browser-ruler/main.go

package main

import (
	"flag"
	"fmt"
	"net/url"
	"os/exec"
	"regexp"
)

// MatchFunc is a signature for a function to match a URL
type MatchFunc = func(url.URL) bool

// A BrowserRule is a rule that will launch a browser, if matched
type BrowserRule struct {
	matcher MatchFunc
	command string
	args    []string
}

// IsMatched will check to see the rule matches the provied URL
func (r BrowserRule) IsMatched(dest url.URL) bool {
	return r.matcher(dest)
}

// Launch will launch the browser with the provided URL
func (r BrowserRule) Launch(dest url.URL) error {
	args := append(r.args, "--", dest.String())
	cmd := exec.Command(r.command, args...)
	return cmd.Start()
}

// MaybeLaunch will lauch the browser with the provided URL if it matches the rule
func (r BrowserRule) MaybeLaunch(dest url.URL) (bool, error) {
	if r.IsMatched(dest) {
		return true, r.Launch(dest)
	}
	return false, nil
}

func matchHostname(hostnames ...string) MatchFunc {
	return func(dest url.URL) bool {
		for _, host := range hostnames {
			if host == dest.Hostname() {
				return true
			}
		}
		return false
	}
}

func matchHostRegexp(hostRegexp ...string) MatchFunc {
	matchers := []*regexp.Regexp{}
	for _, s := range hostRegexp {
		matchers = append(matchers, regexp.MustCompile(s))
	}
	return func(dest url.URL) bool {
		for _, matcher := range matchers {
			if matcher.MatchString(dest.Hostname()) {
				return true
			}
		}
		return false
	}
}

func matchRegexp(urlRegexp ...string) MatchFunc {
	matchers := []*regexp.Regexp{}
	for _, s := range urlRegexp {
		matchers = append(matchers, regexp.MustCompile(s))
	}
	return func(dest url.URL) bool {
		for _, matcher := range matchers {
			if matcher.MatchString(dest.String()) {
				return true
			}
		}
		return false
	}
}

func matchAny(matchFuncs ...MatchFunc) MatchFunc {
	return func(dest url.URL) bool {
		for _, f := range matchFuncs {
			if f(dest) {
				return true
			}
		}
		return false
	}
}

// Always returns true
func defaultBrowser(dest url.URL) bool {
	return true
}

// Never returns true
func noop(dest url.URL) bool {
	return false
}

func handleURL(browserRules []BrowserRule, urlString string) error {
	dest, err := url.Parse(urlString)
	if err != nil {
		return fmt.Errorf("failed to parse url: %s, %w", urlString, err)
	}

	var matched bool
	for _, rule := range browserRules {
		matched, err = rule.MaybeLaunch(*dest)
		if err != nil {
			return fmt.Errorf("failed launching browser: %w", err)
		}

		if matched {
			break
		}
	}

	return nil
}

func main() {
	configPath := flag.String("config", "", "Path to config file, otherwise it will default to $XDG_CONFIG_HOME/browser-ruler/config.hcl or $HOME/.browser-ruler.hcl")
	flag.Parse()

	// Read config path from option or find default
	if *configPath == "" {
		defaultConfigPath, err := DefaultConfigPath()
		if err != nil {
			fmt.Println("Failed to get a path to any config files")
			panic(err)
		}
		configPath = &defaultConfigPath
	}

	// Read rules from config path
	browserRules, err := LoadConfig(*configPath)
	if err != nil {
		fmt.Printf("Could not read config from path %s\n", *configPath)
		panic(err)
	}

	// Get urls from args
	urls := flag.Args()

	// For each url, run matcher
	for _, urlString := range urls {
		err := handleURL(browserRules, urlString)
		if err != nil {
			panic(err)
		}
	}
}