从PHP转换为JSON文件

Question

I am a Laravel learner. What I am trying to learn now is to send a JSON file from a back end into the front-end, so that I will use this JSON file to draw a graph.

In my model, I write a function that will extract the values and time stamp created_at . Here is a piece of code that will return the google page speed value associated with a single website and the time stamp.then I want to use JS to draw the graph where the vertical value is the google page speed and the horizontal is the time stamp created at .

Anyone who can help me? Do I need to change the return value to an array?

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Notification;
use App\Status;

class ChartController extends Controller
{

     public  function speedHistory(){

        $o_status = Status::where('name','speed')->first();
        $o_response = $this->statuses()->where('status_id', $o_status->id)
        ->select('values AS value', 'created_at AS timestamp')->orderBy('created_at','DESC')->get();


        if($o_response){
            return response()->json($o_response);
        }
            // return an empty json array instead of false
            //return false;
        return response()->json(array());
    }
}

and trhe route is

Route::get('json','ChartController@speedHistory');

keeps complaining the methods is not defined. this is my model lass Notification extends Model { protected $fillable = ['id','website_url','email','slack_channel','check_frequency','alert_frequency','speed_frequency','active'];

public function statuses(){
    return $this->belongsToMany('App\Status')->withPivot('values')->withTimestamps();
}

Answer 1

To improve on my answer, you will need to return 'response()->json()' which will change the content type to json, essentially making the response a so called "JSON file".

Can you try this? I think you are trying to get values and created_at from a collection which should not work. I assume you use L5, see Danis Abols comment otherwise.

public function speedHistory(){
    $o_status = Status::where('name','speed')->first();
    $o_response = Notification::where('status_id', $o_status->id)
    ->select('values AS value', 'created_at AS timestamp')->orderBy('created_at','DESC')->get();

    if($o_response){
        return response()->json($o_response);
    }
// I would return an empty json array instead of false
//return false;
return response()->json(array());
}

Update: added Notification:: based on comments from op

Answer 2

In your function:

public function speedHistory(){

 try{ 

       $o_speed = Status::where('name','speed')->first();
       $o_response = $this->statuses()->where('status_id', $o_status->id)
    ->select('values', 'created_at')->orderBy('created_at','DESC')->get();

       if($o_response === null)
//You can use this to go in catch: "throw new Exception();" or "return false" if you want
              throw new Exception();

      // Returns a json to be consumed in ajax
      return response()->json(['status' => 1, 'code' => 200, 'message' => 'Your message', 'value' => $o_response->values, 'timestamp' => $o_response->created_at], 200);
    }catch(\Exception $e){
      return response()->json(['status' => 0, 'code' => 400, 'message' => $e->getMessage()], 400);
    }

In your ajax you consume this way:

var request = $.ajax({
// Here's your route of speedHistory
  url: "YOUR_ROUTE",
  type: "GET",
  dataType: "json"
});

request.done(function(response) {
    if(response.status == '1'){
         $("#youDiv").html(response.value + ' - ' + response.timestamp);
     }
});

request.fail(function(jqXHR, textStatus) {
  alert( "Request failed: " + textStatus );
});

Answer 3

You could use the json() method on response() .

The json method will automatically set the Content-Type header to application/json , as well as convert the given array to JSON using the json_encode PHP function:

$array = ['data'];
return response()->json($array);

Laravel Documentation (json-response)

Answer 4

尝试这个

return json_encode(array('value' => $o_response->values,'timestamp' => $o_response->created_at));