5 files changed, 248 insertions(+), 0 deletions(-)

A LICENSE
A README.md
A cmd/smee/main.go
A go.mod
A smee.go

@@ 1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2022 Simon Ser
+
+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.

@@ 1,9 @@
+# go-smee
+
+A Go library and client for [smee].
+
+## License
+
+MIT
+
+[smee]: https://smee.io/

@@ 1,59 @@
+package main
+
+import (
+	"bytes"
+	"flag"
+	"log"
+	"net/http"
+	"net/url"
+
+	"git.sr.ht/~emersion/go-smee"
+)
+
+func main() {
+	var proxy, target string
+	flag.StringVar(&proxy, "proxy", "https://smee.io", "Proxy URL")
+	flag.StringVar(&target, "target", "http://localhost:8080", "Target URL")
+	flag.Parse()
+
+	ch, err := smee.CreateChannel(proxy)
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Printf("Opened channel: %v", ch.URL)
+
+	targetURL, err := url.Parse(target)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for {
+		wh, err := ch.ReadWebHook()
+		if err != nil {
+			log.Fatalf("failed to read webhook: %v", err)
+		}
+
+		log.Println(wh)
+
+		u := *targetURL
+		q := u.Query()
+		for k, v := range wh.Query {
+			q.Set(k, v)
+		}
+		u.RawQuery = q.Encode()
+		req, err := http.NewRequest(http.MethodPost, u.String(), bytes.NewReader(wh.Body))
+		if err != nil {
+			log.Fatalf("failed to create HTTP request: %v", err)
+		}
+		for k, v := range wh.Header {
+			req.Header.Set(k, v)
+		}
+
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			log.Printf("failed to deliver webhook: %v", err)
+			continue
+		}
+		resp.Body.Close()
+	}
+}

@@ 1,3 @@
+module git.sr.ht/~emersion/go-smee
+
+go 1.16

@@ 1,156 @@
+package smee
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+type message struct {
+	Event string
+	ID    string
+	Data  string
+}
+
+type webHook struct {
+	Body  json.RawMessage   `json:"body"`
+	Query map[string]string `json:"query"`
+}
+
+type WebHook struct {
+	Body   []byte
+	Query  map[string]string
+	Header map[string]string
+}
+
+type Channel struct {
+	URL string
+
+	resp    *http.Response
+	scanner *bufio.Scanner
+}
+
+func CreateChannel(url string) (*Channel, error) {
+	url, err := createChannel(url)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create channel: %v", err)
+	}
+
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create HTTP request: %v", err)
+	}
+
+	req.Header.Set("Cache-Control", "no-store")
+	req.Header.Set("Accept", "text/event-stream")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to connect to SSE endpoint: %v", err)
+	}
+
+	return &Channel{
+		URL:     url,
+		resp:    resp,
+		scanner: bufio.NewScanner(resp.Body),
+	}, nil
+}
+
+func createChannel(url string) (string, error) {
+	if url == "" {
+		url = "https://smee.io"
+	}
+	req, err := http.NewRequest(http.MethodHead, url+"/new", nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to create HTTP request: %v", err)
+	}
+	c := http.Client{
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+		Timeout: 30 * time.Second,
+	}
+	resp, err := c.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("HTTP request failed: %v", err)
+	}
+	resp.Body.Close()
+	return resp.Header.Get("Location"), nil
+}
+
+func (ch *Channel) Close() error {
+	return ch.resp.Body.Close()
+}
+
+func (ch *Channel) readMessage() (*message, error) {
+	msg := &message{Event: "message"}
+	for ch.scanner.Scan() {
+		line := ch.scanner.Text()
+		if line == "" {
+			return msg, nil
+		} else if line[0] == ':' {
+			continue
+		}
+
+		k, v, _ := strings.Cut(line, ":")
+		v = strings.TrimPrefix(v, " ")
+
+		switch k {
+		case "event":
+			msg.Event = v
+		case "data":
+			msg.Data = v
+		case "id":
+			msg.ID = v
+			// TODO: "retry"
+		}
+	}
+	return nil, ch.scanner.Err()
+}
+
+func (ch *Channel) ReadWebHook() (*WebHook, error) {
+	var msg *message
+	for {
+		var err error
+		msg, err = ch.readMessage()
+		if err != nil {
+			return nil, err
+		} else if msg.Event == "message" {
+			break
+		}
+	}
+
+	var data webHook
+	if err := json.Unmarshal([]byte(msg.Data), &data); err != nil {
+		return nil, fmt.Errorf("failed to decode webhook data: %v", err)
+	}
+
+	var fields map[string]interface{}
+	if err := json.Unmarshal([]byte(msg.Data), &fields); err != nil {
+		return nil, fmt.Errorf("failed to decode webhook fields: %v", err)
+	}
+
+	header := make(map[string]string, len(fields))
+	for k, v := range fields {
+		s, ok := v.(string)
+		if !ok {
+			continue
+		}
+
+		switch k {
+		case "query", "body":
+			// Ignore
+		default:
+			header[k] = s
+		}
+	}
+
+	return &WebHook{
+		Body:   []byte(data.Body),
+		Query:  data.Query,
+		Header: header,
+	}, nil
+}