Merge pull request #63 from messagebird/fix-voice-error-response

Fix voice error response

Author: marcelcorso

README.md

@@ -7,7 +7,7 @@ This repository contains the open source Go client for MessageBird's REST API. D
 Requirements
 ------------
 - [Sign up](https://www.messagebird.com/en/signup) for a free MessageBird account
-- Create a new access key in the developers sections
+- Create a new access key in the [dashboard](https://dashboard.messagebird.com/en-us/developers/access).
 - An application written in Go to make use of this API
 
 Installation
@@ -26,43 +26,88 @@ Here is a quick example on how to get started. Assuming the **go get** installat
 import "github.com/messagebird/go-rest-api"
 ```
 
-Then, create an instance of **messagebird.Client**:
+Then, create an instance of **messagebird.Client**. It can be used to access the MessageBird APIs.
 
 ```go
-client := messagebird.New("test_gshuPaZoeEG6ovbc8M79w0QyM")
-```
+// Access keys can be managed through our dashboard.
+accessKey := "your-access-key"
 
-Now you can query the API for information or send data. For example, if we want to request our balance information you'd do something like this:
+// Create a client.
+client := messagebird.New(accessKey)
 
-```go
-// Request the balance information, returned as a Balance object.
+// Request the balance information, returned as a balance.Balance object.
 balance, err := balance.Read(client)
 if err != nil {
-	switch errResp := err.(type) {
-	case messagebird.ErrorResponse:
-		for _, mbError := range errResp.Errors {
-			fmt.Printf("Error: %#v\n", mbError)
-		}
-	}
-
+	// Handle error.
 	return
 }
 
-fmt.Println("  payment :", balance.Payment)
-fmt.Println("  type    :", balance.Type)
-fmt.Println("  amount  :", balance.Amount)
+// Display the results.
+fmt.Println("Payment: ", balance.Payment)
+fmt.Println("Type:", balance.Type)
+fmt.Println("Amount:", balance.Amount)
 ```
 
 This will give you something like:
-```shell
+
+```bash
 $ go run example.go
-  payment : prepaid
-  type    : credits
-  amount  : 9
+Payment: prepaid
+Type: credits
+Amount: 9
 ```
 
 Please see the other examples for a complete overview of all the available API calls.
 
+Errors
+------
+When something goes wrong, our APIs can return more than a single error. They are therefore returned by the client as "error responses" that contain a slice of errors.
+
+It is important to notice that the Voice API returns errors with a format that slightly differs from other APIs.
+For this reason, errors returned by the `voice` package are of type `voice.ErrorResponse`. It contains `voice.Error` structs. All other packages return `messagebird.ErrorResponse` structs that contain a slice of `messagebird.Error`.
+
+An example of "simple" error handling is shown in the example above. Let's look how we can gain more in-depth insight in what exactly went wrong:
+
+```go
+import "github.com/messagebird/go-rest-api"
+import "github.com/messagebird/go-rest-api/sms"
+
+// ...
+
+_, err := sms.Read(client, "some-id")
+if err != nil {
+	mbErr, ok := err.(messagebird.ErrorResponse)
+	if !ok {
+		// A non-MessageBird error occurred (no connection, perhaps?) 
+		return err
+	}
+	
+	fmt.Println("Code:", mbErr.Errors[0].Code)
+	fmt.Println("Description:", mbErr.Errors[0].Description)
+	fmt.Println("Parameter:", mbErr.Errors[0].Parameter)
+}
+```
+
+`voice.ErrorResponse` is very similar, except that it holds `voice.Error` structs - those contain only `Code` and `Message` (not description!) fields:
+
+```go
+import "github.com/messagebird/go-rest-api/voice"
+
+// ...
+
+_, err := voice.CallFlowByID(client, "some-id")
+if err != nil {
+	vErr, ok := err.(voice.ErrorResponse)
+	if !ok {
+    		// A non-MessageBird (Voice) error occurred (no connection, perhaps?) 
+    		return err
+    }
+	
+	fmt.Println("Code:", vErr.Errors[0].Code)
+	fmt.Println("Message:", vErr.Errors[0].Message)
+}
+```
+
 Documentation
 -------------
 Complete documentation, instructions, and examples are available at:

client.go

@@ -32,6 +32,9 @@ const (
 
 	// httpClientTimeout is used to limit http.Client waiting time.
 	httpClientTimeout = 15 * time.Second
+
+	// voiceHost is the host name for the Voice API.
+	voiceHost = "voice.messagebird.com"
 )
 
 var (
@@ -55,6 +58,11 @@ const (
 	contentTypeFormURLEncoded contentType = "application/x-www-form-urlencoded"
 )
 
+// errorReader reads the provided byte slice into an appropriate error.
+type errorReader func([]byte) error
+
+var voiceErrorReader errorReader
+
 // New creates a new MessageBird client object.
 func New(accessKey string) *Client {
 	return &Client{
@@ -65,6 +73,12 @@ func New(accessKey string) *Client {
 	}
 }
 
+// SetVoiceErrorReader takes an errorReader that must parse raw JSON errors
+// returned from the Voice API.
+func SetVoiceErrorReader(r errorReader) {
+	voiceErrorReader = r
+}
+
 // Request is for internal use only and unstable.
 func (c *Client) Request(v interface{}, method, path string, data interface{}) error {
 	if !strings.HasPrefix(path, "https://") && !strings.HasPrefix(path, "http://") {
@@ -135,6 +149,10 @@ func (c *Client) Request(v interface{}, method, path string, data interface{}) e
 		return ErrUnexpectedResponse
 	default:
 		// Anything else than a 200/201/204/500 should be a JSON error.
+		if uri.Host == voiceHost && voiceErrorReader != nil {
+			return voiceErrorReader(responseBody)
+		}
+
 		var errorResponse ErrorResponse
 		if err := json.Unmarshal(responseBody, &errorResponse); err != nil {
 			return err

voice/testdata/error.json

@@ -0,0 +1,9 @@
+{
+  "data": null,
+  "errors": [
+    {
+      "code": 13,
+      "message": "some-error"
+    }
+  ]
+}

voice/testdata/errors.json

@@ -0,0 +1,13 @@
+{
+  "data": null,
+  "errors": [
+    {
+      "code": 11,
+      "message": "some-error"
+    },
+    {
+      "code": 15,
+      "message": "other-error"
+    }
+  ]
+}

voice/voice.go

@@ -1,3 +1,52 @@
 package voice
 
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/messagebird/go-rest-api"
+)
+
 const apiRoot = "https://voice.messagebird.com"
+
+type ErrorResponse struct {
+	Errors []Error
+}
+
+type Error struct {
+	Code int
+	Message string
+}
+
+func init() {
+	// The Voice API returns errors in a format that slightly differs from other
+	// APIs. Here we instruct package messagebird to use our custom
+	// voice.errorReader func, which has access to voice.ErrorResponse, to
+	// unmarshal those. Package messagebird must not import the voice package to
+	// safeguard against import cycles, so it can not use voice.ErrorResponse
+	// directly.
+	messagebird.SetVoiceErrorReader(errorReader)
+}
+
+// errorReader takes a []byte representation of a Voice API JSON error and
+// parses it to a voice.ErrorResponse.
+func errorReader(b []byte) error {
+	var er ErrorResponse
+	if err := json.Unmarshal(b, &er); err != nil {
+		return fmt.Errorf("encoding/json: Unmarshal: %v", err)
+	}
+	return er
+}
+
+func (e ErrorResponse) Error() string {
+	errStrings := make([]string, len(e.Errors))
+	for i, v := range e.Errors {
+		errStrings[i] = v.Error()
+	}
+	return strings.Join(errStrings, "; ")
+}
+
+func (e Error) Error() string {
+	return fmt.Sprintf("code: %d, message: %q", e.Code, e.Message)
+}

voice/voice_test.go

@@ -0,0 +1,78 @@
+package voice
+
+import (
+	"testing"
+
+	"github.com/messagebird/go-rest-api/internal/mbtest"
+)
+
+func TestErrorReader(t *testing.T) {
+	t.Run("Single error", func(t *testing.T) {
+		b := mbtest.Testdata(t, "error.json")
+		err := errorReader(b).(ErrorResponse)
+
+		if count := len(err.Errors); count != 1 {
+			t.Fatalf("Got %d, expected 1", count)
+		}
+
+		if err.Errors[0].Code != 13 {
+			t.Errorf("Got %d, expected 13", err.Errors[0].Code)
+		}
+		if err.Errors[0].Message != "some-error" {
+			t.Errorf("Got %q, expected some-error", err.Errors[0].Message)
+		}
+	})
+
+	t.Run("Multiple errors", func(t *testing.T) {
+		b := mbtest.Testdata(t, "errors.json")
+		err := errorReader(b).(ErrorResponse)
+
+		if count := len(err.Errors); count != 2 {
+			t.Fatalf("Got %d, expected 2", count)
+		}
+
+		if err.Errors[0].Code != 11 {
+			t.Errorf("Got %d, expected 11", err.Errors[0].Code)
+		}
+		if err.Errors[0].Message != "some-error" {
+			t.Errorf("Got %q, expected some-error", err.Errors[0].Message)
+		}
+		if err.Errors[1].Code != 15 {
+			t.Errorf("Got %d, expected 15", err.Errors[1].Code)
+		}
+		if err.Errors[1].Message != "other-error" {
+			t.Errorf("Got %q, expected other-error", err.Errors[1].Message)
+		}
+	})
+
+	t.Run("Invalid JSON", func(t *testing.T) {
+		b := []byte("clearly not json")
+		_, ok := errorReader(b).(ErrorResponse)
+
+		if ok {
+			// If the data b is not JSON, we expect a "generic" errorString
+			// (from fmt.Errorf), but we somehow got our own ErrorResponse back.
+			t.Fatalf("Got ErrorResponse, expected errorString")
+		}
+	})
+}
+
+func TestErrorResponseError(t *testing.T) {
+	err := ErrorResponse{
+		[]Error{
+			{
+				Code: 1,
+				Message: "foo",
+			},
+			{
+				Code: 2,
+				Message: "bar",
+			},
+		},
+	}
+
+	expect := `code: 1, message: "foo"; code: 2, message: "bar"`
+	if actual := err.Error(); actual != expect {
+		t.Fatalf("Got %q, expected %q", actual, expect)
+	}
+}