nodemcu-firmware/lua_modules/phant

phant-nodemcu

The goal of this library is to provide a simple interface for logging data to phant. It should take any data type, convert it to a String, and build a url. This library will not handle interaction with WiFi or ethernet shields, it's only purpose is to make it easier for users to build phant compatible requests without worrying about data types and string concatenation.

Installation

Save "phant.lua" to your nodemcu.

Usage

To create a new instance of the request builder, pass the server's hostname, your public key, and your private key to the phant.init() method.

phant.init("data.sparkfun.com", "VGb2Y1jD4VIxjX3x196z", "9YBaDk6yeMtNErDNq4YM")

To add data, you can make calls to phant.add(key, value). The library will convert any value data type to a string, so there is no need for conversion before sending data. For example, if you have a stream with fields titled wind, temp, and raining, your code would add data to the request like this:

phant.add("wind", 12.0);
phant.add("temp", 70.1);
phant.add("raining", false);

Remember that in order to use float data-type values you must use a version of nodemcu that has been compiled with support for float data-type.

To get the request string for adding data, you have two options phant.url() and phant.post(). Both methods will clear the current request data after building and returning the current request. Unless there is some compelling reason to do otherwise, you should always use phant.post() to get a HTTP POST request string. phant.url() will return a URL that you can use in your web browser to test data logging.

print(phant.post())

or

conn = net.createConnection(net.TCP, 0)

conn:on("connection", function(conn, payload)
    conn:send(phant.post())
end)

conn:connect(80, 'data.sparkfun.com')

To clear all of the data in your stream, you can use phant.clear() to get a HTTP DELETE request string. Clearing the data will not delete the stream definition, it will only delete the logged data.

print(phant.clear())

If you would like to retrieve your logged data, phant.get() will return a HTTP GET request string that will cause the server to respond with your logged data in CSV format. Parsing CSV is outside of the scope of this library.

As an added functionality, if you which to retrieve your logged data in another format like JSON, you can supply that format in the method as a parameter. If no format is given to the method it will default to CSV.

print(phant.get())

print(phant.get("json"))

Output Example

Sketch

require("phant")

hostName = "data.sparkfun.com"
publicKey = "VGb2Y1jD4VIxjX3x196z"
privateKey = "9YBaDk6yeMtNErDNq4YM"

phant.init(hostName, publicKey, privateKey)

phant.add("val1", "url")
phant.add("val2", 22)
phant.add("val3", 0.1234)

print("----TEST URL-----")
print(phant.url() .. "\n")

phant.add("val1", "post")
phant.add("val2", false)
phant.add("val3", 98.6)

print("----HTTP POST----")
print(phant.post() .. "\n")

print("----HTTP GET----")
print(phant.get())

print("----HTTP DELETE----")
print(phant.clear())

phant = nil
package.loaded["phant"] = nil

Output

This example prints the following to the serial monitor:

----TEST URL-----
http://data.sparkfun.com/input/VGb2Y1jD4VIxjX3x196z.txt?private_key=9YBaDk6yeMtNErDNq4YM&val1=url&val2=22&val3=0.1234

----HTTP POST----
POST /input/VGb2Y1jD4VIxjX3x196z.txt HTTP/1.1
Host: data.sparkfun.com
Phant-Private-Key: 9YBaDk6yeMtNErDNq4YM
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 30

val1=post&val2=false&val3=98.6

----HTTP GET----
GET /output/VGb2Y1jD4VIxjX3x196z.csv HTTP/1.1
Host: data.sparkfun.com
Connection: close

----HTTP DELETE----
DELETE /input/VGb2Y1jD4VIxjX3x196z.txt HTTP/1.1
Host: data.sparkfun.com
Phant-Private-Key: 9YBaDk6yeMtNErDNq4YM
Connection: close