d3 Fetch Parameter

[stutr...@gmail.com]

Hi Folks,

I know this is more d3 but does anyone know how to pass a parameter with d3 fetch?

Normally I just use this:

d3.json("dataset.php").then(function(dataSet) {

//dc stuff here

});

But i'm using a (separate) Select to pick an item which I then want to pass to the above.

My latest attempt is:

d3.json("dataset.php", {

  method: "POST",

  headers: {

    'Accept': 'application/json',

    'Content-Type': 'application/json'

  },

  body: "selectedItem= selectedItem  "

}).then(function(dataSet) {

//dc stuff here

});

dataset.php is :

<?php

$hostname_base = "localhost";

$username_base = "un";

$password_base = "pw";

$database_base = "db";

$connection = mysqli_connect($hostname_base,$username_base,$password_base,$database_base) or die("Error " . mysqli_error($connection));

$selectedItem = $_POST['selectedItem'];

 $sql = "SELECT * from myTable WHERE item = '".$selectedItem."' ";

$result = mysqli_query($connection, $sql) or die("Error in: " . mysqli_error($connection));

$emparray = array();

    while($row =mysqli_fetch_assoc($result))

    {

        $emparray[] = $row;

    }

    echo json_encode($emparray);

    mysqli_close($connection);

?>

With ajax I would normally do this:

$.ajax({

url: 'dataset.php',

type: 'POST',

dataType: "json",

data: {

selectedItem:  selectedItem

},

Thanks all

[Gordon Woodhull]

That looks about right, you might try

"Content-Type": "application/x-www-form-urlencoded"

or change the body to json.

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[stutr...@gmail.com]

Thanks for the info Gordon.

In the end I modified in line with the method here.

For completeness this is what I ended up with (I left the iteration in place in case I needed to add other params later):

var data = {selectedItem:selectedItem};

var fd = new FormData();

for(var i in data){

   fd.append(i,data[i]);

}

d3.json("data/dataset.php", {

 method:"POST",

   body:fd,

   mode:"cors",

 }).then(function(dataSet) {

//dc stuff here

});

[Gordon Woodhull]

Thanks for following up and posting your solution!

Good point: as mentioned in the Q&A you linked, it depends on what content types your server can parse. And the body must match the specified content type.

The default content type is FormData - probably the oldest format and most supported.

On Dec 15, 2020, at 7:56 AM, stutr...@gmail.com <stutr...@gmail.com> wrote:

Thanks for the info Gordon.

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