feat(openai): retrieve uploaded file metadata

internal/httpapi/openai/files/handler_files.go

@@ -1,11 +1,15 @@
 package files
 
 import (
+	"context"
+	"errors"
 	"io"
 	"net/http"
 	"strings"
 	"time"
 
+	"github.com/go-chi/chi/v5"
+
 	"ds2api/internal/auth"
 	"ds2api/internal/chathistory"
 	"ds2api/internal/config"
@@ -22,6 +26,10 @@ type Handler struct {
 	ChatHistory *chathistory.Store
 }
 
+type fileFetcher interface {
+	FetchUploadedFile(ctx context.Context, a *auth.RequestAuth, fileID string) (*dsclient.UploadFileResult, error)
+}
+
 func (h *Handler) UploadFile(w http.ResponseWriter, r *http.Request) {
 	a, err := h.Auth.Determine(r)
 	if err != nil {
@@ -85,6 +93,44 @@ func (h *Handler) UploadFile(w http.ResponseWriter, r *http.Request) {
 	shared.WriteJSON(w, http.StatusOK, buildOpenAIFileObject(result))
 }
 
+func (h *Handler) RetrieveFile(w http.ResponseWriter, r *http.Request) {
+	a, err := h.Auth.Determine(r)
+	if err != nil {
+		status := http.StatusUnauthorized
+		detail := err.Error()
+		if err == auth.ErrNoAccount {
+			status = http.StatusTooManyRequests
+		}
+		shared.WriteOpenAIError(w, status, detail)
+		return
+	}
+	defer h.Auth.Release(a)
+
+	fileID := strings.TrimSpace(chi.URLParam(r, "file_id"))
+	if fileID == "" {
+		shared.WriteOpenAIError(w, http.StatusBadRequest, "file_id is required")
+		return
+	}
+	fetcher, ok := h.DS.(fileFetcher)
+	if !ok {
+		shared.WriteOpenAIError(w, http.StatusNotImplemented, "file retrieval is not available")
+		return
+	}
+	result, err := fetcher.FetchUploadedFile(r.Context(), a, fileID)
+	if err != nil {
+		if errors.Is(err, dsclient.ErrUploadFileNotFound) {
+			shared.WriteOpenAIError(w, http.StatusNotFound, "file not found")
+			return
+		}
+		shared.WriteOpenAIError(w, http.StatusInternalServerError, "Failed to retrieve file.")
+		return
+	}
+	if result != nil && result.AccountID == "" {
+		result.AccountID = a.AccountID
+	}
+	shared.WriteJSON(w, http.StatusOK, buildOpenAIFileObject(result))
+}
+
 func resolveUploadModelType(store shared.ConfigReader, r *http.Request) string {
 	for _, candidate := range []string{r.FormValue("model_type"), r.Header.Get("X-Model-Type")} {
 		if modelType := normalizeUploadModelType(candidate); modelType != "" {