add Rate to github.Client

update Do() to update client.Rate on every API call. Fixes #12

github/github.go

@@ -53,12 +53,16 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/url"
+	"strconv"
 )
 
 const (
 	libraryVersion = "0.1"
 	defaultBaseURL = "https://api.github.com/"
 	userAgent      = "go-github/" + libraryVersion
+
+	headerRateLimit     = "X-RateLimit-Limit"
+	headerRateRemaining = "X-RateLimit-Remaining"
 )
 
 // A Client manages communication with the GitHub API.
@@ -74,6 +78,12 @@ type Client struct {
 	// User agent used when communicating with the GitHub API.
 	UserAgent string
 
+	// Rate specifies the current rate limit for the client as determined by the
+	// most recent API call.  If the client is used in a multi-user application,
+	// this rate may not always be up-to-date.  Call RateLimit() to check the
+	// current rate.
+	Rate Rate
+
 	// Services used for talking to different parts of the API
 
 	Issues        *IssuesService
@@ -150,6 +160,14 @@ func (c *Client) Do(req *http.Request, v interface{}) (*http.Response, error) {
 
 	defer resp.Body.Close()
 
+	// update rate limit
+	if limit := resp.Header.Get(headerRateLimit); limit != "" {
+		c.Rate.Limit, _ = strconv.Atoi(limit)
+	}
+	if remaining := resp.Header.Get(headerRateRemaining); remaining != "" {
+		c.Rate.Remaining, _ = strconv.Atoi(remaining)
+	}
+
 	err = CheckResponse(resp)
 	if err != nil {
 		return resp, err

github/github_test.go

@@ -193,6 +193,58 @@ func TestDo_redirectLoop(t *testing.T) {
 	}
 }
 
+func TestDo_rateLimit(t *testing.T) {
+	setup()
+	defer teardown()
+
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add(headerRateLimit, "60")
+		w.Header().Add(headerRateRemaining, "59")
+	})
+
+	var want int
+
+	if want = 0; client.Rate.Limit != want {
+		t.Errorf("Client rate limit = %v, want %v", client.Rate.Limit, want)
+	}
+	if want = 0; client.Rate.Limit != want {
+		t.Errorf("Client rate remaining, got %v", client.Rate.Remaining, want)
+	}
+
+	req, _ := client.NewRequest("GET", "/", nil)
+	client.Do(req, nil)
+
+	if want = 60; client.Rate.Limit != want {
+		t.Errorf("Client rate limit = %v, want %v", client.Rate.Limit, want)
+	}
+	if want = 59; client.Rate.Remaining != want {
+		t.Errorf("Client rate remaining = %v, want %v", client.Rate.Remaining, want)
+	}
+}
+
+func TestDo_rateLimit_errorResponse(t *testing.T) {
+	setup()
+	defer teardown()
+
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add(headerRateLimit, "60")
+		w.Header().Add(headerRateRemaining, "59")
+		http.Error(w, "Bad Request", 400)
+	})
+
+	var want int
+
+	req, _ := client.NewRequest("GET", "/", nil)
+	client.Do(req, nil)
+
+	if want = 60; client.Rate.Limit != want {
+		t.Errorf("Client rate limit = %v, want %v", client.Rate.Limit, want)
+	}
+	if want = 59; client.Rate.Remaining != want {
+		t.Errorf("Client rate remaining = %v, want %v", client.Rate.Remaining, want)
+	}
+}
+
 func TestCheckResponse(t *testing.T) {
 	res := &http.Response{
 		Request:    &http.Request{},