132 lines
2.9 KiB
Go
132 lines
2.9 KiB
Go
package services
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import (
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"bytes"
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"encoding/base64"
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"errors"
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"fmt"
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"html/template"
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"image/png"
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"strings"
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"github.com/boombuler/barcode"
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"github.com/boombuler/barcode/code128"
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"github.com/boombuler/barcode/ean"
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"github.com/boombuler/barcode/qr"
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)
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type Templater interface {
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Execute(template *template.Template, data interface{}) (string, error)
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StringToTemplate(templateString string) (*template.Template, error)
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}
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type DefaultTemplater struct {
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}
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func idToEan13(id string, prefix string) (string, error) {
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if len(id) > 12 {
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return "", errors.New("id too long")
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}
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for len(id) < 11 {
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id = "0" + id
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}
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id = prefix + id
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return id, nil
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}
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func (t *DefaultTemplater) GenerateBarcode(code string, format string, prefix string) (string, error) {
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var generatedCode barcode.Barcode
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var err error
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switch format {
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case "ean13":
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encodedEan, err := idToEan13(code, prefix)
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if err != nil {
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return "", err
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}
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generatedCode, err = ean.Encode(encodedEan)
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if err != nil {
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return "", err
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}
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break
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case "code128":
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generatedCode, err = code128.Encode(prefix + code)
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if err != nil {
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return "", err
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}
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break
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case "qr":
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generatedCode, err = qr.Encode(prefix+code, qr.M, qr.AlphaNumeric)
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if err != nil {
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return "", err
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}
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break
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default:
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return "", errors.New("unknown barcode format")
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}
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scaledCode, err := barcode.Scale(generatedCode, 1000, 500)
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if err != nil {
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return "", err
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}
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var buf bytes.Buffer
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err = png.Encode(&buf, scaledCode)
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if err != nil {
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return "", err
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}
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return base64.StdEncoding.EncodeToString(buf.Bytes()), nil
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}
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func (t *DefaultTemplater) SelectSponsorImage(id int) (string, error) {
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sponsors, err := ListFilesInStaticSubFolder("images/sponsors")
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if err != nil {
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return "", err
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}
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return GetImage("sponsors/" + strings.TrimSuffix(sponsors[id%len(sponsors)], ".base64")), nil
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}
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func (t *DefaultTemplater) LoadImage(name string) (string, error) {
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return GetImage(name), nil
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}
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func (t *DefaultTemplater) FormatUnit(unit string, locale string, amount int) (string, error) {
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var formatted string
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switch unit {
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case "kilometer":
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formatted = fmt.Sprintf("%.3f", float64(amount)/1000)
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case "euro":
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formatted = fmt.Sprintf("%.2f", float64(amount)/100)
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default:
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return "", errors.New("unknown unit")
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}
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if locale == "de" {
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return strings.Replace(formatted, ".", ",", -1), nil
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}
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return formatted, nil
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}
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func (t *DefaultTemplater) StringToTemplate(templateString string) (*template.Template, error) {
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return template.New("template").Funcs(template.FuncMap{
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"barcode": t.GenerateBarcode,
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"sponsorLogo": t.SelectSponsorImage,
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"formatUnit": t.FormatUnit,
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"loadImage": t.LoadImage,
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}).Parse(templateString)
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}
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func (t *DefaultTemplater) Execute(baseTemplate *template.Template, data interface{}) (string, error) {
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resultBuffer := new(bytes.Buffer)
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err := baseTemplate.Execute(resultBuffer, data)
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if err != nil {
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return "", err
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}
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return resultBuffer.String(), nil
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}
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