swift - Firebase snapshot not being cast to dictionary -


i have function supposed fetch data comments node firebase. want implement pagination not load 100+ comments @ once. seems working code seems failing @ casting snapchat.value dictionary

     func fetchcomments(){         messagesref = database.database().reference().child("comments").child(eventkey)         var query = messagesref?.queryorderedbykey()         if comments.count > 0 {            let value =  comments.last?.commentid             query = query?.querystarting(atvalue: value)         }         query?.querylimited(tofirst: 2).observe(.childadded, with: { (snapshot) in              var allobjects = snapshot.children.allobjects as? [datasnapshot]              allobjects?.foreach({ (snapshot) in                  // print out snapshot , isn't empty                  print(snapshot.value) // here keeps going else statement though snapshot.value exist.                  guard let commentdictionary = snapshot.value as? [string:any] else{                     return                 }                  print(commentdictionary)             })                    }) { (err) in             print("failed observe comments")         }     }

my question can take @ , maybe see went wrong? code looks fine me , can't see what's wrong.

my tree looks this

"comments" : { "ccds" : {   "-krrsxkj6fznzrd0-xzs" : {     "content" : "shawn",     "profileimageurl" : "https://firebasestorage.googleapis.com/v0/b/eventful-3d558.appspot.com/o/profile_images%2fbc868f8f-e9ec-4b9d-a248-dd2187bc140c.png?alt=media&token=fb14700c-2b05-4077-b45c-afd3de705801",     "timestamp" : 1.503102381340935e9,     "uid" : "oxgjbrhingbf7vbahpflhw6g7tb2"   } }, "mia" : {   "-krghz9d5_cpjkmdffef" : {     "content" : "22",     "profileimageurl" : "https://firebasestorage.googleapis.com/v0/b/eventful-3d558.appspot.com/o/profile_images%2ff50f6915-deab-4a5b-b1ab-cabc1e349148.png?alt=media&token=4eb7c708-ec87-45bf-952d-0bd410faee50",     "timestamp" : 1.502915064803007e9,     "uid" : "oxgjbrhingbf7vbahpflhw6g7tb2"   },   "-krpoennysmrz5guoruj" : {     "content" : "23",     "profileimageurl" : "https://firebasestorage.googleapis.com/v0/b/eventful-3d558.appspot.com/o/profile_images%2fbc868f8f-e9ec-4b9d-a248-dd2187bc140c.png?alt=media&token=fb14700c-2b05-4077-b45c-afd3de705801",     "timestamp" : 1.503067700479352e9,     "uid" : "oxgjbrhingbf7vbahpflhw6g7tb2"   } }   }

based off code bypasses key , goes straight children. example if pass in mia should go mia , grab key corresponding each comment "-krrsxkj6fznzrd0-xzs" , "-krpoennysmrz5guoruj" returning under unique id instead. problem

the code in callback seems assume called collection of comments. such collection need observe .value event. when observe .value event, callback gets invoked single snapshot contains nodes matching query:

   query?.querylimited(tofirst: 2).observe(.value, with: { (snapshot) in          var allobjects = snapshot.children.allobjects as? [datasnapshot]          allobjects?.foreach({ (snapshot) in             print(snapshot.key)             print(snapshot.value)              guard let commentdictionary = snapshot.value as? [string:any] else{                 return             }              print(commentdictionary)         })     }) { (err) in         print("failed observe comments")     }

when observe .childadded, callback instead gets called every individual node matching query. means need rid of loop in code:

   query?.querylimited(tofirst: 2).observe(.childadded, with: { (snapshot) in         print(snapshot.key)         print(snapshot.value)          guard let commentdictionary = snapshot.value as? [string:any] else{             return         }          print(commentdictionary)      }) { (err) in         print("failed observe comments")     }

Comments

Post a Comment

Popular posts from this blog

What is happening when Matlab is starting a "parallel pool"? -

running parallel cpu processes in matlab starts command parpool() according documentation , function: [creates] special job on pool of workers, , [connects] matlab client parallel pool. this function takes bit of time execute, on order of 30 seconds. in other multi-cpu paradigms openmp, parallel execution seems totally transparent -- i've never noticed behavior analogous matlab (granted i'm not experienced parallel programming). so, happening between time parpool() called , when finishes executing? takes long? parallel computing toolbox enables run matlab code in parallel using several different paradigms (e.g. jobs , tasks, parfor , spmd , parfeval , batch processing), , run either locally (parallelised across cores in local machine) or remotely (parallelised across machines in cluster - either 1 own, or 1 in cloud). in of these cases, code run on matlab workers , copies of matlab without interactive desktop. if you're intending run on remo...
Read more

angular - DownloadURL return null in below code -

when change file updated in firebase storage when try downloadurl show null. filechange(event: any) { const imagefolder: string = this.employee.id; const filelist: filelist = event.target.files; const file: file = filelist[0]; const storageref = firebase.storage().ref().child(`${imagefolder}/profile.jpg`).put(file); console.log(storageref.snapshot.downloadurl); } the put() asynchronous. if want url after file uploaded have this: firebase.storage().ref().child(`${imagefolder}/profile.jpg`).put(file).then((snapshot) => { storageref = snapshot.downloadurl: console.log(snapshot.downloadurl); });
Read more

php - Cannot override Laravel Spark authentication with own implementation -

during login process of laravel spark need request token of remote api. api stores exact same users , passwords laravel spark application. therefore need username , non hashed password of user during authentication process. i thought overriding authenticated method solution problem. in routes/web.php override post /login endpoint , pointing endpoint own logincontroller: <?php namespace app\http\controllers\auth; use illuminate\support\facades\log; use illuminate\http\request; use laravel\spark\http\controllers\auth\logincontroller sparklogincontroller; class logincontroller extends sparklogincontroller { /** * create new login controller instance. * * @return void */ public function __construct() { parent::__construct(); } /** * handle successful authentication attempt. * * @param request $request * @param \illuminate\contracts\auth\authenticatable $user * @return response */ public fu...
Read more