sw-convert and sw-fetch tools

1 files changed, 134 insertions, 0 deletions

diff --git a/tools/sw-fetch/main.go b/tools/sw-fetch/main.go
new file mode 100644
index 0000000..ccf8ac8
--- /dev/null
+++ b/tools/sw-fetch/main.go
@@ -0,0 +1,134 @@
+package main
+
+import (
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net/url"
+	"os"
+
+	"tildegit.org/tjp/sliderule"
+	"tildegit.org/tjp/sliderule/gemini"
+)
+
+const usage = `Resource fetcher for the small web.
+
+Usage:
+  sw-fetch (-h | --help)
+  sw-fetch [-v | --verbose] [-o PATH | --output PATH] [-k | --keyfile PATH] [ -c | --certfile PATH ] [ -s | --skip-verify ] URL
+
+Options:
+  -h --help           Show this screen.
+  -v --verbose        Display more diagnostic information on standard error.
+  -o --output PATH    Send the fetched resource to PATH instead of standard out.
+  -k --keyfile PATH   Path to the TLS key file to use.
+  -c --certfile PATH  Path to the TLS certificate file to use.
+  -s --skip-verify    Don't verify server TLS certificates.
+`
+
+func main() {
+	conf := configure()
+	cl := sliderule.NewClient(conf.clientTLS)
+
+	response, err := cl.Fetch(conf.url.String())
+	if err != nil {
+		fail(err.Error() + "\n")
+	}
+	defer func() {
+		_ = response.Close()
+		_ = conf.output.Close()
+	}()
+
+	_, _ = io.Copy(conf.output, response.Body)
+}
+
+type config struct {
+	verbose   bool
+	output    io.WriteCloser
+	url       *url.URL
+	clientTLS *tls.Config
+}
+
+func configure() config {
+	if len(os.Args) == 1 {
+		fail(usage)
+	}
+
+	conf := config{output: os.Stdout}
+	key := ""
+	cert := ""
+	verify := true
+
+	for i := 1; i <= len(os.Args)-1; i += 1 {
+		switch os.Args[i] {
+		case "-h", "--help":
+			os.Stdout.WriteString(usage)
+			os.Exit(0)
+		case "-v", "--verbose":
+			conf.verbose = true
+		case "-o", "--output":
+			if i+1 == len(os.Args)-1 {
+				fail(usage)
+			}
+
+			out := os.Args[i+1]
+			if out != "-" {
+				output, err := os.OpenFile(out, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+				if err != nil {
+					fmt.Println(err.Error())
+					failf("'%s' is not a valid path\n", out)
+				}
+				conf.output = output
+			}
+
+			i += 1
+		case "-k", "--keyfile":
+			if i+1 == len(os.Args)-1 {
+				fail(usage)
+			}
+
+			i += 1
+			key = os.Args[i]
+		case "-c", "--certfile":
+			if i+1 == len(os.Args)-1 {
+				fail(usage)
+			}
+
+			i += 1
+			cert = os.Args[i]
+		case "-s", "--skip-verify":
+			verify = false
+		}
+	}
+
+	conf.clientTLS = &tls.Config{}
+	if key != "" || cert != "" {
+		if key == "" || cert == "" {
+			fail("-k|--keyfile and -c|--certfile must both be present, or neither\n")
+		}
+		tlsConf, err := gemini.FileTLS(cert, key)
+		if err != nil {
+			failf("failed to load TLS key pair")
+		}
+		conf.clientTLS = tlsConf
+	}
+	conf.clientTLS.InsecureSkipVerify = !verify
+
+	u, err := url.Parse(os.Args[len(os.Args)-1])
+	if err != nil || u.Scheme == "" {
+		fail(usage)
+	}
+	conf.url = u
+
+	return conf
+}
+
+func fail(msg string) {
+	os.Stderr.WriteString(msg)
+	os.Exit(1)
+}
+
+func failf(msg string, args ...any) {
+	fmt.Fprintf(os.Stderr, msg, args...)
+	os.Exit(1)
+}