Error handling in getJSON calls

Question

How can you handle errors in a getJSON call  Im trying to reference a cross-domain script service using jsonp  how do you register an error method

User · Answer

Why not  getJSON  get php   cmd  1   typeID     typesSelect    function data                    function getJSON url params callback        return   getJSON url params callback           fail function jqXMLHttpRequest textStatus errorThrown                console dir jqXMLHttpRequest               alert  Ajax data request failed     textStatus     errorThrown    - see javascript console for details                        For details on the used  fail   method  jQuery 1 5    see http   api jquery com jQuery ajax  jqXHR  Since the jqXHR is returned by the function  a chaining like     when getJSON       then function               is possible

User · Answer

Here s my addition   From http   www learnjavascript co uk jq reference ajax getjson html and the official source   The jqXHR success    jqXHR error    and jqXHR complete   callback methods introduced in jQuery 1 5 are deprecated as of jQuery 1 8  To prepare your code for their eventual removal  use jqXHR done    jqXHR fail    and jqXHR always   instead    I did that and here is Luciano s updated code snippet     getJSON  example json   function       alert  success        done function     alert  getJSON request succeeded         fail function     alert  getJSON request failed          always function     alert  getJSON request ended           And with error description plus showing all json data as a string     getJSON  example json   function data      alert JSON stringify data        done function     alert  getJSON request succeeded         fail function jqXHR  textStatus  errorThrown    alert  getJSON request failed      textStatus       always function     alert  getJSON request ended           If you don t like alerts  substitute them with console log    getJSON  example json   function data      console log JSON stringify data        done function     console log  getJSON request succeeded         fail function jqXHR  textStatus  errorThrown    console log  getJSON request failed      textStatus       always function     console log  getJSON request ended

User · Answer

In some cases  you may run into a problem of synchronization with this method  I wrote the callback call inside a setTimeout function  and it worked synchronously just fine     E G   function obterJson callback          jqxhr     getJSON window location href    js data json   function data         setTimeout function            callback data         0

User · Answer

I know it s been a while since someone answerd here and the poster probably already got his answer either from here or from somewhere else  I do however think that this post will help anyone looking for a way to keep track of errors and timeouts while doing getJSON requests  Therefore below my answer to the question  The getJSON structure is as follows  found on http   api jqueri com      selector  getJSON url data success data status xhr     most people implement that using     getJSON url  datatosend  function data         do something with the data       where they use the url var to provide a link to the JSON data  the datatosend as a place to add the   callback    and other variables that have to be send to get the correct JSON data returned  and the success funcion as a function for processing the data    You can however add the status and xhr variables in your success function  The status variable contains one of the following strings    success    notmodified    error    timeout   or  parsererror   and the xhr variable contains the returned XMLHttpRequest object  found on w3schools     getJSON url  datatosend  function data  status  xhr       if  status     success              do something with the data      else if  status     timeout            alert  Something is wrong with the connection         else if  status     error     status     parsererror             alert  An error occured         else          alert  datatosend did not change                         This way it is easy to keep track of timeouts and errors without having to implement a custom timeout tracker that is started once a request is done   Hope this helps someone still looking for an answer to this question

User · Answer

x000D   x000D    getJSON  example json   function     x000D    alert  success    x000D     x000D   success function     alert  second success       x000D   error function     alert  error       x000D   x000D   x000D    It is fixed in jQuery 2 x  In jQuery  1 x you will never get an error callback

User · Answer

I was faced with this same issue  but rather than creating callbacks for a failed request  I simply returned an error with the json data object   If possible  this seems like the easiest solution  Here s a sample of the Python code I used   Using Flask  Flask s jsonify f and SQLAlchemy   try      snip   Snip query filter by user id current user get id    id snip id  first       db session delete snip      db session commit       return jsonify success True  except Exception  e      logging debug e      return jsonify error  Sorry  we couldn t delete that clip      Then you can check on Javascript like this     getJSON   ajax deleteSnip     data id      function data       console log data       if  data success     true           console log  successfully deleted snip               snippet data-id      data id         slideUp              else            only shows if the data object was returned

User · Answer

getJSON   is a kind of abstraction of a regular AJAX call where you would have to tell that you want a JSON encoded response    ajax     url  url    dataType   json     data  data    success  callback      You can handle errors in two ways  generically  by configuring your AJAX calls before actually calling them  or specifically  with method chain    generic  would be something like    ajaxSetup          quot error quot  function     alert  quot error quot            And the  specific  way    getJSON  quot example json quot   function       alert  quot success quot        done function     alert  quot second success quot        fail function     alert  quot error quot        always function     alert  quot complete quot

User · Answer

This is quite an old thread  but it does come up in Google search  so I thought I would add a jQuery 3 answer using promises  This snippet also shows   You no longer need to switch to   ajax to pass in your bearer token Uses  then   to make sure you can process synchronously any outcome  I was coming across this problem  always   callback firing too soon - although I m not sure that was 100  true  I m using  always   to simply show the outcome whether positive or negative In the  always   function I m updating two targets with the HTTP Status code and message body  The code snippet is        getJSON            url   quot https   myurl com api quot            headers     quot Authorization quot    quot Bearer  quot    user access token         then   always    function  data  textStatus               quot  txtAPIStatus quot   html data status              quot  txtAPIValue quot   html data responseText

User · Answer

Someone give Luciano these points     I just tested his answer -had a similar question- and worked perfectly     I even add my 50 cents    error function jqXHR  textStatus  errorThrown            console log  error     textStatus           console log  incoming Text     jqXHR responseText

[jquery] Error handling in getJSON calls

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