");
+	ETags etags;
+	boost::split(etags, e, boost::is_any_of(" ,"), boost::algorithm::token_compress_on);
+	return etags;
+}
+
 time_t
 CgiEnvironment::getRequestModifiedSince() const
 {
diff --git a/project2/cgi/cgiEnvironment.h b/project2/cgi/cgiEnvironment.h
index 5aded69..cfe9c7b 100644
--- a/project2/cgi/cgiEnvironment.h
+++ b/project2/cgi/cgiEnvironment.h
@@ -27,6 +27,9 @@ class HostnamePlatformIdentifier : public Options::Target {
 
 class CgiEnvironment : public Environment {
 	public:
+		typedef std::string ETag;
+		typedef std::vector<ETag> ETags;
+
 		CgiEnvironment();
 		virtual ~CgiEnvironment();
 
@@ -37,6 +40,7 @@ class CgiEnvironment : public Environment {
 		std::string getScriptName() const;
 		std::string getRedirectURL() const;
 		std::string getRequestMethod() const;
+		ETags getRequestETags() const;
 		time_t getRequestModifiedSince() const;
 		std::string getCookieValue(const std::string & name) const;
 
diff --git a/project2/cgi/cgiResultStatic.cpp b/project2/cgi/cgiResultStatic.cpp
index 542212e..b5fecd7 100644
--- a/project2/cgi/cgiResultStatic.cpp
+++ b/project2/cgi/cgiResultStatic.cpp
@@ -13,6 +13,7 @@ class StaticToCgiResult : public TransformImpl<StaticContent, CgiResult> {
 			gmtime_r(&mtime, &stm);
 			strftime(buf, sizeof(buf), "%a, %d %b %Y %T %z", &stm);
 			cr->header->addHeader("Last-Modified", buf);
+			cr->header->addHeader("Etag", sc->getSHA1());
 			cr->header->addHeader("Cache-Control", "must-revalidate");
 			cr->header->render(cr->stream);
 			sc->writeTo(cr->stream);
diff --git a/project2/cgi/cgiStagePresent.cpp b/project2/cgi/cgiStagePresent.cpp
index d997e1d..1c6edaf 100644
--- a/project2/cgi/cgiStagePresent.cpp
+++ b/project2/cgi/cgiStagePresent.cpp
@@ -2,6 +2,7 @@
 #include "cgiAppEngine.h"
 #include "cgiEnvironment.h"
 #include "cgiHttpHeader.h"
+#include "safeMapFind.h"
 #include <boost/foreach.hpp>
 #include <boost/bind.hpp>
 
@@ -23,9 +24,10 @@ CgiApplicationEngine::PresentStage::run()
 	runChecks();
 	PresenterCaches backFill;
 	time_t reqMS = this->env()->getRequestModifiedSince();
+	CgiEnvironment::ETags etags = this->env()->getRequestETags();
 	BOOST_FOREACH(const PresenterCachePtr & pc, caches) {
 		if (pc->check(root->script->modifiedTime())) {
-			if (reqMS >= pc->getModifiedTime()) {
+			if (reqMS >= pc->getModifiedTime() && (etags.empty() || containerContains(etags, pc->getSHA1()))) {
 				header = HttpHeaderPtr(new Project2HttpHeader("304 Not Modified"));
 				return NextStage(NULL, this, NULL, NULL);
 			}
diff --git a/project2/common/presenterCache.h b/project2/common/presenterCache.h
index 891535c..15375da 100644
--- a/project2/common/presenterCache.h
+++ b/project2/common/presenterCache.h
@@ -5,11 +5,10 @@
 #include "scripts.h"
 #include "iHaveParameters.h"
 
-class PresenterCache : public SourceObject, public virtual TransformSource, public IHaveParameters {
+class PresenterCache : public SourceObject, public virtual TransformSource, public StaticContent, public SourceOf<StaticContent>, public IHaveParameters {
 	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/safeMapFind.h b/project2/common/safeMapFind.h
index b461074..a5786bc 100644
--- a/project2/common/safeMapFind.h
+++ b/project2/common/safeMapFind.h
@@ -34,5 +34,12 @@ safeMapLookup(const Map & map, const typename Map::key_type & key)
 	return i->second;
 }
 
+template <class Cont>
+bool
+containerContains(const Cont & c, const typename Cont::value_type & v)
+{
+	return (std::find(c.begin(), c.end(), v) != c.end());
+}
+
 #endif
 
diff --git a/project2/common/transform.h b/project2/common/transform.h
index 2061374..ef8fe83 100644
--- a/project2/common/transform.h
+++ b/project2/common/transform.h
@@ -83,6 +83,7 @@ class StaticContent {
 		virtual Glib::ustring getContentType() const = 0;
 		virtual Glib::ustring getEncoding() const = 0;
 		virtual time_t getModifiedTime() const = 0;
+		virtual std::string getSHA1() const = 0;
 		virtual size_t getSizeInBytes() const = 0;
 		virtual void writeTo(std::ostream &) const = 0;
 };
diff --git a/project2/files/Jamfile.jam b/project2/files/Jamfile.jam
index bdb851f..b8ae31e 100644
--- a/project2/files/Jamfile.jam
+++ b/project2/files/Jamfile.jam
@@ -5,6 +5,7 @@ alias glibmm : : : :
 lib boost_system : : <name>boost_system ;
 lib boost_filesystem : : <name>boost_filesystem ;
 lib boost_iostreams : : <name>boost_iostreams ;
+lib gcrypt : : <name>gcrypt ;
 
 cpp-pch pch : pch.hpp :
 	<library>../common//p2common
@@ -18,6 +19,7 @@ lib p2files :
 	<library>boost_filesystem
 	<library>boost_system
 	<library>boost_iostreams
+	<library>gcrypt
 	<library>../common//p2common
 	: :
 	<include>.
diff --git a/project2/files/presenterCache.cpp b/project2/files/presenterCache.cpp
index d475824..90c2bc9 100644
--- a/project2/files/presenterCache.cpp
+++ b/project2/files/presenterCache.cpp
@@ -14,11 +14,13 @@
 #include <boost/tuple/tuple_comparison.hpp>
 #include <glibmm/convert.h>
 #include <sys/file.h>
+#include <gcrypt.h>
 
 SimpleSysCallException(OpenCacheFile);
 SimpleSysCallException(StatCacheFile);
 SimpleSysCallException(LockCacheFile);
 SimpleSysCallException(TruncateCacheFile);
+SimpleSysCallException(WriteCacheFile);
 SimpleSysCallException(CacheFileXAttr);
 
 template <class E>
@@ -29,7 +31,7 @@ int safesys(int n, int r) {
 	return r;
 }
 
-class FilePresenterCache : public PresenterCache, public StaticContent, public SourceOf<StaticContent> {
+class FilePresenterCache : public PresenterCache {
 	public:
 		typedef std::vector<std::string> Path;
 		typedef std::map<std::string, VariableType> Parameters;
@@ -47,13 +49,46 @@ class FilePresenterCache : public PresenterCache, public StaticContent, public S
 		typedef boost::intrusive_ptr<CacheFile> CacheFilePtr;
 		typedef std::map<Key, CacheFilePtr> OpenCaches;
 
+		class WriteCacheFile : public boost::iostreams::sink {
+			public:
+				WriteCacheFile(int f) : fd(f) {
+					gcry_md_open(&state, GCRY_MD_SHA1, 0);
+				}
+				WriteCacheFile(const WriteCacheFile & wcf) : fd(dup(wcf.fd)) {
+					gcry_md_copy(&state, wcf.state);
+				}
+				~WriteCacheFile() {
+					gcry_md_close(state);
+					::close(fd);
+				}
+				std::streamsize write(const char * data, std::streamsize len)
+				{
+					gcry_md_write(state, data, len);
+					return safesys<WriteCacheFile>(-1, ::write(fd, data, len));
+				}
+				std::string hash() const
+				{
+					int hash_len = gcry_md_get_algo_dlen(GCRY_MD_SHA1);
+					unsigned char * hash = gcry_md_read(state, GCRY_MD_SHA1);
+					std::string hashstr(hash_len * 2, '-');
+					char * p = &hashstr[0];
+					for (int i = 0; i < hash_len; i++, p += 2) {
+						snprintf(p, 3, "%02x", hash[i]);
+					}
+					return hashstr;
+				}
+				const int fd;
+			private:
+				gcry_md_hd_t state;
+		};
+		typedef boost::iostreams::stream<WriteCacheFile> WriteCacheStrm;
+		typedef boost::shared_ptr<WriteCacheStrm> WriteCacheStrmPtr;
+
 		FilePresenterCache(ScriptNodePtr s) :
-			PresenterCache(s),
-			writecache(NULL) {
+			PresenterCache(s) {
 		}
 		~FilePresenterCache()
 		{
-			delete writecache;
 		}
 		bool check(time_t scriptMtime) const
 		{
@@ -131,15 +166,20 @@ class FilePresenterCache : public PresenterCache, public StaticContent, public S
 			safesys<TruncateCacheFile>(-1, ::ftruncate(fd, 0));
 			safesys<CacheFileXAttr>(-1, fsetxattr(fd, "user.content-type", ct.c_str(), ct.length(), 0));
 			safesys<CacheFileXAttr>(-1, fsetxattr(fd, "user.encoding", enc.c_str(), enc.length(), 0));
-			writecache = new boost::iostreams::stream<boost::iostreams::file_descriptor_sink>(fd, boost::iostreams::close_handle);
+			writecache = WriteCacheStrmPtr(new boost::iostreams::stream<WriteCacheFile>(fd));
 			return *writecache;
 		}
 		void flushCache()
 		{
-			delete writecache;
-			writecache = NULL;
+			std::string hash((*writecache)->hash());
+			safesys<CacheFileXAttr>(-1, fsetxattr((*writecache)->fd, "user.sha1", hash.c_str(), hash.length(), 0));
+			writecache.reset();
+		}
+		std::string getSHA1() const
+		{
+			return getXAttr("user.sha1");
 		}
-		std::ostream * writecache;
+		WriteCacheStrmPtr writecache;
 
 	private:
 		Key getCacheKey() const