Add functions of create, get, update, delete and list webhooks (#146)

* Add webhook creation function

* Add webhook list function

* Add webhook delete function

* Add webhook get function

* Add webhook update function

* Update documentation related to webhooks

* Fix addressed issues on code review

README.md

@@ -42,6 +42,11 @@ Currently supports **v2** only, if you want to use **v1**, use **v1.1.4** git ta
  * PATCH /v2/payments/billing-plans/***ID***
  * POST /v2/payments/billing-agreements
  * POST /v2/payments/billing-agreements/***TOKEN***/agreement-execute
+ * POST /v1/notifications/webhooks
+ * GET /v1/notifications/webhooks
+ * GET /v1/notifications/webhooks/**ID**
+ * PATCH /v1/notifications/webhooks/**ID**
+ * DELETE /v1/notifications/webhooks/**ID**
  * POST /v1/notifications/verify-webhook-signature
 
 ### Missing endpoints
@@ -281,6 +286,42 @@ c.GetCreditCard("CARD-ID-123")
 c.GetCreditCards(nil)
 ```
 
+### Webhooks
+```go
+// Create a webhook
+c.CreateWebhook(paypal.CreateWebhookRequest{
+    URL: "webhook URL",
+    EventTypes: []paypal.WebhookEventType{
+        paypal.WebhookEventType{
+            Name: "PAYMENT.AUTHORIZATION.CREATED",
+            },
+    },
+})
+
+// Update a registered webhook
+c.UpdateWebhook("WebhookID", []paypal.WebhookField{
+    paypal.WebhookField{
+        Operation: "replace",
+        Path:      "/event_types",
+        Value: []interface{}{
+            map[string]interface{}{
+                "name": "PAYMENT.SALE.REFUNDED",
+            },
+        },
+    },
+})
+
+// Get a registered webhook
+c.GetWebhook("WebhookID")
+
+// Delete a webhook
+c.DeleteWebhook("WebhookID")
+
+// List registered webhooks
+c.ListWebhooks(paypal.AncorTypeApplication)
+
+```
+
 ### How to Contribute
 
 * Fork a repository

integration_test.go

@@ -132,3 +132,85 @@ func TestPatchCreditCard(t *testing.T) {
 		t.Errorf("Error is expected for empty update info")
 	}
 }
+
+// Creates, gets, and deletes single webhook
+func TestCreateAndGetWebhook(t *testing.T) {
+	c, _ := NewClient(testClientID, testSecret, APIBaseSandBox)
+	c.GetAccessToken()
+
+	payload := &CreateWebhookRequest{
+		URL: "https://example.com/paypal_webhooks",
+		EventTypes: []WebhookEventType{
+			WebhookEventType{
+				Name: "PAYMENT.AUTHORIZATION.CREATED",
+			},
+		},
+	}
+
+	createdWebhook, err := c.CreateWebhook(payload)
+	if err != nil {
+		t.Errorf("Webhook couldn't be created, error %v", err)
+	}
+
+	_, err = c.GetWebhook(createdWebhook.ID)
+	if err != nil {
+		t.Errorf("An error occurred while getting webhook, error %v", err)
+	}
+
+	err = c.DeleteWebhook(createdWebhook.ID)
+	if err != nil {
+		t.Errorf("An error occurred while webhooks deletion, error %v", err)
+	}
+}
+
+// Creates, updates, and deletes single webhook
+func TestCreateAndUpdateWebhook(t *testing.T) {
+	c, _ := NewClient(testClientID, testSecret, APIBaseSandBox)
+	c.GetAccessToken()
+
+	creationPayload := &CreateWebhookRequest{
+		URL: "https://example.com/paypal_webhooks",
+		EventTypes: []WebhookEventType{
+			WebhookEventType{
+				Name: "PAYMENT.AUTHORIZATION.CREATED",
+			},
+		},
+	}
+
+	createdWebhook, err := c.CreateWebhook(creationPayload)
+	if err != nil {
+		t.Errorf("Webhook couldn't be created, error %v", err)
+	}
+
+	updatePayload := []WebhookField{
+		WebhookField{
+			Operation: "replace",
+			Path:      "/event_types",
+			Value: []interface{}{
+				map[string]interface{}{
+					"name": "PAYMENT.SALE.REFUNDED",
+				},
+			},
+		},
+	}
+
+	_, err = c.UpdateWebhook(createdWebhook.ID, updatePayload)
+	if err != nil {
+		t.Errorf("Couldn't update webhook, error %v", err)
+	}
+
+	err = c.DeleteWebhook(createdWebhook.ID)
+	if err != nil {
+		t.Errorf("An error occurred while webhooks deletion, error %v", err)
+	}
+}
+
+func TestListWebhooks(t *testing.T) {
+	c, _ := NewClient(testClientID, testSecret, APIBaseSandBox)
+	c.GetAccessToken()
+
+	_, err := c.ListWebhooks(AncorTypeApplication)
+	if err != nil {
+		t.Errorf("Cannot registered list webhooks, error %v", err)
+	}
+}

types.go

@@ -124,6 +124,11 @@ const (
 	LinkRelActionURL string = "action_url"
 )
 
+const (
+	AncorTypeApplication string = "APPLICATION"
+	AncorTypeAccount     string = "ACCOUNT"
+)
+
 type (
 	// JSONTime overrides MarshalJson method to format in ISO8601
 	JSONTime time.Time
@@ -963,10 +968,20 @@ type (
 		UserAction        string `json:"user_action,omitempty"`
 	}
 
+	// VerifyWebhookResponse struct
 	VerifyWebhookResponse struct {
 		VerificationStatus string `json:"verification_status,omitempty"`
 	}
 
+	// Webhook strunct
+	Webhook struct {
+		ID         string             `json:"id"`
+		URL        string             `json:"url"`
+		EventTypes []WebhookEventType `json:"event_types"`
+		Links      []Link             `json:"links"`
+	}
+
+	// WebhookEvent struct
 	WebhookEvent struct {
 		ID              string    `json:"id"`
 		CreateTime      time.Time `json:"create_time"`
@@ -979,6 +994,28 @@ type (
 		ResourceVersion string    `json:"resource_version,omitempty"`
 	}
 
+	// WebhookEventType struct
+	WebhookEventType struct {
+		Name        string `json:"name"`
+		Description string `json:"description"`
+	}
+
+	// CreateWebhookRequest struct
+	CreateWebhookRequest struct {
+		URL        string             `json:"url"`
+		EventTypes []WebhookEventType `json:"event_types"`
+	}
+
+	ListWebhookResponse struct {
+		Webhooks []Webhook `json:"webhooks"`
+	}
+
+	WebhookField struct {
+		Operation string      `json:"op"`
+		Path      string      `json:"path"`
+		Value     interface{} `json:"value"`
+	}
+
 	Resource struct {
 		// Payment Resource type
 		ID                     string                  `json:"id,omitempty"`

webhooks.go

@@ -8,6 +8,76 @@ import (
 	"net/http"
 )
 
+// CreateWebhook - Subscribes your webhook listener to events.
+// Endpoint: POST /v1/notifications/webhooks
+func (c *Client) CreateWebhook(createWebhookRequest *CreateWebhookRequest) (*Webhook, error) {
+	req, err := c.NewRequest(http.MethodPost, fmt.Sprintf("%s%s", c.APIBase, "/v1/notifications/webhooks"), createWebhookRequest)
+	webhook := &Webhook{}
+	if err != nil {
+		return webhook, err
+	}
+
+	err = c.SendWithAuth(req, webhook)
+	return webhook, err
+}
+
+// GetWebhook - Shows details for a webhook, by ID.
+// Endpoint: GET /v1/notifications/webhooks/ID
+func (c *Client) GetWebhook(webhookID string) (*Webhook, error) {
+	req, err := c.NewRequest(http.MethodGet, fmt.Sprintf("%s%s%s", c.APIBase, "/v1/notifications/webhooks/", webhookID), nil)
+	webhook := &Webhook{}
+	if err != nil {
+		return webhook, err
+	}
+
+	err = c.SendWithAuth(req, webhook)
+	return webhook, err
+}
+
+// UpdateWebhook - Updates a webhook to replace webhook fields with new values.
+// Endpoint: PATCH /v1/notifications/webhooks/ID
+func (c *Client) UpdateWebhook(webhookID string, fields []WebhookField) (*Webhook, error) {
+	req, err := c.NewRequest(http.MethodPatch, fmt.Sprintf("%s/v1/notifications/webhooks/%s", c.APIBase, webhookID), fields)
+	webhook := &Webhook{}
+	if err != nil {
+		return webhook, err
+	}
+
+	err = c.SendWithAuth(req, webhook)
+	return webhook, err
+}
+
+// ListWebhooks - Lists webhooks for an app.
+// Endpoint: GET /v1/notifications/webhooks
+func (c *Client) ListWebhooks(anchorType string) (*ListWebhookResponse, error) {
+	if len(anchorType) == 0 {
+		anchorType = AncorTypeApplication
+	}
+	req, err := c.NewRequest(http.MethodGet, fmt.Sprintf("%s%s", c.APIBase, "/v1/notifications/webhooks"), nil)
+	q := req.URL.Query()
+	q.Add("anchor_type", anchorType)
+	req.URL.RawQuery = q.Encode()
+	resp := &ListWebhookResponse{}
+	if err != nil {
+		return nil, err
+	}
+
+	err = c.SendWithAuth(req, resp)
+	return resp, err
+}
+
+// DeleteWebhook - Deletes a webhook, by ID.
+// Endpoint: DELETE /v1/notifications/webhooks/ID
+func (c *Client) DeleteWebhook(webhookID string) error {
+	req, err := c.NewRequest(http.MethodDelete, fmt.Sprintf("%s/v1/notifications/webhooks/%s", c.APIBase, webhookID), nil)
+	if err != nil {
+		return err
+	}
+
+	err = c.SendWithAuth(req, nil)
+	return err
+}
+
 // VerifyWebhookSignature - Use this to verify the signature of a webhook recieved from paypal.
 // Endpoint: POST /v1/notifications/verify-webhook-signature
 func (c *Client) VerifyWebhookSignature(httpReq *http.Request, webhookID string) (*VerifyWebhookResponse, error) {