Initial commit

8 files changed, 371 insertions, 0 deletions

diff --git a/client.go b/client.go
new file mode 100644
index 0000000..d529b60
--- /dev/null
+++ b/client.go
@@ -0,0 +1,107 @@
+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
+}
+
+// Fetch a resource from a Gemini server with the given URL
+func Fetch(url string) (res Response, err error) {
+	conn, err := connectByURL(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 connectByURL(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{
+		InsecureSkipVerify: true,
+	}
+
+	return tls.Dial("tcp", parsedURL.Host, conf)
+}
+
+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
+		}
+	}
+}
diff --git a/client_test.go b/client_test.go
new file mode 100644
index 0000000..34d6158
--- /dev/null
+++ b/client_test.go
@@ -0,0 +1,77 @@
+package gemini
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func compareResponses(expected, given Response) (diff string) {
+	diff = cmp.Diff(expected.Meta, given.Meta)
+	if diff != "" {
+		return
+	}
+
+	diff = cmp.Diff(expected.Meta, given.Meta)
+	if diff != "" {
+		return
+	}
+
+	expectedBody, err := ioutil.ReadAll(expected.Body)
+	if err != nil {
+		return fmt.Sprintf("failed to get expected body: %v", err)
+	}
+
+	givenBody, err := ioutil.ReadAll(given.Body)
+	if err != nil {
+		return fmt.Sprintf("failed to get givenponse body: %v", err)
+	}
+
+	diff = cmp.Diff(expectedBody, givenBody)
+	return
+}
+
+func TestGetResponse(t *testing.T) {
+	tests := []struct {
+		file     string
+		expected Response
+	}{
+		{"resources/tests/simple_response", Response{20, "text/gemini", ioutil.NopCloser(strings.NewReader("This is the content of the page\r\n"))}},
+	}
+
+	for _, tc := range tests {
+		f, err := os.Open(tc.file)
+		if err != nil {
+			t.Fatalf("failed to get test case file %s: %v", tc.file, err)
+		}
+
+		res, err := getResponse(f)
+		if err != nil {
+			t.Fatalf("failed to parse response %s: %v", tc.file, err)
+		}
+
+		diff := compareResponses(tc.expected, res)
+		if diff != "" {
+			t.Fatalf(diff)
+		}
+	}
+
+}
+
+func TestGetResponseEmptyResponse(t *testing.T) {
+	_, err := getResponse(ioutil.NopCloser(strings.NewReader("")))
+	if err == nil {
+		t.Fatalf("expected to get an error for empty response, got nil instead")
+	}
+}
+
+func TestGetResponseInvalidStatus(t *testing.T) {
+	_, err := getResponse(ioutil.NopCloser(strings.NewReader("AA\tmeta\r\n")))
+	if err == nil {
+		t.Fatalf("expected to get an error for invalid status response, got nil instead")
+	}
+}
diff --git a/gemini.go b/gemini.go
new file mode 100644
index 0000000..5ebaa6a
--- /dev/null
+++ b/gemini.go
@@ -0,0 +1,37 @@
+package gemini
+
+// Gemini status codes as defined in the Gemini spec Appendix 1.
+const (
+	StatusInput = 10
+
+	StatusSuccess                              = 20
+	StatusSuccessEndOfClientCertificateSession = 21
+
+	StatusRedirect          = 30
+	StatusRedirectTemporary = 30
+	StatusRedirectPermanent = 31
+
+	StatusTemporaryFailure = 40
+	StatusUnavailable      = 41
+	StatusCGIError         = 42
+	StatusProxyError       = 43
+	StatusSlowDown         = 44
+
+	StatusPermanentFailure    = 50
+	StatusNotFound            = 51
+	StatusGone                = 52
+	StatusProxyRequestRefused = 53
+	StatusBadRequest          = 59
+
+	StatusClientCertificateRequired     = 60
+	StatusTransientCertificateRequested = 61
+	StatusAuthorisedCertificateRequired = 62
+	StatusCertificateNotAccepted        = 63
+	StatusFutureCertificateRejected     = 64
+	StatusExpiredCertificateRejected    = 65
+)
+
+// SimplifyStatus simplify the response status by omiting the detailed second digit of the status code.
+func SimplifyStatus(status int) int {
+	return (status / 10) * 10
+}
diff --git a/gemini_test.go b/gemini_test.go
new file mode 100644
index 0000000..59fe3c8
--- /dev/null
+++ b/gemini_test.go
@@ -0,0 +1,23 @@
+package gemini
+
+import "testing"
+
+func TestSimplifyStatus(t *testing.T) {
+	tests := []struct {
+		ComplexStatus int
+		SimpleStatus  int
+	}{
+		{10, 10},
+		{20, 20},
+		{21, 20},
+		{44, 40},
+		{59, 50},
+	}
+
+	for _, tt := range tests {
+		result := SimplifyStatus(tt.ComplexStatus)
+		if result != tt.SimpleStatus {
+			t.Errorf("Expected the simplified status of %d to be %d, got %d instead", tt.ComplexStatus, tt.SimpleStatus, result)
+		}
+	}
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..4afecd0
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module git.sr.ht/~yotam/go-gemini
+
+go 1.12
+
+require github.com/google/go-cmp v0.3.1
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..a6ddb1d
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/google/go-cmp v0.3.1 h1:Xye71clBPdm5HgqGwUkwhbynsUJZhDbS20FvLhQ2izg=
+github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
diff --git a/resources/tests/simple_response b/resources/tests/simple_response
new file mode 100644
index 0000000..10c8fee
--- /dev/null
+++ b/resources/tests/simple_response
@@ -0,0 +1,2 @@
+20	text/gemini

+This is the content of the page

diff --git a/server.go b/server.go
new file mode 100644
index 0000000..ff7df80
--- /dev/null
+++ b/server.go
@@ -0,0 +1,118 @@
+package gemini
+
+import (
+	"bufio"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net"
+	"strings"
+)
+
+// Request contains the data of the client request
+type Request struct {
+	URL string
+}
+
+// Handler is the interface a struct need to implement to be able to handle Gemini requests
+type Handler interface {
+	Handle(r Request) Response
+}
+
+// ListenAndServe create a TCP server on the specified address and pass
+// new connections to the given handler.
+// Each request is handled in a separate goroutine.
+func ListenAndServe(addr, certFile, keyFile string, handler Handler) error {
+	if addr == "" {
+		addr = "127.0.0.1:1965"
+	}
+
+	listener, err := listen(addr, certFile, keyFile)
+	if err != nil {
+		return err
+	}
+
+	err = serve(listener, handler)
+	if err != nil {
+		return err
+	}
+
+	err = listener.Close()
+	if err != nil {
+		return fmt.Errorf("failed to close the listener: %v", err)
+	}
+
+	return nil
+}
+
+func listen(addr, certFile, keyFile string) (net.Listener, error) {
+	cer, err := tls.LoadX509KeyPair(certFile, keyFile)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load certificates: %v", err)
+	}
+
+	config := &tls.Config{Certificates: []tls.Certificate{cer}}
+	ln, err := tls.Listen("tcp", addr, config)
+	if err != nil {
+		return nil, fmt.Errorf("failed to listen: %v", err)
+	}
+
+	return ln, nil
+}
+
+func serve(listener net.Listener, handler Handler) error {
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			continue
+		}
+
+		go handleConnection(conn, handler)
+	}
+}
+
+func handleConnection(conn io.ReadWriteCloser, handler Handler) {
+	defer conn.Close()
+
+	requestURL, err := getRequestURL(conn)
+	if err != nil {
+		return
+	}
+
+	request := Request{requestURL}
+	response := handler.Handle(request)
+	defer response.Body.Close()
+
+	err = writeResponse(conn, response)
+	if err != nil {
+		return
+	}
+}
+
+func getRequestURL(conn io.Reader) (string, error) {
+	scanner := bufio.NewScanner(conn)
+	if ok := scanner.Scan(); !ok {
+		return "", scanner.Err()
+	}
+
+	rawURL := scanner.Text()
+	if strings.Contains(rawURL, "://") {
+		return rawURL, nil
+	}
+
+	return fmt.Sprintf("gemini://%s", rawURL), nil
+}
+
+func writeResponse(conn io.Writer, response Response) error {
+	_, err := fmt.Fprintf(conn, "%d %s\r\n", response.Status, response.Meta)
+	if err != nil {
+		return fmt.Errorf("failed to write header line to the client: %v", err)
+	}
+
+	_, err = io.Copy(conn, response.Body)
+	if err != nil {
+		return fmt.Errorf("failed to write the response body to the client: %v", err)
+	}
+
+	return nil
+}