Cache efa replies by default

2 files changed, 121 insertions, 14 deletions

diff --git a/bin/efa-m b/bin/efa-m
index d788932..eb78069 100755
--- a/bin/efa-m
+++ b/bin/efa-m
@@ -16,6 +16,8 @@ use Travel::Status::DE::EFA;
 my $service = 'VRR';
 my $efa_url;
 my $efa_encoding;
+my $use_cache = 1;
+my $cache;
 my ( $date,        $time, $input_type, $list_lines, $offset, $relative_times );
 my ( $full_routes, $filter_via, $show_jid );
 my ( $timeout,     $developer_mode );
@@ -54,6 +56,7 @@ GetOptions(
 	'u|efa-url=s'                   => \$efa_url,
 	'v|via=s'                       => \$filter_via,
 	'V|track-via=s'                 => \$filter_via,
+	'cache!'                        => \$use_cache,
 	'version'                       => \&show_version,
 	'devmode'                       => \$developer_mode,
 
@@ -67,6 +70,21 @@ if ( @ARGV < 1 or @ARGV > 2 ) {
 	show_help(1);
 }
 
+if ($use_cache) {
+	my $cache_path = ( $ENV{XDG_CACHE_HOME} // "$ENV{HOME}/.cache" ) . '/efa-m';
+	eval {
+		require Cache::File;
+		$cache = Cache::File->new(
+			cache_root      => $cache_path,
+			default_expires => '90 seconds',
+			lock_level      => Cache::File::LOCK_LOCAL(),
+		);
+	};
+	if ($@) {
+		$cache = undef;
+	}
+}
+
 # --line=foo,bar support
 @edata_pre      = split( qr{,}, join( q{,}, @edata_pre ) );
 @grep_lines     = split( qr{,}, join( q{,}, @grep_lines ) );
@@ -130,6 +148,7 @@ sub new_efa {
 	my $res = Travel::Status::DE::EFA->new(
 		service        => $s,
 		efa_url        => $u,
+		cache          => $cache,
 		date           => $date,
 		developer_mode => $developer_mode,
 		efa_encoding   => $efa_encoding,
diff --git a/lib/Travel/Status/DE/EFA.pm b/lib/Travel/Status/DE/EFA.pm
index 6aa505b..75caf8e 100644
--- a/lib/Travel/Status/DE/EFA.pm
+++ b/lib/Travel/Status/DE/EFA.pm
@@ -32,17 +32,9 @@ sub new_p {
 
 	$self->{promise} = $opt{promise};
 
-	$self->{ua}->post_p( $self->{efa_url} => form => $self->{post} )->then(
+	$self->post_with_cache_p->then(
 		sub {
-			my ($tx) = @_;
-			if ( my $err = $tx->error ) {
-				$promise->reject(
-"POST $self->{efa_url} returned HTTP $err->{code} $err->{message}"
-				);
-				return;
-			}
-			my $content = $tx->res->body;
-
+			my ($content) = @_;
 			$self->{response} = $self->{json}->decode($content);
 
 			if ( $self->{developer_mode} ) {
@@ -149,6 +141,7 @@ sub new {
 	}
 
 	my $self = {
+		cache          => $opt{cache},
 		response       => $opt{from_json},
 		developer_mode => $opt{developer_mode},
 		efa_url        => $opt{efa_url},
@@ -218,6 +211,13 @@ sub new {
 		$self->{ua}->env_proxy;
 	}
 
+	if ( $self->{cache} ) {
+		$self->{cache_key}
+		  = $self->{efa_url} . '?'
+		  . join( '&',
+			map { $_ . '=' . $self->{post}{$_} } sort keys %{ $self->{post} } );
+	}
+
 	if ( $opt{async} ) {
 		return $self;
 	}
@@ -230,14 +230,14 @@ sub new {
 	}
 
 	if ( not $self->{response} ) {
-		my $response = $self->{ua}->post( $self->{efa_url}, $self->{post} );
+		my ( $response, $error ) = $self->post_with_cache;
 
-		if ( $response->is_error ) {
-			$self->{errstr} = $response->status_line;
+		if ($error) {
+			$self->{errstr} = $error;
 			return $self;
 		}
 
-		$self->{response} = $self->{json}->decode( $response->content );
+		$self->{response} = $self->{json}->decode($response);
 	}
 
 	if ( $self->{developer_mode} ) {
@@ -249,6 +249,94 @@ sub new {
 	return $self;
 }
 
+sub post_with_cache {
+	my ($self) = @_;
+	my $cache  = $self->{cache};
+	my $url    = $self->{efa_url};
+
+	if ( $self->{developer_mode} ) {
+		say 'POST ' . ( $self->{cache_key} // $url );
+	}
+
+	if ($cache) {
+		my $content = $cache->thaw( $self->{cache_key} );
+		if ($content) {
+			if ( $self->{developer_mode} ) {
+				say '  cache hit';
+			}
+			return ( ${$content}, undef );
+		}
+	}
+
+	if ( $self->{developer_mode} ) {
+		say '  cache miss';
+	}
+
+	my $reply = $self->{ua}->post( $url, $self->{post} );
+
+	if ( $reply->is_error ) {
+		return ( undef, $reply->status_line );
+	}
+	my $content = $reply->content;
+
+	if ($cache) {
+		$cache->freeze( $self->{cache_key}, \$content );
+	}
+
+	return ( $content, undef );
+}
+
+sub post_with_cache_p {
+	my ($self) = @_;
+	my $cache  = $self->{cache};
+	my $url    = $self->{efa_url};
+
+	if ( $self->{developer_mode} ) {
+		say 'POST ' . ( $self->{cache_key} // $url );
+	}
+
+	my $promise = $self->{promise}->new;
+
+	if ($cache) {
+		my $content = $cache->thaw( $self->{cache_key} );
+		if ($content) {
+			if ( $self->{developer_mode} ) {
+				say '  cache hit';
+			}
+			return $promise->resolve( ${$content} );
+		}
+	}
+
+	if ( $self->{developer_mode} ) {
+		say '  cache miss';
+	}
+
+	$self->{ua}->post_p( $url, form => $self->{post} )->then(
+		sub {
+			my ($tx) = @_;
+			if ( my $err = $tx->error ) {
+				$promise->reject(
+					"POST $url returned HTTP $err->{code} $err->{message}");
+				return;
+			}
+			my $content = $tx->res->body;
+			if ($cache) {
+				$cache->freeze( $self->{cache_key}, \$content );
+			}
+			$promise->resolve($content);
+			return;
+		}
+	)->catch(
+		sub {
+			my ($err) = @_;
+			$promise->reject($err);
+			return;
+		}
+	)->wait;
+
+	return $promise;
+}
+
 sub errstr {
 	my ($self) = @_;