interfaces: refactor

interfaces/05-log-parser/oop/jsonparser.go

@@ -0,0 +1,69 @@
+// For more tutorials: https://bp.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+)
+
+type jsonParser struct {
+	r      io.Reader
+	update func(r result)
+}
+
+func newJSONParser(r io.Reader) *jsonParser {
+	return &jsonParser{
+		r:      r,
+		update: func(result) {},
+	}
+}
+
+func (p *jsonParser) parse() error {
+	defer readClose(p.r)
+
+	bytes, err := ioutil.ReadAll(p.r)
+	if err != nil {
+		return err
+	}
+
+	return p.parseJSON(bytes)
+}
+
+func (p *jsonParser) parseJSON(bytes []byte) error {
+	var rs []struct {
+		Domain  string
+		Page    string
+		Visits  int
+		Uniques int
+	}
+
+	if err := json.Unmarshal(bytes, &rs); err != nil {
+		if serr, ok := err.(*json.SyntaxError); ok {
+			return fmt.Errorf("%v %q", serr, bytes[:serr.Offset])
+		}
+		return err
+	}
+
+	for _, r := range rs {
+		p.update(result{
+			domain:  r.Domain,
+			page:    r.Page,
+			visits:  r.Visits,
+			uniques: r.Uniques,
+		})
+	}
+
+	return nil
+}
+
+func (p *jsonParser) notify(f func(r result)) {
+	p.update = f
+}