FIX: Uploading File With Unkown Catagory Id

cms/docs/docs.go

@@ -78,8 +78,14 @@ const docTemplate = `{
                             "$ref": "#/definitions/api.ProblemDetails"
                         }
                     },
+                    "404": {
+                        "description": "categoryIds referenced a category that does not exist",
+                        "schema": {
+                            "$ref": "#/definitions/api.ProblemDetails"
+                        }
+                    },
                     "422": {
-                        "description": "title was empty, key was missing or not a key issued by this API, or categoryIds was empty or contained an id that does not exist",
+                        "description": "title was empty, key was missing or not a key issued by this API, or categoryIds was empty",
                         "schema": {
                             "$ref": "#/definitions/api.ProblemDetails"
                         }

cms/docs/swagger.json

@@ -71,8 +71,14 @@
                             "$ref": "#/definitions/api.ProblemDetails"
                         }
                     },
+                    "404": {
+                        "description": "categoryIds referenced a category that does not exist",
+                        "schema": {
+                            "$ref": "#/definitions/api.ProblemDetails"
+                        }
+                    },
                     "422": {
-                        "description": "title was empty, key was missing or not a key issued by this API, or categoryIds was empty or contained an id that does not exist",
+                        "description": "title was empty, key was missing or not a key issued by this API, or categoryIds was empty",
                         "schema": {
                             "$ref": "#/definitions/api.ProblemDetails"
                         }

cms/docs/swagger.yaml

@@ -186,9 +186,13 @@ paths:
           description: Request body was not valid JSON
           schema:
             $ref: '#/definitions/api.ProblemDetails'
+        "404":
+          description: categoryIds referenced a category that does not exist
+          schema:
+            $ref: '#/definitions/api.ProblemDetails'
         "422":
           description: title was empty, key was missing or not a key issued by this
-            API, or categoryIds was empty or contained an id that does not exist
+            API, or categoryIds was empty
           schema:
             $ref: '#/definitions/api.ProblemDetails'
         "500":

cms/internal/handlers/errors.go

@@ -0,0 +1,16 @@
+package handlers
+
+import "errors"
+
+// Sentinel errors the handlers branch on with errors.Is to decide which
+// problem response a failure deserves. They exist to separate a client's
+// mistake from a server fault where the code that detects both is the same
+// code — the repositories return plain errors, so without these every failure
+// out of a lookup would have to be answered as a 500.
+
+// errUnknownCatagoryID reports that a submitted category id is not in the
+// category table. It is kept distinct from the error the lookup itself
+// returns because the two are not the same kind of failure: an id nobody has
+// is the client's mistake and answers 404, while a lookup that could not run
+// is the server's and answers 500.
+var errUnknownCatagoryID = errors.New("unknown catagory id")

cms/internal/handlers/videos.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"log"
 	"net/http"
@@ -111,7 +112,8 @@ func PresignVideoUpload(w http.ResponseWriter, r *http.Request) {
 //	@Param			request	body		api.CompleteRequest	true	"Video metadata plus the storage key from the presign step. title, key and categoryIds are required; categoryIds must hold at least one id from GET /api/categories."
 //	@Success		201		{object}	api.CompleteResponse
 //	@Failure		400		{object}	api.ProblemDetails	"Request body was not valid JSON"
-//	@Failure		422		{object}	api.ProblemDetails	"title was empty, key was missing or not a key issued by this API, or categoryIds was empty or contained an id that does not exist"
+//	@Failure		404		{object}	api.ProblemDetails	"categoryIds referenced a category that does not exist"
+//	@Failure		422		{object}	api.ProblemDetails	"title was empty, key was missing or not a key issued by this API, or categoryIds was empty"
 //	@Failure		500		{object}	api.ProblemDetails	"Categories could not be read, the transcoding job could not be queued, or the video record could not be saved"
 //	@Router			/api/videos [post]
 func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
@@ -151,7 +153,12 @@ func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	err := validateCatagoryIDS(r.Context(), req.CategoryIDs)
+	unknownCatagoryID, err := validateCatagoryIDS(r.Context(), req.CategoryIDs)
+	if errors.Is(err, errUnknownCatagoryID) {
+		writeProblem(w, http.StatusNotFound, "Catagory Does Not Exist",
+			fmt.Sprintf("The 'categoryIds' field referenced the id %d, which no category has. Send only ids taken from the 'id' field of GET /api/categories. No video record was created and no transcoding job was queued; the uploaded file is still in storage, so retry this request with the same 'key'.", unknownCatagoryID))
+		return
+	}
 	if err != nil {
 		log.Printf("Something Went Wrong Loading Categories: %s", err)
 		writeProblem(w, http.StatusInternalServerError, "Something Went Wrong Loading Categories",
@@ -201,19 +208,22 @@ func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
-func validateCatagoryIDS(ctx context.Context, submitted []int16) (err error) {
+// validateCatagoryIDS checks every submitted id against the category table. On
+// the first id that has no category it returns that id alongside
+// errUnknownCatagoryID, so the handler can name it in the response.
+func validateCatagoryIDS(ctx context.Context, submitted []int16) (int16, error) {
 	categoryIDS, err := repositories.CatagoriesRepo.ListCategoriesIDs(ctx)
 	if err != nil {
-		return err
+		return 0, err
 	}
 
 	for _, submittedID := range submitted {
 		if !slices.Contains(categoryIDS, submittedID) {
-			return fmt.Errorf("Incorrect Category IDs")
+			return submittedID, errUnknownCatagoryID
 		}
 	}
 
-	return nil
+	return 0, nil
 }
 
 func randomFilename(original string) (string, error) {