169 lines
3.3 KiB
Go
169 lines
3.3 KiB
Go
// +build ignore
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// This example illustrates a Gemini client.
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package main
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import (
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"bufio"
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"bytes"
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"context"
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"crypto/x509"
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"errors"
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"fmt"
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"io"
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"log"
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"net/url"
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"os"
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"path/filepath"
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"time"
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"git.sr.ht/~adnano/go-gemini"
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"git.sr.ht/~adnano/go-gemini/tofu"
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)
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var (
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hosts tofu.KnownHosts
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hostsfile *tofu.HostWriter
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scanner *bufio.Scanner
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)
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func xdgDataHome() string {
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if s, ok := os.LookupEnv("XDG_DATA_HOME"); ok {
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return s
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}
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return filepath.Join(os.Getenv("HOME"), ".local", "share")
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}
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func init() {
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// Load known hosts file
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path := filepath.Join(xdgDataHome(), "gemini", "known_hosts")
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err := hosts.Load(path)
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if err != nil {
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log.Fatal(err)
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}
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hostsfile, err = tofu.OpenHostsFile(path)
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if err != nil {
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log.Fatal(err)
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}
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scanner = bufio.NewScanner(os.Stdin)
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}
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const trustPrompt = `The certificate offered by %s is of unknown trust. Its fingerprint is:
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%s
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If you knew the fingerprint to expect in advance, verify that this matches.
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Otherwise, this should be safe to trust.
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[t]rust always; trust [o]nce; [a]bort
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=> `
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func trustCertificate(hostname string, cert *x509.Certificate) error {
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host := tofu.NewHost(hostname, cert.Raw, cert.NotAfter)
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knownHost, ok := hosts.Lookup(hostname)
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if ok && time.Now().Before(knownHost.Expires) {
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// Check fingerprint
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if bytes.Equal(knownHost.Fingerprint, host.Fingerprint) {
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return nil
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}
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return errors.New("error: fingerprint does not match!")
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}
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fmt.Printf(trustPrompt, hostname, host.Fingerprint)
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scanner.Scan()
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switch scanner.Text() {
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case "t":
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hosts.Add(host)
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hostsfile.WriteHost(host)
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return nil
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case "o":
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hosts.Add(host)
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return nil
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default:
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return errors.New("certificate not trusted")
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}
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}
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func getInput(prompt string, sensitive bool) (input string, ok bool) {
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fmt.Printf("%s ", prompt)
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scanner.Scan()
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return scanner.Text(), true
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}
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func do(req *gemini.Request, via []*gemini.Request) (*gemini.Response, error) {
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client := gemini.Client{
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TrustCertificate: trustCertificate,
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}
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ctx := context.Background()
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resp, err := client.Do(ctx, req)
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if err != nil {
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return resp, err
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}
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switch resp.Status().Class() {
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case gemini.StatusInput:
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input, ok := getInput(resp.Meta(), resp.Status() == gemini.StatusSensitiveInput)
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if !ok {
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break
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}
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req.URL.ForceQuery = true
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req.URL.RawQuery = gemini.QueryEscape(input)
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return do(req, via)
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case gemini.StatusRedirect:
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via = append(via, req)
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if len(via) > 5 {
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return resp, errors.New("too many redirects")
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}
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target, err := url.Parse(resp.Meta())
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if err != nil {
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return resp, err
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}
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target = req.URL.ResolveReference(target)
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redirect := *req
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redirect.URL = target
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return do(&redirect, via)
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}
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return resp, err
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}
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func main() {
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if len(os.Args) < 2 {
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fmt.Printf("usage: %s <url> [host]\n", os.Args[0])
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os.Exit(1)
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}
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// Do the request
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url := os.Args[1]
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req, err := gemini.NewRequest(url)
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if err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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if len(os.Args) == 3 {
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req.Host = os.Args[2]
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}
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resp, err := do(req, nil)
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if err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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defer resp.Close()
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// Handle response
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if resp.Status().Class() == gemini.StatusSuccess {
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_, err := io.Copy(os.Stdout, resp)
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if err != nil {
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log.Fatal(err)
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}
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} else {
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fmt.Printf("%d %s\n", resp.Status, resp.Meta)
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os.Exit(1)
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}
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}
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