106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
// Copyright © 2018 Inanc Gumus
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// Learn Go Programming Course
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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//
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// For more tutorials : https://learngoprogramming.com
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// In-person training : https://www.linkedin.com/in/inancgumus/
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// Follow me on twitter: https://twitter.com/inancgumus
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package pipe
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import (
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"encoding/json"
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"errors"
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"fmt"
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"strconv"
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"strings"
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)
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const fieldsLength = 4
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// record stores fields of a log line.
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type record struct {
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domain string
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page string
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visits int
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uniques int
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}
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// recordJSON is used for marshaling and unmarshaling JSON.
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type recordJSON struct {
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Domain string
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Page string
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Visits int
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Uniques int
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}
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// sum the numeric fields with another record.
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func (r record) sum(other record) record {
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r.visits += other.visits
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r.uniques += other.uniques
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return r
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}
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// UnmarshalText to a *record.
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func (r *record) UnmarshalText(p []byte) (err error) {
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fields := strings.Fields(string(p))
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if len(fields) != fieldsLength {
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return fmt.Errorf("wrong number of fields %q", fields)
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}
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r.domain, r.page = fields[0], fields[1]
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if r.visits, err = parseStr("visits", fields[2]); err != nil {
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return err
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}
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if r.uniques, err = parseStr("uniques", fields[3]); err != nil {
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return err
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}
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return validate(*r)
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}
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// UnmarshalJSON to a *record.
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func (r *record) UnmarshalJSON(data []byte) error {
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var rj recordJSON
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if err := json.Unmarshal(data, &rj); err != nil {
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return err
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}
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*r = record{rj.Domain, rj.Page, rj.Visits, rj.Uniques}
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return validate(*r)
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}
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// MarshalJSON of a *record.
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func (r *record) MarshalJSON() ([]byte, error) {
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rj := recordJSON{r.domain, r.page, r.visits, r.uniques}
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return json.Marshal(rj)
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}
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// parseStr helps UnmarshalText for string to positive int parsing.
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func parseStr(name, v string) (int, error) {
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n, err := strconv.Atoi(v)
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if err != nil {
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return 0, fmt.Errorf("Record.UnmarshalText %q: %v", name, err)
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}
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return n, nil
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}
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// validate whether a parsed record is valid or not.
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func validate(r record) (err error) {
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switch {
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case r.domain == "":
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err = errors.New("record.domain cannot be empty")
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case r.page == "":
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err = errors.New("record.page cannot be empty")
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case r.visits < 0:
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err = errors.New("record.visits cannot be negative")
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case r.uniques < 0:
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err = errors.New("record.uniques cannot be negative")
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}
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return
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}
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