Develop module with API

htilburgs

Hi all,
Let me start saying, I’m a new MM enthousiast. I’ve several ideas for a new MM Module, but I’m not a programmer. I can read the javascript en mostly I understand how it works, but writing my own is going to be the first time.

I like to build one from scratch and started with Head first developing mm module for extreme beginners.

Now I’m trying to go further and in particular using an API to:

Get data from a site (in JSON format)
Extract the correct data from the JSON result
Display the extracted data nicely in de module

I’m reading Javascript for Dummies, I’ve been looking on the forum and looking into existing modules, but I’m not getting there. The question is:

Is there a template or are there sites/instructions on how to get started with what I like to do so, I can get started and figure it out (with or without the awesome support of this forum? I hope to hear from somebody!

@htilburgs
You need to check this first.

Does API exist? (First, API should exist, of course there could be many tricks without API - screen scrapping, crawling, … but could be hard for novice.)
Is API opened publicly or reachable? (Some APIs are blocked or limited. By example, To use Some Apple related things, you should be registered as a devloper with payment. In that case, that module will have some barrier to other ppl to use)

The design of each API is very different each other. So, there is no royal road to use API basically.
The best practice is analyzing other’s module. Many MM modules are using various APIs.
Describe here what API to use, and jump headfirst. Ppl will help you gladly.

Mykle1

@htilburgs

Have a look at this. It is a very simple module meant to teach someone to do exactly what you described in your post.

https://github.com/mykle1/MMM-UFO

htilburgs

Thanks for the reply.
I’ve an api for getting the Prayer Times.

http://api.aladhan.com/v1/timings/19-03-2019?latitude=51.508515&longitude=-0.1254872&method=2

In this case there a 4 parameters: date, latitude, longitude and method.
The result is a json file

{"code":200,"status":"OK","data":{"timings":{"Fajr":"04:34","Sunrise":"06:06","Dhuhr":"12:08","Asr":"15:23","Sunset":"18:11","Maghrib":"18:11","Isha":"19:44","Imsak":"04:24","Midnight":"00:09"},"date":{"readable":"19 Mar 2019","timestamp":"1552953600","hijri":{"date":"12-07-1440","format":"DD-MM-YYYY","day":"12","weekday":{"en":"Al Thalaata","ar":"\u0627\u0644\u062b\u0644\u0627\u062b\u0627\u0621"},"month":{"number":7,"en":"Rajab","ar":"\u0631\u064e\u062c\u064e\u0628"},"year":"1440","designation":{"abbreviated":"AH","expanded":"Anno Hegirae"},"holidays":[]},"gregorian":{"date":"19-03-2019","format":"DD-MM-YYYY","day":"19","weekday":{"en":"Tuesday"},"month":{"number":3,"en":"March"},"year":"2019","designation":{"abbreviated":"AD","expanded":"Anno Domini"}}},"meta":{"latitude":51.508515,"longitude":-0.1254872,"timezone":"Europe\/London","method":{"id":2,"name":"Islamic Society of North America (ISNA)","params":{"Fajr":15,"Isha":15}},"latitudeAdjustmentMethod":"ANGLE_BASED","midnightMode":"STANDARD","school":"STANDARD","offset":{"Imsak":0,"Fajr":0,"Sunrise":0,"Dhuhr":0,"Asr":0,"Maghrib":0,"Sunset":0,"Isha":0,"Midnight":0}}}}

I like to filter on the first object “timings” (Fajr until Midnight) and present this information in a table on the Mirror (HTML layout comes later)

I’ve been looking in other modules and trying to learn, but some use node_helper, some don’t and I’m a littlebit stuck right now.

@htilburgs
If your API can be reached simply (without authentification, or any other dependencies), You can use xmlHttpRequest to get contents of specific URL in your main module js.
When you need that result of API, Use this logic. (It’s better to make function. but here is just example)

var url = "http://api.aladhan.com/......"
var req = new XMLHttpRequest()
req.overrideMimeType("application/json")
req.open('GET', url, true)
req.onload  = () => {
   var jsonResult = JSON.parse(req.responseText)
   // do your job with jsonResult
   console.log(jsonResult)
}
req.send()

See https://www.w3schools.com/xml/xml_http.asp to learn about XMLHttpRequest

@htilburgs
Then, you can access the jsonData like this; (This will be your main job)

...
var Fajr = jsonResult.data.timings.Fajr
console.log(Fajr)

last, you can print it MM screen with .getDom()(You should call .updateDom() to update screen) or DOM manipulation.

...
this.dataToShow.Fajr = jsonResult.data.timings.Fajr
...


getDom : function() {
  var dom = document.createElement("div")
  if (this.dataToShow) dom.innerHTML = this.dataToShow.Fajr
  return dom
},

I’m skipping many things. This is just hint or sample. Remains will be your homework.

htilburgs

@Mykle1 @Sean
Both thanks for the quick reply.
For now I’ve information that I can use to start.
If there are any questions, I know where to be

htilburgs

I used the example from MMM-UFO, and started the module.
How can I check if there is data from the API URL?

htilburgs

Oke, got it. I had to add some console.log settings…

htilburgs

@Mykle1 I’m using MMM-UFO as example and trying to figure out. I’m getting somewhere but… The data is retrieved through the api and this is the result:

Asr: "16:01"
Dhuhr: "12:46"
Fajr: "05:12"
Imsak: "05:02"
Isha: "20:21"
Maghrib: "18:49"
Midnight: "00:46"
Sunrise: "06:44"
Sunset: "18:49"

The module is generated on the MM

alt text

But as you can see, it cannot read or display the data in the correct way.
This is the code that I use to get the data from the resultset.

// Fajr from data
var mptFajr = document.createElement("div");
mptFajr.classList.add("small", "bright", "fajr");
mptFajr.innerHTML = "Fajr : " + MPT.Fajr;
wrapper.appendChild(mptFajr);

I can’t figure out what the problem is. It seems have something to do with the time-string that is returned. But whatever I try, no luck. Any idea?