1 files changed, 145 insertions, 0 deletions

diff --git a/pkg/libgemini/libgemini.go b/pkg/libgemini/libgemini.go
new file mode 100644
index 0000000..303490c
--- /dev/null
+++ b/pkg/libgemini/libgemini.go
@@ -0,0 +1,145 @@
+package libgemini
+
+import (
+        "bufio"
+        "crypto/tls"
+        "errors"
+        "fmt"
+        "io"
+        "mime"
+        "net"
+        "net/url"
+        "regexp"
+        "strconv"
+        "strings"
+)
+
+const (
+        CRLF = "\r\n"
+)
+
+const (
+        STATUS_INPUT                  = 10
+        STATUS_SUCCESS                = 20
+        STATUS_SUCCESS_CERT           = 21
+        STATUS_REDIRECT_TEMP          = 30
+        STATUS_REDIRECT_PERM          = 31
+        STATUS_TEMP_FAILURE           = 40
+        STATUS_SERVER_UNAVAILABLE     = 41
+        STATUS_CGI_ERROR              = 42
+        STATUS_PROXY_ERROR            = 43
+        STATUS_SLOW_DOWN              = 44
+        STATUS_PERM_FAILURE           = 50
+        STATUS_NOT_FOUND              = 51
+        STATUS_GONE                   = 52
+        STATUS_PROXY_REFUSED          = 53
+        STATUS_BAD_REQUEST            = 59
+        STATUS_CLIENT_CERT_EXPIRED    = 60
+        STATUS_TRANSIENT_CERT_REQUEST = 61
+        STATUS_AUTH_CERT_REQUIRED     = 62
+        STATUS_CERT_REJECTED          = 63
+        STATUS_FUTURE_CERT_REJECTED   = 64
+        STATUS_EXPIRED_CERT_REJECTED  = 65
+)
+
+const (
+        MIME_GEMINI     = "text/gemini"
+        DEFAULT_MIME    = MIME_GEMINI
+        DEFAULT_CHARSET = "utf-8"
+)
+
+var (
+        HeaderPattern = regexp.MustCompile("^(\\d\\d)[ \\t]+(.*)$")
+        LinkPattern   = regexp.MustCompile("^=>[ \\t]*([^ \\t]+)(?:[ \\t]+(.*))?$")
+)
+
+type Header struct {
+        Status int
+        Meta   string
+}
+
+type Response struct {
+        Header *Header
+        Body   io.Reader
+}
+
+func Get(uri string) (*Response, error) {
+        u, err := url.Parse(uri)
+        if err != nil {
+                return nil, err
+        }
+
+        if u.Scheme != "gemini" {
+                return nil, errors.New("invalid scheme for uri")
+        }
+
+        host := u.Hostname()
+        port := u.Port()
+
+        if port == "" {
+                port = "1965"
+        }
+
+        conn, err := tls.Dial("tcp", net.JoinHostPort(host, port), &tls.Config{
+                MinVersion:         tls.VersionTLS12,
+                InsecureSkipVerify: true,
+        })
+        if err != nil {
+                return nil, err
+        }
+
+        _, err = conn.Write([]byte(u.String() + CRLF))
+        if err != nil {
+                conn.Close()
+                return nil, err
+        }
+
+        reader := bufio.NewReader(conn)
+
+        line, _, err := reader.ReadLine()
+        if err != nil {
+                conn.Close()
+                return nil, err
+        }
+
+        header, err := ParseHeader(string(line))
+        if err != nil {
+                conn.Close()
+                return nil, err
+        }
+
+        return &Response{
+                Header: header,
+                Body:   reader,
+        }, nil
+}
+
+func ParseHeader(line string) (header *Header, err error) {
+        matches := HeaderPattern.FindStringSubmatch(line)
+
+        status, err := strconv.Atoi(matches[1])
+        if err != nil {
+                return nil, err
+        }
+
+        meta := matches[2]
+
+        if int(status/10) == 2 {
+                mediaType, params, err := mime.ParseMediaType(meta)
+
+                if err != nil {
+                        meta = fmt.Sprintf("%s;charset=%s", DEFAULT_MIME, DEFAULT_CHARSET)
+                } else if strings.HasPrefix(mediaType, "text/") {
+                        if _, ok := params["charset"]; !ok {
+                                meta += ";charset=" + DEFAULT_CHARSET
+                        }
+                }
+        }
+
+        header = &Header{
+                Status: status,
+                Meta:   meta,
+        }
+
+        return
+}