adding CORS support and separaring some api handliers into own file

1 files changed, 173 insertions, 0 deletions

diff --git a/system/api/handlers.go b/system/api/handlers.go
new file mode 100644
index 0000000..c1519e5
--- /dev/null
+++ b/system/api/handlers.go
@@ -0,0 +1,173 @@
+package api
+
+import (
+	"bytes"
+	"encoding/json"
+	"log"
+	"net/http"
+
+	"github.com/nilslice/cms/content"
+	"github.com/nilslice/cms/system/db"
+)
+
+func typesHandler(res http.ResponseWriter, req *http.Request) {
+	var types = []string{}
+	for t := range content.Types {
+		types = append(types, string(t))
+	}
+
+	j, err := toJSON(types)
+	if err != nil {
+		res.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	sendData(res, j, http.StatusOK)
+}
+
+func postsHandler(res http.ResponseWriter, req *http.Request) {
+	q := req.URL.Query()
+	t := q.Get("type")
+	// TODO: implement pagination
+	// num := q.Get("num")
+	// page := q.Get("page")
+
+	if t == "" {
+		res.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	posts := db.ContentAll(t)
+	var all = []json.RawMessage{}
+	for _, post := range posts {
+		all = append(all, post)
+	}
+
+	j, err := fmtJSON(all...)
+	if err != nil {
+		res.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	sendData(res, j, http.StatusOK)
+}
+
+func postHandler(res http.ResponseWriter, req *http.Request) {
+	q := req.URL.Query()
+	id := q.Get("id")
+	t := q.Get("type")
+
+	if t == "" || id == "" {
+		res.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	post, err := db.Content(t + ":" + id)
+	if err != nil {
+		res.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	j, err := fmtJSON(json.RawMessage(post))
+	if err != nil {
+		res.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	sendData(res, j, http.StatusOK)
+}
+
+func fmtJSON(data ...json.RawMessage) ([]byte, error) {
+	var msg = []json.RawMessage{}
+	for _, d := range data {
+		msg = append(msg, d)
+	}
+
+	resp := map[string][]json.RawMessage{
+		"data": msg,
+	}
+
+	var buf = &bytes.Buffer{}
+	enc := json.NewEncoder(buf)
+	err := enc.Encode(resp)
+	if err != nil {
+		log.Println("Failed to encode data to JSON:", err)
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func toJSON(data []string) ([]byte, error) {
+	var buf = &bytes.Buffer{}
+	enc := json.NewEncoder(buf)
+	resp := map[string][]string{
+		"data": data,
+	}
+
+	err := enc.Encode(resp)
+	if err != nil {
+		log.Println("Failed to encode data to JSON:", err)
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func wrapJSON(json []byte) []byte {
+	var buf = &bytes.Buffer{}
+	buf.Write([]byte(`{"data":`))
+	buf.Write(json)
+	buf.Write([]byte(`}`))
+
+	return buf.Bytes()
+}
+
+// sendData() should be used any time you want to communicate
+// data back to a foreign client
+func sendData(res http.ResponseWriter, data []byte, code int) {
+	res.Header().Set("Access-Control-Allow-Headers", "Accept, Authorization, Content-Type")
+	res.Header().Set("Access-Control-Allow-Origin", "*")
+	res.Header().Set("Content-Type", "application/json")
+	res.WriteHeader(code)
+	res.Write(data)
+}
+
+// SendPreflight is used to respond to a cross-origin "OPTIONS" request
+func SendPreflight(res http.ResponseWriter) {
+	res.Header().Set("Access-Control-Allow-Headers", "Accept, Authorization, Content-Type")
+	res.Header().Set("Access-Control-Allow-Origin", "*")
+	res.WriteHeader(200)
+	return
+}
+
+// SendJSON returns a Response to a client as JSON
+func SendJSON(res http.ResponseWriter, j map[string]interface{}) {
+	var data []byte
+	var err error
+
+	data, err = json.Marshal(j)
+	if err != nil {
+		data, _ = json.Marshal(map[string]interface{}{
+			"status":  "fail",
+			"message": err.Error(),
+		})
+	}
+
+	sendData(res, data, 200)
+}
+
+// ResponseFunc ...
+type ResponseFunc func(http.ResponseWriter, *http.Request)
+
+// CORS wraps a HandleFunc to response to OPTIONS requests properly
+func CORS(next http.HandlerFunc) http.HandlerFunc {
+	return http.HandlerFunc(func(res http.ResponseWriter, req *http.Request) {
+		if req.Method == http.MethodOptions {
+			SendPreflight(res)
+			return
+		}
+
+		next.ServeHTTP(res, req)
+	})
+}