I've investegated a way to mock HTTP request and response when writing a code to access to a HTTP API with http.Client. Finally, I found that I can do it by just implementing RoundTrip method of http.RoundTripper.
Here is an example of mocking and proxying HTTP request and response. Running with go run main.go -mock mock, you can get mocked result and with go run main.go -mock proxy, you can get proxied result with httptest.Server.
package main import ( "flag" "fmt" "io/ioutil" "net/http" "net/http/httptest" "net/url" "strings" ) var mock = flag.String("mock", "", "Doesn't perform real access when 'proxy' or 'mock' is specified") func main() { flag.Parse() client := http.DefaultClient if *mock == "proxy" { server := newServer() defer server.Close() client.Transport = &http.Transport{ // Proxy to httptest.Server which created above Proxy: func(req *http.Request) (*url.URL, error) { return url.Parse(server.URL) }, } } else if *mock == "mock" { client.Transport = newMockTransport() } resp, err := client.Get("http://ifconfig.co/all.json") if err != nil { panic(err) } defer resp.Body.Close() body, err := ioutil.ReadAll(resp.Body) fmt.Println("GET http://ifconfig.co/all.json") fmt.Println(string(body)) } // Create a HTTP server to return mocked response func newServer() *httptest.Server { return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(200) w.Header().Set("Content-Type", "application/json") fmt.Fprintln(w, `{ "Accept-Encoding": [ "proxy" ], "User-Agent": [ "proxy" ], "X-Ip-Country": [ "Japan(Proxy)" ], "X-Real-Ip": [ "192.168.1.1" ] }`) })) } type mockTransport struct{} func newMockTransport() http.RoundTripper { return &mockTransport{} } // Implement http.RoundTripper func (t *mockTransport) RoundTrip(req *http.Request) (*http.Response, error) { // Create mocked http.Response response := &http.Response{ Header: make(http.Header), Request: req, StatusCode: http.StatusOK, } response.Header.Set("Content-Type", "application/json") responseBody := `{ "Accept-Encoding": [ "mock" ], "User-Agent": [ "mock" ], "X-Ip-Country": [ "Japan(Mock)" ], "X-Real-Ip": [ "192.168.1.1" ] }` response.Body = ioutil.NopCloser(strings.NewReader(responseBody)) return response, nil }
I think it's very simple to mock a HTTP request in GoLang. net/http package is awesome.
- 作者: Mat Ryer
- 出版社/メーカー: Packt Publishing
- 発売日: 2015/01/23
- メディア: ペーパーバック
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