Merge pull request #2 from 178inaba/empty_parse

Fix to return nil if parse empty string

.travis.yml

@@ -1,14 +1,6 @@
 language: go
 
 go:
-  - 1.5
   - 1.6
+  - 1.7
   - tip
-
-install:
-  - ./script/bootstrap
-
-script:
-  - ./script/test
-#  - ./script/lint
-

README.mkd

@@ -1,6 +1,6 @@
 # Golang Link Header Parser
 
-Library for parsing HTTP Link headers. Requires Go 1.2 or higher.
+Library for parsing HTTP Link headers. Requires Go 1.6 or higher.
 
 Docs can be found on [the GoDoc page](https://godoc.org/github.com/tomnomnom/linkheader).
 

main.go

@@ -63,6 +63,10 @@ func (l Links) FilterByRel(r string) Links {
 // String returns the string representation of multiple Links
 // for use in HTTP responses etc
 func (l Links) String() string {
+	if l == nil {
+		return fmt.Sprint(nil)
+	}
+
 	var strs []string
 	for _, link := range l {
 		strs = append(strs, link.String())
@@ -74,7 +78,7 @@ func (l Links) String() string {
 //   <url>; rel="foo", <url>; rel="bar"; wat="dis"
 // returning a slice of Link structs
 func Parse(raw string) Links {
-	links := make(Links, 0)
+	var links Links
 
 	// One chunk: <url>; rel="foo"
 	for _, chunk := range strings.Split(raw, ",") {
@@ -110,8 +114,10 @@ func Parse(raw string) Links {
 
 		}
 
+		if link.URL != "" {
 			links = append(links, link)
 		}
+	}
 
 	return links
 }

main_test.go

@@ -38,6 +38,27 @@ func TestSimple(t *testing.T) {
 
 }
 
+func TestEmpty(t *testing.T) {
+	links := Parse("")
+	if links != nil {
+		t.Errorf("Return value should be nil, but was %s", len(links))
+	}
+}
+
+// Although not often seen in the wild, the grammar in RFC 5988 suggests that it's
+// valid for a link header to have nothing but a URL.
+func TestNoRel(t *testing.T) {
+	links := Parse("<http://example.com>")
+
+	if len(links) != 1 {
+		t.Fatalf("Length of links should be 1, but was %d", len(links))
+	}
+
+	if links[0].URL != "http://example.com" {
+		t.Errorf("URL should be http://example.com, but was %s", links[0].URL)
+	}
+}
+
 func TestLinkMethods(t *testing.T) {
 	header := "<https://api.github.com/user/9287/repos?page=1&per_page=100>; rel=\"prev\"; pet=\"cat\""
 	links := Parse(header)