also accpt text/tsv

main.go

@@ -11,6 +11,7 @@ import (
 	"net"
 	"net/http"
 	"os/signal"
+	"sort"
 	"strconv"
 	"strings"
 	"syscall"
@@ -97,7 +98,7 @@ func newHandlerGetAPIV1Messages(cfg Config) http.HandlerFunc {
 			return
 		}
 
-		json.NewEncoder(w).Encode(map[string]any{"messages": messages})
+		encodeResponse(w, r, map[string]any{"messages": messages})
 	}
 }
 
@@ -119,7 +120,7 @@ func newHandlerGetAPIV1Threads(cfg Config) http.HandlerFunc {
 			return
 		}
 
-		json.NewEncoder(w).Encode(map[string]any{"threads": threads})
+		encodeResponse(w, r, map[string]any{"threads": threads})
 	}
 }
 
@@ -137,7 +138,7 @@ func newHandlerGetAPIV1ThreadsThread(cfg Config) http.HandlerFunc {
 			return
 		}
 
-		json.NewEncoder(w).Encode(map[string]any{"thread": map[string]any{"messages": messages}})
+		encodeResponse(w, r, map[string]any{"thread": messages})
 	}
 }
 
@@ -168,7 +169,7 @@ func handlerPostAPIV1EventsSlackInitialize(w http.ResponseWriter, r *http.Reques
 		return
 	}
 
-	json.NewEncoder(w).Encode(map[string]any{"challenge": challenge.Challenge})
+	encodeResponse(w, r, map[string]any{"challenge": challenge.Challenge})
 }
 
 func _newHandlerPostAPIV1EventsSlack(cfg Config) http.HandlerFunc {
@@ -243,3 +244,68 @@ func parseSince(s string) (time.Time, error) {
 
 	return time.Time{}, fmt.Errorf("failed to parse since=%q", s)
 }
+
+func encodeResponse(w http.ResponseWriter, r *http.Request, v interface{}) error {
+	if strings.Contains(r.Header.Get("Accept"), "text/csv") {
+		return encodeCSVResponse(w, v)
+	}
+	if strings.Contains(r.Header.Get("Accept"), "text/tsv") {
+		return encodeTSVResponse(w, v)
+	}
+	return encodeJSONResponse(w, v)
+}
+
+func encodeJSONResponse(w http.ResponseWriter, v interface{}) error {
+	return json.NewEncoder(w).Encode(v)
+}
+
+func encodeTSVResponse(w http.ResponseWriter, v interface{}) error {
+	return encodeSVResponse(w, v, "\t")
+}
+
+func encodeCSVResponse(w http.ResponseWriter, v interface{}) error {
+	return encodeSVResponse(w, v, ",")
+}
+
+func encodeSVResponse(w http.ResponseWriter, v interface{}, delim string) error {
+	b, err := json.Marshal(v)
+	if err != nil {
+		return err
+	}
+
+	var data map[string][]map[string]json.RawMessage
+	if err := json.Unmarshal(b, &data); err != nil {
+		return err
+	}
+
+	var objects []map[string]json.RawMessage
+	for k := range data {
+		objects = data[k]
+	}
+
+	fields := []string{}
+	for i := range objects {
+		for k := range objects[i] {
+			b, _ := json.Marshal(k)
+			fields = append(fields, string(b))
+		}
+		break
+	}
+	sort.Strings(fields)
+
+	w.Write([]byte(strings.Join(fields, delim)))
+	w.Write([]byte("\n"))
+
+	for _, object := range objects {
+		for j, field := range fields {
+			json.Unmarshal([]byte(field), &field)
+			if j > 0 {
+				w.Write([]byte(delim))
+			}
+			w.Write(object[field])
+		}
+		w.Write([]byte("\n"))
+	}
+
+	return nil
+}

main_test.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"context"
+	"encoding/csv"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -139,16 +140,56 @@ func TestRun(t *testing.T) {
 		}
 
 		var result struct {
-			Thread struct {
+			Thread []Message
-				Messages []Message
-			}
 		}
 		if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
 			t.Fatal(err)
-		} else if len(result.Thread.Messages) != 1 {
+		} else if len(result.Thread) != 1 {
 			t.Fatal(result.Thread)
 		} else {
 			t.Logf("%+v", result)
 		}
 	})
+
+	t.Run("CSV GET /api/v1/threads/1712911957.023359", func(t *testing.T) {
+		req, err := http.NewRequest(http.MethodGet, fmt.Sprintf("%s/api/v1/threads/1712911957.023359", u), nil)
+		if err != nil {
+			t.Fatal(err)
+		}
+		req.Header.Set("Accept", "text/csv")
+
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode != http.StatusOK {
+			b, _ := io.ReadAll(resp.Body)
+			t.Fatalf("(%d) %s", resp.StatusCode, b)
+		}
+
+		dec := csv.NewReader(resp.Body)
+		var lastLine []string
+		for {
+			line, err := dec.Read()
+			if err == io.EOF {
+				break
+			} else if err != nil {
+				t.Error(err)
+			}
+
+			if lastLine == nil {
+			} else if len(lastLine) != len(line) {
+				t.Errorf("last line had %v elements but this line has %v", len(lastLine), len(line))
+			}
+
+			t.Logf("%+v", line)
+			lastLine = line
+		}
+		if lastLine == nil {
+			t.Error("no lines found")
+		}
+
+	})
 }