Performer urls (#4958)

* Populate URLs from legacy fields
* Return nil properly in xpath/json scrapers
* Improve migration logging

pkg/utils/url_test.go

@@ -0,0 +1,47 @@
+package utils
+
+import "testing"
+
+func TestURLFromHandle(t *testing.T) {
+	type args struct {
+		input   string
+		siteURL string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "input is already a URL https",
+			args: args{
+				input:   "https://foo.com",
+				siteURL: "https://bar.com",
+			},
+			want: "https://foo.com",
+		},
+		{
+			name: "input is already a URL http",
+			args: args{
+				input:   "http://foo.com",
+				siteURL: "https://bar.com",
+			},
+			want: "http://foo.com",
+		},
+		{
+			name: "input is not a URL",
+			args: args{
+				input:   "foo",
+				siteURL: "https://foo.com",
+			},
+			want: "https://foo.com/foo",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := URLFromHandle(tt.args.input, tt.args.siteURL); got != tt.want {
+				t.Errorf("URLFromHandle() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}