Trigger ID not found with Slack slash command? - php

Question

My goal is to be able to use a slash command to open a dialog and process the feedback into a database. I am trying to get the dialog to open but am getting an error regarding the slash command where it says "trigger_id" not found.
My app is set up with an API and the proper OAuth.
I added a slash command to my app with the url of my php page (domain.com/slash.php)
The slash command is set up with the code below.
When I run it from my slack, I get the output of
'{"ok":false,"error":"invalid_arguments","response_metadata":{"messages":["[ERROR] missing required field: trigger_id"]}}'
I have tried some debugging and output the trigger_id to the screen and find that the trigger_id is indeed null. What am I missing to pass this?
I admit that I am new to the slack realm. I have followed (I think) the documentation from the slack site on setting up the app correctly.
Am I missing something with my slack app setup or something in my code that is causing this error message?
Thank you in advance for your time!
<?
$command = $_POST['command'];
$text = $_POST['text'];
$token = $_POST['token'];
$cn = $_POST['channel_id'];
$user_id = $_POST['user_id'];
$triggerid = $_POST['trigger_id'];
// define the dialog for the user (from Slack documentation example)
$dialog = [
'callback_id' => 'validres-3100',
'title' => 'Test',
'submit_label' => 'Submit',
'elements' => [
[
'type' => 'text',
'label' => 'Test Field 1',
'name' => 'field_1'
],
[
'type' => 'text',
'label' => 'Test Field 2',
'name' => 'field_2'
]
]
];
// define POST query parameters
$query = [
'token' => '<my api auth code>',
'dialog' => json_encode($dialog),
'trigger_id' => $triggerid
];
// define the curl request
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://slack.com/api/dialog.open');
curl_setopt($ch, CURLOPT_HTTPHEADER, [
'Content-Type: application/x-www-form-urlencoded'
]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
// set the POST query parameters
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($query));
// execute curl request
$response = curl_exec($ch);
// close
curl_close($ch);
var_export($response);
?>

Answer 1

To open dialog box in slack you can use this api "https://slack.com/api/views.open".
With api you need to send trigger id which is valid only for 3 seconds.
Your url will looks like :
"https://slack.com/api/views.open?trigger_id=" + "xxxx.xxxxxxxxx.xxxxxxxxxxxx" + "&view=your data".
with this request you need to send token with your post request like :-
(URL,"POST", { "token" ,"xoxb-xxxxxx-xxxxx-xxxxxxx"});
Need to add view.open API in your slack app also for this use following step:
Use "Bot User OAuth Access Token" , In "OAuth and permissions Tab" Format is xoxb-xxxxx-xxxxx-xxxx. And then add scope "views:open" and reinstall your app in slack. And then try to get open view dialog.
Hope this will be helpful.