GetCallEventsExample.java

// Copyright 2025 NFON AG
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//
// NFON CTI API SSE example: Get call details and state change events
//
// What it does:
// 1. Logs in with API username and password to obtain an access token
// 2. Opens a Server-Sent Events (SSE) stream to receive call details and state changes
// 3. Continuously logs incoming events until terminated
//
// Steps to run:
// 1. Set environment variables:
//    Linux/macOS:        export NFON_API_USERNAME='<YOUR API USERNAME>'
//                        export NFON_API_PASSWORD='<YOUR API PASSWORD>'
//    Windows CMD:        set NFON_API_USERNAME=<YOUR API USERNAME>
//                        set NFON_API_PASSWORD=<YOUR API PASSWORD>
//    Windows PowerShell: $env:NFON_API_USERNAME='<YOUR API USERNAME>'
//                        $env:NFON_API_PASSWORD='<YOUR API PASSWORD>'
// 2. Run: java GetCallEventsExample.java
//
// Requirements:
// - Java 11+

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URL;
import java.nio.charset.StandardCharsets;

public class GetCallEventsExample {

    // TODO: Change these values to match your application
    private static final String APP_NAME = "NFON-GitHub-Example";  // Replace with your application name
    private static final String APP_VERSION = "1.0";               // Replace with your application version
    private static final String USER_AGENT = APP_NAME + "/" + APP_VERSION;

    private static final String USERNAME = System.getenv("NFON_API_USERNAME");
    private static final String PASSWORD = System.getenv("NFON_API_PASSWORD");

    public static void main(String[] args) {
        try {
            if (USERNAME == null || USERNAME.isEmpty() || PASSWORD == null || PASSWORD.isEmpty()) {
                System.err.println("Error: NFON_API_USERNAME and NFON_API_PASSWORD must be set");
                System.exit(1);
            }
            String token = getAccessToken();
            System.out.println("Access token retrieved successfully.");
            openEventStream(token);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static String getAccessToken() throws Exception {
        URL url = URI.create("https://providersupportdata.cloud-cfg.com/v1/login").toURL();
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type", "application/json");
        conn.setRequestProperty("Accept", "application/json");
        conn.setRequestProperty("User-Agent", USER_AGENT);
        conn.setDoOutput(true);

        String jsonBody = String.format("{\"username\":\"%s\", \"password\":\"%s\"}", USERNAME, PASSWORD);
        try (OutputStream os = conn.getOutputStream()) {
            os.write(jsonBody.getBytes(StandardCharsets.UTF_8));
        }

        if (conn.getResponseCode() / 100 != 2) {
            throw new IOException("Login failed: " + conn.getResponseCode() + " " + conn.getResponseMessage());
        }

        String resp = readAll(conn.getInputStream());
        return resp.replaceAll(".*\"access-token\"\\s*:\\s*\"([^\"]+)\".*", "$1");
    }

    private static void openEventStream(String token) throws Exception {
        URL url = URI.create("https://providersupportdata.cloud-cfg.com/v1/extensions/phone/calls").toURL();
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        conn.setRequestProperty("Accept", "text/event-stream");
        conn.setRequestProperty("Authorization", "Bearer " + token);
        conn.setRequestProperty("User-Agent", USER_AGENT);
        conn.setReadTimeout(0);

        if (conn.getResponseCode() / 100 != 2) {
            throw new IOException("Failed to open SSE: " + conn.getResponseCode() + " " + conn.getResponseMessage());
        }

        System.out.println("Connected to SSE: " + url);
        System.out.println("Waiting for call events...\n(Stop the program to end)");

        try (BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8))) {
            String line;
            StringBuilder eventBuf = new StringBuilder();
            while ((line = br.readLine()) != null) {
                if (line.isEmpty()) {
                    handleEventBlock(eventBuf.toString());
                    eventBuf.setLength(0);
                } else {
                    eventBuf.append(line).append("\n");
                }
            }
            System.out.println("SSE connection closed by server.");
        }
    }

    private static void handleEventBlock(String block) {
        if (block == null || block.isEmpty()) return;
        String[] lines = block.split("\\r?\\n");

        String eventName = "message";
        StringBuilder data = new StringBuilder();

        for (String l : lines) {
            if (l.startsWith("event:")) eventName = l.substring(6).trim();
            else if (l.startsWith("data:")) data.append(l.substring(5).trim()).append("\n");
        }
        String payload = data.toString().trim();

        System.out.println("[" + eventName + "] " + payload);
    }

    private static String readAll(InputStream is) throws IOException {
        try (BufferedReader br = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8))) {
            StringBuilder sb = new StringBuilder();
            String ln;
            while ((ln = br.readLine()) != null) sb.append(ln);
            return sb.toString();
        }
    }
}