Centralize link URL validation

internal/publish/links.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"gitea.maximumdirect.net/eric/distributor/internal/config"
+	"gitea.maximumdirect.net/eric/distributor/internal/link"
 	"gitea.maximumdirect.net/eric/distributor/internal/state"
 )
 
@@ -13,6 +14,9 @@ func PlanLinks(req Request, outputs []Output) ([]Output, string, error) {
 	if req.Links == nil {
 		return outputs, "", nil
 	}
+	if err := link.ValidateHTTPURL(req.Links.BaseURL); err != nil {
+		return nil, "", fmt.Errorf("link base URL: %w", err)
+	}
 	linked := make([]Output, 0, len(outputs))
 	for _, output := range outputs {
 		outputURL, err := OutputURL(req.Links.BaseURL, req.DestinationBundlePath, output.DestinationPath)

internal/publish/links_test.go

@@ -1,6 +1,7 @@
 package publish
 
 import (
+	"strings"
 	"testing"
 
 	"gitea.maximumdirect.net/eric/distributor/internal/config"
@@ -147,3 +148,22 @@ func TestPlanLinksLeavesOutputsUnchangedWithoutConfig(t *testing.T) {
 		t.Fatalf("output URL = %q, want empty", linked[0].URL)
 	}
 }
+
+func TestPlanLinksValidatesBaseURLBeforePlanning(t *testing.T) {
+	_, _, err := PlanLinks(Request{
+		DestinationBundlePath: "daily",
+		Links: &config.Links{
+			BaseURL: "https://reports.example.com/archive?preview=1",
+			Primary: config.LinkPrimaryAuto,
+		},
+	}, []Output{{
+		DestinationPath: "report.md",
+		Kind:            state.OutputKindSource,
+	}})
+	if err == nil {
+		t.Fatal("PlanLinks() error = nil, want error")
+	}
+	if !strings.Contains(err.Error(), "link base URL: must not include a query string") {
+		t.Fatalf("PlanLinks() error = %q, want link base URL context", err)
+	}
+}