barcodes/web/generate.route.go

115 lines
2.8 KiB
Go

package web
import (
"encoding/json"
"errors"
"fmt"
"image"
"image/png"
"net/http"
"git.fjla.uk/fred.boniface/barcodes/generation"
"git.fjla.uk/fred.boniface/barcodes/validation"
"github.com/boombuler/barcode"
)
// Generates a barcode from the data and options provided in the request
func generateBarcode(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodPost && r.Method != http.MethodGet {
http.Error(w, "Use a POST or GET request for barcode generation. See the help page for more information", http.StatusMethodNotAllowed)
return
}
var req *BarcodeRequest
var err error
if r.Method == http.MethodGet {
req, err = generateFromGet(r)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
} else {
err := json.NewDecoder(r.Body).Decode(&req)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
}
parameters := generation.Parameters{
Format: generation.BarcodeType(req.BarcodeType),
ECCLevel: generation.ECCLevel(req.ECCLevel),
Content: req.Content,
}
validate := validation.Validate(parameters)
if !validate {
fmt.Println("Validation Failed")
http.Error(w, "Validation Failed", http.StatusBadRequest)
return
}
barcodeGen, err := generation.Generate(parameters)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if barcodeGen == nil {
fmt.Println("Generation failed, no barcode created")
http.Error(w, "Barcode Generation Failed", http.StatusInternalServerError)
return
}
barcodeGen, _ = barcode.Scale(barcodeGen, int(req.Width), int(req.Height))
image, isImage := barcodeGen.(image.Image)
if !isImage {
fmt.Println("Generation failed - no image")
http.Error(w, "Generated Barcode is not an image", http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "image/png")
err = png.Encode(w, image)
if err != nil {
http.Error(w, "Error streaming barcode", http.StatusInternalServerError)
}
}
func generateFromGet(r *http.Request) (*BarcodeRequest, error) {
//var parameters generation.Parameters
if r.Method == http.MethodGet {
validTypes := map[string]bool{
"qr": true,
"aztec": true,
"datamatrix": true,
}
typeParam := r.URL.Query().Get("type")
content := r.URL.Query().Get("text")
if typeParam == "" || content == "" {
return nil, errors.New("both 'type' and 'text' parameters are required")
}
if !validTypes[typeParam] {
return nil, errors.New("'type' must be 'qr', 'aztec', or 'datamatrix'")
}
barcodeReq := &BarcodeRequest{
BarcodeType: typeParam,
Width: 300,
Height: 300,
ECCLevel: 2,
Content: content,
}
return barcodeReq, nil
} else {
return nil, errors.New("incorrect request type passed to function")
}
}