|
| 1 | +package api |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "errors" |
| 6 | + "io" |
| 7 | + "mime" |
| 8 | + "net/http" |
| 9 | + "strings" |
| 10 | + "time" |
| 11 | + |
| 12 | + "github.com/gastownhall/wasteland/internal/observability" |
| 13 | +) |
| 14 | + |
| 15 | +const maxBrowserTracePayloadBytes = 1 << 20 |
| 16 | + |
| 17 | +var browserTraceProxyClient = &http.Client{ |
| 18 | + Timeout: 10 * time.Second, |
| 19 | + Transport: observability.NewTransport(http.DefaultTransport), |
| 20 | +} |
| 21 | + |
| 22 | +func (s *Server) handleBrowserTraces(w http.ResponseWriter, r *http.Request) { |
| 23 | + if r.Method == http.MethodOptions { |
| 24 | + w.WriteHeader(http.StatusNoContent) |
| 25 | + return |
| 26 | + } |
| 27 | + if r.Method != http.MethodPost { |
| 28 | + writeError(w, http.StatusMethodNotAllowed, "method not allowed") |
| 29 | + return |
| 30 | + } |
| 31 | + |
| 32 | + target := observability.BrowserTraceProxyTarget() |
| 33 | + if target == "" || !observability.BrowserTracingEnabled() { |
| 34 | + writeError(w, http.StatusNotFound, "browser tracing not enabled") |
| 35 | + return |
| 36 | + } |
| 37 | + if !allowedBrowserTraceContentType(r.Header.Get("Content-Type")) { |
| 38 | + writeError(w, http.StatusUnsupportedMediaType, "unsupported browser trace content type") |
| 39 | + return |
| 40 | + } |
| 41 | + |
| 42 | + reader := http.MaxBytesReader(w, r.Body, maxBrowserTracePayloadBytes) |
| 43 | + defer reader.Close() //nolint:errcheck // request cleanup |
| 44 | + |
| 45 | + payload, err := io.ReadAll(reader) |
| 46 | + if err != nil { |
| 47 | + status := http.StatusBadRequest |
| 48 | + if strings.Contains(err.Error(), "http: request body too large") { |
| 49 | + status = http.StatusRequestEntityTooLarge |
| 50 | + } |
| 51 | + writeError(w, status, "invalid browser trace payload") |
| 52 | + return |
| 53 | + } |
| 54 | + |
| 55 | + req, err := http.NewRequestWithContext(r.Context(), http.MethodPost, target, bytes.NewReader(payload)) |
| 56 | + if err != nil { |
| 57 | + writeError(w, http.StatusInternalServerError, "failed to prepare browser trace proxy request") |
| 58 | + return |
| 59 | + } |
| 60 | + req.Header.Set("Content-Type", contentTypeOrDefault(r.Header.Get("Content-Type"), "application/x-protobuf")) |
| 61 | + if enc := r.Header.Get("Content-Encoding"); enc != "" { |
| 62 | + req.Header.Set("Content-Encoding", enc) |
| 63 | + } |
| 64 | + |
| 65 | + resp, err := browserTraceProxyClient.Do(req) |
| 66 | + if err != nil { |
| 67 | + writeError(w, http.StatusBadGateway, "browser trace collector unavailable") |
| 68 | + return |
| 69 | + } |
| 70 | + defer resp.Body.Close() //nolint:errcheck // upstream cleanup |
| 71 | + |
| 72 | + for _, header := range []string{"Content-Type"} { |
| 73 | + if value := resp.Header.Get(header); value != "" { |
| 74 | + w.Header().Set(header, value) |
| 75 | + } |
| 76 | + } |
| 77 | + w.WriteHeader(resp.StatusCode) |
| 78 | + if _, copyErr := io.Copy(w, resp.Body); copyErr != nil && !errors.Is(copyErr, io.EOF) { |
| 79 | + return |
| 80 | + } |
| 81 | +} |
| 82 | + |
| 83 | +func contentTypeOrDefault(value, fallback string) string { |
| 84 | + if strings.TrimSpace(value) == "" { |
| 85 | + return fallback |
| 86 | + } |
| 87 | + return value |
| 88 | +} |
| 89 | + |
| 90 | +func allowedBrowserTraceContentType(value string) bool { |
| 91 | + if strings.TrimSpace(value) == "" { |
| 92 | + return true |
| 93 | + } |
| 94 | + mediaType, _, err := mime.ParseMediaType(value) |
| 95 | + if err != nil { |
| 96 | + return false |
| 97 | + } |
| 98 | + switch mediaType { |
| 99 | + case "application/x-protobuf", "application/json": |
| 100 | + return true |
| 101 | + default: |
| 102 | + return false |
| 103 | + } |
| 104 | +} |
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