Updating and Deleting Records

The update and delete endpoints follow a similar pattern to get_one(): they accept an ID from the URL, verify the record exists, perform the operation, and return an appropriate response.

Updating a Record - PUT

The update() endpoint combines patterns from get_one() (ID extraction, existence check) and create() (JSON parsing, validation):

PHP

public function update(): void {
    $this->authenticate();

    $update_id = segment(3, 'int');

    if ($update_id === 0) {
        http_response_code(400);
        echo json_encode([
            'error' => 'No country ID provided.'
        ]);
        return;
    }

    $existing = $this->model->get_one($update_id);

    if ($existing === false) {
        http_response_code(404);
        echo json_encode([
            'error' => 'Country not found.'
        ]);
        return;
    }

    $data = $this->get_post_data();

    if ($data === null) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Invalid or missing JSON payload.'
        ]);
        return;
    }

    $validation_errors = $this->validate($data);

    if (!empty($validation_errors)) {
        http_response_code(400);
        echo json_encode([
            'error' => 'Validation failed.',
            'fields' => $validation_errors
        ]);
        return;
    }

    $this->model->update($update_id, $data);

    http_response_code(200);
    echo json_encode([
        'message' => 'Country updated successfully.',
        'id' => $update_id,
        'country' => $data
    ]);

    $this->log_request('update', $update_id);
}

The method checks each precondition in order and returns early if any check fails. This is sometimes called the guard clause pattern - validate everything before doing work, and return immediately on the first error.

The Model Update

PHP

public function update(int $update_id, array $data): void {
    $update_data = [
        'country_title' => trim($data['country_title']),
        'country_code' => strtoupper(
            trim($data['country_code'])
        )
    ];

    $this->db->update(
        $update_id, $update_data, 'countries'
    );
}

Deleting a Record - DELETE

The destroy() endpoint is the simplest of the write operations:

PHP

public function destroy(): void {
    $this->authenticate();

    $update_id = segment(3, 'int');

    if ($update_id === 0) {
        http_response_code(400);
        echo json_encode([
            'error' => 'No country ID provided.'
        ]);
        return;
    }

    $existing = $this->model->get_one($update_id);

    if ($existing === false) {
        http_response_code(404);
        echo json_encode([
            'error' => 'Country not found.'
        ]);
        return;
    }

    $this->model->destroy($update_id);

    http_response_code(200);
    echo json_encode([
        'message' => 'Country deleted successfully.'
    ]);

    $this->log_request('destroy', $update_id);
}

200 vs 204 for Deletion

You may have seen REST APIs that return 204 No Content after a successful deletion. There is genuine debate about which is correct. We use 200 in this chapter because we include a confirmation message in the response body, which provides a better developer experience - the client can display "Country deleted successfully" to the user without needing to synthesise their own success message.

If you prefer the purist approach, simply change http_response_code(200) to http_response_code(204) and omit the echo json_encode(...) line. Both are valid.

Testing

BASH

# Update a record
curl -X PUT \
  -H "Trongatetoken: your-token" \
  -H "Content-Type: application/json" \
  -d '{"country_title":"New Name","country_code":"NN"}' \
  http://localhost/countries_api/update/1

# Delete a record
curl -X DELETE \
  -H "Trongatetoken: your-token" \
  http://localhost/countries_api/destroy/1

# Update non-existent record
curl -X PUT \
  -H "Trongatetoken: your-token" \
  -H "Content-Type: application/json" \
  -d '{"country_title":"Nope","country_code":"NP"}' \
  http://localhost/countries_api/update/999

The third test case - attempting to update a record that does not exist - should return 404 Not Found with an informative error message.

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