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Issue #2950502: API for querying sensor data

This commit is contained in:
Michael Stenta 2018-11-07 15:33:19 -05:00
parent 3697a85614 3e10078bb0
commit d81b6be854
1 changed files with 142 additions and 45 deletions
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187
modules/farm/farm_sensor/farm_sensor_listener/farm_sensor_listener.module
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@ -77,11 +77,17 @@ function farm_sensor_listener_mail($key, &$message, $params) {
}
/**
* Callback function for receiving JSON over HTTP and storing data to the {farm_sensor_data} table.
* Callback function for processing GET and POST requests to a listener.
* Handles receiving JSON over HTTP and storing data to the {farm_sensor_data}
* table. Serves data back via API requests with optional parameters.
*
* @param $public_key
* The public key of the sensor that is pushing the data.
*
* The private key should be provided as a URL query string.
*
* Use HTTPS to encrypt data in transit.
*
* JSON should be in the following format:
* {
* "timestamp": 1234567890,
@ -125,52 +131,72 @@ function farm_sensor_listener_page_callback($public_key) {
return MENU_ACCESS_DENIED;
}
// Pull the data from the request.
$data = drupal_json_decode(file_get_contents("php://input"));
// If this is a POST request, process the data.
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
// If data was posted, process it.
if (!empty($data)) {
farm_sensor_listener_process_data($sensor, $data);
// Pull the data from the request.
$data = drupal_json_decode(file_get_contents("php://input"));
// If data was posted, process it.
if (!empty($data)) {
farm_sensor_listener_process_data($sensor, $data);
}
// Return success.
return MENU_FOUND;
}
// Otherwise, return the latest values for each name.
else {
// If this is a GET request, retrieve sensor data.
elseif ($_SERVER['REQUEST_METHOD'] == 'GET') {
// Query the database for latest values from this sensor,
$query = db_select('farm_sensor_data', 'fsd');
$query->fields('fsd', array('timestamp', 'name', 'value_numerator', 'value_denominator'));
$subselect = db_select('farm_sensor_data', 'fsd');
$subselect->addExpression('MAX(timestamp)', 'timestamp');
$subselect->addField('fsd', 'name');
$subselect->condition('fsd.id', $sensor->id);
$subselect->groupBy('fsd.name');
$query->addJoin('LEFT', $subselect, 'fsd2', 'fsd.timestamp = fsd2.timestamp AND fsd.name = fsd2.name');
$query->condition('fsd.id', $sensor->id);
$query->isNotNull('fsd2.timestamp');
$result = $query->execute();
// Add 'Access-Control-Allow-Origin' header to allow pulling this data into
// other domains.
/**
* @todo
* Move this to a more official place, or adopt the CORS module in farmOS.
*/
drupal_add_http_header('Access-Control-Allow-Origin', '*');
// Build an array of latest readings.
$readings = array();
foreach ($result as $row) {
// If name or timestamp are empty, skip.
if (empty($row->timestamp) || empty($row->name)) {
continue;
}
// Convert the value numerator and denominator to a decimal.
$value = fraction($row->value_numerator, $row->value_denominator)->toDecimal(0, TRUE);
// Create a data object for the sensor value.
$data = new stdClass();
$data->timestamp = $row->timestamp;
$data->{$row->name} = $value;
$readings[] = $data;
// If the 'name' parameter is set, filter by name.
$name = '';
if (!empty($params['name'])) {
$name = $params['name'];
}
// If the 'start' parameter is set, limit results to timestamps after it.
$start = NULL;
if (!empty($params['start'])) {
$start = $params['start'];
}
// If the 'end' parameter is set, limit to results before it.
$end = NULL;
if (!empty($params['end'])) {
$end = $params['end'];
}
// If the 'limit' parameter is set, limit the number of results.
$limit = 1;
if (!empty($params['limit'])) {
$limit = $params['limit'];
}
// If the 'offset' parameter is set, offset the results.
$offset = 0;
if (!empty($params['offset'])) {
$offset = $params['offset'];
}
// Get the data from the sensor.
$data = farm_sensor_listener_data($sensor->id, $name, $start, $end, $limit, $offset);
// Return the latest readings as JSON.
drupal_json_output($readings);
drupal_json_output($data);
}
// Return success and do nothing on all other request types.
else {
return MENU_FOUND;
}
}
@ -364,6 +390,79 @@ function farm_sensor_listener_process_notifications($sensor, $data_name, $value)
}
}
/**
* Fetch sensor data from the database.
*
* @param $id
* The sensor asset ID.
* @param $name
* The sensor value name.
* @param $start
* Filter data to timestamps greater than or equal to this start timestamp.
* @param $end
* Filter data to timestamps less than or equal to this end timestamp.
* @param $limit
* The number of results to return.
* @param $offset
* The value to start at.
*
* @return array
* Returns an array of data.
*/
function farm_sensor_listener_data($id, $name = '', $start = NULL, $end = NULL, $limit = 1, $offset = 0) {
// Query the database for data from this sensor.
$query = db_select('farm_sensor_data', 'fsd');
$query->fields('fsd', array('timestamp', 'name', 'value_numerator', 'value_denominator'));
$query->condition('fsd.id', $id);
// If a name is specified, filter by name.
if (!empty($name)) {
$query->condition('fsd.name', $name);
}
// If a start timestamp is specified, filter to data after it (inclusive).
if (!is_null($start) && is_numeric($start)) {
$query->condition('fsd.timestamp', $start, '>=');
}
// If an end timestamp is specified, filter to data before it (inclusive).
if (!is_null($end) && is_numeric($end)) {
$query->condition('fsd.timestamp', $end, '<=');
}
// Order by timestamp descending.
$query->orderBy('fsd.timestamp', 'DESC');
// Limit the results.
$query->range($offset, $limit);
// Run the query.
$result = $query->execute();
// Build an array of data.
$data = array();
foreach ($result as $row) {
// If name or timestamp are empty, skip.
if (empty($row->timestamp) || empty($row->name)) {
continue;
}
// Convert the value numerator and denominator to a decimal.
$value = fraction($row->value_numerator, $row->value_denominator)->toDecimal(0, TRUE);
// Create a data object for the sensor value.
$point = new stdClass();
$point->timestamp = $row->timestamp;
$point->{$row->name} = $value;
$data[] = $point;
}
// Return the data.
return $data;
}
/**
* Implements hook_farm_sensor_type_info().
*/
@ -428,13 +527,11 @@ function farm_sensor_listener_settings_form($sensor, $settings = array()) {
$form['info'] = array(
'#type' => 'fieldset',
'#title' => t('Developer Information'),
'#description' => t('A "listener" sensor allows you to send sensor data to
farmOS over standard HTTP in a JSON array. Set up your sensor to post JSON
to the URL below. Note that multiple sensor values can be included in each request (if a
device has multiple sensors, for example). The name given to each value
can be any string of numbers and letters ("timestamp" is reserved). Each
value will be stored in a separate row in the database, with the "name"
column used for filtering purposes.'),
'#description' => t('This sensor type will listen for data posted to it
from other web-connected devices. Use the information below to configure your
device to begin posting data to this sensor. For more information, refer to
the <a href="@sensor_url">farmOS sensor guide</a>.',
array('@sensor_url' => 'https://farmOS.org/guide/assets/sensors')),
'#collapsible' => TRUE,
'#collapsed' => TRUE,
);