Question

I have to write a script which will be hosted on differents domains. This script has to get information from my server.

So, stackoverflow’s user told me that i have to use JSON-P format, which, after research, is what i’m going to do. (the data provided in JSON-P is for displaying some information hosted on my server on other website)

1. How do I output JSON-P from my server ? Is it the same as the json_encode function from PHP

2. How do i design the tree pattern for the output JSON-P
   (you know, like : ({“name” : “foo”, “id” : “xxxxx”, “blog” : “http://xxxxxx.com“});
   can I steal this from my XML output ? (http://bit.ly/9kzBDP)

3. Each time a visitor browse a website on which my widget is it’ll make a request on my server, requesting the JSON-P data to display on the client side.
   It’ll increase dramatically the CPU load (1 visitor on the website who will have the script = 1 SQL request on my server to output data), so is there any way to ‘caching’ the JSON-P information output to refresh it only one or twice a day and stores it into a ‘file’ (in which extension?).

BUT on the other hand i would say that requesting the JSON-P data directly (without caching it) is a plus, because, websites which will integrates the script only want to display THEIR information and not the whole data. So, making a script with something like that:

jQuery.getJSON("http://www.something.com/json-p/outpout?filter=5&callback=?", function(data) {
................);
});

Where filter= the information the website wants to display.

• Bonus question : do I have to use a JS framework to read JSON-P ? or JS pure without any framework to include on the page can do that ?

What do you think ?

Thank you very much
😉

Answer 1

JSONP request

$.ajax({
  type: "get",
  dataType: "jsonp",
  url: "mothership.com/widget_data",
  data: {whatever: "here", requested_from: "someonesblog.com" },
  cache: true,
  success: function(data, textStatus, XMLHttpRequest){
    // respond to ajax call here

    // debug: make sure your data is getting loaded properly
    console.log(data);

    // do other necessary things here
  }
});

Encode and Output JSON from server

<?php
  header("Content-Type: application/json");

  # You can access data from the jQuery.ajax() call with $_GET here

  $data = array(
    "name" => "foo",
    "id"   => 1234,
    "blog" => $_GET["requested_from"]
  );
  echo $_GET["callback"] . "(" . json_encode($data). ");" ;

  # this will output something like
  # jsonp1255285823({"name":"foo","id":1234,"blog":"someonesblog.com"});

  exit;
?>