Fix missing default for format flag

cmd/microdata/main.go

@@ -0,0 +1,92 @@
+// Copyright 2015 Lars Wiegman
+
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"net/url"
+	"os"
+	"text/template"
+
+	"github.com/namsral/microdata"
+)
+
+var fnmap = template.FuncMap{
+	"jsonMarshal": jsonMarshal,
+}
+
+func main() {
+	var data *microdata.Microdata
+	var err error
+
+	baseURL := flag.String("base-url", "http://example.com", "base url to use for the data in the stdin stream.")
+	contentType := flag.String("content-type", "", "content type of the data in the stdin stream.")
+	format := flag.String("format", "{{. |jsonMarshal }}", `alternate format for the output of the
+	microdata, using the syntax of package html/template. The default output is
+	equivalent to -f '{{. |jsonMarshal }}'. The struct being passed to the
+	template is:
+		
+		type Microdata struct
+			Items []*Item 'json:"items"'
+		}
+
+		type Item struct {
+			Types      []string    'json:"type"'
+			Properties PropertyMap 'json:"properties"'
+			Id         string      'json:"id,omitempty"'
+		}
+
+		type PropertyMap map[string]ValueList
+		
+		type ValueList []interface{}
+
+	The template function "jsonMarshal" calls json.Marshal
+`)
+
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "Usage of %s [options] [url]:\n", os.Args[0])
+		flag.PrintDefaults()
+		fmt.Fprint(os.Stderr, "\nExtract the HTML Microdata from a HTML5 document. Format to JSON or using the syntax of package html/template.")
+		fmt.Fprint(os.Stderr, " Provide an URL to a valid HTML5 document or stream a valid HTML5 document through stdin.\n")
+	}
+
+	flag.Parse()
+
+	// Fetch and parse microdata
+	switch len(flag.Args()) {
+	case 0:
+		u, err := url.Parse(*baseURL)
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+		data, err = microdata.ParseHTML(os.Stdin, *contentType, u)
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+	default:
+		data, err = microdata.ParseURL(flag.Args()[0])
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+	}
+
+	t := template.Must(template.New("format").Funcs(fnmap).Parse(*format))
+	if err := t.Execute(os.Stdout, data); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}
+
+// jsonMarshal encodes the given data to JSON.
+func jsonMarshal(data interface{}) (string, error) {
+	b, err := json.MarshalIndent(data, "", "  ")
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}