initial commit

client.go

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// errHostUnreachable marks a transport-level failure (tunnel down, host server
+// not running) as distinct from an HTTP-level rejection, so the client can fall
+// back to the local opener only when forwarding genuinely failed.
+var errHostUnreachable = errors.New("host unreachable")
+
+var httpClient = &http.Client{
+	Transport: &http.Transport{
+		DialContext: (&net.Dialer{Timeout: 3 * time.Second}).DialContext,
+	},
+}
+
+func runClient(args []string, openerName string) int {
+	if len(args) == 0 {
+		fmt.Fprintln(os.Stderr, "open: missing operand")
+		return 2
+	}
+
+	c := &client{
+		base:  "http://" + envAddr(),
+		token: envToken(),
+	}
+
+	exit := 0
+	for _, arg := range args {
+		err := c.openOne(arg)
+		if errors.Is(err, errHostUnreachable) {
+			if ferr := localOpen(openerName, arg); ferr != nil {
+				fmt.Fprintf(os.Stderr, "open: %s: host unreachable, local fallback failed: %v\n", arg, ferr)
+				exit = 1
+			}
+			continue
+		}
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "open: %s: %v\n", arg, err)
+			exit = 1
+		}
+	}
+	return exit
+}
+
+type client struct {
+	base  string
+	token string
+}
+
+func (c *client) openOne(arg string) error {
+	// Existing local file takes priority: copy it so self-contained files render
+	// on the host. Directories and missing paths fall through to string/URL.
+	if info, err := os.Stat(arg); err == nil && info.Mode().IsRegular() {
+		return c.sendFile(arg)
+	}
+	return c.sendString(arg)
+}
+
+func (c *client) sendFile(path string) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = f.Close() }()
+
+	req, err := http.NewRequest(http.MethodPost, c.base+"/file", f)
+	if err != nil {
+		return err
+	}
+	req.Header.Set(fileNameHeader, filepath.Base(path))
+	req.Header.Set("Content-Type", "application/octet-stream")
+	return c.do(req)
+}
+
+func (c *client) sendString(s string) error {
+	req, err := http.NewRequest(http.MethodPost, c.base+"/open", strings.NewReader(s))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "text/plain")
+	return c.do(req)
+}
+
+func (c *client) do(req *http.Request) error {
+	if c.token != "" {
+		req.Header.Set(tokenHeader, c.token)
+	}
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("%w: %s: %v", errHostUnreachable, c.base, err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+	body, _ := io.ReadAll(io.LimitReader(resp.Body, 4<<10))
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("host returned %s: %s", resp.Status, strings.TrimSpace(string(body)))
+	}
+	return nil
+}