Begin adding WebUI

See #10

src/webui/serveApiUpdateSettings.go

@@ -0,0 +1,59 @@
+package webui
+
+import (
+    "encoding/json"
+	"fmt"
+	"net/http"
+    "gitea.armuli.eu/museum-digital/museum-digital-webdav-uploader/src/configloader"
+)
+
+type updateSettingsResponse struct {
+    Success bool `json:"success"`
+    ValidationError string `json:"error"`
+}
+
+// Provides the API for updating the general configuration.
+func serveApiUpdateSettings(w http.ResponseWriter, r *http.Request) {
+
+	setHeadersForJson(w)
+
+    // Parse POST data
+    parseErr := r.ParseForm()
+    if parseErr != nil {
+        fmt.Println("Failed to load form data")
+        return
+    }
+
+    // Load new config from a POST variable 'settings' that provides the full
+    // settings as a JSON-encoded string.
+    rawInputConfig := r.PostForm.Get("settings")
+    var newConfig configloader.MDWebDavUploaderConfig
+    unmarshalErr := json.Unmarshal([]byte(rawInputConfig), &newConfig)
+    if unmarshalErr != nil {
+        fmt.Fprint(w, "{\"success\": false, \"error\": \"Invalid input JSON\"}")
+        return
+    }
+
+    // Attempt to store the new settings. Validation takes place while storing
+    var output updateSettingsResponse
+    validationErr := configloader.StoreConfigToFile(newConfig, "")
+    if validationErr == nil {
+        output = updateSettingsResponse{Success: true, ValidationError: ""}
+
+        // Reload config
+        config, setupRequired, _ = configloader.LoadFromFile("")
+
+    } else {
+        output = updateSettingsResponse{Success: false, ValidationError: validationErr.Error()}
+    }
+
+    // Format response in JSON, then print it
+    outputJson, encodeErr := json.Marshal(output)
+    if encodeErr != nil {
+        panic("Failed to create JSON")
+    }
+
+	fmt.Fprint(w, string(outputJson))
+
+
+}