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Add input file and os.Stdin support #5

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23 changes: 19 additions & 4 deletions qrcode/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -10,9 +10,11 @@ import (
"strings"

qrcode "github.com/skip2/go-qrcode"
"io/ioutil"
)

func main() {
inFile := flag.String("i", "", "content file, empty for STDIN")
outFile := flag.String("o", "", "out PNG file prefix, empty for stdout")
size := flag.Int("s", 256, "image size (pixel)")
flag.Usage = func() {
Expand Down Expand Up @@ -41,12 +43,25 @@ Usage:
if *size <= 0 {
checkError(fmt.Errorf("Error: value of -s should > 0"))
}
if len(flag.Args()) == 0 {
flag.Usage()
checkError(fmt.Errorf("Error: no content given"))
}

content := strings.Join(flag.Args(), " ")
if *inFile != "" {
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I suggest prioritising the -i flag, then command line arguments, then reading from STDIN last, like:

content := ""
argsContent := strings.Join(flag.Args(), " ")

if *inFile != "" {
	b, err := ioutil.ReadFile(*inFile)
	if err != nil {
		checkError(err)
	}
	content = string(b)
} else if argsContent != "" {
	content = argsContent
} else {
	b, err := ioutil.ReadAll(os.Stdin)
	if err != nil {
		checkError(err)
	}
	content = string(b)
}

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Hey,

I think reading content from STDIN/a file is a nice addition :)

After this pull request there are three ways to specify content:

  • String from input file:

$ qrcode -i input_filename | display

  • String on command line:

$ qrcode hello | display

  • String on STDIN:

$ echo -n hello | qrcode | display

  • No arguments: (same as string on STDIN, only you type into the terminal and then press Ctrl+D)

$ qrcode | display

If you try the "qrcode hello | display" method, it now hangs and waits for something on STDIN.

I suggest taking content from one source only (first the -i flag, then command line arguments, or lastly STDIN), so the usage is more obvious and easier to explain. This would work well.

thanks,

Tom

b, err := ioutil.ReadFile(*inFile)
if err != nil {
checkError(err)
}
content += string(b)
} else {
b, err := ioutil.ReadAll(os.Stdin)
if err != nil {
checkError(err)
}
content += string(b)
}
if content == "" {
flag.Usage()
checkError(fmt.Errorf("Error: no content given？"))
}

var err error
var q *qrcode.QRCode
Expand Down