Converting Nsarray -> JSON -> Nsdata -> PHP Server ->JSON Representation

Converting NSArray - JSON - NSData - PHP server -JSON representation

Turns out I needed to do it like this:

To Create My data:

NSMutableArray *arrayOfDicts = [[NSMutableArray alloc] init];

for (int i = 0; i < 2; i++) {
    NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
                                  @"MySong", @"title",
                                  @"MyArtist", @"artist",
                                  nil];
    [arrayOfDicts addObject:dict];         
}
 NSArray *info = [NSArray arrayWithArray:arrayOfDicts];

And Sent it like this:

NSData *jsonData = [NSJSONSerialization dataWithJSONObject:info 
          options:NSJSONWritingPrettyPrinted error:&error];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

    // Start request
    NSURL *url = [NSURL URLWithString:@"http://www.mywebsite.com/index.php"];
    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
    [request setPostValue:jsonString forKey:@"songs"];
    [request setDelegate:self];
    [request startAsynchronous];

The key was to convert the info to NSData, then to a JSON String which I sent to my server, not just sending the raw NSData.

Thanks everyone for the help!

Convert result_array() to JSON object

Try to return the query result not result_array

model function

function getRecords(){
   $sql = 'SELECT * FROM table';
   $query = $this->db->query($sql);
   return $query->result();
}

Convert to json

$object = getRecords();
$json_obj = json_encode($object);

How do I receive a JSON object from PHP backend and convert to JavaScript array for frontend

ok so with some of the answers and a little more experimenting this is what I have and its a start to the rest of the solution

I changed this line

 this.setState({data:response})

 this.setState({data:response.data})

and changed the render to this

  render() {
    const {data} = this.state
    let result = [];
    Object.values(data).map(num =>
      result.push(num)
     );
    return (
          <div>
            {result.map(tile => 
             `<div><img src='${tile.image}'/></div>` 
              )}
          </div>
      )
  }

Representing null in JSON

Let's evaluate the parsing of each:

http://jsfiddle.net/brandonscript/Y2dGv/

var json1 = '{}';
var json2 = '{"myCount": null}';
var json3 = '{"myCount": 0}';
var json4 = '{"myString": ""}';
var json5 = '{"myString": "null"}';
var json6 = '{"myArray": []}';

console.log(JSON.parse(json1)); // {}
console.log(JSON.parse(json2)); // {myCount: null}
console.log(JSON.parse(json3)); // {myCount: 0}
console.log(JSON.parse(json4)); // {myString: ""}
console.log(JSON.parse(json5)); // {myString: "null"}
console.log(JSON.parse(json6)); // {myArray: []}

The tl;dr here:
The fragment in the json2 variable is the way the JSON spec indicates null should be represented. But as always, it depends on what you're doing -- sometimes the "right" way to do it doesn't always work for your situation. Use your judgement and make an informed decision.

JSON1 {}

This returns an empty object. There is no data there, and it's only going to tell you that whatever key you're looking for (be it myCount or something else) is of type undefined.

JSON2 {"myCount": null}

In this case, myCount is actually defined, albeit its value is null. This is not the same as both "not undefined and not null", and if you were testing for one condition or the other, this might succeed whereas JSON1 would fail.

This is the definitive way to represent null per the JSON spec.

JSON3 {"myCount": 0}

In this case, myCount is 0. That's not the same as null, and it's not the same as false. If your conditional statement evaluates myCount > 0, then this might be worthwhile to have. Moreover, if you're running calculations based on the value here, 0 could be useful. If you're trying to test for null however, this is actually not going to work at all.

JSON4 {"myString": ""}

In this case, you're getting an empty string. Again, as with JSON2, it's defined, but it's empty. You could test for if (obj.myString == "") but you could not test for null or undefined.

JSON5 {"myString": "null"}

This is probably going to get you in trouble, because you're setting the string value to null; in this case, obj.myString == "null" however it is not == null.

JSON6 {"myArray": []}

This will tell you that your array myArray exists, but it's empty. This is useful if you're trying to perform a count or evaluation on myArray. For instance, say you wanted to evaluate the number of photos a user posted - you could do myArray.length and it would return 0: defined, but no photos posted.

Pretty-Printing JSON with PHP

PHP 5.4 offers the JSON_PRETTY_PRINT option for use with the json_encode() call.

https://php.net/manual/en/function.json-encode.php

<?php
...
$json_string = json_encode($data, JSON_PRETTY_PRINT);

Convert JSON string to an array in JavaScript

One option is to use eval:

var arr = eval('(' + json_text + ')');

The above is easiest and most widely supported way of doing this, but you should only use eval if you trust the source as it will execute any JavaScript code.

Some browsers have a native JSON parser in which case you can do the following:

var arr = JSON.parse(json_text);

Third-party libraries such as jQuery can also provide functions for dealing with JSON. In jQuery, you can do the following:

var arr = jQuery.parseJSON(json_text);

The bottom two methods (which use a parser) are preferred as they provide a level of protection.

Binary Data in JSON String. Something better than Base64

There are 94 Unicode characters which can be represented as one byte according to the JSON spec (if your JSON is transmitted as UTF-8). With that in mind, I think the best you can do space-wise is base85 which represents four bytes as five characters. However, this is only a 7% improvement over base64, it's more expensive to compute, and implementations are less common than for base64 so it's probably not a win.

You could also simply map every input byte to the corresponding character in U+0000-U+00FF, then do the minimum encoding required by the JSON standard to pass those characters; the advantage here is that the required decoding is nil beyond builtin functions, but the space efficiency is bad -- a 105% expansion (if all input bytes are equally likely) vs. 25% for base85 or 33% for base64.

Final verdict: base64 wins, in my opinion, on the grounds that it's common, easy, and not bad enough to warrant replacement.

Converting Nsarray -> JSON -> Nsdata -> PHP Server ->JSON Representation