package gemini
import (
"bytes"
"crypto/tls"
"fmt"
"io"
"net/url"
"strconv"
"strings"
)
// Response represent the response from a Gemini server.
type Response struct {
Status int
Meta string
Body io.ReadCloser
}
type header struct {
status int
meta string
}
type Client struct {
InsecureSkipVerify bool
}
var DefaultClient = &Client{}
// Fetch a resource from a Gemini server with the given URL
func (c Client) Fetch(url string) (res Response, err error) {
conn, err := c.connect(url)
if err != nil {
return Response{}, fmt.Errorf("failed to connect to the server: %v", err)
}
err = sendRequest(conn, url)
if err != nil {
conn.Close()
return Response{}, err
}
return getResponse(conn)
}
func (c Client) connect(rawURL string) (io.ReadWriteCloser, error) {
parsedURL, err := url.Parse(rawURL)
if err != nil {
return nil, fmt.Errorf("failed to parse given URL: %v", err)
}
conf := &tls.Config{
MinVersion: tls.VersionTLS12,
InsecureSkipVerify: c.InsecureSkipVerify,
}
return tls.Dial("tcp", parsedURL.Host, conf)
}
// Fetch a resource from a Gemini server with the default client
func Fetch(url string) (res Response, err error) {
return DefaultClient.Fetch(url)
}
func sendRequest(conn io.Writer, requestURL string) error {
_, err := fmt.Fprintf(conn, "%s\r\n", requestURL)
if err != nil {
return fmt.Errorf("could not send request to the server: %v", err)
}
return nil
}
func getResponse(conn io.ReadCloser) (Response, error) {
header, err := getHeader(conn)
if err != nil {
conn.Close()
return Response{}, fmt.Errorf("failed to get header: %v", err)
}
return Response{header.status, header.meta, conn}, nil
}
func getHeader(conn io.Reader) (header, error) {
line, err := readHeader(conn)
if err != nil {
return header{}, fmt.Errorf("failed to read header: %v", err)
}
fields := strings.Fields(string(line))
status, err := strconv.Atoi(fields[0])
if err != nil {
return header{}, fmt.Errorf("unexpected status value %v: %v", fields[0], err)
}
meta := strings.Join(fields[1:], " ")
return header{status, meta}, nil
}
func readHeader(conn io.Reader) ([]byte, error) {
var line []byte
delim := []byte("\r\n")
// A small buffer is inefficient but the maximum length of the header is small so it's okay
buf := make([]byte, 1)
for {
_, err := conn.Read(buf)
if err != nil {
return []byte{}, err
}
line = append(line, buf...)
if bytes.HasSuffix(line, delim) {
return line[:len(line)-len(delim)], nil
}
}
}