util.go

package main

import (
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	neturl "net/url"
	"os"
	"os/exec"
	"runtime"
	"strings"
)

const GitIOURL = "http://git.io"

func GistParseError(body []byte) error {
	var err map[string]json.RawMessage
	if err := json.Unmarshal(body, &err); err != nil {
		return err
	}

	message := string(err["message"])

	if err["errors"] != nil {
		var errs []map[string]string
		if err := json.Unmarshal(err["errors"], &errs); err != nil {
			return err
		}

		var messages []string
		for _, m := range errs {
			messages = append(messages, fmt.Sprintf("%s %s", m["resource"], m["code"]))
		}
		message += " (" + strings.Join(messages, ", ") + ")"
	}

	return errors.New(message)
}

func Shorten(url string) (string, error) {
	resp, err := http.PostForm(GitIOURL, neturl.Values{"url": {url}})
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode == 201 {
		url = resp.Header.Get("Location")
	}

	return url, nil
}

func OpenBrowser(url string) {
	var browser string

	if os.Getenv("BROWSER") != "" {
		browser = os.Getenv("BROWSER")
	} else if runtime.GOOS == "darwin" {
		browser = "open"
	} else if runtime.GOOS == "windows" {
		browser = `start ""`
	} else {
		cmds := []string{
			"sensible-browser",
			"xdg-open",
			"firefox",
			"firefox-bin",
		}

		for _, c := range cmds {
			cmd := exec.Command("which", c)
			if err := cmd.Run(); err == nil {
				browser = c
			}
		}
	}

	if browser != "" {
		exec.Command(browser, url).Run()
	} else {
		fmt.Println("Couldn't open a browser.")
	}
}