termtap/internal/proxy/handler.go
2026-04-13 20:28:10 -07:00

143 lines
3.5 KiB
Go

package proxy
import (
"bytes"
"fmt"
"io"
"net/http"
"sort"
"strings"
"time"
"termtap.dev/internal/model"
)
// NOTE: Much of this code is AI generated, and is not expected to make it into production
const maxPreviewBytes = 1024
func proxyHandler(ch chan<- model.Message) http.Handler {
transport := http.DefaultTransport
// TODO: This should be wired into the main channel, but that will require a model package
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
if req.Method == http.MethodConnect {
http.Error(w, "CONNECT is not supported yet", http.StatusNotImplemented)
ch <- model.Message{
Type: model.MessageTypeWarn,
Body: fmt.Sprintf("CONNECT is not supported: %s", req.Host),
}
return
}
if req.URL.Scheme == "" || req.URL.Host == "" {
http.Error(w, "request must use absolute-form URLs through the proxy", http.StatusBadRequest)
ch <- model.Message{
Type: model.MessageTypeWarn,
Body: fmt.Sprintf("rejected non-proxy request %s %s", req.Method, req.URL.String()),
}
return
}
start := time.Now()
// requestPreview, err := readAndRestoreBody(&req.Body)
// if err != nil {
// http.Error(w, "failed to read request body", http.StatusBadRequest)
// log.Printf("!! read request body %s %s: %v", req.Method, req.URL.String(), err)
// return
// }
outReq := req.Clone(req.Context())
outReq.RequestURI = ""
ch <- model.Message{
Type: model.MessageTypeRequestStarted,
Body: fmt.Sprintf("-> %s %s", outReq.Method, outReq.URL.String()),
}
resp, err := transport.RoundTrip(outReq)
if err != nil {
http.Error(w, "bad gateway", http.StatusBadGateway)
ch <- model.Message{
Type: model.MessageTypeRequestFailed,
Body: fmt.Sprintf("upstream error for %s %s: %v", outReq.Method, outReq.URL.String(), err),
}
return
}
defer resp.Body.Close()
// responsePreview, err := readAndRestoreBody(&resp.Body)
// if err != nil {
// http.Error(w, "bad gateway", http.StatusBadGateway)
// log.Printf("!! read response body %s %s: %v", outReq.Method, outReq.URL.String(), err)
// return
// }
copyHeader(w.Header(), resp.Header)
w.WriteHeader(resp.StatusCode)
if _, err := io.Copy(w, resp.Body); err != nil {
ch <- model.Message{
Type: model.MessageTypeRequestFailed,
Body: fmt.Sprintf("write response body %s %s: %v", outReq.Method, outReq.URL.String(), err),
}
return
}
ch <- model.Message{
Type: model.MessageTypeRequestFinished,
Body: fmt.Sprintf("<- %s %s %d %s",
outReq.Method,
outReq.URL.String(),
resp.StatusCode,
time.Since(start).Round(time.Millisecond),
),
}
})
}
func copyHeader(dst, src http.Header) {
for key, values := range src {
for _, value := range values {
dst.Add(key, value)
}
}
}
func readAndRestoreBody(body *io.ReadCloser) (string, error) {
if body == nil || *body == nil {
return "", nil
}
payload, err := io.ReadAll(*body)
if err != nil {
return "", err
}
*body = io.NopCloser(bytes.NewReader(payload))
preview := payload
if len(preview) > maxPreviewBytes {
preview = preview[:maxPreviewBytes]
}
text := strings.ReplaceAll(string(preview), "\n", "\\n")
if len(payload) > maxPreviewBytes {
text += "..."
}
return text, nil
}
func formatHeaders(headers http.Header) string {
if len(headers) == 0 {
return "<none>"
}
parts := make([]string, 0, len(headers))
for key, values := range headers {
parts = append(parts, fmt.Sprintf("%s=%q", key, strings.Join(values, ",")))
}
sort.Strings(parts)
return strings.Join(parts, ", ")
}