func gerritAPI()

in git-codereview/api.go [233:293]
51 lines of code
12 McCabe index (conditional complexity)

func gerritAPI(path string, requestBody []byte, target interface{}) error {
	// Strictly speaking, we might be able to use unauthenticated
	// access, by removing the /a/ from the URL, but that assumes
	// that all the information we care about is publicly visible.
	// Using authentication makes it possible for this to work with
	// non-public CLs or Gerrit hosts too.
	loadAuth()

	if !strings.HasPrefix(path, "/") {
		dief("internal error: gerritAPI called with malformed path")
	}

	url := auth.url + path
	method := "GET"
	var reader io.Reader
	if requestBody != nil {
		method = "POST"
		reader = bytes.NewReader(requestBody)
	}
	req, err := http.NewRequest(method, url, reader)
	if err != nil {
		return err
	}
	if requestBody != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	if auth.cookieName != "" {
		req.AddCookie(&http.Cookie{
			Name:  auth.cookieName,
			Value: auth.cookieValue,
		})
	} else {
		req.SetBasicAuth(auth.user, auth.password)
	}

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	body, err := ioutil.ReadAll(resp.Body)
	resp.Body.Close()

	if err != nil {
		return fmt.Errorf("reading response body: %v", err)
	}
	if resp.StatusCode != http.StatusOK {
		return &gerritError{url, resp.StatusCode, resp.Status, string(body)}
	}

	if target != nil {
		i := bytes.IndexByte(body, '\n')
		if i < 0 {
			return fmt.Errorf("%s: malformed json response - bad header", url)
		}
		body = body[i:]
		if err := json.Unmarshal(body, target); err != nil {
			return fmt.Errorf("%s: malformed json response", url)
		}
	}
	return nil
}