From 52a1f1900e8a800e610e70c24f4e70d683d47578 Mon Sep 17 00:00:00 2001
From: Alejandro Lazarte <inbox@alazarte.com>
Date: Thu, 14 Oct 2021 16:22:35 -0300
Subject: [PATCH] Initial commit

Unmarshall of simple config file, just to practice Go's reflect lib
---
 test                |  5 ++++
 unmarshaler.go      | 71 +++++++++++++++++++++++++++++++++++++++++++++
 unmarshaler_test.go | 36 +++++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 test
 create mode 100644 unmarshaler.go
 create mode 100644 unmarshaler_test.go

diff --git a/test b/test
new file mode 100644
index 0000000..f900f3b
--- /dev/null
+++ b/test
@@ -0,0 +1,5 @@
+Pem=fullchainfile.pem
+Sk=privkeyfile.pem
+Handler.Name=someName
+Handler.Path=/tmp
+Handler.Type=type
diff --git a/unmarshaler.go b/unmarshaler.go
new file mode 100644
index 0000000..9609ead
--- /dev/null
+++ b/unmarshaler.go
@@ -0,0 +1,71 @@
+package cfgreader
+
+import (
+	"bufio"
+	"io"
+	"os"
+	"reflect"
+	"regexp"
+)
+
+type unmarshalError string
+
+func (e unmarshalError) Error() string {
+	return string(e)
+}
+
+func unmarshalKeyValue(m map[string]interface{}, v *reflect.Value) {
+	for key, ival := range m {
+		if reflect.ValueOf(ival).Kind() == reflect.Map {
+			v2 := v.FieldByName(key)
+			unmarshalKeyValue(ival.(map[string]interface{}), &v2)
+		}
+		switch v.FieldByName(key).Type().Kind() {
+		case reflect.String:
+			v.FieldByName(key).SetString(ival.(string))
+		}
+	}
+}
+
+func unmarshalCfg(m map[string]interface{}, v interface{}) error {
+	vt := reflect.ValueOf(v).Elem()
+	if !vt.CanSet() {
+		return unmarshalError("cannot set interface")
+	}
+	unmarshalKeyValue(m, &vt)
+	return nil
+}
+
+func FromFile(filepath string, v interface{}) error {
+	f, err := os.Open(filepath)
+	if err != nil {
+		return err
+	}
+	buf := bufio.NewReader(f)
+	group := regexp.MustCompile(`(?:([A-Z][a-z]+)\.)?([A-Z][a-z]+)=([A-Za-z0-9\./]+)\n`)
+	m := make(map[string]interface{})
+	for {
+		l, err := buf.ReadString('\n')
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			continue
+		}
+		ss := group.FindAllStringSubmatch(l, -1)
+		if len(ss) == 0 {
+			continue
+		}
+		if ss[0][1] == "" {
+			// "" "Key" "Value"
+			m[ss[0][2]] = ss[0][3]
+			continue
+		}
+		if m[ss[0][1]] == nil {
+			m[ss[0][1]] = make(map[string]interface{})
+		}
+		// "Group" "Key" "Value"
+		m[ss[0][1]].(map[string]interface{})[ss[0][2]] = ss[0][3]
+	}
+	return unmarshalCfg(m, v)
+}
diff --git a/unmarshaler_test.go b/unmarshaler_test.go
new file mode 100644
index 0000000..54d90ac
--- /dev/null
+++ b/unmarshaler_test.go
@@ -0,0 +1,36 @@
+package cfgreader
+
+import (
+	"fmt"
+	"os"
+	"testing"
+)
+
+func TestInit(t *testing.T) {
+	contents := `Pem=fullchainfile.pem
+Sk=privkeyfile.pem
+Handler.Name=someName
+Handler.Path=/tmp
+Handler.Type=type
+`
+	if err := os.WriteFile("test", []byte(contents), 0644); err != nil {
+		t.Fatal(err)
+	}
+}
+func TestHelloWorld(t *testing.T) {
+	c := struct {
+		Pem     string
+		Sk      string
+		Handler struct {
+			Name string
+			Path string
+			Type string
+		}
+	}{}
+	if err := FromFile("test", &c); err != nil {
+		t.Fatal(err)
+	}
+	if fmt.Sprintf("%q", &c) != "&{\"fullchainfile.pem\" \"privkeyfile.pem\" {\"someName\" \"/tmp\" \"type\"}}" {
+		t.Fatal("Not what I expected")
+	}
+}
-- 
2.34.2