Implemented developer database downloads

pages/database/download.go

@@ -1,10 +1,90 @@
 package database
 
 import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
 	"github.com/aerogo/aero"
+	"github.com/aerogo/api"
+	"github.com/akyoto/stringutils/unsafe"
+	"github.com/animenotifier/notify.moe/arn"
+	"github.com/mohae/deepcopy"
 )
 
+// privateTypes are types that are not available for download.
+var privateTypes = []string{
+	"EditLogEntry",
+	"EmailToUser",
+	"PayPalPayment",
+	"Purchase",
+	"Session",
+}
+
 // Download downloads a snapshot of a database collection.
 func Download(ctx aero.Context) error {
-	return nil
+	typ := ctx.Get("type")
+
+	if !arn.DB.HasType(typ) {
+		return ctx.Error(http.StatusNotFound, "Type doesn't exist")
+	}
+
+	if arn.Contains(privateTypes, typ) {
+		return ctx.Error(http.StatusUnauthorized, "Type is private and can not be downloaded")
+	}
+
+	// Send headers necessary for file downloads
+	ctx.Response().SetHeader("Content-Disposition", fmt.Sprintf(`attachment; filename="%s.dat"`, typ))
+
+	// Stream data
+	reader, writer := io.Pipe()
+	encoder := json.NewEncoder(writer)
+
+	go func() {
+		for object := range arn.DB.All(typ) {
+			idObject, hasID := object.(arn.Identifiable)
+
+			if !hasID {
+				continue
+			}
+
+			// Filter out private data
+			filter, isFilter := object.(api.Filter)
+
+			if isFilter && filter.ShouldFilter(ctx) {
+				object = deepcopy.Copy(object)
+				filter = object.(api.Filter)
+				filter.Filter()
+			}
+
+			// Write ID
+			_, err := writer.Write(unsafe.StringToBytes(idObject.GetID()))
+
+			if err != nil {
+				_ = writer.CloseWithError(err)
+				return
+			}
+
+			// Write newline
+			_, err = writer.Write([]byte("\n"))
+
+			if err != nil {
+				_ = writer.CloseWithError(err)
+				return
+			}
+
+			// Write JSON (newline included)
+			err = encoder.Encode(object)
+
+			if err != nil {
+				_ = writer.CloseWithError(err)
+				return
+			}
+		}
+
+		writer.Close()
+	}()
+
+	return ctx.Reader(reader)
 }