1 files changed, 195 insertions, 0 deletions
diff --git a/src/StaticFarm/CacheControl.pm b/src/StaticFarm/CacheControl.pm
new file mode 100644
index 0000000..1525cd2
--- /dev/null
+++ b/src/StaticFarm/CacheControl.pm
@@ -0,0 +1,195 @@
+# (C) 2013 Paul Buetow
+
+package StaticFarm::CacheControl;
+
+use strict;
+use warnings;
+
+use Apache2::Const -compile => qw(HTTP_OK HTTP_NO_CONTENT HTTP_NOT_FOUND);
+use Apache2::Log;
+use Apache2::RequestIO;
+use Apache2::RequestRec;
+use Apache2::Response;
+use Apache2::ServerUtil;
+use APR::Table;
+
+use File::Basename;
+use File::Copy qw(move);
+use File::MimeInfo;
+use File::Path qw(make_path);
+use LWP::Simple qw($ua getstore);
+
+my $FETCH_FALLBACK_ENABLE = $ENV{CACHECONTROL_FETCH_FALLBACK_ENABLE};
+my $FETCH_FALLBACK_HOSTSDIR = $ENV{CACHECONTROL_FETCH_FALLBACK_HOSTSDIR};
+my $FETCH_MW_HA_HOST = $ENV{CACHECONTROL_FETCH_MW_HA_HOST};
+my $FETCH_PROTO = $ENV{CACHECONTROL_FETCH_PROTO};
+my $FETCH_REASK_AFTER = $ENV{CACHECONTROL_FETCH_REASK_AFTER};
+my $FETCH_TIMEOUT = $ENV{CACHECONTROL_FETCH_TIMEOUT};
+my $FETCH_MAX_LIMIT = $ENV{CACHECONTROL_FETCH_MAX_LIMIT};
+my $FETCH_MAX_INTERVAL = $ENV{CACHECONTROL_FETCH_MAX_INTERVAL};
+my $VERBOSE = $ENV{CACHECONTROL_WARN_VERBOSE};
+
+# ... now setup some serious stuff!!
+my $SERVER_ROOT = Apache2::ServerUtil::server_root();
+my $DOCUMENT_ROOT = "$SERVER_ROOT/htdocs";
+my $RUN_DIR = "$SERVER_ROOT/run";
+my $STATIC_ROOT = "$DOCUMENT_ROOT/static";
+my $DOT_RE = qr/\.\./;
+my $QRY_RE = qr/\?.*/;
+my $IGNORE_RE = qr/favicon.ico/;
+
+# TMP_DIR is in DOCUMENT_ROOT due FS performance issue (must be on same partition)
+my $TMP_DIR = "$RUN_DIR/cachetmp";
+
+my %NOT_FOUND;
+my $FETCH_MAX_COUNTER = 0;
+my $FETCH_MAX_TIME = 0;
+
+sub my_warn {
+  my $msg = shift;
+
+  Apache2::ServerRec::warn("CacheControl: $msg");
+}
+
+sub my_response {
+  my ($r, $what, $msg) = @_;
+
+  $r->custom_response($what, "<body><html>$msg</html></body>");
+
+  return $what;
+}
+
+sub my_getstore {
+  my ($url, $tmp_file) = @_;
+
+  my_warn("Fetching $url -> $tmp_file with timeout $FETCH_TIMEOUT") if $VERBOSE == 1;
+
+  $ua->timeout($FETCH_TIMEOUT);
+  my $http_code = getstore($url, $tmp_file); 
+
+  if ($http_code >= 301) {
+    unlink $tmp_file if -f $tmp_file;
+
+    my_warn("Document $url not fetchable (HTTP status is $http_code)");
+  }
+
+  return $http_code;
+}
+
+sub handler {
+  my $r = shift;
+
+  return fetch_file($r);
+}
+
+sub get_fallback_mw_hosts {
+  opendir my $dh, $FETCH_FALLBACK_HOSTSDIR or return ();
+
+  my @fallbacks;
+  while (my $d = readdir($dh)) { 
+    next if $d =~ /^\./;
+    push @fallbacks, $d;
+  }
+  close $dh;
+
+  return @fallbacks;
+}
+sub fetch_file {
+  my $r = shift;
+
+  unless (-e $STATIC_ROOT) {
+    my_warn("Static root $STATIC_ROOT does not exist.");
+    return my_response($r, Apache2::Const::HTTP_NOT_FOUND, "File not found!");
+  }
+
+  my $request_uri = $ENV{REQUEST_URI}; 
+  $request_uri =~ s/$DOT_RE//g;
+  $request_uri =~ s/$QRY_RE//;
+
+  my $mw_url = "$FETCH_PROTO://$FETCH_MW_HA_HOST/static/$ENV{SERVER_NAME}";
+  my $file = "$STATIC_ROOT/$ENV{SERVER_NAME}$request_uri";
+  my $basename = basename($file);
+  my $tmp_file = "$TMP_DIR/$basename";
+
+  if ($request_uri =~ $IGNORE_RE) {
+    my_warn("Ignoring $file, don't try to fetch from MW");
+    return my_response($r, Apache2::Const::HTTP_NOT_FOUND, "File not found!");
+  }
+
+  $r->uri($request_uri);
+
+  unless (-e $TMP_DIR) {
+    my_warn("Creating directory $TMP_DIR") if $VERBOSE == 1;
+    make_path($TMP_DIR);
+  }
+
+  my $now = time();
+  # Prevent DOS attacks against the middleware server
+  if (++$FETCH_MAX_COUNTER > $FETCH_MAX_LIMIT) {
+    if ($now - $FETCH_MAX_TIME > $FETCH_MAX_INTERVAL) {
+      $FETCH_MAX_COUNTER = 1;
+      $FETCH_MAX_TIME= $now;
+    } else {
+      my_warn("Don't try to fetch $request_uri from mw, because in FETCH_MAX_INTERVAL=$FETCH_MAX_INTERVAL seconds we had already $FETCH_MAX_COUNTER tries but FETCH_MAX_LIMIT=$FETCH_MAX_LIMIT seconds");
+      return my_response($r, Apache2::Const::HTTP_NOT_FOUND, "File not found!");
+      #return Apache2::Const::HTTP_NOT_FOUND;
+    }
+  }
+
+  if ($FETCH_REASK_AFTER != 0 && exists $NOT_FOUND{$request_uri}) {
+    my $last_access = $now - $NOT_FOUND{$request_uri};
+    if ($last_access < $FETCH_REASK_AFTER) {
+      my_warn("Don't try to fetch $request_uri from mw, because you can ask for this file only 1 time within FETCH_REASK_AFTER=$FETCH_REASK_AFTER seconds");
+      return my_response($r, Apache2::Const::HTTP_NOT_FOUND, "File not found!");
+      #return Apache2::Const::HTTP_NOT_FOUND;
+    } else {
+      delete $NOT_FOUND{$request_uri};
+    }
+  }
+
+  my $url = "$FETCH_PROTO://$FETCH_MW_HA_HOST/static/$ENV{SERVER_NAME}/$request_uri";
+  my $http_code = my_getstore($url, $tmp_file);
+
+  if ($http_code >= 500 && $FETCH_FALLBACK_ENABLE == 1) {
+    # The staticmw ha address (FETCH_MW_HA_HOST) is not reachable or broken, try fallback MW hosts
+    for (get_fallback_mw_hosts()) {
+      $url = "$FETCH_PROTO://$_/static/$ENV{SERVER_NAME}/$request_uri";
+      $http_code = my_getstore($url, $tmp_file);
+      last if $http_code < 400;
+    }
+  } 
+
+  if ($http_code >= 301) {
+    $NOT_FOUND{$request_uri} = time() if $FETCH_REASK_AFTER != 0;
+    return my_response($r, Apache2::Const::HTTP_NOT_FOUND, "File not found!");
+    #return Apache2::Const::HTTP_NOT_FOUND;
+
+  } else {
+    my $dirname = dirname($file);
+
+    unless (-d $dirname) {
+      my_warn("Creating directory $dirname") if $VERBOSE == 1;
+      make_path($dirname);
+    }
+
+    my_warn("Moving $tmp_file -> $file") if $VERBOSE == 1;
+
+    unless (move($tmp_file, $file)) {
+      my_warn("Could not move file $tmp_file -> $file: $!");
+      return Apache2::Const::HTTP_NO_CONTENT;
+    }
+
+    open my $fh, $file or do {
+      my_warn("Could not open file $file: $!");
+      return Apache2::Const::HTTP_NO_CONTENT;
+    };
+
+    $r->content_type(mimetype($file));
+    print while <$fh>;
+    close $fh;
+
+    return Apache2::Const::OK;
+  }
+}
+
+1;