Write logic for createElection validation

cmd/web/handlers.go

@@ -1,7 +1,40 @@
 package main
 
-import "net/http"
+import (
+	api "code.dlmw.ch/dlmw/qv/internal"
+	"code.dlmw.ch/dlmw/qv/internal/validator"
+	"net/http"
+	"time"
+)
+
+type createElectionRequestWithValidator struct {
+	api.CreateElectionRequest
+	validator.Validator
+}
 
 func (app *application) createElection(w http.ResponseWriter, r *http.Request) {
+	var request createElectionRequestWithValidator
+	err := app.decodePostForm(r, &request)
+	if err != nil {
+		app.clientError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	request.CheckField(validator.NotBlank(request.Name), "name", "must not be blank")
+	request.CheckField(validator.GreaterThan(request.Tokens, 0), "tokens", "must be greater than 0")
+	request.CheckField(validator.After(request.ExpiresAt, time.Now()), "expiresAt", "must expire in a future date")
+	request.CheckField(validator.GreaterThan(len(request.Choices), 1), "choices", "there must be more than 1 choice")
+
+	request.CheckField(
+		!request.IsAnonymous || (request.IsAnonymous && *request.MaxVoters > 0),
+		"maxVoters",
+		"must be greater than 0 for anonymous elections",
+	)
+
+	if !request.Valid() {
+		app.unprocessableEntityError(w, request.Validator)
+		return
+	}
+
 	w.Write([]byte("TODO"))
 }

cmd/web/helpers.go

@@ -1,12 +1,63 @@
 package main
 
-import "net/http"
+import (
+	api "code.dlmw.ch/dlmw/qv/internal"
+	"code.dlmw.ch/dlmw/qv/internal/validator"
+	"encoding/json"
+	"errors"
+	"github.com/go-playground/form/v4"
+	"net/http"
+)
 
 func (app *application) serverError(w http.ResponseWriter, r *http.Request, err error) {
-	var (
-		method = r.Method
-		uri    = r.URL.RequestURI()
-	)
-	app.logger.Error(err.Error(), "method", method, "uri", uri)
-	http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+	w.WriteHeader(http.StatusInternalServerError)
+	var response = api.ErrorResponse{
+		Code:    http.StatusInternalServerError,
+		Details: nil,
+		Message: "There was an error in the request",
+	}
+	json.NewEncoder(w).Encode(response)
+}
+
+func (app *application) clientError(w http.ResponseWriter, status int, message string) {
+	w.WriteHeader(status)
+	var response = api.ErrorResponse{
+		Code: http.StatusUnprocessableEntity,
+		Details: &map[string]interface{}{
+			"error": message,
+		},
+		Message: "There was an error in the request",
+	}
+	json.NewEncoder(w).Encode(response)
+}
+
+func (app *application) unprocessableEntityError(w http.ResponseWriter, v validator.Validator) {
+	w.WriteHeader(http.StatusUnprocessableEntity)
+	var response = api.ErrorResponse{
+		Code: http.StatusUnprocessableEntity,
+		Details: &map[string]interface{}{
+			"fields": v.FieldErrors,
+		},
+		Message: "Election data is invalid",
+	}
+	json.NewEncoder(w).Encode(response)
+}
+
+func (app *application) decodePostForm(r *http.Request, dst any) error {
+	err := r.ParseForm()
+	if err != nil {
+		return err
+	}
+
+	err = app.formDecoder.Decode(dst, r.PostForm)
+	if err != nil {
+		var invalidDecoderError *form.InvalidDecoderError
+		if errors.As(err, &invalidDecoderError) {
+			panic(err)
+		}
+
+		return err
+	}
+
+	return nil
 }

cmd/web/main.go

@@ -1,4 +1,4 @@
-//go:generate go run github.com/oapi-codegen/oapi-codegen/v2/cmd/oapi-codegen --config=oapi-codegen.yml openapi.yml
+//go:generate oapi-codegen --config=oapi-codegen.yml openapi.yml
 
 package main
 

cmd/web/openapi.yml

@@ -34,8 +34,8 @@ paths:
       responses:
         201:
           description: Election created
-        400:
-          description: Bad request
+        422:
+          description: Unprocessable Content
           content:
             application/json:
               schema:
@@ -187,7 +187,7 @@ components:
           type: string
           description: Human-readable error message
         code:
-          type: string
+          type: integer
           description: Machine-readable error code
         details:
           type: object