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I'm looking to get some input on how to make modular code that performs a PHP parse_ini_file and then uses the returned values to run JSON decodes.

I have a BACnet API that returns a JSON structure for BACnet points in an automation system. I wrote the following code to decode the JSON data to return just the "present-value" field and then I display the value on a webpage.

<?php 
$url = "http://hostname.lcl:47800/api/v1/bacnet/devices/10100/objects/0.0";
$json = file_get_contents($url);
$json_data = json_decode($json, true);
echo "<b>Room temperature</b>: ". $json_data["present-value"]. " DEG F";
;?>

This works well but I want to make this code modular so it can be used for many other points.

I created an INI file with a list of other points and the URL that contains the JSON data from the API. 

## BACnet Configuration File
# BACnet Object URLs from WACNET Browser API
[bacnet]
SEA_RMT                     = http://hostname.lcl:47800/api/v1/bacnet/devices/10100/objects/0.0
SEA_SRV_SEA_SV1_01_EXHT     = http://hostname.lcl:47800/api/v1/bacnet/devices/10100/objects/0.3
SEA_SRV_SEA_SV1_02_EXHT     = http://hostname.lcl:47800/api/v1/bacnet/devices/10100/objects/0.4
SEA_SRV_SEA_SV1_03_EXHT     = http://hostname.lcl:47800/api/v1/bacnet/devices/10100/objects/0.5

What I'd like to do is use the INI file to get the present value of each point in the list and then create a variable that is the name of the point and set it equal to the "present-value" field. Then I can reference the point using the PHP variable on the HTML page like this:

<?php echo "$SEA_SRV_SEA_SV1_01_EXHT";?>

I started with the code below but it doesn't work. 

<?php

// Parse the settings file
$bacnetini = parse_ini_file('/var/www/config/bacnet.ini');

// Parse the keys to variables and add data
foreach ($bacnetini as $key => $value) {
    $url = $value;
    $json = file_get_contents($url);
    $json_data = json_decode($json, true);
    $$key = $json_data; 
}

?>

I'd love to get some other opinions on the best way to accomplish this since I don't really know where to go from here.

I've looked through these other Stack Overflow questions but I don't know how to get the pieces to all fit together.

Community
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Taylor V
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  • Using variable variables like `$$key` is rarely a good idea, because you have no idea what they might be called without looping through the keys of `$bacnetini` again.... why not simply build an array? – Mark Baker Dec 24 '16 at 19:16
  • Thanks Mark. How could I use an array instead? Can you elaborate more? – Taylor V Dec 24 '16 at 19:36
  • Define the array as an empty array before your loop (`$bacnetData = [];`); populate that array using `$bacnetData[$key] = $json_data;` instead of `$$key = $json_data;`; and display using `` – Mark Baker Dec 24 '16 at 19:58

1 Answers1

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Why not try something like this instead? This will allow you to create other sections in your INI file that won't affect your script.

<?php

$bacnetini = parse_ini_file('/var/www/config/bacnet.ini', true);

$data = array();

foreach ($bacnetini['bacnet'] as $key => $url) {
    $data[$key] = json_decode(file_get_contents($url), true);
}

var_dump($data['SEA_SRV_SEA_SV1_01_EXHT']);

?>
mim.ms
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