Swift POST JSON返回500

Question

我的POST有问题，它会返回500作为回复。

这是我的代码：

let postParams: Dictionary<String, AnyObject> = ["user_id": user_id, "prayer": [["user_id":data["user_id"], "prayer_date":data["prayer_date"], "name":data["name"]]]]
        let request = NSMutableURLRequest(URL: url)
        request.HTTPMethod = "POST"
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addValue("application/json", forHTTPHeaderField: "Accept")
        do {
            request.HTTPBody = try NSJSONSerialization.dataWithJSONObject(postParams, options: NSJSONWritingOptions())
        } catch {
            print("bad things happened")
        }
        print(request.HTTPBody)
        // Make the POST call and handle it in a completion handler
        session.dataTaskWithRequest(request, completionHandler: { ( data: NSData?, response: NSURLResponse?, error: NSError?) -> Void in
            // Make sure we get an OK response
            guard let realResponse = response as? NSHTTPURLResponse where realResponse.statusCode == 200 else {
                print("Not a 200 response")
                print(response)
                return
            }

            // Read the JSON
            if let postString = NSString(data:data! , encoding: NSUTF8StringEncoding) as? String {
                // Print what we got from the call
                let dictionary = self.JSONParseDictionary(postString)

                let status = (dictionary as NSDictionary)["status"] as! Bool
                print(status)
            }

        }).resume()

从API开始，它需要user_id作为int和prayer作为数组。