Add handling for Retry-After header.

Handles both plain-text and JSON responses. Include unit tests.
Fixes #33

Also updated API spec.

Author: Diwaker Gupta

dropbox/auth/client.go

@@ -80,7 +80,7 @@ func (dbx *apiImpl) TokenFromOauth1(arg *TokenFromOAuth1Arg) (res *TokenFromOAut
 		return
 	}
 
-	dbx.Config.LogDebug("body: %v", body)
+	dbx.Config.LogDebug("body: %s", body)
 	if resp.StatusCode == http.StatusOK {
 		err = json.Unmarshal(body, &res)
 		if err != nil {
@@ -98,7 +98,11 @@ func (dbx *apiImpl) TokenFromOauth1(arg *TokenFromOAuth1Arg) (res *TokenFromOAut
 		err = apiError
 		return
 	}
-	err = dropbox.HandleCommonAPIErrors(resp, body)
+	err = HandleCommonAuthErrors(dbx.Config, resp, body)
+	if err != nil {
+		return
+	}
+	err = dropbox.HandleCommonAPIErrors(dbx.Config, resp, body)
 	return
 }
 
@@ -134,7 +138,7 @@ func (dbx *apiImpl) TokenRevoke() (err error) {
 		return
 	}
 
-	dbx.Config.LogDebug("body: %v", body)
+	dbx.Config.LogDebug("body: %s", body)
 	if resp.StatusCode == http.StatusOK {
 		return
 	}
@@ -147,7 +151,11 @@ func (dbx *apiImpl) TokenRevoke() (err error) {
 		err = apiError
 		return
 	}
-	err = dropbox.HandleCommonAPIErrors(resp, body)
+	err = HandleCommonAuthErrors(dbx.Config, resp, body)
+	if err != nil {
+		return
+	}
+	err = dropbox.HandleCommonAPIErrors(dbx.Config, resp, body)
 	return
 }
 

dropbox/auth/sdk.go

@@ -0,0 +1,38 @@
+package auth
+
+import (
+	"encoding/json"
+	"mime"
+	"net/http"
+	"strconv"
+
+	"github.com/dropbox/dropbox-sdk-go-unofficial/dropbox"
+)
+
+type RateLimitAPIError struct {
+	dropbox.APIError
+	RateLimitError *RateLimitError `json:"error"`
+}
+
+// HandleCommonAuthErrors handles common authentication errors
+func HandleCommonAuthErrors(c dropbox.Config, resp *http.Response, body []byte) error {
+	if resp.StatusCode == http.StatusTooManyRequests {
+		var apiError RateLimitAPIError
+		// Check content-type
+		contentType, _, _ := mime.ParseMediaType(resp.Header.Get("content-type"))
+		if contentType == "application/json" {
+			if err := json.Unmarshal(body, &apiError); err != nil {
+				c.LogDebug("Error unmarshaling '%s' into JSON", body)
+				return err
+			}
+		} else { // assume plain text
+			apiError.ErrorSummary = string(body)
+			reason := RateLimitReason{dropbox.Tagged{Tag: RateLimitReasonTooManyRequests}}
+			apiError.RateLimitError = NewRateLimitError(&reason)
+			timeout, _ := strconv.ParseInt(resp.Header.Get("retry-after"), 10, 64)
+			apiError.RateLimitError.RetryAfter = uint64(timeout)
+		}
+		return apiError
+	}
+	return nil
+}

dropbox/contacts/client.go

@@ -27,6 +27,7 @@ import (
 	"net/http"
 
 	"github.com/dropbox/dropbox-sdk-go-unofficial/dropbox"
+	"github.com/dropbox/dropbox-sdk-go-unofficial/dropbox/auth"
 )
 
 // Client interface describes all routes in this namespace
@@ -74,7 +75,7 @@ func (dbx *apiImpl) DeleteManualContacts() (err error) {
 		return
 	}
 
-	dbx.Config.LogDebug("body: %v", body)
+	dbx.Config.LogDebug("body: %s", body)
 	if resp.StatusCode == http.StatusOK {
 		return
 	}
@@ -87,7 +88,11 @@ func (dbx *apiImpl) DeleteManualContacts() (err error) {
 		err = apiError
 		return
 	}
-	err = dropbox.HandleCommonAPIErrors(resp, body)
+	err = auth.HandleCommonAuthErrors(dbx.Config, resp, body)
+	if err != nil {
+		return
+	}
+	err = dropbox.HandleCommonAPIErrors(dbx.Config, resp, body)
 	return
 }
 
@@ -131,7 +136,7 @@ func (dbx *apiImpl) DeleteManualContactsBatch(arg *DeleteManualContactsArg) (err
 		return
 	}
 
-	dbx.Config.LogDebug("body: %v", body)
+	dbx.Config.LogDebug("body: %s", body)
 	if resp.StatusCode == http.StatusOK {
 		return
 	}
@@ -144,7 +149,11 @@ func (dbx *apiImpl) DeleteManualContactsBatch(arg *DeleteManualContactsArg) (err
 		err = apiError
 		return
 	}
-	err = dropbox.HandleCommonAPIErrors(resp, body)
+	err = auth.HandleCommonAuthErrors(dbx.Config, resp, body)
+	if err != nil {
+		return
+	}
+	err = dropbox.HandleCommonAPIErrors(dbx.Config, resp, body)
 	return
 }