Call Slack Webincoming hook in Swift but get "interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)"

Question

I've use Swift to post something to Slack use Webhook as an POST request, but get an error like

interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)

in the line of var request = .... Can anyone tell me why I get such an error? Thanks!! :D

("Webhook URL here" refers to a real proper URL, but when post this question I just replace it with "Webhook URL here".)

import UIKit
import XCPlayground

let str = "payload={'channel': '#test', 'username': 'webhookbot', 'text': 'This is posted to #test and comes from a bot named webhookbot.', 'icon_emoji': ':ghost:'}"
let strData = (str as NSString).dataUsingEncoding(NSUTF8StringEncoding)
let cachePolicy = NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData

var request = NSMutableURLRequest(URL: NSURL(string: "Webhook URL here")!, cachePolicy: cachePolicy, timeoutInterval: 2.0)

request.HTTPMethod = "POST"
request.HTTPBody = strData

var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil)
let results = NSString(data:data!, encoding:NSUTF8StringEncoding)

Answer 1

You should also use optional binding to unwrap your data

if let data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil) {
    let results = NSString(data:data, encoding:NSUTF8StringEncoding)
}

You can also try logging the error in the synchronous request like the code below.

So your final code should be something like this

import UIKit
import XCPlayground

let str = "payload={'channel': '#test', 'username': 'webhookbot', 'text': 'This is posted to #test and comes from a bot named webhookbot.', 'icon_emoji': ':ghost:'}"
let strData = (str as NSString).dataUsingEncoding(NSUTF8StringEncoding)
let cachePolicy = NSURLRequestCachePolicy.ReloadIgnoringLocalCacheData

if let url = NSURL(string: "Your Webhook Url")
{
    var request = NSMutableURLRequest(URL: url, cachePolicy: cachePolicy, timeoutInterval: 2.0)

    request.HTTPMethod = "POST"
    request.HTTPBody = strData

    var error : NSError? = nil
    if let data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: &error) {
       let results = NSString(data:data, encoding:NSUTF8StringEncoding)
    }
    else
    {
        println("data invalid")
        println(error)
    }
}
else {
    println("url invalid")
}