Add support for the BROWSER environment variablesupport-for-BROWSER-environment-variable

Allow user-defined URL-opening commands via the BROWSER environment
variable. This enables using a non-default browser, or changing the
browser for a single command.

For example, on Mac:

    $ export BROWSER='open -a Firefox'

Windows:

    > setx BROWSER "start iexplore"

In UNIX environments, the command is run through `$SHELL -c`, or
`/bin/sh` if `$SHELL` is not set. On Windows, it uses `cmd /c`.

Ensure that URLs are properly quoted between UNIX and Windows
environments in `fmtBrowserCmd()`.

1 files changed, 9 insertions, 0 deletions

diff --git a/browser_windows.go b/browser_windows.go
index a964c7b..0be67a2 100644
--- a/browser_windows.go
+++ b/browser_windows.go
@@ -1,6 +1,7 @@
 package browser
 
 import (
+	"fmt"
 	"os/exec"
 	"strings"
 	"syscall"
@@ -14,3 +15,11 @@ func openBrowser(url string) error {
 func setFlags(cmd *exec.Cmd) {
 	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
 }
+
+func shell() (shell, flag string) {
+	return "cmd", "/c"
+}
+
+func fmtBrowserCmd(browser, url string) string {
+	return fmt.Sprintf("%s %s", browser, url)
+}