From c22d088aadf69ff49e52104dbffa47a13c905f99 Mon Sep 17 00:00:00 2001
From: Chris Jones <chris@cjones.org>
Date: Sat, 8 Sep 2018 13:40:49 -0600
Subject: [PATCH] Updated content-type parsing to respect wildcards.

---
 context.go      |  2 +-
 context_test.go | 26 ++++++++++++++++++++------
 utils.go        | 20 ++++++++++++++++++++
 3 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/context.go b/context.go
index 063c72f0..5ace552d 100644
--- a/context.go
+++ b/context.go
@@ -893,7 +893,7 @@ func (c *Context) NegotiateFormat(offered ...string) string {
 	}
 	for _, accepted := range c.Accepted {
 		for _, offert := range offered {
-			if accepted == offert {
+			if contentMatches(accepted, offert) {
 				return offert
 			}
 		}
diff --git a/context_test.go b/context_test.go
index 782f7bed..1832ea8c 100644
--- a/context_test.go
+++ b/context_test.go
@@ -1122,13 +1122,27 @@ func TestContextNegotiationFormat(t *testing.T) {
 }
 
 func TestContextNegotiationFormatWithAccept(t *testing.T) {
-	c, _ := CreateTestContext(httptest.NewRecorder())
-	c.Request, _ = http.NewRequest("POST", "/", nil)
-	c.Request.Header.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
+	typicalAccept := "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
+	testCases := []struct {
+		accept string
+		offer  []string
+		expect string
+	}{
+		{"*/*", []string{MIMEJSON}, MIMEJSON},
+		{"", []string{MIMEJSON, MIMEXML}, MIMEJSON},
+		{MIMEJSON, []string{MIMEXML}, ""},
+		{MIMEJSON, []string{MIMEXML, MIMEJSON, MIMEHTML}, MIMEJSON},
+		{typicalAccept, []string{MIMEJSON, MIMEXML}, MIMEXML},
+		{typicalAccept, []string{MIMEXML, MIMEHTML}, MIMEHTML},
+		{typicalAccept, []string{MIMEJSON}, MIMEJSON},
+	}
 
-	assert.Equal(t, MIMEXML, c.NegotiateFormat(MIMEJSON, MIMEXML))
-	assert.Equal(t, MIMEHTML, c.NegotiateFormat(MIMEXML, MIMEHTML))
-	assert.Empty(t, c.NegotiateFormat(MIMEJSON))
+	for i, tc := range testCases {
+		c, _ := CreateTestContext(httptest.NewRecorder())
+		c.Request, _ = http.NewRequest("POST", "/", nil)
+		c.Request.Header.Add("Accept", tc.accept)
+		assert.Equal(t, tc.expect, c.NegotiateFormat(tc.offer...), fmt.Sprintf("test case %d", i))
+	}
 }
 
 func TestContextNegotiationFormatCustum(t *testing.T) {
diff --git a/utils.go b/utils.go
index bf32c775..c1a36cd8 100644
--- a/utils.go
+++ b/utils.go
@@ -110,6 +110,26 @@ func parseAccept(acceptHeader string) []string {
 	return out
 }
 
+// contentMatches returns true if content matches the pattern.
+// See RFC2616, section 14.1.
+func contentMatches(pattern, content string) bool {
+	patternParts := strings.SplitN(pattern, "/", 2)
+	contentParts := strings.SplitN(content, "/", 2)
+	if patternParts[0] == "*" {
+		return true
+	}
+	if patternParts[0] != contentParts[0] {
+		return false
+	}
+	if patternParts[1] == "*" {
+		return true
+	}
+	if patternParts[1] != contentParts[1] {
+		return false
+	}
+	return true
+}
+
 func lastChar(str string) uint8 {
 	if str == "" {
 		panic("The length of the string can't be 0")