Initial commit

.gitignore

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+.idea/
+dist/
+vendor/
+*.sh
+twins

.gitlab-ci.yml

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+image: golang:latest
+
+stages:
+  - validate
+  - build
+
+fmt:
+  stage: validate
+  script:
+    - gofmt -l -s -e .
+    - exit $(gofmt -l -s -e . | wc -l)
+
+vet:
+  stage: validate
+  script:
+    - go vet -composites=false ./...
+
+test:
+  stage: validate
+  script:
+    - go test -race -v ./...

CONFIGURATION.md

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+# config.yaml
+
+```yaml
+# Path to certificate and private key
+cert: /home/twins/data/certfile.crt
+key: /home/twins/data/keyfile.key
+
+# Paths to serve
+serve:
+  -
+    dir: /sites
+    root: /home/twins/data/sites
+  -
+    regexp: ^/(help|info)$
+    root: /home/twins/data/help
+  -
+    dir: /
+    root: /home/twins/data/home
+```

LICENSE

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+MIT License
+
+Copyright (c) 2020 Trevor Slocum <trevor@rocketnine.space>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# twins
+[![CI status](https://gitlab.com/tslocum/twins/badges/master/pipeline.svg)](https://gitlab.com/tslocum/twins/commits/master)
+[![Donate](https://img.shields.io/liberapay/receives/rocketnine.space.svg?logo=liberapay)](https://liberapay.com/rocketnine.space)
+
+[Gemini](https://gemini.circumlunar.space) server
+
+## Features
+
+- Serve static files
+
+## Download
+
+```bash
+go get gitlab.com/tslocum/twins
+```
+
+## Configure
+
+See [CONFIGURATION.md](https://gitlab.com/tslocum/twins/blob/master/CONFIGURATION.md)
+
+## Run
+
+```bash
+twins
+```
+
+## Support
+
+Please share issues and suggestions [here](https://gitlab.com/tslocum/twins/issues).
+
+## Dependencies
+
+- [go-gemini](https://github.com/makeworld-the-better-one/go-gemini)

config.go

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+package main
+
+import (
+	"errors"
+	"io/ioutil"
+	"os"
+	"regexp"
+
+	"gopkg.in/yaml.v3"
+)
+
+type serveConfig struct {
+	Dir    string
+	Regexp string
+	Root   string
+
+	r *regexp.Regexp
+}
+
+type serverConfig struct {
+	Cert  string
+	Key   string
+	Serve []*serveConfig
+}
+
+var config = &serverConfig{}
+
+func readconfig(configPath string) error {
+	if configPath == "" {
+		return errors.New("file unspecified")
+	}
+
+	if _, err := os.Stat(configPath); os.IsNotExist(err) {
+		return errors.New("file not found")
+	}
+
+	configData, err := ioutil.ReadFile(configPath)
+	if err != nil {
+		return err
+	}
+
+	err = yaml.Unmarshal(configData, &config)
+	if err != nil {
+		return err
+	}
+
+	for _, serve := range config.Serve {
+		if serve.Dir != "" && serve.Dir[len(serve.Dir)-1] == '/' {
+			serve.Dir = serve.Dir[:len(serve.Dir)-1]
+		}
+		if serve.Regexp != "" {
+			serve.r = regexp.MustCompile(serve.Regexp)
+		}
+	}
+
+	return nil
+}

go.mod

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+module gitlab.com/tslocum/twins
+
+go 1.15
+
+require (
+	github.com/h2non/filetype v1.1.0
+	github.com/makeworld-the-better-one/go-gemini v0.9.0
+	gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776
+)

go.sum

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+github.com/google/go-cmp v0.3.1 h1:Xye71clBPdm5HgqGwUkwhbynsUJZhDbS20FvLhQ2izg=
+github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/h2non/filetype v1.1.0 h1:Or/gjocJrJRNK/Cri/TDEKFjAR+cfG6eK65NGYB6gBA=
+github.com/h2non/filetype v1.1.0/go.mod h1:319b3zT68BvV+WRj7cwy856M2ehB3HqNOt6sy1HndBY=
+github.com/makeworld-the-better-one/go-gemini v0.9.0 h1:Iz4ywRDrfsyoR8xZOkSKGXXftMR2spIV6ibVuhrKvSw=
+github.com/makeworld-the-better-one/go-gemini v0.9.0/go.mod h1:P7/FbZ+IEIbA/d+A0Y3w2GNgD8SA2AcNv7aDGJbaWG4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 h1:tQIYjPdBoyREyB9XMu+nnTclpTYkz2zFM+lzLJFO4gQ=
+gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

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+package main
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/tls"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/url"
+	"os"
+	"path"
+	"strings"
+
+	"github.com/h2non/filetype"
+	"github.com/makeworld-the-better-one/go-gemini"
+)
+
+func writeHeader(c net.Conn, code int, meta string) {
+	fmt.Fprintf(c, "%d %s\r\n", code, meta)
+}
+
+func respond(c net.Conn, code int) {
+	var meta string
+	switch code {
+	case gemini.StatusTemporaryFailure:
+		meta = "Temporary failure"
+	case gemini.StatusBadRequest:
+		meta = "Bad request"
+	case gemini.StatusNotFound:
+		meta = "Not found"
+	}
+	writeHeader(c, code, meta)
+}
+
+func scanCRLF(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if atEOF && len(data) == 0 {
+		return 0, nil, nil
+	}
+	if i := bytes.IndexByte(data, '\r'); i >= 0 {
+		// We have a full newline-terminated line.
+		return i + 1, data[0:i], nil
+	}
+	// If we're at EOF, we have a final, non-terminated line. Return it.
+	if atEOF {
+		return len(data), data, nil
+	}
+	// Request more data.
+	return 0, nil, nil
+}
+
+func handleConn(c net.Conn) {
+	defer c.Close()
+
+	var requestData string
+	scanner := bufio.NewScanner(c)
+	scanner.Split(scanCRLF)
+	if scanner.Scan() {
+		requestData = scanner.Text()
+	}
+	if err := scanner.Err(); err != nil {
+		respond(c, gemini.StatusBadRequest)
+		return
+	}
+
+	request, err := url.Parse(requestData)
+	if err != nil || request.Scheme != "gemini" || request.Host == "" {
+		respond(c, gemini.StatusBadRequest)
+		return
+	}
+	if request.Path == "" {
+		request.Path = "/"
+	}
+	pathBytes := []byte(request.Path)
+	strippedPath := request.Path
+	if strippedPath[0] == '/' {
+		strippedPath = strippedPath[1:]
+	}
+
+	for _, serve := range config.Serve {
+		var realPath string
+		if serve.Dir != "" && strings.HasPrefix(request.Path, serve.Dir) {
+			realPath = path.Join(serve.Root, request.Path[len(serve.Dir):])
+		} else if serve.r != nil && serve.r.Match(pathBytes) {
+			realPath = path.Join(serve.Root, strippedPath)
+		} else {
+			continue
+		}
+
+		fi, err := os.Stat(realPath)
+		if os.IsNotExist(err) {
+			respond(c, gemini.StatusNotFound)
+			return
+		} else if err != nil {
+			respond(c, gemini.StatusTemporaryFailure)
+			return
+		}
+
+		if mode := fi.Mode(); mode.IsDir() {
+			_, err := os.Stat(path.Join(realPath, "index.gemini"))
+			if err == nil {
+				realPath = path.Join(realPath, "index.gemini")
+			} else {
+				realPath = path.Join(realPath, "index.gmi")
+			}
+		}
+
+		fi, err = os.Stat(realPath)
+		if os.IsNotExist(err) {
+			respond(c, gemini.StatusNotFound)
+			return
+		} else if err != nil {
+			respond(c, gemini.StatusTemporaryFailure)
+			return
+		}
+
+		file, _ := os.Open(realPath)
+		defer file.Close()
+
+		buf := make([]byte, 261)
+		n, _ := file.Read(buf)
+
+		mimeType := "text/gemini; charset=utf-8"
+		if !strings.HasSuffix(realPath, ".gmi") && !strings.HasSuffix(realPath, ".gemini") {
+			if strings.HasSuffix(realPath, ".html") && strings.HasSuffix(realPath, ".htm") {
+				mimeType = "text/html; charset=utf-8"
+			} else if strings.HasSuffix(realPath, ".txt") && strings.HasSuffix(realPath, ".text") {
+				mimeType = "text/plain; charset=utf-8"
+			} else {
+				kind, _ := filetype.Match(buf[:n])
+				if kind != filetype.Unknown {
+					mimeType = kind.MIME.Value
+				}
+			}
+		}
+
+		writeHeader(c, gemini.StatusSuccess, mimeType)
+		c.Write(buf[:n])
+		io.Copy(c, file)
+		return
+	}
+
+	respond(c, gemini.StatusNotFound)
+}
+
+func handleListener(l net.Listener) {
+	for {
+		conn, err := l.Accept()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		go handleConn(conn)
+	}
+}
+
+func main() {
+	configFile := flag.String("config", "", "path to configuration file")
+	certFile := flag.String("cert", "", "path to certificate file")
+	keyFile := flag.String("key", "", "path to private key file")
+	flag.Parse()
+
+	if *configFile == "" {
+		homedir, err := os.UserHomeDir()
+		if err == nil && homedir != "" {
+			*configFile = path.Join(homedir, ".config", "twins", "config.yaml")
+		}
+	}
+
+	err := readconfig(*configFile)
+	if err != nil && *certFile == "" {
+		log.Fatalf("failed to read configuration file at %s: %v\nSee CONFIGURATION.md for information on configuring twins", *configFile, err)
+	}
+
+	if *certFile != "" {
+		config.Cert = *certFile
+	}
+	if *keyFile != "" {
+		config.Key = *keyFile
+	}
+
+	if config.Cert == "" || config.Key == "" {
+		log.Fatal("certificate file and private key must be specified (gemini requires TLS for all connections)")
+	}
+
+	cert, err := tls.LoadX509KeyPair(config.Cert, config.Key)
+	if err != nil {
+		log.Fatalf("failed to load certificate: %s", err)
+	}
+
+	tlsConfig := &tls.Config{
+		Certificates: []tls.Certificate{cert},
+	}
+
+	listener, err := tls.Listen("tcp", "localhost:8888", tlsConfig)
+	if err != nil {
+		log.Fatalf("failed to listen on %s: %s", "localhost:8888", err)
+	}
+
+	handleListener(listener)
+}