add support for GitHub's new rate reset

Because the reset date is expressed as a Unix timestamp (rather than an
ISO 8601 timstamp), we can't directly unmarshal the JSON response.
Instead we have to do a little weird indirection to unmarshal it as an
int first, and then convert it into a proper Time object.

github/github.go

@@ -53,6 +53,7 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"time"
 )
 
 const (
@@ -62,6 +63,7 @@ const (
 
 	headerRateLimit     = "X-RateLimit-Limit"
 	headerRateRemaining = "X-RateLimit-Remaining"
+	headerRateReset     = "X-RateLimit-Reset"
 )
 
 // A Client manages communication with the GitHub API.
@@ -168,6 +170,11 @@ func (c *Client) Do(req *http.Request, v interface{}) (*http.Response, error) {
 	if remaining := resp.Header.Get(headerRateRemaining); remaining != "" {
 		c.Rate.Remaining, _ = strconv.Atoi(remaining)
 	}
+	if reset := resp.Header.Get(headerRateReset); reset != "" {
+		if v, _ := strconv.ParseInt(reset, 10, 64); v != 0 {
+			c.Rate.Reset = time.Unix(v, 0)
+		}
+	}
 
 	err = CheckResponse(resp)
 	if err != nil {
@@ -261,7 +268,11 @@ func parseBoolResponse(err error) (bool, error) {
 
 // API response wrapper to a rate limit request.
 type rateResponse struct {
-	Rate *Rate `json:rate`
+	Rate struct {
+		Limit     int   `json:limit`
+		Remaining int   `json:remaining`
+		Reset     int64 `json:reset`
+	} `json:rate`
 }
 
 // Rate represents the rate limit for the current client.  Unauthenticated
@@ -269,10 +280,13 @@ type rateResponse struct {
 // 5,000 per hour.
 type Rate struct {
 	// The number of requests per hour the client is currently limited to.
-	Limit int `json:limit`
+	Limit int
 
 	// The number of remaining requests the client can make this hour.
-	Remaining int `json:remaining`
+	Remaining int
+
+	// The time at which the current rate limit will reset.
+	Reset time.Time
 }
 
 // RateLimit returns the rate limit for the current client.
@@ -284,7 +298,16 @@ func (c *Client) RateLimit() (*Rate, error) {
 
 	response := new(rateResponse)
 	_, err = c.Do(req, response)
-	return response.Rate, err
+	if err != nil {
+		return nil, err
+	}
+
+	rate := &Rate{
+		Limit:     response.Rate.Limit,
+		Remaining: response.Rate.Remaining,
+		Reset:     time.Unix(response.Rate.Reset, 0),
+	}
+	return rate, err
 }
 
 /*

github/github_test.go

@@ -15,6 +15,7 @@ import (
 	"reflect"
 	"strings"
 	"testing"
+	"time"
 )
 
 var (
@@ -199,6 +200,7 @@ func TestDo_rateLimit(t *testing.T) {
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Add(headerRateLimit, "60")
 		w.Header().Add(headerRateRemaining, "59")
+		w.Header().Add(headerRateReset, "1372700873")
 	})
 
 	var want int
@@ -207,7 +209,10 @@ func TestDo_rateLimit(t *testing.T) {
 		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)
+		t.Errorf("Client rate remaining = %v, got %v", client.Rate.Remaining, want)
+	}
+	if !client.Rate.Reset.IsZero() {
+		t.Errorf("Client rate reset not initialized to zero value")
 	}
 
 	req, _ := client.NewRequest("GET", "/", nil)
@@ -219,6 +224,10 @@ func TestDo_rateLimit(t *testing.T) {
 	if want = 59; client.Rate.Remaining != want {
 		t.Errorf("Client rate remaining = %v, want %v", client.Rate.Remaining, want)
 	}
+	reset := time.Date(2013, 7, 1, 17, 47, 53, 0, time.UTC)
+	if client.Rate.Reset.UTC() != reset {
+		t.Errorf("Client rate reset = %v, want %v", client.Rate.Reset, reset)
+	}
 }
 
 func TestDo_rateLimit_errorResponse(t *testing.T) {
@@ -228,6 +237,7 @@ func TestDo_rateLimit_errorResponse(t *testing.T) {
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Add(headerRateLimit, "60")
 		w.Header().Add(headerRateRemaining, "59")
+		w.Header().Add(headerRateReset, "1372700873")
 		http.Error(w, "Bad Request", 400)
 	})
 
@@ -242,6 +252,10 @@ func TestDo_rateLimit_errorResponse(t *testing.T) {
 	if want = 59; client.Rate.Remaining != want {
 		t.Errorf("Client rate remaining = %v, want %v", client.Rate.Remaining, want)
 	}
+	reset := time.Date(2013, 7, 1, 17, 47, 53, 0, time.UTC)
+	if client.Rate.Reset.UTC() != reset {
+		t.Errorf("Client rate reset = %v, want %v", client.Rate.Reset, reset)
+	}
 }
 
 func TestCheckResponse(t *testing.T) {
@@ -350,7 +364,7 @@ func TestRateLimit(t *testing.T) {
 		if m := "GET"; m != r.Method {
 			t.Errorf("Request method = %v, want %v", r.Method, m)
 		}
-		fmt.Fprint(w, `{"rate":{"limit":2,"remaining":1}}`)
+		fmt.Fprint(w, `{"rate":{"limit":2,"remaining":1,"reset":1372700873}}`)
 	})
 
 	rate, err := client.RateLimit()
@@ -358,7 +372,11 @@ func TestRateLimit(t *testing.T) {
 		t.Errorf("Rate limit returned error: %v", err)
 	}
 
-	want := &Rate{Limit: 2, Remaining: 1}
+	want := &Rate{
+		Limit:     2,
+		Remaining: 1,
+		Reset:     time.Date(2013, 7, 1, 17, 47, 53, 0, time.UTC).Local(),
+	}
 	if !reflect.DeepEqual(rate, want) {
 		t.Errorf("RateLimit returned %+v, want %+v", rate, want)
 	}