Add a TryAdd method to RequestHeaders and use it

request_headers.go

@@ -1,18 +1,18 @@
 package abstractions
 
-//RequestHeaders represents a collection of request headers
+// RequestHeaders represents a collection of request headers
 type RequestHeaders struct {
 	header
 }
 
-//NewRequestHeaders creates a new RequestHeaders
+// NewRequestHeaders creates a new RequestHeaders
 func NewRequestHeaders() *RequestHeaders {
 	return &RequestHeaders{
 		header{make(map[string]map[string]struct{})},
 	}
 }
 
-//AddAll adds all headers from the other headers
+// AddAll adds all headers from the other headers
 func (r *RequestHeaders) AddAll(other *RequestHeaders) {
 	if other == nil || other.headers == nil {
 		return
@@ -23,3 +23,13 @@ func (r *RequestHeaders) AddAll(other *RequestHeaders) {
 		}
 	}
 }
+
+// TryAdd adds the header if it's not already present
+func (r *RequestHeaders) TryAdd(key string, value string) bool {
+	if r.ContainsKey(key) {
+		return false
+	}
+
+	r.Add(key, value)
+	return true
+}

request_headers_test.go

@@ -36,6 +36,14 @@ func TestIdAdds(t *testing.T) {
 	assert.Equal(t, "value", instance.Get("key")[0])
 }
 
+func TestIdTryAdds(t *testing.T) {
+	instance := NewRequestHeaders()
+	assert.NotNil(t, instance)
+	assert.True(t, instance.TryAdd("key", "value"))
+	assert.True(t, instance.ContainsKey("key"))
+	assert.Equal(t, "value", instance.Get("key")[0])
+}
+
 func TestItRemoves(t *testing.T) {
 	instance := NewRequestHeaders()
 	assert.NotNil(t, instance)
@@ -72,6 +80,15 @@ func TestItAddsAll(t *testing.T) {
 	assert.Equal(t, "value", instance.Get("key")[0])
 }
 
+func TestItTryAdds(t *testing.T) {
+	instance := NewRequestHeaders()
+	assert.NotNil(t, instance)
+	assert.True(t, instance.TryAdd("key", "value"))
+	assert.True(t, instance.ContainsKey("key"))
+	assert.False(t, instance.TryAdd("key", "value2"))
+	assert.Equal(t, "value", instance.Get("key")[0])
+}
+
 func TestIdListKeys(t *testing.T) {
 	instance := NewRequestHeaders()
 	assert.NotNil(t, instance)

request_information.go

@@ -146,7 +146,7 @@ func (request *RequestInformation) setContentAndContentType(writer s.Serializati
 	}
 	request.Content = content
 	if request.Headers != nil {
-		request.Headers.Add(contentTypeHeader, contentType)
+		request.Headers.TryAdd(contentTypeHeader, contentType)
 	}
 	return nil
 }