101 lines
2.1 KiB
Go
101 lines
2.1 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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"html/template"
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"image/png"
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"strconv"
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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 int, prefix string) (string, error) {
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idStr := strconv.Itoa(id)
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if len(idStr) > 12 {
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return "", errors.New("id too long")
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}
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for len(idStr) < 11 {
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idStr = "0" + idStr
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}
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idStr = prefix + idStr
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return idStr, nil
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}
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func (t *DefaultTemplater) GenerateBarcode(code int, 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 + strconv.Itoa(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+strconv.Itoa(code), qr.M, qr.Numeric)
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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) 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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}).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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