1 files changed, 70 insertions, 0 deletions
diff --git a/src/server/helper/valid.go b/src/server/helper/valid.go
new file mode 100644
index 0000000..9363747
--- /dev/null
+++ b/src/server/helper/valid.go
@@ -0,0 +1,70 @@
+package helper
+
+import (
+	"image"
+	"net/http"
+)
+
+// Checks if the subreact exists, responds with a bad status when false.
+func IsValidSubreact(subreact string, writer http.ResponseWriter) bool {
+	switch subreact {
+	case "":
+		fallthrough
+	case "t":
+		fallthrough
+	case "g":
+		fallthrough
+	case "k":
+		fallthrough
+	case "p":
+		fallthrough
+	case "a":
+		fallthrough
+	case "pr":
+		fallthrough
+	case "m":
+		break
+	default:
+		WriteErrorJson("invalid subreact", writer, http.StatusBadRequest)
+		return false
+	}
+	return true
+}
+
+// Range checks the length of the argument, responds with a bad status when false.
+func IsValidRange(str string, name string, min int, max int, writer http.ResponseWriter) bool {
+	if len(str) < min {
+		WriteErrorJson(name+" too short", writer, http.StatusBadRequest)
+		return false
+	}
+	if len(str) > max {
+		WriteErrorJson(name+" too long", writer, http.StatusBadRequest)
+		return false
+	}
+	return true
+}
+
+// Checks that the image has supported properties, responds with a bad status when false.
+func IsImageSupported(image image.Image, format string, writer http.ResponseWriter) bool {
+	if bounds := image.Bounds(); bounds.Dx() > 4096 || bounds.Dy() > 4096 {
+		WriteErrorJson("image dimensions too large", writer, http.StatusBadRequest)
+		return false
+	} else if bounds.Dx() < 256 || bounds.Dy() < 256 {
+		WriteErrorJson("image dimensions too small", writer, http.StatusBadRequest)
+		return false
+	}
+
+	switch format {
+	case "png":
+		fallthrough
+	case "jpeg":
+		fallthrough
+	case "gif":
+		break
+	default:
+		WriteErrorJson("image format no recognised", writer, http.StatusBadRequest)
+		return false
+	}
+
+	return true
+}