# Record Measurements via API

This is a quick tutorial that will show you how you can use the Datacake GraphQL-API to record measurement values into your devices.

There is a large overview of Endpoints and how they function including some examples on an external developer overview.

## Record Multiple Values at once

### Payload Structure

Make sure that you structure the payload like in the following snippet.

```javascript
[
    {"field": "WATT", "value": msg.payload.watt },
    {"field": "AMPERE", "value": msg.payload.ampere},
    {"field": "VOLT", "value": msg.payload.volt}
];
```

So the general structure is:

```javascript
[{"field":"field1", "value":123.00}, {"field":"field2", "value":"a string"}]
```

### URL

The URL you should use for recording multiple measurements at once is:

`https://api.datacake.co/v1/devices/22h7c45f-2917-358-9db1-d8a544ab78ed/record/?batch=true`

It is structured as follow:

`https://api.datacake.co/v1/devices/<<device-id>>/record/?batch=true`

#### The Device-Id (<\<device-id>>)

This is the ID of your Device. You find this in the URL of the Datacake Portal and on the Device-View.

![Device-ID](/files/-M5vlmHbDosWkr7uP5Zf)

### Rate Limiting

Per default the Datacake GraphQL-API has an internal rate limiting of 1 write per second and per field. If you want to record historical data this might be an issue.

## Examples

Here you find some Examples that show you how to record multiple measurements.

### Curl

```bash
curl https://api.datacake.co/v1/devices/22h7c45f-2917-358-9db1-d8a544ab78ed/record/?batch=true
  -X POST
  -H "Authorization: Token 923847692384769283469823467"
  -H "Content-Type: application/json"
  --data '[\
    {\
        "field": "TEMPERATURE",\
        "value": 23.5,\
        "timestamp": "1555570137"\
    }\,
    {\
        "field": "HUMIDITY",\
        "value": 42,\
        "timestamp": "1555570137"\
    }\
  ]'
```

### Javascript

```javascript
// Set device_id to serial-number of Datacake API Device
device_id = "be525e29-4398-4fc1-a928-dead7fdfe218";

// Set Token to your personal access token or individual token
token = "put your token in here";

// This is the API Information for the HTTP Request Node
url = "https://api.datacake.co/v1/devices/"+device_id+"/record/?batch=true"

// Create Header for Node-RED HTTP Node
headers = {
    "Authorization": "Token "+token,
    "Content-Type": "application/json"
};

// Now we are going to create the Payload we forward to Datacake API
payload = [
    {
        "field": "WATT",
        "value": msg.payload.watt
    },
    {
        "field": "AMPERE",
        "value": msg.payload.ampere
    },
    {
        "field": "VOLT",
        "value": msg.payload.volt
    }
];

// Return it - were all set!
return msg;
```

### Python

```python
import requests
​
DTCK_KEY = 'yourapikey'
DTCK_DEVICE_ID = 'yourdeviceid'

if __name__ == "__main__":

    power_dc1 = 234
    power_dc2 = 345

    requests.post(f"https://api.datacake.co/v1/devices/{DTCK_DEVICE_ID}/record/?batch=true", headers={"Authorization": f"Token {DTCK_KEY}"}, json=[
        {
            "field": "POWER_DC1",
            "value": power_dc1,
            "timestamp": "1555570137" # a timestamp is optional
        },
        {
            "field": "POWER_DC2",
            "value": power_dc2
        }
    ])
```


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