feat(service): Zulip Service integration

README.md

@@ -110,6 +110,7 @@ Yes, please! Contributions of all kinds are very welcome! Feel free to check our
 | [WeChat](https://www.wechat.com)                                                  | [service/wechat](service/wechat)         | [silenceper/wechat](https://github.com/silenceper/wechat)                                       | :heavy_check_mark: |
 | [Webpush Notification](https://developer.mozilla.org/en-US/docs/Web/API/Push_API) | [service/webpush](service/webpush)       | [SherClockHolmes/webpush-go](https://github.com/SherClockHolmes/webpush-go/)                    | :heavy_check_mark: |
 | [WhatsApp](https://www.whatsapp.com)                                              | [service/whatsapp](service/whatsapp)     | [Rhymen/go-whatsapp](https://github.com/Rhymen/go-whatsapp)                                     |        :x:         |
+| [Zulip](https://zulip.com/)                                             | [service/zulip](service/zulip)                     | -                                                                                               | :heavy_check_mark: |
 
 ## Special Thanks <a id="special_thanks"></a>
 

service/zulip/README.md

@@ -0,0 +1,43 @@
+# Zulip
+
+## Steps for creating a Zulip Bot
+
+Follow the below instructions to create a bot email and api key required for the service:
+
+1. Create a Zulip Organization
+2. Go to settings and create a new bot. Copy the bot email and api key.
+3. Copy your Oranization URL. Copy the entire url `https://your-domain.zulipchat.com`
+4. Copy the stream name of the stream and its topic if you want to post a message to stream or just copy an email address of the receiver.
+
+## Sample Code
+
+```go
+	package main
+
+	import (
+		"context"
+		"log"
+
+		"github.com/nikoksr/notify"
+		"github.com/nikoksr/notify/service/zulip"
+	)
+
+	func main() {
+	    zulipSvc, err := zulip.New("server-base-url", "bot-email", "api-key")
+		if err != nil {
+			log.Fatalf("zulip.New() failed: %s", err.Error())
+		}
+
+	    zulipSvc.AddReceivers(Direct("[email protected]"), Stream("stream", "topic"))
+
+		notifier := notify.New()
+		notifier.UseServices(zulipSvc)
+
+		err = notifier.Send(context.Background(), "subject", "message")
+		if err != nil {
+			log.Fatalf("notifier.Send() failed: %s", err.Error())
+		}
+
+		log.Println("notification sent")
+	}
+```

service/zulip/client/client.go

@@ -0,0 +1,135 @@
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+const (
+	// DefaultBaseURL contains example base URL of zulip service.
+	DefaultBaseURL = "https://yourZulipDomain.zulipchat.com"
+
+	// DefaultTimeout duration in second
+	DefaultTimeout time.Duration = 30 * time.Second
+)
+
+// Client abstracts the interaction between the application server and the
+// Zulip server via HTTP protocol. The developer must obtain an API key from the
+// Zulip's personal settings page and pass it to the `Client` so that it can
+// perform authorized requests on the application server's behalf.
+// To send a message to one or more devices use the Client's Send.
+//
+// If the `HTTP` field is nil, a zeroed http.Client will be allocated and used
+// to send messages.
+type Client struct {
+	email   string
+	apiKey  string
+	baseURL string
+	client  *http.Client
+	timeout time.Duration
+}
+
+type Option func(*Client) error
+
+// NewClient creates new Zulip Client based on opts passed and
+// with default endpoint and http client.
+func NewClient(opts ...Option) (*Client, error) {
+	c := &Client{
+		baseURL: DefaultBaseURL,
+		client:  &http.Client{},
+		timeout: DefaultTimeout,
+	}
+
+	for _, opt := range opts {
+		if err := opt(c); err != nil {
+			return nil, err
+		}
+	}
+
+	if c.apiKey == "" || c.email == "" {
+		return nil, ErrInvalidCreds
+	}
+
+	return c, nil
+}
+
+type Response struct {
+	ID     int    `json:"id"`
+	Msg    string `json:"msg"`
+	Result string `json:"result"`
+	Code   string `json:"code"`
+}
+
+// SendWithContext sends a message to the Zulip server without retrying in case of service
+// unavailability. A non-nil error is returned if a non-recoverable error
+// occurs (i.e. if the response status is not "200 OK").
+// Behaves just like regular send, but uses external context.
+func (c *Client) SendWithContext(ctx context.Context, msg *Message) (*Response, error) {
+	// validate
+	if err := msg.Validate(); err != nil {
+		return nil, err
+	}
+
+	return c.send(ctx, msg)
+}
+
+// Send sends a message to the Zulip server without retrying in case of service
+// unavailability. A non-nil error is returned if a non-recoverable error
+// occurs (i.e. if the response status is not "200 OK").
+func (c *Client) Send(msg *Message) (*Response, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), c.timeout)
+	defer cancel()
+
+	return c.SendWithContext(ctx, msg)
+}
+
+// send sends a request.
+func (c *Client) send(ctx context.Context, msg *Message) (*Response, error) {
+	// set the message data
+	data := url.Values{}
+	data.Set("type", msg.Type)
+	data.Set("to", fmt.Sprintf("%v", msg.To))
+	data.Set("topic", msg.Topic)
+	data.Set("content", msg.Content)
+
+	// create request
+	url, _ := url.JoinPath(c.baseURL, "/api/v1/messages")
+	req, err := http.NewRequest("POST", url, strings.NewReader(data.Encode()))
+	if err != nil {
+		return nil, err
+	}
+
+	req = req.WithContext(ctx)
+
+	// add headers
+	req.SetBasicAuth(c.email, c.apiKey)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	// execute request
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	// check response status
+	if resp.StatusCode != http.StatusOK {
+		if resp.StatusCode >= http.StatusInternalServerError {
+			return nil, fmt.Errorf("%d error: %s", resp.StatusCode, resp.Status)
+		}
+		return nil, fmt.Errorf("%d error: %s", resp.StatusCode, resp.Status)
+	}
+
+	// build return
+	response := new(Response)
+	if err := json.NewDecoder(resp.Body).Decode(response); err != nil {
+		return nil, err
+	}
+
+	return response, nil
+}