cedar.go: add cacheFor

1 files changed, 32 insertions, 0 deletions

diff --git a/cedar.go b/cedar.go
index 6571259..49b1330 100644
--- a/cedar.go
+++ b/cedar.go
@@ -1,10 +1,12 @@
 package main
 
 import (
+	"encoding/json"
 	"encoding/xml"
 	"io"
 	"net/http"
 	"os"
+	"path"
 )
 
 type Link struct {
@@ -24,6 +26,8 @@ type Feed struct {
 	Entry   []Entry  `xml:"entry"`
 }
 
+type Ids []string
+
 func newsFeed() ([]byte, error) {
 	// Init feed.
 	feed := make([]byte, 0)
@@ -75,4 +79,32 @@ func readFile(f *os.File) ([]byte, error) {
 	return bs, nil
 }
 
+func cacheFor(section string) (Ids, error) {
+	cache := make(Ids, 0)
+
+	h, _ := os.UserHomeDir()
+	d := path.Join(h, ".cedar")
+
+	err := os.MkdirAll(d, 0700)
+	if err != nil {
+		return cache, err
+	}
+
+	f, err := os.Open(path.Join(d, section+".json"))
+	if os.IsNotExist(err) {
+		return cache, nil
+	}
+
+	bs, err := readFile(f)
+	if err != nil {
+		return cache, err
+	}
+
+	err = json.Unmarshal(bs, &cache)
+	if err != nil {
+		return cache, err
+	}
+	return cache, nil
+}
+
 func main() {}