As seen here: https://anidiots.guide/coding-guides/storing-data-in-a-json-file.html
It shows you how to create a point system in discord.js. But what caught my eye is how they used let points = JSON.parse(fs.readFileSync("./points.json", "utf8"));
to read the file. So i am trying to learn how to make a database where i get the points plus money that can be redeemed daily and shared. kinda like a bank. but i don't know how to do that. If anyone could help me with a hastebin link or anywhere i can learn in depth how to use the JSON.parse(fs.readFileSync("./points.json", "utf8")); thing.
and if you want to see my bot in action don't hesitate to use https://discord.me/knut
The line you're asking about is made of two call to the functions JSON.parse and fs.readFileSync.
JSON.parse. This function receives a bunch of text and transform it (parse it) into a javascript object. It can be very useful when you want to, for example, build something dynamically based on the content of a file. Maybe w3school is a good place to start looking for info about it.
Example
var string = "{id: 4, name:'Volley'}"
var parseObject = JSON.parse(string)
console.log(parseObject.id); //4
console.log(parseObject.name); //Volley
fs.readFileSync. As you probably know, most of the functions in javascript and node.js are asynchronous, that is, instead of calling and get the returned value, you have to define a callback within which you would use the value you want. fs.readFileSync is just the synchronous version of fs.readFile(callback), which returns the content of the read file. Here you have the docs about that function.
These functions are actually simple to use, you should struggle in finding some examples or trying them by yourself.
If you want to imitate what the tutorial said, then you would need to define another file, with the money of each point, or edit the first file if you can, so you could an object like
var point_and_money = {
points : [...],
money : [....]
}
or two objects with the separate information
var points = JSON.parse(fs.readFileSync("./points.json", "utf8"));
var money = JSON.parse(fs.readFileSync("./money.json", "utf8"));
Hope I gave you a hint about what you asked
not really sure what you are trying to achieve?
JSON.parse(fs.readFileSync("./points.json", "utf8"));
This line reads a json file and parse it to a Javascript-Method. Nothing less and nothing more. this can also be done in Nodejs via
var points = require('./points.json');
You mentioned something like how to do a database? Basically I am not sure if you want to develop a database or better use an existing one. Look for MongoDB, SQLLite,IndexedDB, etc. There a tons of database for almost every use case.
Remember that your line of code reads synchronous in a blocking way when the file gets large.
And when multiple users would access the file at the same time you need to handle this somehow. So definitely would suggest to look for some existing database solution and have more time to focus on your business logic.
I hope I understand your question correct and my answer helps.
Maybe this one is also a good question to start: Lightweight Javascript DB for use in Node.js
Related
I know I might be asking something quite simple but for the life of me I can't seem to get my head around this and I'm definitely overseeing something simple but I don't know what. Any help would be very appreciated.
I'm generating a static site using Hugo. On one of my pages, I want to create something like a progress bar, using a variable which I need to get from a file from a Github Gist.
Say this is the gist: https://gist.github.com/bogdanbacila/c5a9683089c74d613ad17cdedc08f56b#file-thesis-words-txt
The file only has one number, that's it. What I'm asking is how to get that number from the gist and store it in hugo or at least just display it in some raw html. I want to mention that I'm not looking to use the provided embedded text, I'd rather just get the raw value. At the end of the day all I need is to read and display the number from the raw link here: https://gist.githubusercontent.com/bogdanbacila/c5a9683089c74d613ad17cdedc08f56b/raw/8380782afede80d234209293d4c5033a890e44b6/thesis-words.txt
I've asked this question on the Hugo forum and that wasn't very helpful, instead of providing me with some guidance I got sent here. Here was my original question: https://discourse.gohugo.io/t/get-raw-content-from-github-gist-to-a-variable/38781
Any help would be greatly appreciated, I know there's something very obvious which I'm not seeing, please guide me to the right direction, this doesn't feel like it should be that complicated.
Best,
Bogdan
You could fetch this data and store it in Hugo as a data file but I don't recommend it.
Since Hugo is a static site generator, you would need to not only modify the data files in your repo every time the value changes, but re-build your site as well. Then you have to worry about running the script on a schedule. Meaning you can't be sure that the value is current the second someone visits your site. This is more headache than it's worth in my opinion.
The better route would be to write some client-side JavaScript that makes a call to the raw URL of the gist to get the content. This is Hugo-agnostic which is why I suspect you were pointed here.
From the Gists API docs:
If you need the full contents of the file, you can make a GET request to the URL specified by raw_url.
You can use something like the Fetch API for this or any other JS client. Simply make a GET request to the URL, parse the value from the response body, and write some JavaScript to insert the value in the DOM when someone makes a request to the page it's on.
#wjh18
Cheers! I didn't know about GET requests so I had to dig around for that a little bit but I managed to get it going with this:
<script>
fetch('https://gist.githubusercontent.com/bogdanbacila/c5a9683089c74d613ad17cdedc08f56b/raw').then(function(response) {
return response.json();
}).then(function(data) {
console.log(data);
}).catch(function() {
console.log("Booo");
});
</script>
I guess this is as much a call to attention on the fact that the documentation seems to be outright incorrect in its application, as well as just generally lacking. Normally, I would send that part of the message to them personally, but, their contact form is also giving me errors and not sending, so it's not like I have the means to anyway. In the mean time, I'm more worried about getting this code to work, so hopefully someone experienced with this SDK or an Image4io team member sees this and can provide a public answer for others stumbling into this road block.
For starters, I initialized the Image4io object as described in the github here: https://github.com/Image4IO/image4ionodeSDK/
website documentation: https://image4.io/en/documentation/api-sdk/#operation/UploadImage
The image upload example provided on the website's documentation looks like this:
let client=new Image4ioAPI.Image4ioAPI(apiKey,apiSecret);
var request = new Models.UploadImagesRequest("/folderName", true, true);
request.Add("/path/to/image/location/name-of-the-image.jpg", "name-of-the-image", "name-of-the-image.jpg");
let response=client.UploadImage(request);
3 out of the very sparse 4 lines of code they provide give errors. Where did this Models object come from? There is no corresponding class in the import and the code example obviously doesn't show where it was defined. Just what is it and where did it come from?
Well, I found a matching function "UploadImagesRequest" in the original import class, so my guess is Models was deprecated and its functionality was moved into the Image4io class object. If that was the case the solution would be to simply access that function instead... But it's not used the same. It has 4 arguments, the 4th being a "Image4io.UploadFile[]" type. This type has no use examples in the documentation or further details describing what it is exactly. I assume image byte data goes in there somehow, but how?
Finally we have request.Add... except we don't because that isn't a function :( it looks like this was used to actually get the image data (maybe of the type UploadFile?) based on the path of the image. If this function is gone now, how do get file data for use in the upload request function?
Any and all help in figuring out this SDK would be greatly appreciated. Google searches yielded no meaningful results, so hopefully we can help in that department as well. For all I know I just got the wrong version somehow. I guess I could try downgrading to a version that matches the documentation but... that's not a fix in my eyes at all.
Let me know if there's any more info I could provide to help
You can upload image like this:
var client=new Image4ioClient(API_KEY,API_SECRET);
var files=Array();
files.push(new UploadFile("./test.jpg","test.jpg"));
client.UploadImage(new UploadImagesRequest("/",true,false,files))
.then(res=>console.log(res))
If you have binary data at hand, you can write it to a temporary file and then upload them.
I'm relatively new to both JavaScript and Discord.JS and I'm stuck on a little thing that is giving me a serious headache.
The bot should be able to do the following:
store a message (after a certain prefix) in a variable
pass it to an array in a JSON file
where the message is converted to a (given) number and stored in a new variable in the first JS file.
I explicitly do not ask for any finished code (including code skeletons), as I cannot learn anything from it and it would be useless in the end. All I want are maybe tips on how to realize this. :)
I hope the whole thing is at least somehow understandable, if not, I would be happy to explain details in more detail!
For one of our Insights platform, we plan to generate summary SQLite3 databases in the background and let it be rendered on the browser as charts. Currently, we are intending to a server-side endpoint that will service the data requirement.
We are looking to optimize this further by eliminating the server-side endpoint altogether. We are fine (from a security perspective) to expose the SQLite3 directly on S3 and have a javascript module read and generate the charts.
The SQLite3 files are expected to fairly small - perhaps 4-6 columns and perhaps 10-500 rows of data, and all of them containing one table only. Test runs indicate file sizes of less than 15KB.
We don't intend to write or manipulate the SQLite3 on the browser.
We don't need to cache it on the browser as a WebSQL or an IndexedDB form, but we are ok with using them if that is what is needed.
From my web searches, We are unable to find a Javascript library that can read a SQLite3 file and query it for results. If you know of any javascript libraries that can do this, then please let us know.
On the other hand, if you think that we shouldn't be doing this for whatever reason, then please throw them as comments/answers too, because this is something we are trying for the first time and seems a little out-of-the-box, so feedback welcome!
There is a javascript library called sql.js that can do exactly what you want. In your case, you would use it like that
const SQL = await initSqlJs(options);
const fetched = await fetch("/path/to/database.sqlite");
const buf = await fetched.arrayBuffer();
const db = new SQL.Database(new Uint8Array(buf));
const contents = db.exec("SELECT * FROM my_table");
// contents is now [{columns:['col1','col2',...], values:[[first row], [second row], ...]}]
See the documentation on sql-js.github.io/sql.js/documentation/
I can not tell the best, but one: Write a JavaScript SQLite reader library yourself. This will be a tedious task, but I am sure it can be done. Some cool folks have done pdf.js, which is a JavaScript renderer for PDF files, which are also binary BLOB's like SQLite files are.
You will most probably start with the FileReader API to walk thru the SQLite file, then create some in-memory representation of the content, which your chart tool can use.
Disclaimer: You probably want to solve your initial problem with another solution, as proposed by others, but this answers your question.
I'm trying to wrap my head around Node.js streams, not that I'm pretty new to JavaScript and node, the last languages I really got were Perl and PHP :-D
I've read the Buffer/Streams documentation # nodejs.org, watched James Halliday # LXJS, read his stream-handbook and Thorsten Lorenz event-stream post. I start to understand the basics :)
I process data which is serialized in RDF (which is neither JSON nor XML). I manage to fetch the data (in real code via request) and parse it into a JS object using rdfstore module.
So far I do this:
s.createReadStream('myRDFdata.ttl').pipe(serialize()).pipe(process.stdout);
Where serialize()does the job of parsing an serializing the code at the same time right now. I use through module to interface to the stream.
Now I have some more methods (not the real function declaration but I hope you get the point):
getRecipe(parsedRDF) -> takes the parsed RDF (as a JavaScript object) and tells me how to use it
createMeal(parsedRDF, recipe) -> takes the parsed RDF and the recipe from above and creates a new RDF object out of it
this new object needs to get serialized and sent to the browser
(In the real world getRecipe will have to do a user interaction in the browser)
I like the idea of chaining this together via pipes for higher flexibility when I enhance the code later. But I don't want to serialize it to a RDF serialization every time but just send around the JS object. From what I've read in the documentation I could use the stringify module to get a string out of each step for piping it to the next step. But:
does this actually make sense? In terms of do I add unnecessary overhead or is this negligible?
I don't see how I could give the parsedRDF to both methods with the dependency that getRecipe would have to be called first and the output is input for createMeal as well. Are there modules which help me on that?
It might be that I have to ask the user for the final recipe selection so I might need to send stuff to the browser there to get the final answer. Can I do something like this over sockets while the pipe is "waiting"?
I hope this shows what I'm trying to do, if not I will try to give more details/rephrase.
Update: After sleeping over it I figured out some more things:
It probably doesn't make sense to serialize a format like RDF into something non-standard if there are official serialization formats. So instead of using stringify I will simply pass an official RDF serialization between the steps
This does imply that I parse/serialize the objects in each step and this surely does add overhead. Question is do I care? I could extend the RDF module I use to parse from stream and serialize into one
I can solve the problem with the dependency between getRecipe and createMeal by simply adding some information from getRecipe to parseRDF, this can be done very easily with RDF without breaking the original data model. But I would still be interested to know if I could handle dependencies like this with pipes
yes, It's okay to make a stream of js objects,
you just have to remember to pipe it through something that will serialize the stream again after before writing it to IO.
I'd recomend writing a module called rdfStream that parses and serializes rdf, you would use it like this
var rdf = require('rdf-stream')
fs.createReadStream(file) //get a text stream
.pipe(rdf.parse()) //turn it into objects
.pipe(transform) //optional, do something with the objects
.pipe(rdf.stringify()) //turn back into text
.pipe(process.stdout) //write to IO.
and it could also be used by other people working with rdf in node, awesome!