2 files changed, 59 insertions, 0 deletions
diff --git a/common/myurl/urlparse.go b/common/myurl/urlparse.go
new file mode 100644
index 0000000..69695d1
--- /dev/null
+++ b/common/myurl/urlparse.go
@@ -0,0 +1,27 @@
+package myurl
+
+import (
+	"errors"
+	"net/url"
+	"strings"
+)
+
+type Url string
+
+func (o Url) Url() string {
+	return string(o)
+}
+
+// FileExtension returns file extension of file name from this url.
+// copied from https://elisegev.medium.com/get-a-file-extension-from-a-url-in-golang-5061d4a298a
+func (o Url) FileExtension() (string, error) {
+	u, err := url.Parse(o.Url())
+	if err != nil {
+		return "", err
+	}
+	pos := strings.LastIndex(u.Path, ".")
+	if pos == -1 {
+		return "", errors.New("couldn't find a period to indicate a file extension")
+	}
+	return u.Path[pos+1 : len(u.Path)], nil
+}
diff --git a/common/myurl/urlparse_test.go b/common/myurl/urlparse_test.go
new file mode 100644
index 0000000..b7df7bd
--- /dev/null
+++ b/common/myurl/urlparse_test.go
@@ -0,0 +1,32 @@
+package myurl
+
+import "testing"
+
+func TestGetFileExtensionFromUrl(t *testing.T) {
+	tests := []struct {
+		Expected string
+		Actual   string
+	}{
+		{Expected: "html"},
+		{Expected: "htm"},
+		{Expected: "flv"},
+	}
+	var err error
+	tests[0].Actual, err = Url("http://www.example.com/index.html").FileExtension()
+	if err != nil {
+		t.Fatalf("GetFileExtensionFromUrl: %v", err)
+	}
+	tests[1].Actual, err = Url("https://www.example.com/index.htm").FileExtension()
+	if err != nil {
+		t.Fatalf("GetFileExtensionFromUrl: %v", err)
+	}
+	tests[2].Actual, err = Url("https://www.example.com/video.flv?a=1&b=2flv").FileExtension()
+	if err != nil {
+		t.Fatalf("GetFileExtensionFromUrl: %v", err)
+	}
+	for i, tc := range tests {
+		if tc.Expected != tc.Actual {
+			t.Fatalf("Test %v failed: %v", i, tc)
+		}
+	}
+}