commit 0d65b5e1006f9ede022ccb0cfc898942c6528221 equwal <13551856+equwal@users.noreply.github.com> 2026-09-24 21:36:04 -0700 Publish an sbm bookmark file as links on a web site Serve the links as JSON on /links/links.json. Give the owner an admin page to add, delete and import links. Import takes an sbm file or a browser HTML export.
.gitignore | 3 + LICENSE | 662 ++++++++++++++++++++++++++++++++++++++++++ README.md | 58 ++++ admin.html | 45 +++ deploy/nginx-location.conf | 10 + deploy/sbm-webpublish.service | 25 ++ go.mod | 5 + go.sum | 2 + links.go | 256 ++++++++++++++++ links_test.go | 121 ++++++++ main.go | 242 +++++++++++++++ server_test.go | 125 ++++++++ 12 files changed, 1554 insertions(+)
diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..cb6361c --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +/sbm-webpublish +/sbm-webpublish.exe +/links.sbm diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..fe6b903 --- /dev/null +++ b/LICENSE @@ -0,0 +1,662 @@ + GNU AFFERO GENERAL PUBLIC LICENSE + Version 3, 19 November 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/> + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU Affero General Public License is a free, copyleft license for +software and other kinds of works, specifically designed to ensure +cooperation with the community in the case of network server software. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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There are many ways you could offer source, and different +solutions will be better for different programs; see section 13 for the +specific requirements. + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU AGPL, see +<https://www.gnu.org/licenses/>. + diff --git a/README.md b/README.md new file mode 100644 index 0000000..5811fd0 --- /dev/null +++ b/README.md @@ -0,0 +1,58 @@ +# sbm-webpublish + +sbm-webpublish publishes an [sbm](https://github.com/equwal/sbm) bookmark +file as a list of links on a web site. The links page of +[recentlywritten.com](https://recentlywritten.com/links.html) uses it. + +It is one small Go program with no dependencies outside the standard +library. It keeps the links in one plain sbm file: one line for each link, + + URL<tab>description<tab>tag tag tag + +so `bm` can read and edit the same file. + +## Pages + +| Path | Who | What | +|---|---|---| +| `GET /links/links.json` | everyone | The links, newest first, as JSON: `url`, `title`, `host`, `tags`. Only http and https links are in the list. | +| `GET /links/admin` | owner | Add a link, delete a link, import a file. | + +The admin pages use HTTP basic auth. Any user name works. The password is +the value of `ADMIN_PASSWORD`. The server refuses a form POST that comes +from another site. + +The import takes an sbm file or the Netscape HTML that browsers export. +The folders of a browser bookmark become its tags. A URL that is a link +already is skipped. Two URLs are the same link when they differ only in +scheme, a leading `www.`, trailing slashes or the case of the host, as in +`bm`. + +## Run + + ADMIN_PASSWORD=secret go run . + +Then open http://127.0.0.1:8082/links/admin. + +| Variable | Default | Meaning | +|---|---|---| +| `ADMIN_PASSWORD` | none, required | The password of the admin pages. | +| `LINKS_FILE` | `links.sbm` | The sbm file of the links. | +| `ADDR` | `127.0.0.1:8082` | The address to listen on. | + +## Put it on a site + +1. Install the service with `deploy/sbm-webpublish.service`. +2. Add `deploy/nginx-location.conf` to the nginx server block of the site. +3. On a page of the site, get `links/links.json` and show the links. See + `pages/links.md` in + [recentlywritten](https://github.com/equwal/recentlywritten) for an + example. + +## Test + + go test ./... + +## License + +AGPL-3.0, as sbm-sync. diff --git a/admin.html b/admin.html new file mode 100644 index 0000000..bab0bca --- /dev/null +++ b/admin.html @@ -0,0 +1,45 @@ +<!DOCTYPE html> +<html lang="en"> +<head> +<meta charset="UTF-8"> +<meta name="viewport" content="width=device-width, initial-scale=1"> +<title>Links admin</title> +<style> +body { font-family: sans-serif; max-width: 48rem; margin: 1rem auto; padding: 0 1rem; } +form { margin: 0.5rem 0; } +input[type=text], input[type=url] { width: 100%; box-sizing: border-box; margin: 0.2rem 0; } +li { margin: 0.4rem 0; } +.host, .tags { color: #666; font-size: 0.9em; } +.message { background: #ffd; padding: 0.5rem; } +li form { display: inline; } +</style> +</head> +<body> +<h1>Links</h1> +<p><a href="links.json">links.json</a> ยท <a href="/links.html">public page</a></p> +{{with .Message}}<p class="message">{{.}}</p>{{end}} + +<h2>Add a link</h2> +<form method="post" action="admin/add"> +<input type="url" name="url" placeholder="https://example.com" required> +<input type="text" name="desc" placeholder="Description"> +<input type="text" name="tags" placeholder="Tags, with spaces between them"> +<button>Add</button> +</form> + +<h2>Import a file</h2> +<p>An sbm bookmark file, or the HTML that a browser exports. URLs that are links already are skipped.</p> +<form method="post" action="admin/import" enctype="multipart/form-data"> +<input type="file" name="file" required> +<button>Import</button> +</form> + +<h2>{{len .Links}} links, newest first</h2> +<ul> +{{range .Links}}<li>{{if .Href}}<a href="{{.Href}}">{{.Title}}</a>{{else}}{{.Title}}{{end}} +<span class="host">{{.Host}}</span> +{{with .Tags}}<span class="tags">{{range .}}{{.}} {{end}}</span>{{end}} +<form method="post" action="admin/delete"><input type="hidden" name="url" value="{{.URL}}"><button>Delete</button></form></li> +{{end}}</ul> +</body> +</html> diff --git a/deploy/nginx-location.conf b/deploy/nginx-location.conf new file mode 100644 index 0000000..a13b214 --- /dev/null +++ b/deploy/nginx-location.conf @@ -0,0 +1,10 @@ +# Example for nginx. Add this block to the server block of the site. +# nginx continues to serve the static site. It sends only /links/ to +# sbm-webpublish. Serve the site over HTTPS: the admin page uses basic auth. +location /links/ { + proxy_pass http://127.0.0.1:8082; + proxy_set_header Host $host; + proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; + proxy_set_header X-Forwarded-Proto $scheme; + client_max_body_size 10m; +} diff --git a/deploy/sbm-webpublish.service b/deploy/sbm-webpublish.service new file mode 100644 index 0000000..9c746c5 --- /dev/null +++ b/deploy/sbm-webpublish.service @@ -0,0 +1,25 @@ +# systemd unit for sbm-webpublish. +# Install: +# GOOS=linux GOARCH=amd64 go build -o sbm-webpublish . +# copy the binary to /usr/local/bin/sbm-webpublish +# put ADMIN_PASSWORD=... in /etc/sbm-webpublish.env (mode 600) +# copy this file to /etc/systemd/system/sbm-webpublish.service +# systemctl daemon-reload && systemctl enable --now sbm-webpublish +[Unit] +Description=sbm-webpublish: links from an sbm bookmark file +After=network-online.target +Wants=network-online.target + +[Service] +EnvironmentFile=/etc/sbm-webpublish.env +Environment=LINKS_FILE=/var/lib/sbm-webpublish/links.sbm +ExecStart=/usr/local/bin/sbm-webpublish +DynamicUser=yes +StateDirectory=sbm-webpublish +ProtectSystem=strict +ProtectHome=yes +NoNewPrivileges=yes +Restart=on-failure + +[Install] +WantedBy=multi-user.target diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..6366cd9 --- /dev/null +++ b/go.mod @@ -0,0 +1,5 @@ +module github.com/equwal/sbm-webpublish + +go 1.26.2 + +require pgregory.net/rapid v1.3.0 diff --git a/go.sum b/go.sum new file mode 100644 index 0000000..2ecce80 --- /dev/null +++ b/go.sum @@ -0,0 +1,2 @@ +pgregory.net/rapid v1.3.0 h1:vBvO0VSqti75J1jjYqpgPNBLKMd1+gxa9fYo7vk/Exc= +pgregory.net/rapid v1.3.0/go.mod h1:dPlE4OBBxgXPqkP79flB6sJL1dx5azpI7HQ9MY9Z7uk= diff --git a/links.go b/links.go new file mode 100644 index 0000000..18d2699 --- /dev/null +++ b/links.go @@ -0,0 +1,256 @@ +package main + +// The links file is an sbm bookmark file. Each line is one link: +// +// URL<tab>description<tab>tag tag tag +// +// The parse, import and duplicate rules are the rules of bm and sbm-sync, +// so a file from bm works here, and the file here works in bm. + +import ( + "html" + "regexp" + "slices" + "strings" +) + +var ( + scheme = regexp.MustCompile(`^[a-zA-Z][a-zA-Z0-9+.-]*://`) + notTag = regexp.MustCompile(`[^a-z0-9]+`) + imported = regexp.MustCompile(`^(https?|ftp|file)://`) +) + +// Link is one link of the file. +type Link struct { + URL, Desc string + Tags []string +} + +// Title gives the text of the link. +func (l Link) Title() string { + if strings.TrimSpace(l.Desc) == "" { + return l.URL + } + return l.Desc +} + +// Host gives the host of the URL. +func (l Link) Host() string { + u := scheme.ReplaceAllString(l.URL, "") + if i := strings.IndexAny(u, "/?#"); i >= 0 { + u = u[:i] + } + return u +} + +// Href gives the address for the link on the page. Only http and https +// addresses come out, so that a line of the file cannot run script in the +// page. An address without a scheme gets https. Other schemes give "". +func (l Link) Href() string { + s := strings.ToLower(l.URL) + switch { + case strings.HasPrefix(s, "https://") || strings.HasPrefix(s, "http://"): + return l.URL + case !strings.Contains(l.URL, ":"): + return "https://" + l.URL + } + return "" +} + +// lines splits a file into lines without their ends. CRLF counts as LF. +func lines(text string) []string { + text = strings.ReplaceAll(text, "\r\n", "\n") + if text == "" { + return nil + } + return strings.Split(strings.TrimSuffix(text, "\n"), "\n") +} + +// join is the reverse of lines: each line ends with LF. +func join(ls []string) string { + if len(ls) == 0 { + return "" + } + return strings.Join(ls, "\n") + "\n" +} + +// norm gives the form of a URL that bm uses to find duplicates: two URLs are +// the same link when they differ only in scheme, a leading "www.", trailing +// slashes or the case of the host. +func norm(u string) string { + u = scheme.ReplaceAllString(u, "") + host, rest := u, "" + if i := strings.IndexByte(u, '/'); i >= 0 { + host, rest = u[:i], u[i:] + } + host = strings.TrimPrefix(strings.ToLower(host), "www.") + return host + strings.TrimRight(rest, "/") +} + +// key gives the normal form of the URL of a line. Comments and empty lines +// give "". +func key(line string) string { + if strings.TrimSpace(line) == "" || strings.HasPrefix(line, "#") { + return "" + } + u, _, _ := strings.Cut(line, "\t") + if !strings.Contains(line, "\t") { + u = strings.Fields(line)[0] + } + return norm(strings.TrimSpace(u)) +} + +// parseLine gives the link of a line, and false for a comment or an empty +// line. A line without a tab has the old format "URL description". Its +// first word is the URL. +func parseLine(line string) (Link, bool) { + if strings.TrimSpace(line) == "" || strings.HasPrefix(line, "#") { + return Link{}, false + } + fields := strings.Split(line, "\t") + if len(fields) == 1 { + words := strings.Fields(line) + return Link{URL: words[0], Desc: strings.Join(words[1:], " ")}, true + } + l := Link{URL: strings.TrimSpace(fields[0]), Desc: fields[1]} + if len(fields) > 2 { + l.Tags = strings.Fields(fields[2]) + } + return l, l.URL != "" +} + +// parse gives the links of a file, in the order of the file. +func parse(text string) []Link { + var out []Link + for _, s := range lines(text) { + if l, ok := parseLine(s); ok { + out = append(out, l) + } + } + return out +} + +// line gives the file line of a link, as bm writes it: the URL without +// white space, the description without tabs and line breaks, and the tags +// with one space between them. It gives "" when the URL is empty or starts +// with "#". +func line(url, desc, tags string) string { + u := strings.Join(strings.Fields(url), "") + if u == "" || strings.HasPrefix(u, "#") { + return "" + } + d := strings.TrimSpace(strings.NewReplacer("\t", " ", "\r", " ", "\n", " ").Replace(desc)) + return u + "\t" + d + "\t" + strings.Join(strings.Fields(tags), " ") +} + +// importRows gives the link lines of an imported file: the Netscape HTML +// that browsers export, or an sbm file. +func importRows(text string) []string { + text = strings.TrimPrefix(text, string(rune(0xFEFF))) + if strings.HasPrefix(strings.TrimSpace(text), "<") { + return fromHTML(text) + } + return lines(text) +} + +// fromHTML gives the link lines of the Netscape HTML that browsers export, +// as bm-import does: <H3> opens a folder, </DL> closes it, and the folders +// of a link become its tags. Only http, https, ftp and file URLs stay. +func fromHTML(text string) []string { + var folders, out []string + for _, s := range lines(text) { + upper := upperASCII(s) + if at := strings.Index(upper, "<H3"); at >= 0 { + name := s[at:] + name = name[strings.IndexByte(name, '>')+1:] + if end := strings.Index(upperASCII(name), "</H3"); end >= 0 { + name = name[:end] + } + folders = append(folders, folderTag(htmlText(name))) + } + if at := strings.Index(upper, `HREF="`); at >= 0 { + u, rest, ok := strings.Cut(s[at+len(`HREF="`):], `"`) + name := rest[strings.IndexByte(rest, '>')+1:] + if end := strings.Index(upperASCII(name), "</A"); end >= 0 { + name = name[:end] + } + var tags []string + for _, f := range folders { + if f != "" && !slices.Contains(tags, f) { + tags = append(tags, f) + } + } + if u = htmlText(u); ok && imported.MatchString(u) { + out = append(out, u+"\t"+htmlText(name)+"\t"+strings.Join(tags, " ")) + } + } + if strings.Contains(upper, "</DL>") && len(folders) > 0 { + folders = folders[:len(folders)-1] + } + } + return out +} + +// upperASCII gives s with the letters a to z in upper case. Each byte keeps +// its index, so an index in the result is an index in s. +func upperASCII(s string) string { + b := []byte(s) + for i, c := range b { + if 'a' <= c && c <= 'z' { + b[i] = c - 'a' + 'A' + } + } + return string(b) +} + +// htmlText gives the text of HTML without its entities, with one space in +// place of each run of white space. +func htmlText(s string) string { + return strings.Join(strings.Fields(html.UnescapeString(s)), " ") +} + +// folderTag gives the tag of a folder name: "Dev Tools" is dev-tools. +func folderTag(name string) string { + return strings.Trim(notTag.ReplaceAllString(strings.ToLower(name), "-"), "-") +} + +// merge adds to text the rows whose URL is not in text and not in a row +// before them, as bm --merge does. It gives the new text, the number of rows +// that it added, and the number that it skipped as duplicates. +func merge(text string, rows []string) (string, int, int) { + ls := lines(text) + seen := map[string]bool{} + for _, s := range ls { + seen[key(s)] = true + } + added, skipped := 0, 0 + for _, row := range rows { + k := key(row) + switch { + case k == "": + case seen[k]: + skipped++ + default: + seen[k] = true + f := append(strings.SplitN(row, "\t", 4), "", "") + if !strings.Contains(row, "\t") { + words := strings.Fields(row) + f = []string{words[0], strings.Join(words[1:], " "), ""} + } + ls = append(ls, line(f[0], f[1], f[2])) + added++ + } + } + return join(ls), added, skipped +} + +// remove gives text without the lines whose URL has the normal form k. +func remove(text, k string) string { + var out []string + for _, s := range lines(text) { + if k == "" || key(s) != k { + out = append(out, s) + } + } + return join(out) +} diff --git a/links_test.go b/links_test.go new file mode 100644 index 0000000..4354436 --- /dev/null +++ b/links_test.go @@ -0,0 +1,121 @@ +package main + +import ( + "slices" + "strings" + "testing" + + "pgregory.net/rapid" +) + +// genRow makes a file line: a URL, a description and tags, with tabs, +// spaces and line breaks in awkward places. +func genRow(t *rapid.T) string { + host := rapid.SampledFrom([]string{"a.com", "www.a.com", "b.org", "c.net"}).Draw(t, "host") + path := rapid.SampledFrom([]string{"", "/", "/x", "/x/", "/y"}).Draw(t, "path") + sch := rapid.SampledFrom([]string{"https://", "http://", ""}).Draw(t, "scheme") + desc := rapid.StringMatching(`[a-z \t\n]{0,8}`).Draw(t, "desc") + tags := rapid.StringMatching(`[a-z ]{0,8}`).Draw(t, "tags") + return line(sch+host+path, desc, tags) +} + +func TestLineParsesBack(t *testing.T) { + rapid.Check(t, func(t *rapid.T) { + u := rapid.StringMatching(`[a-z:/. ]{1,12}`).Draw(t, "url") + desc := rapid.String().Draw(t, "desc") + tags := rapid.StringMatching(`[a-z \t]{0,12}`).Draw(t, "tags") + row := line(u, desc, tags) + if row == "" { + return + } + if strings.ContainsAny(row, "\n\r") || strings.Count(row, "\t") != 2 { + t.Fatalf("bad line %q", row) + } + l, ok := parseLine(row) + if !ok || l.URL != strings.Join(strings.Fields(u), "") || !slices.Equal(l.Tags, strings.Fields(tags)) { + t.Fatalf("line %q parsed as %+v", row, l) + } + }) +} + +func TestMergeKeepsOneLineForEachURL(t *testing.T) { + rapid.Check(t, func(t *rapid.T) { + base, _, _ := merge("", rapid.SliceOf(rapid.Custom(genRow)).Draw(t, "base")) + rows := rapid.SliceOf(rapid.Custom(genRow)).Draw(t, "rows") + text, added, skipped := merge(base, rows) + if added+skipped != len(rows) { + t.Fatalf("added %d + skipped %d != %d rows", added, skipped, len(rows)) + } + seen := map[string]bool{} + for _, s := range lines(text) { + if seen[key(s)] { + t.Fatalf("duplicate %q in %q", key(s), text) + } + seen[key(s)] = true + } + for _, r := range rows { + if !seen[key(r)] { + t.Fatalf("row %q is missing", r) + } + } + if again, n, _ := merge(text, rows); n != 0 || again != text { + t.Fatalf("second merge changed the file") + } + }) +} + +func TestRemove(t *testing.T) { + rapid.Check(t, func(t *rapid.T) { + text, _, _ := merge("", rapid.SliceOf(rapid.Custom(genRow)).Draw(t, "rows")) + k := key(genRow(t)) + out := remove(text, k) + var want []string + for _, s := range lines(text) { + if key(s) != k { + want = append(want, s) + } + } + if out != join(want) { + t.Fatalf("remove %q from %q gave %q", k, text, out) + } + }) +} + +func TestHrefIsOnlyHTTP(t *testing.T) { + for u, want := range map[string]string{ + "https://a.com": "https://a.com", + "HTTP://a.com": "HTTP://a.com", + "a.com/x": "https://a.com/x", + "javascript:alert(1)": "", + "data:text/html,x": "", + "ftp://a.com": "", + "JavaScript:alert(1)//": "", + } { + if got := (Link{URL: u}).Href(); got != want { + t.Errorf("Href(%q) = %q, want %q", u, got, want) + } + } +} + +func TestFromHTML(t *testing.T) { + in := `<!DOCTYPE NETSCAPE-Bookmark-file-1> +<DL><p> +<DT><H3>Dev Tools</H3> +<DL><p> +<DT><A HREF="https://go.dev/" ADD_DATE="1">Go & more</A> +<DT><A HREF="javascript:x">bad</A> +</DL><p> +<DT><A HREF="https://a.com">A</A> +</DL>` + want := []string{"https://go.dev/\tGo & more\tdev-tools", "https://a.com\tA\t"} + if got := importRows(in); !slices.Equal(got, want) { + t.Fatalf("got %q, want %q", got, want) + } +} + +func TestMergeOldFormat(t *testing.T) { + text, added, _ := merge("", []string{"https://a.com some site"}) + if added != 1 || text != "https://a.com\tsome site\t\n" { + t.Fatalf("got %q", text) + } +} diff --git a/main.go b/main.go new file mode 100644 index 0000000..48878bb --- /dev/null +++ b/main.go @@ -0,0 +1,242 @@ +// sbm-webpublish publishes an sbm bookmark file as a list of links on a +// web site. The site gets the links as JSON from /links/links.json. The +// owner adds, deletes and imports links on /links/admin. +package main + +import ( + "crypto/subtle" + _ "embed" + "encoding/json" + "errors" + "html/template" + "io" + "io/fs" + "log" + "net/http" + "os" + "path/filepath" + "slices" + "strconv" + "sync" +) + +//go:embed admin.html +var adminHTML string + +var adminTmpl = template.Must(template.New("admin").Parse(adminHTML)) + +// maxImport is the largest file that the import form takes. +const maxImport = 10 << 20 + +// store keeps the links file. One mutex puts the changes in a sequence. +type store struct { + mu sync.Mutex + path string +} + +func (s *store) read() (string, error) { + b, err := os.ReadFile(s.path) + if errors.Is(err, fs.ErrNotExist) { + return "", nil + } + return string(b), err +} + +// change reads the file, gives its text to f, and writes the result. It +// writes a temporary file and renames it, so that a reader never sees half +// a file. +func (s *store) change(f func(string) string) error { + s.mu.Lock() + defer s.mu.Unlock() + text, err := s.read() + if err != nil { + return err + } + tmp, err := os.CreateTemp(filepath.Dir(s.path), ".links-*") + if err != nil { + return err + } + defer os.Remove(tmp.Name()) + if _, err := tmp.WriteString(f(text)); err != nil { + tmp.Close() + return err + } + if err := tmp.Close(); err != nil { + return err + } + return os.Rename(tmp.Name(), s.path) +} + +type server struct { + links *store + password string +} + +// jsonLink is one link in links.json. +type jsonLink struct { + URL string `json:"url"` + Title string `json:"title"` + Host string `json:"host"` + Tags []string `json:"tags"` +} + +// publicLinks gives the links that the page can show: only the links with +// an http or https address. The newest link is first. +func publicLinks(text string) []jsonLink { + out := []jsonLink{} + for _, l := range parse(text) { + if h := l.Href(); h != "" { + tags := l.Tags + if tags == nil { + tags = []string{} + } + out = append([]jsonLink{{h, l.Title(), l.Host(), tags}}, out...) + } + } + return out +} + +func (s *server) linksJSON(w http.ResponseWriter, r *http.Request) { + text, err := s.links.read() + if err != nil { + http.Error(w, "cannot read the links", http.StatusInternalServerError) + log.Print(err) + return + } + w.Header().Set("Content-Type", "application/json; charset=utf-8") + w.Header().Set("Cache-Control", "max-age=60") + json.NewEncoder(w).Encode(publicLinks(text)) +} + +// admin lets only the owner through: HTTP basic auth with any user name +// and the password of ADMIN_PASSWORD. +func (s *server) admin(h http.HandlerFunc) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { + _, pw, ok := r.BasicAuth() + if !ok || subtle.ConstantTimeCompare([]byte(pw), []byte(s.password)) != 1 { + w.Header().Set("WWW-Authenticate", `Basic realm="sbm-webpublish", charset="UTF-8"`) + http.Error(w, "sign in", http.StatusUnauthorized) + return + } + h(w, r) + } +} + +type adminData struct { + Links []Link + Message string +} + +func (s *server) show(w http.ResponseWriter, message string) { + text, err := s.links.read() + if err != nil { + http.Error(w, "cannot read the links", http.StatusInternalServerError) + log.Print(err) + return + } + ls := parse(text) + slices.Reverse(ls) + w.Header().Set("Content-Type", "text/html; charset=utf-8") + if err := adminTmpl.Execute(w, adminData{ls, message}); err != nil { + log.Print(err) + } +} + +func (s *server) adminPage(w http.ResponseWriter, r *http.Request) { + s.show(w, r.URL.Query().Get("m")) +} + +// done sends the browser back to the admin page with a message. +func done(w http.ResponseWriter, r *http.Request, message string) { + http.Redirect(w, r, "../admin?m="+template.URLQueryEscaper(message), http.StatusSeeOther) +} + +func (s *server) add(w http.ResponseWriter, r *http.Request) { + row := line(r.FormValue("url"), r.FormValue("desc"), r.FormValue("tags")) + if row == "" { + done(w, r, "Give a URL.") + return + } + var added int + err := s.links.change(func(text string) string { + text, added, _ = merge(text, []string{row}) + return text + }) + switch { + case err != nil: + log.Print(err) + http.Error(w, "cannot write the links", http.StatusInternalServerError) + case added == 0: + done(w, r, "That URL is a link already.") + default: + done(w, r, "Added.") + } +} + +func (s *server) delete(w http.ResponseWriter, r *http.Request) { + k := norm(r.FormValue("url")) + if err := s.links.change(func(text string) string { return remove(text, k) }); err != nil { + log.Print(err) + http.Error(w, "cannot write the links", http.StatusInternalServerError) + return + } + done(w, r, "Deleted.") +} + +func (s *server) importFile(w http.ResponseWriter, r *http.Request) { + r.Body = http.MaxBytesReader(w, r.Body, maxImport) + f, _, err := r.FormFile("file") + if err != nil { + done(w, r, "Choose a file of 10 MB or less.") + return + } + defer f.Close() + b, err := io.ReadAll(f) + if err != nil { + done(w, r, "Cannot read the file.") + return + } + var added, skipped int + err = s.links.change(func(text string) string { + text, added, skipped = merge(text, importRows(string(b))) + return text + }) + if err != nil { + log.Print(err) + http.Error(w, "cannot write the links", http.StatusInternalServerError) + return + } + done(w, r, "Imported "+strconv.Itoa(added)+" links. Skipped "+strconv.Itoa(skipped)+" duplicates.") +} + +// routes gives the handler of the server. The paths start with /links/, +// so that nginx can send /links/ here and serve the rest of the site. +func (s *server) routes() http.Handler { + mux := http.NewServeMux() + mux.HandleFunc("GET /links/links.json", s.linksJSON) + mux.HandleFunc("GET /links/admin", s.admin(s.adminPage)) + mux.HandleFunc("POST /links/admin/add", s.admin(s.add)) + mux.HandleFunc("POST /links/admin/delete", s.admin(s.delete)) + mux.HandleFunc("POST /links/admin/import", s.admin(s.importFile)) + // The admin forms use basic auth, which the browser sends with each + // request. CrossOriginProtection refuses a POST from another site. + return http.NewCrossOriginProtection().Handler(mux) +} + +func env(name, fallback string) string { + if v := os.Getenv(name); v != "" { + return v + } + return fallback +} + +func main() { + pw := os.Getenv("ADMIN_PASSWORD") + if pw == "" { + log.Fatal("set ADMIN_PASSWORD") + } + s := &server{links: &store{path: env("LINKS_FILE", "links.sbm")}, password: pw} + addr := env("ADDR", "127.0.0.1:8082") + log.Printf("listening on %s, links file %s", addr, s.links.path) + log.Fatal(http.ListenAndServe(addr, s.routes())) +} diff --git a/server_test.go b/server_test.go new file mode 100644 index 0000000..a02a218 --- /dev/null +++ b/server_test.go @@ -0,0 +1,125 @@ +package main + +import ( + "bytes" + "encoding/json" + "mime/multipart" + "net/http" + "net/http/httptest" + "net/url" + "os" + "path/filepath" + "strings" + "testing" +) + +func newServer(t *testing.T) (*server, http.Handler) { + s := &server{links: &store{path: filepath.Join(t.TempDir(), "links.sbm")}, password: "pw"} + return s, s.routes() +} + +func do(h http.Handler, r *http.Request, auth bool) *httptest.ResponseRecorder { + if auth { + r.SetBasicAuth("me", "pw") + } + w := httptest.NewRecorder() + h.ServeHTTP(w, r) + return w +} + +func form(path string, v url.Values) *http.Request { + r := httptest.NewRequest("POST", path, strings.NewReader(v.Encode())) + r.Header.Set("Content-Type", "application/x-www-form-urlencoded") + return r +} + +func publicJSON(t *testing.T, h http.Handler) []jsonLink { + w := do(h, httptest.NewRequest("GET", "/links/links.json", nil), false) + var ls []jsonLink + if err := json.Unmarshal(w.Body.Bytes(), &ls); err != nil { + t.Fatal(err, w.Body.String()) + } + return ls +} + +func TestAdminNeedsPassword(t *testing.T) { + _, h := newServer(t) + for _, r := range []*http.Request{ + httptest.NewRequest("GET", "/links/admin", nil), + form("/links/admin/add", url.Values{"url": {"https://a.com"}}), + } { + if w := do(h, r, false); w.Code != http.StatusUnauthorized { + t.Errorf("%s %s: code %d", r.Method, r.URL, w.Code) + } + } + r := httptest.NewRequest("GET", "/links/admin", nil) + r.SetBasicAuth("me", "wrong") + if w := do(h, r, false); w.Code != http.StatusUnauthorized { + t.Errorf("wrong password: code %d", w.Code) + } +} + +func TestAddDeleteAndJSON(t *testing.T) { + s, h := newServer(t) + if ls := publicJSON(t, h); len(ls) != 0 { + t.Fatalf("empty store gave %v", ls) + } + do(h, form("/links/admin/add", url.Values{"url": {"https://a.com"}, "desc": {"A"}, "tags": {"x y"}}), true) + w := do(h, form("/links/admin/add", url.Values{"url": {"https://b.com"}}), true) + if w.Code != http.StatusSeeOther || w.Header().Get("Location") != "/links/admin?m=Added." { + t.Fatalf("add: %d %q", w.Code, w.Header().Get("Location")) + } + w = do(h, form("/links/admin/add", url.Values{"url": {"http://www.a.com/"}}), true) + if !strings.Contains(w.Header().Get("Location"), "already") { + t.Fatalf("duplicate add: %q", w.Header().Get("Location")) + } + ls := publicJSON(t, h) + if len(ls) != 2 || ls[0].URL != "https://b.com" || ls[1].Title != "A" || len(ls[1].Tags) != 2 { + t.Fatalf("json: %+v", ls) + } + do(h, form("/links/admin/delete", url.Values{"url": {"https://b.com"}}), true) + b, _ := os.ReadFile(s.links.path) + if string(b) != "https://a.com\tA\tx y\n" { + t.Fatalf("file: %q", b) + } +} + +func TestJSONHidesUnsafeLinks(t *testing.T) { + s, h := newServer(t) + os.WriteFile(s.links.path, []byte("javascript:alert(1)\tx\t\nhttps://a.com\tA\t\n"), 0o644) + if ls := publicJSON(t, h); len(ls) != 1 || ls[0].URL != "https://a.com" { + t.Fatalf("json: %+v", ls) + } +} + +func TestImport(t *testing.T) { + s, h := newServer(t) + os.WriteFile(s.links.path, []byte("https://a.com\tA\t\n"), 0o644) + var body bytes.Buffer + mw := multipart.NewWriter(&body) + f, _ := mw.CreateFormFile("file", "bookmarks.sbm") + f.Write([]byte("https://a.com/\tagain\t\nhttps://b.com\tB\tt\n")) + mw.Close() + r := httptest.NewRequest("POST", "/links/admin/import", &body) + r.Header.Set("Content-Type", mw.FormDataContentType()) + w := do(h, r, true) + if loc := w.Header().Get("Location"); !strings.Contains(loc, "Imported+1+links.+Skipped+1") { + t.Fatalf("import: %d %q", w.Code, loc) + } + b, _ := os.ReadFile(s.links.path) + if string(b) != "https://a.com\tA\t\nhttps://b.com\tB\tt\n" { + t.Fatalf("file: %q", b) + } +} + +func TestCrossOriginPostRefused(t *testing.T) { + s, h := newServer(t) + r := form("/links/admin/add", url.Values{"url": {"https://evil.com"}}) + r.Header.Set("Sec-Fetch-Site", "cross-site") + if w := do(h, r, true); w.Code != http.StatusForbidden { + t.Fatalf("code %d", w.Code) + } + if _, err := os.Stat(s.links.path); err == nil { + t.Fatal("cross-site POST wrote the file") + } +}