# Working with APIs # Creating a Simple JSON API with PHP In this tutorial, you will create a simple API using PHP. The API will return JSON data when visited in a browser. This is the same type of data format used by many real-world APIs. --- ## Project Structure Create a folder called: ```text api-demo ``` Inside the folder place: ```text api-demo ├── api.php └── smart_security_data.json ``` --- ## Create the API File Create: ```text api.php ``` Add: ```php ``` Save the file. --- ## Understanding the Code This line tells the browser that JSON data is being returned: ```php header( "Content-Type: application/json" ); ``` This line reads the JSON file: ```php file_get_contents( "smart_security_data.json" ); ``` This line sends the JSON data to the browser: ```php echo file_get_contents( "smart_security_data.json" ); ``` --- ## Test the API Open: ```text http://localhost/api-demo/api.php ``` You should see: ```json { "homeId": "GC-HOME-014", "location": "Gold Coast" } ``` along with the rest of the JSON data. ## Test the API in a New Browser Tab Notice that the URL now behaves like a data source. Instead of displaying a webpage, it returns structured JSON data. This is the same concept used by many modern APIs. Example: ```text https://example.com/api/users https://example.com/api/products https://example.com/api/weather ``` --- ## Complete API File ```php ``` You have successfully created a JSON API using PHP. Next tutorial: **Reading API Data with JavaScript**. # Reading API Data with JavaScript In the previous tutorial, you created a simple API using PHP. The API returns JSON data when visited in a browser. In this tutorial, you will use JavaScript to read data from the API and display it on a webpage. --- ## Project Structure Your project should contain: ```text api-demo ├── api.php ├── index.html └── smart_security_data.json ``` --- ## Create the HTML Page Create: ```text index.html ``` Add: ```html API Demo

API Dashboard

``` Save the file. --- ## Read the API Inside the ` ``` You have successfully consumed data from an API using JavaScript. Next tutorial: **Creating a Database-Driven API with PHP and MySQL**. # Creating a Database-Driven API with PHP and MySQL In the previous tutorials, the API returned data from a JSON file. In this tutorial, you will create an API that reads data from a MySQL database and returns it as JSON. --- ## The System Architecture The completed system will work like this: ```text security_events table ↓ api.php ↓ JSON ↓ JavaScript ``` Instead of reading a JSON file, the API will generate JSON directly from the database. --- ## Create the API File Create: ```text api_events.php ``` Add the database connection: ```php connect_error) { die("Connection failed: " . $conn->connect_error); } ?> ``` --- ## Set the Content Type Add: ```php header( "Content-Type: application/json" ); ``` The API will now return JSON instead of HTML. --- ## Query the Database Add: ```php $query = " SELECT * FROM security_events "; $result = $conn->query($query); ``` This retrieves all records from the table. --- ## Create an Array Add: ```php $events = []; ``` This array will hold all database records. --- ## Loop Through the Results Add: ```php while ( $row = $result->fetch_assoc() ) { $events[] = $row; } ``` This converts each database record into an array item. --- ## Convert the Array to JSON Add: ```php echo json_encode( $events, JSON_PRETTY_PRINT ); ``` The completed API should now return JSON. --- ## Test the API Open: ```text http://localhost/api-demo/api_events.php ``` You should see: ```json [ { "event_id":"1", "device_id":"CAM-01", "event_type":"motion_detected", "severity":"high" }, { "event_id":"2", "device_id":"CAM-01", "event_type":"remote_access_attempt", "severity":"critical" } ] ``` The exact records will depend on your database. ## Complete API File ```php connect_error) { die("Connection failed: " . $conn->connect_error); } header( "Content-Type: application/json" ); $query = " SELECT * FROM security_events "; $result = $conn->query($query); $events = []; while ( $row = $result->fetch_assoc() ) { $events[] = $row; } echo json_encode( $events, JSON_PRETTY_PRINT ); ?> ``` --- ## Create a Webpage to Read the API Create: ```text events.html ``` Add: ```html Security Events

Security Events

``` --- ## Test the Complete System Open: ```text http://localhost/api-demo/events.html ``` The page should display the records stored in MySQL. ## Why This Is Useful Previously: ```text JSON File ↓ JavaScript ``` Now: ```text MySQL Database ↓ PHP API ↓ JavaScript ``` This means: * New records can be added to the database * The API updates automatically * The webpage updates automatically * No JSON file needs to be edited manually This is the foundation of many modern web applications. Next tutorial: **Creating API Endpoints for Specific Data (Critical Events, Devices and Statistics)**. # Creating API Endpoints for Specific Data In the previous tutorial, you created an API that returned every record from the `security_events` table. In this tutorial, you will create multiple API endpoints that return different types of data. This approach is commonly used in modern web applications. --- ## Why Create Multiple Endpoints? Your current API returns all records: ```text api_events.php ``` This works, but many applications need smaller, more focused datasets. For example: ```text api_events.php api_critical_events.php api_statistics.php ``` Each endpoint has a specific purpose. --- ## Create a Critical Events API Create: ```text api_critical_events.php ``` Add: ```php query($query); $events = []; while ( $row = $result->fetch_assoc() ) { $events[] = $row; } echo json_encode( $events, JSON_PRETTY_PRINT ); ?> ``` --- ## Test the Endpoint Open: ```text http://localhost/api-demo/api_critical_events.php ``` You should only see critical events. > **Screenshot Placeholder** > > Insert screenshot showing critical event results. --- ## Create a Statistics API Create: ```text api_statistics.php ``` Add: ```php 0, "critical_events" => 0, "high_events" => 0 ]; $result = $conn->query( "SELECT COUNT(*) AS total FROM security_events" ); $statistics["total_events"] = $result->fetch_assoc()["total"]; $result = $conn->query( "SELECT COUNT(*) AS total FROM security_events WHERE severity='critical'" ); $statistics["critical_events"] = $result->fetch_assoc()["total"]; $result = $conn->query( "SELECT COUNT(*) AS total FROM security_events WHERE severity='high'" ); $statistics["high_events"] = $result->fetch_assoc()["total"]; echo json_encode( $statistics, JSON_PRETTY_PRINT ); ?> ``` --- ## Test the Statistics Endpoint Open: ```text http://localhost/api-demo/api_statistics.php ``` Example: ```json { "total_events": 3, "critical_events": 1, "high_events": 1 } ``` ## Read the Statistics API with JavaScript Create: ```text dashboard.html ``` Add: ```html Dashboard

Security Dashboard

``` --- ## Common Endpoint Examples Many real systems use endpoints such as: ```text /api/users /api/products /api/orders /api/messages /api/statistics ``` Each endpoint returns only the data required by the application. --- ## Summary You now have: ```text api_events.php ``` Returns all events. ```text api_critical_events.php ``` Returns only critical events. ```text api_statistics.php ``` Returns dashboard statistics. This approach keeps APIs organised and makes applications easier to maintain. Next tutorial: **Adding Parameters to an API Using URL Variables**.