1 files changed, 99 insertions, 0 deletions
diff --git a/examples/cowsay/main.go b/examples/cowsay/main.go
new file mode 100644
index 0000000..e724421
--- /dev/null
+++ b/examples/cowsay/main.go
@@ -0,0 +1,99 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"log"
+	"net"
+	"os"
+	"os/exec"
+
+	guslog "tildegit.org/tjp/gus/contrib/log"
+	"tildegit.org/tjp/gus/gemini"
+)
+
+func main() {
+	// Get TLS files from the environment
+	certfile, keyfile := envConfig()
+
+	// build a TLS configuration suitable for gemini
+	tlsconf, err := gemini.FileTLS(certfile, keyfile)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// set up the network listener
+	listener, err := net.Listen("tcp4", ":1965")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// add request logging to the request handler
+	handler := guslog.Requests(os.Stdout, nil)(cowsayHandler)
+
+	// run the server
+	gemini.NewServer(context.Background(), tlsconf, listener, handler).Serve()
+}
+
+func cowsayHandler(ctx context.Context, req *gemini.Request) *gemini.Response {
+	// prompt for a query if there is none already
+	if req.RawQuery == "" {
+		return gemini.Input("enter a phrase")
+	}
+
+	// find the "cowsay" executable
+	binpath, err := exec.LookPath("cowsay")
+	if err != nil {
+		return gemini.Failure(err)
+	}
+
+	// build the command and set the query to be passed to its stdin
+	cmd := exec.CommandContext(ctx, binpath)
+	cmd.Stdin = bytes.NewBufferString(req.UnescapedQuery())
+
+	// set up a pipe so we can read the command's stdout
+	rd, err := cmd.StdoutPipe()
+	if err != nil {
+		return gemini.Failure(err)
+	}
+
+	// start the command
+	if err := cmd.Start(); err != nil {
+		return gemini.Failure(err)
+	}
+
+	// read the complete stdout contents, clean up the process on error
+	buf, err := io.ReadAll(rd)
+	if err != nil {
+		cmd.Process.Kill()
+		cmd.Wait()
+		return gemini.Failure(err)
+	}
+
+	// wait for the process to close
+	cmd.Wait()
+
+	// pass the buffer to the response wrapped in ``` toggles,
+	// and include a link to start over
+	out := io.MultiReader(
+		bytes.NewBufferString("```\n"),
+		bytes.NewBuffer(buf),
+		bytes.NewBufferString("\n```\n=> . again"),
+	)
+	return gemini.Success("text/gemini", out)
+}
+
+func envConfig() (string, string) {
+	certfile, ok := os.LookupEnv("SERVER_CERTIFICATE")
+	if !ok {
+		log.Fatal("missing SERVER_CERTIFICATE environment variable")
+	}
+
+	keyfile, ok := os.LookupEnv("SERVER_PRIVATEKEY")
+	if !ok {
+		log.Fatal("missing SERVER_PRIVATEKEY environment variable")
+	}
+
+	return certfile, keyfile
+}