Migrated to a Library structure with gopherproxy cmd for reuse by gopherclient

1 files changed, 131 insertions, 0 deletions

diff --git a/gopherproxy.go b/gopherproxy.go
new file mode 100644
index 0000000..4a2255f
--- /dev/null
+++ b/gopherproxy.go
@@ -0,0 +1,131 @@
+package gopherproxy
+
+import (
+        "fmt"
+        "html/template"
+        "io"
+        "io/ioutil"
+        "log"
+        "net/http"
+        "net/url"
+        "strings"
+
+        "github.com/prologic/go-gopher"
+)
+
+type tplRow struct {
+        Link template.URL
+        Type string
+        Text string
+}
+
+// Handler is an aliased type for the standard HTTP handler functions
+type Handler func(w http.ResponseWriter, req *http.Request)
+
+func renderDirectory(w http.ResponseWriter, tpl *template.Template, hostport string, d gopher.Directory) error {
+        out := make([]tplRow, len(d))
+
+        for i, x := range d {
+                tr := tplRow{
+                        Text: x.Description,
+                        Type: x.Type.String(),
+                }
+
+                if x.Type == gopher.INFO {
+                        out[i] = tr
+                        continue
+                }
+
+                if strings.HasPrefix(x.Selector, "URL:") {
+                        tr.Link = template.URL(x.Selector[4:])
+                } else {
+                        var hostport string
+                        if x.Port == 70 {
+                                hostport = x.Host
+                        } else {
+                                hostport = fmt.Sprintf("%s:%d", x.Host, x.Port)
+                        }
+                        path := url.QueryEscape(x.Selector)
+                        path = strings.Replace(path, "%2F", "/", -1)
+                        tr.Link = template.URL(
+                                fmt.Sprintf(
+                                        "/%s/%s%s",
+                                        hostport,
+                                        string(byte(x.Type)),
+                                        path,
+                                ),
+                        )
+                }
+
+                out[i] = tr
+        }
+
+        return tpl.Execute(w, struct {
+                Title string
+                Lines []tplRow
+        }{hostport, out})
+}
+
+// MakeGopherProxyHandler returns a Handler that proxies requests
+// to the specified Gopher server as denoated by the first argument
+// to the request path and renders the content using the provided template.
+func MakeGopherProxyHandler(tpl *template.Template, uri string) Handler {
+        return func(w http.ResponseWriter, req *http.Request) {
+                parts := strings.Split(strings.TrimPrefix(req.URL.Path, "/"), "/")
+                hostport := parts[0]
+                path := strings.Join(parts[1:], "/")
+
+                if len(hostport) == 0 {
+                        http.Redirect(w, req, "/"+uri, http.StatusFound)
+                        return
+                }
+
+                uri, err := url.QueryUnescape(path)
+                if err != nil {
+                        io.WriteString(w, fmt.Sprintf("<b>Error:</b><pre>%s</pre>", err))
+                        return
+                }
+                res, err := gopher.Get(
+                        fmt.Sprintf(
+                                "gopher://%s/%s",
+                                hostport,
+                                uri,
+                        ),
+                )
+                if err != nil {
+                        io.WriteString(w, fmt.Sprintf("<b>Error:</b><pre>%s</pre>", err))
+                        return
+                }
+
+                if res.Body != nil {
+                        io.Copy(w, res.Body)
+                } else {
+                        if err := renderDirectory(w, tpl, hostport, res.Dir); err != nil {
+                                io.WriteString(w, fmt.Sprintf("<b>Error:</b><pre>%s</pre>", err))
+                                return
+                        }
+                }
+        }
+}
+
+// ListenAndServe creates a listening HTTP server bound to
+// the interface specified by bind and sets up a Gopher to HTTP
+// proxy proxying requests as requested and by default will prozy
+// to a Gopher server address specified by uri if no servers is
+// specified by the request.
+func ListenAndServe(bind, uri string) error {
+        var tpl *template.Template
+
+        tpldata, err := ioutil.ReadFile(".template")
+        if err == nil {
+                tpltext = string(tpldata)
+        }
+
+        tpl, err = template.New("gophermenu").Parse(tpltext)
+        if err != nil {
+                log.Fatal(err)
+        }
+
+        http.HandleFunc("/", MakeGopherProxyHandler(tpl, uri))
+        return http.ListenAndServe(bind, nil)
+}