move: log parsers

logparser/oop/record.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const fieldsLength = 4
+
+type record struct {
+	domain  string
+	page    string
+	visits  int
+	uniques int
+}
+
+func (r record) sum(other record) record {
+	r.visits += other.visits
+	r.uniques += other.uniques
+	return r
+}
+
+// UnmarshalText to a *record
+func (r *record) UnmarshalText(p []byte) (err error) {
+	fields := strings.Fields(string(p))
+	if len(fields) != fieldsLength {
+		return fmt.Errorf("wrong number of fields %q", fields)
+	}
+
+	r.domain, r.page = fields[0], fields[1]
+
+	if r.visits, err = parseStr("visits", fields[2]); err != nil {
+		return err
+	}
+	if r.uniques, err = parseStr("uniques", fields[3]); err != nil {
+		return err
+	}
+	return validate(*r)
+}
+
+// UnmarshalJSON to a *record
+func (r *record) UnmarshalJSON(data []byte) error {
+	var re struct {
+		Domain  string
+		Page    string
+		Visits  int
+		Uniques int
+	}
+
+	if err := json.Unmarshal(data, &re); err != nil {
+		return err
+	}
+
+	*r = record{re.Domain, re.Page, re.Visits, re.Uniques}
+	return validate(*r)
+}
+
+// parseStr helps UnmarshalText for string to positive int parsing
+func parseStr(name, v string) (int, error) {
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return 0, fmt.Errorf("record.UnmarshalText %q: %v", name, err)
+	}
+	return n, nil
+}
+
+func validate(r record) (err error) {
+	switch {
+	case r.domain == "":
+		err = errors.New("record.domain cannot be empty")
+	case r.page == "":
+		err = errors.New("record.page cannot be empty")
+	case r.visits < 0:
+		err = errors.New("record.visits cannot be negative")
+	case r.uniques < 0:
+		err = errors.New("record.uniques cannot be negative")
+	}
+	return
+}