feat(services): EAN 13 generation

go.mod

@@ -13,6 +13,7 @@ require (
 require (
 	github.com/KyleBanks/depth v1.2.1 // indirect
 	github.com/andybalholm/brotli v1.1.1 // indirect
+	github.com/boombuler/barcode v1.0.2 // indirect
 	github.com/go-openapi/jsonpointer v0.21.0 // indirect
 	github.com/go-openapi/jsonreference v0.21.0 // indirect
 	github.com/go-openapi/spec v0.21.0 // indirect
@@ -21,6 +22,7 @@ require (
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/klauspost/compress v1.17.11 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/makiuchi-d/gozxing v0.1.1 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-runewidth v0.0.16 // indirect
@@ -32,5 +34,6 @@ require (
 	github.com/valyala/tcplisten v1.0.0 // indirect
 	golang.org/x/sys v0.27.0 // indirect
 	golang.org/x/tools v0.27.0 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -2,6 +2,8 @@ github.com/KyleBanks/depth v1.2.1 h1:5h8fQADFrWtarTdtDudMmGsC7GPbOAu6RVB3ffsVFHc
 github.com/KyleBanks/depth v1.2.1/go.mod h1:jzSb9d0L43HxTQfT+oSA1EEp2q+ne2uh6XgeJcm8brE=
 github.com/andybalholm/brotli v1.1.1 h1:PR2pgnyFznKEugtsUo0xLdDop5SKXd5Qf5ysW+7XdTA=
 github.com/andybalholm/brotli v1.1.1/go.mod h1:05ib4cKhjx3OQYUY22hTVd34Bc8upXjOLL2rKwwZBoA=
+github.com/boombuler/barcode v1.0.2 h1:79yrbttoZrLGkL/oOI8hBrUKucwOL0oOjUgEguGMcJ4=
+github.com/boombuler/barcode v1.0.2/go.mod h1:paBWMcWSl3LHKBqUq+rly7CNSldXjb2rDl3JlRe0mD8=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-openapi/jsonpointer v0.21.0 h1:YgdVicSA9vH5RiHs9TZW5oyafXZFc6+2Vc1rr/O9oNQ=
@@ -28,6 +30,8 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
+github.com/makiuchi-d/gozxing v0.1.1 h1:xxqijhoedi+/lZlhINteGbywIrewVdVv2wl9r5O9S1I=
+github.com/makiuchi-d/gozxing v0.1.1/go.mod h1:eRIHbOjX7QWxLIDJoQuMLhuXg9LAuw6znsUtRkNw9DU=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
@@ -68,6 +72,8 @@ golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
 golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/tools v0.27.0 h1:qEKojBykQkQ4EynWy4S8Weg69NumxKdn40Fce3uc/8o=
 golang.org/x/tools v0.27.0/go.mod h1:sUi0ZgbwW9ZPAq26Ekut+weQPR5eIM6GQLQ1Yjm1H0Q=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

handlers/contract.go

@@ -41,13 +41,20 @@ func GenerateContract(c *fiber.Ctx) error {
 	contract.Runners = duplicatedRunners
 
 	generator := services.DefaultTemplater{}
-	template, err := templates.GetTemplate(contract.Locale, "contract")
+	templateString, err := templates.GetTemplate(contract.Locale, "contract")
 	if err != nil {
 		log.Println(err)
 		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{
 			"error": "Template not found",
 		})
 	}
+	template, err := generator.StringToTemplate(templateString)
+	if err != nil {
+		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{
+			"error": err.Error(),
+		})
+	}
+
 	result, err := generator.Execute(template, &services.ContractTemplateOptions{
 		Runners:              contract.Runners,
 		CurrencySymbol:       "€",

services/templater.go

@@ -2,13 +2,21 @@ package services
 
 import (
 	"bytes"
+	"encoding/base64"
+	"errors"
 	"html/template"
+	"image/png"
+	"math"
+	"strconv"
 
 	"git.odit.services/lfk/document-server/models"
+	"github.com/boombuler/barcode"
+	"github.com/boombuler/barcode/ean"
 )
 
 type Templater interface {
 	Execute(template *template.Template, data interface{}) (string, error)
+	StringToTemplate(templateString string) (*template.Template, error)
 }
 
 type DefaultTemplater struct {
@@ -23,10 +31,59 @@ type ContractTemplateOptions struct {
 	SponsoringHeader     string          `json:"base_url"`
 }
 
-func (t *DefaultTemplater) Execute(template *template.Template, data interface{}) (string, error) {
+func idToEan13(id int) (string, error) {
+	multiply := [2]int{1, 3}
+	idStr := strconv.Itoa(id)
+
+	if len(idStr) > 12 {
+		return "", errors.New("id too long")
+	}
+	for len(idStr) < 12 {
+		idStr = "0" + idStr
+	}
+
+	total := 0
+	for i, char := range idStr {
+		num, err := strconv.Atoi(string(char))
+		if err != nil {
+			return "", err
+		}
+		total += num * multiply[i%2]
+	}
+	checkSum := (int(math.Ceil(float64(total)/10)) * 10) - total
+	return idStr + strconv.Itoa(checkSum), nil
+}
+
+func (t *DefaultTemplater) GenerateBarcode(code int) (string, error) {
+	encodedEan, err := idToEan13(code)
+	eanCode, err := ean.Encode(encodedEan)
+	if err != nil {
+		return "", err
+	}
+	scaledCode, err := barcode.Scale(eanCode, 100, 50)
+	if err != nil {
+		return "", err
+	}
+
+	var buf bytes.Buffer
+	err = png.Encode(&buf, scaledCode)
+	if err != nil {
+		return "", err
+	}
+
+	return base64.StdEncoding.EncodeToString(buf.Bytes()), nil
+}
+
+func (t *DefaultTemplater) StringToTemplate(templateString string) (*template.Template, error) {
+	return template.New("template").Funcs(template.FuncMap{
+		"barcode": t.GenerateBarcode,
+	}).Parse(templateString)
+}
+
+func (t *DefaultTemplater) Execute(baseTemplate *template.Template, data interface{}) (string, error) {
 	resultBuffer := new(bytes.Buffer)
 
-	err := template.Execute(resultBuffer, data)
+	err := baseTemplate.Execute(resultBuffer, data)
 	if err != nil {
 		return "", err
 	}

templates/contract/de.html

@@ -56,7 +56,7 @@
         </div>
         <div class="column">
           <img style="vertical-align: revert; margin-top: auto; object-fit: cover; max-height: 2cm;"
-            src="{{/* TODO: BARCODE*/}}" />
+            src="data:image/png;base64,{{ barcode .ID }}" />
         </div>
       </div>
       <div class="columns" style="padding-top: 1rem;">

templates/contract/en.html

@@ -55,7 +55,7 @@
         </div>
         <div class="column">
           <img style="vertical-align: revert; margin-top: auto; object-fit: cover; max-height: 2cm;"
-            src="{{/* TODO: BARCODE*/}}" />
+            src="data:image/png;base64,{{ barcode .ID}}" />
         </div>
       </div>
       <div class="columns" style="padding-top: 1rem;">

templates/templates.go

@@ -3,7 +3,6 @@ package templates
 import (
 	_ "embed"
 	"fmt"
-	"html/template"
 )
 
 //go:embed card/en.html
@@ -21,22 +20,22 @@ var ContractTemplateDe string
 //go:embed images/sponsoringheader.base64
 var ImageSponsoringHeaderBase64 string
 
-func GetTemplate(locale, templateName string) (*template.Template, error) {
+func GetTemplate(locale, templateName string) (string, error) {
 	switch templateName {
 	case "card":
 		switch locale {
 		case "en":
-			return template.New("card").Parse(CardTemplateEn)
+			return CardTemplateEn, nil
 		case "de":
-			return template.New("card").Parse(CardTemplateDe)
+			return CardTemplateDe, nil
 		}
 	case "contract":
 		switch locale {
 		case "en":
-			return template.New("contract").Parse(ContractTemplateEn)
+			return ContractTemplateEn, nil
 		case "de":
-			return template.New("contract").Parse(ContractTemplateDe)
+			return ContractTemplateDe, nil
 		}
 	}
-	return nil, fmt.Errorf("template not found with name %s and locale %s", templateName, locale)
+	return "", fmt.Errorf("template not found with name %s and locale %s", templateName, locale)
 }