add json backend

backends/json.go

@@ -0,0 +1,40 @@
+package backends
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"log"
+
+	"github.com/schachmat/wego/iface"
+)
+
+type jsnConfig struct {
+}
+
+func (c *jsnConfig) Setup() {
+}
+
+// Fetch will try to open the file specified in the location string argument and
+// read it as json content to fill the data. The numdays argument will only work
+// to further limit the amount of days in the output. It obviously cannot
+// produce more data than is available in the file.
+func (c *jsnConfig) Fetch(loc string, numdays int) (ret iface.Data) {
+	b, err := ioutil.ReadFile(loc)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = json.Unmarshal(b, &ret)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if len(ret.Forecast) > numdays {
+		ret.Forecast = ret.Forecast[:numdays]
+	}
+	return
+}
+
+func init() {
+	iface.AllBackends["json"] = &jsnConfig{}
+}