fix: return 404 for nonexistent question with api scraper

src/routes/question.go

@@ -4,6 +4,7 @@ import (
 	"anonymousoverflow/config"
 	"anonymousoverflow/src/scraper"
 	"anonymousoverflow/src/utils"
+	"errors"
 	"fmt"
 	"os"
 	"regexp"
@@ -41,7 +42,11 @@ func ViewQuestion(c *gin.Context) {
 
 	newFilteredQuestion, answers, err := questionScraper.GetQuestion(params)
 	if err != nil {
-		c.HTML(500, "home.html", gin.H{
+		status := 500
+		if errors.Is(err, scraper.ErrQuestionNotFound) {
+			status = 404
+		}
+		c.HTML(status, "home.html", gin.H{
 			"errorMessage": err,
 			"version":      config.Version,
 		})

src/scraper/api.go

@@ -4,6 +4,7 @@ import (
 	"anonymousoverflow/src/types"
 	"anonymousoverflow/src/utils"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"html/template"
 	"net/http"
@@ -92,6 +93,8 @@ type ApiScraper struct{ ApiKey string }
 
 const API_URL = "https://api.stackexchange.com/2.3"
 
+var ErrQuestionNotFound = errors.New("Question not found")
+
 func (s ApiScraper) GetQuestion(params ViewQuestionInputs) (types.FilteredQuestion, []types.FilteredAnswer, error) {
 	client := resty.New()
 	if s.ApiKey != "" {
@@ -150,6 +153,9 @@ func getQuestionContent(client *resty.Client, params ViewQuestionInputs) (types.
 	if err := json.Unmarshal(resp.Body(), &questionsResp); err != nil {
 		return types.FilteredQuestion{}, err
 	}
+	if len(questionsResp.Results) == 0 {
+		return types.FilteredQuestion{}, ErrQuestionNotFound
+	}
 	question := questionsResp.Results[0]
 
 	questionBody := template.HTML(utils.ProcessHTMLBody(question.Body))

src/scraper/api_test.go

@@ -0,0 +1,31 @@
+package scraper
+
+import (
+	"errors"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/go-resty/resty/v2"
+)
+
+type roundTripperFunc func(*http.Request) (*http.Response, error)
+
+func (f roundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) { return f(r) }
+
+func TestGetQuestionContentNotFound(t *testing.T) {
+	client := resty.New().SetTransport(roundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		return &http.Response{
+			StatusCode: http.StatusOK,
+			Header:     http.Header{"Content-Type": {"application/json"}},
+			Body:       io.NopCloser(strings.NewReader(`{"items":[]}`)),
+			Request:    r,
+		}, nil
+	}))
+
+	_, err := getQuestionContent(client, ViewQuestionInputs{QuestionID: "2120178", Sub: "stackoverflow"})
+	if !errors.Is(err, ErrQuestionNotFound) {
+		t.Fatalf("expected ErrQuestionNotFound, got %v", err)
+	}
+}