I'm creating an android app which takes in some json data, is there a way to set up a directory such as;
http://......./jsons/*.json
Alternatively, a way to add into a json file called a.json, and extend its number of containing array data, pretty much add more data into the .json file this increase its size.
It could be by PHP or Javascript.
Look into Parsing JSON, you can use the JSON.parse() function, in addition, I'm not sure about getting all your JSON files from a directory call, maybe someone else will explain that.
var data ='{"name":"Ray Wlison",
"position":"Staff Author",
"courses":[
"JavaScript & Ajax",
"Buildinf Facebook Apps"]}';
var info = JSON.parse(data);
//var infostoring = JSON.stringify(info);
One way to add to a json file is to parse it, add to it, then save it again. This might not be optimal if you have large amounts of data but in that case you'll probably want a proper database anyway (like mongo).
Using PHP:
$json_data = json_decode(file_get_contents('a.json'));
array_push($json_data, 'some value');
file_put_contents('a.json', json_encode($json_data));
Related
How can I create a function that loops through a folder in my directory called "data." It contains only image files, and I will keep adding more image files to it. Previously, I was using the following function that returns an array of URLs:
function _image_urls(){return(
[
"https://images.pexels.com/photos/4050284/pexels-photo-4050284.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
"https://images.pexels.com/photos/1323550/pexels-photo-1323550.jpeg?auto=compress&cs=tinysrgb&w=600",
"https://images.pexels.com/photos/2002719/pexels-photo-2002719.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
"https://images.pexels.com/photos/919606/pexels-photo-919606.jpeg?auto=compress&cs=tinysrgb&w=600",
"https://images.pexels.com/photos/1983038/pexels-photo-1983038.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
"https://images.pexels.com/photos/1702624/pexels-photo-1702624.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
"https://images.pexels.com/photos/3631430/pexels-photo-3631430.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
"https://images.pexels.com/photos/5011647/pexels-photo-5011647.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
"https://images.pexels.com/photos/135018/pexels-photo-135018.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
"https://images.pexels.com/photos/161154/stained-glass-spiral-circle-pattern-161154.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1"
]
)}
I'm trying to create a function that returns an array of paths for all the images in the data folder. I have been trying the following approach:
function _image_urls(){
const image_folder = 'data';
const image_extension = '.jpg';
let image_urls = [];
for (let i = 0; i < 10; i++) {
let image_url = image_folder + i + image_extension;
image_urls.push(image_url);
}
return image_urls;
}
It seems like this will just return an array like:
[
"data0.jpg",
"data1.jpg",
"data2.jpg",
"data3.jpg",
"data4.jpg",
"data5.jpg",
"data6.jpg",
"data7.jpg",
"data8.jpg",
"data9.jpg"
]
If that's what you're getting, then you need to use i as the index for an array that contains the file names.
The bigger question is how are you getting that list of files in the first place? This is generally not something that JavaScript can do on its own. If the files exist on the server, you'd need some server-side script to actually access the folder and output the array of file names - this can then be put into an array several ways (either writing it directly to the code if you allow your server side code to process the JS file or probably more likely using an XHR to request the file names and then populate the array when you get the response.)
If you write this server side script such that it formats the output as JSON, then it could simply be a matter of using JSON.parse() to convert the output to an array directly without any need to iterate over the response such as the function in the question.
EDIT/UPDATE after comment from OP:
Since you're using PHP on the server side, I would create a server side script that readers the contents of the "Data" folder and outputs a JSON formatted string which can then be parsed by the JS on the front end.
In general, this is done using the scandir function. See https://www.php.net/manual/en/function.scandir.php for details.
and the steps would be as follows:
Use scandir to get an array of files in the Data folder
Remove the first two items in the array (. and ..)
Use the json_encode function to convert the array to a JSON formatted string
Echo that string
Then on the page where you have your JS you have two options:
Include the PHP script described above such that it becomes a JS array using JSON.parse().
Use an XHR to request the PHP script, and when you get a response use JSON.parse() to set it as an array variable.
The first method is outdated, but very simple - though it does require that your JS code is parsed by PHP which may or may not be possible/advisable depending on your server configuration.
The second method is probably what you should do, as long as you're fine with the array being populated after the page loads and that you wait for the XHR to complete before calling any functions that rely on the array.
The main thing to know here is that what you want to do is not possible using only JavaScript because JS cannot read the contents of a folder on the server. Your JS will need to interact with some server side code in order to read the contents of a folder into any array.
my website relies on a database which is a big JSON file like this:
var myjsonData =
[ {
"ID": 0,
"name": "Henry",
"surname": "McLarry",
"...": "...",
}]
I do generate this data every month at high cost to me, therefore I would like to avoid calling it straight in my html <head>, because this will allow any user to download the full database in no time.
I would like to build a "something" that can only call specific items from the json file (just the only one I want to show) without "exposing" the full .json onto client side.
today I use the call
var myvar= myjsonData.ID.Name
to get "Henry" into myvar, I would like to build something like
var myvar = mycallfunction(ID,Name)
I did try with PHP as intermediary but the ajax calls from javacript doesn't allow me to fetch the data.
Can I use JQuery with the JSON Url to get only the item I need?
What you can do is parse your json for an object. So you can get any value you want from json.
Example:
var myjsonData = '{"ID": 0,"name": "Henry","surname": "McLarry"}';
obj = JSON.parse(myjsonData);
console.log(myjsonData.ID); //print the id
console.log(myjsonData.name); //print the name
console.log(myjsonData.surname); //print the surname
So you have a NoSQL Database which has only one kind of Document that is the full JSON element you use in your website. In that scenario you have three options:
Depending on the NoSQL Database you're using you can limit the fields which will be returned(I.e: For MongoDB you can look here: https://docs.mongodb.com/manual/tutorial/project-fields-from-query-results/)
Change the way you store you data into more modular documents and make the logic to connect them in you application. So instead of one big document you'll have modular ones as Users, Products, Transactions and etc and you can use your application to query them individually.
Build a Server Side logic as an API to deal with your data and provide only what you need, so the API(Which can be node.js, php, or any you may like) will get the full JSON it`s endpoints will only the data you want. For example: myapi.com/getUser, myapi.com/getProducts and so on.
If you're able to provide more info on the technologies you're using that would help us. Hope that helped :).
I have json file with given data (total.json)
var data = {"trololo":{"info":"61511","path".... }}
I need to get object "info" and then print data "61511" in alert window
I include my json like
var FILE = 'total'
var data_file_names = {};
data_file_names[FILE] = 'total.json';
And then i use it like
var data_trololo = data_file_names[FILE];
Plese, help me print object "info". Maybe there is another way to solve this problem
You need to make an ajax call to the json file. Then you can access the array like the below example.
Note : Your json wasn't properly formatted.
var data = {
"trololo":{
"info": ["61511","path"]
}
};
console.log(data.trololo.info[0]); //this one will print 61511
Usually one can make an ajax call to read the file on the server.
But if you are ok with using HTML5 features then go through the link find out how to read the file on the browser itself. Though File API being part of HTML5 spec is stable across browsers.
http://www.html5rocks.com/en/tutorials/file/dndfiles/
I query the db i my model like so
function graphRate($userid, $courseid){
$query = $this->db->get('tblGraph');
return $query->result();
}
My controller gets data back from my model and I json encode it like so
if($query = $this->rate_model->graphRate($userid, $courseid)){
$data['graph_json'] = json_encode($query);
}
$this->load->view('graph', $data);
And thats returns me a json object like so
[
{"id":"1","title":"myTitle","score":"16","date":"2013-08-02"},
{"id":"2","title":"myTitle2","score":"17","date":"2013-09-02"},
{"id":"3","title":"myTitle3","score":"18","date":"2013-10-02"}
]
In my view graph I'm loading an js file
<script type="text/javascript" src="script.js"></script>
Now I want to use $data that is being sent from my controller to my view, to my external script.js to use as labels and data to feed my chart. But How do I get that Json data to my external script.js so I can use it?
1 more thing about the json data, isn't it possible to get the output of the json data as
{
"obj1":{"id":"1","title":"myTitle","score":"16","date":"2013-08-02"},
"obj2":{"id":"2","title":"myTitle2","score":"17","date":"2013-09-02"},
"obj3":{"id":"3","title":"myTitle3","score":"18","date":"2013-10-02"}
}
The problem isn't a Codeigniter problem, it's a javascript scope/file inclusion/where-do-i-get-my-data-from problem.
I run into this all the time and have used these solutions:
naming my php files with .php extensions and loading them as if they're views.
Just putting the script that needs data from a view IN the view file where it's used
Using an ajax request in my included js file to hit a controller and get json data.
I use #2 most frequently (for things like datatables where I WANT the js code right there next to the table it's referencing.
I use #1 occasionally, but try NOT to do that because it means some .js files are in my webroot/js dir and some are in teh application/views directory, making it confusing for me or anyone else who wants to support this project.
#3 is sometimes necessary...but I like to avoid that approach to minimize the number of requests being made and to try to eliminate totally superfluous requests (which that is).
You need to print the result of the output json string to the html generated file.
But you need to parse the string with some script. I would recommend you: http://api.jquery.com/jQuery.parseJSON/
For the second question. It is possible by doing:
$returnValue = json_encode(
array (
"obj1" => array("id"=>"1","title"=>"myTitle","score"=>"16","date"=>"2013-08-02"),
"obj2" => array("id"=>"2","title"=>"myTitle2","score"=>"17","date"=>"2013-09-02"),
"obj3" => array("id"=>"3","title"=>"myTitle3","score"=>"18","date"=>"2013-10-02"),
)
);
Print the output using PHP like:
echo json_encode($query);
Then from the client-side (where JavaScript resides) load that JSON that you printed using PHP. This can be done easily using JQuery.
Like this:
$.get("test.php", function(data) {
alert("Data Loaded: " + data);
});
You can find more information about this here: http://api.jquery.com/jQuery.get/
Now you'll need to parse this data so that JavaScript can understand what you got as text from the server. For that you can use the JSON.parse method on the "data" object in the aforementioned example. Once parsed, you can use the object like any other object in JavaScript. You can find more information about JSON.parse here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse
I hope that helps.
Here's something I want to learn and do. I have a JSON file that contains my product and details (size, color, description). In the website I can't use PHP and MySQL, I can only use Javascript and HTML. Now what I want to happen is using JQuery I can read and write a JSON file (JSON file will serve as my database). I am not sure if it can be done using only JQuery and JSON.
First thing, How to query a JSON file? (Example: I would search for the name and color of the product.)
How to parse the JSON datas that were searched into an HTML?
How to add details, product to the JSON file?
It will also be great if you can point me to a good tutorial about my questions.
I'm new to both JQuery and JSON.
Thanks!
Since Javascript is client side, you won't be able to write to the JSON file on the server using only Javascript. You would need some server side code in order to do that.
Reading and parsing the JSON file is not a problem though. You would use the jQuery.getJSON function. You would supply both a url and a callback parameter (data isn't needed, because you're reading a file, so no need to send data). The url would be the path to your JSON file, and the callback would be a function that uses the data.
Here's an example of what your code might look like. I don't know exactly what your JSON is, but if you have a set called "products" containing a set of objects with the details "name" and "price", this code would print those out:
$.getJSON("getProductJSON.htm",
function(data) {
$.each(data.products, function(i, item) {
var name = item.name;
var price = item.price;
// now display the name and price on the page here!
});
},
);
Basically, the data variable in $.getJSON makes the entire contents of the JSON available to you, very easily. And the $.each is used to loop over a set of JSON objects.