How to send json data in the Http request using NSURLRequest

Question

I m new to objective-c and I m starting to put a great deal of effort into request response as of recent   I have a working example that can call a url  via http GET  and parse the json returned   The working example of this is below  -  void connection  NSURLConnection   connection didReceiveResponse  NSURLResponse   response        responseData setLength 0      -  void connection  NSURLConnection   connection didReceiveData  NSData   data        responseData appendData data      -  void connection  NSURLConnection   connection didFailWithError  NSError   error     NSLog  NSString stringWithFormat   Connection failed        error description        -  void connectionDidFinishLoading  NSURLConnection   connection        connection release       do something with the json that comes back      the fun part     -  void viewDidLoad      self searchForStuff   iPhone       - void searchForStuff  NSString   text     responseData     NSMutableData data  retain       NSURLRequest  request    NSURLRequest requestWithURL  NSURL URLWithString   http   www whatever com json           NSURLConnection alloc  initWithRequest request delegate self       My first question is - will this approach scale up  Or is this not async  meaning I block the UI thread while the app is waiting for the response   My second question is - how might I modify the request part of this to do a POST instead of GET  Is it simply to modify the HttpMethod like so    request setHTTPMethod   POST      And finally - how do I add a set of json data to this post as a simple string  for example          magic                    real  true                     options                    happy  true                   joy  true                   joy2  true                       key   123      Thank you in advance

User · Answer

Since my edit to Mike G s answer to modernize the code was rejected 3 to 2 as      This edit was intended to address the author of the post and makes no   sense as an edit  It should have been written as a comment or an   answer   I m reposting my edit as a separate answer here  This edit removes the JSONRepresentation dependency with NSJSONSerialization as Rob s comment with 15 upvotes suggests       NSArray  objects    NSArray arrayWithObjects   NSUserDefaults standardUserDefaults valueForKey   StoreNickName            UIDevice currentDevice  uniqueIdentifier    dict objectForKey   user question        nil       NSArray  keys    NSArray arrayWithObjects   nick name     UDID     user question   nil       NSDictionary  questionDict    NSDictionary dictionaryWithObjects objects forKeys keys        NSDictionary  jsonDict    NSDictionary dictionaryWithObject questionDict forKey   question         NSLog   jsonRequest is      jsonRequest        NSURL  url    NSURL URLWithString   https   xxxxxxx com questions         NSMutableURLRequest  request    NSMutableURLRequest requestWithURL url                  cachePolicy NSURLRequestUseProtocolCachePolicy timeoutInterval 60 0         NSData  requestData    NSJSONSerialization dataWithJSONObject dict options 0 error nil     TODO handle error       request setHTTPMethod   POST         request setValue   application json  forHTTPHeaderField   Accept         request setValue   application json  forHTTPHeaderField   Content-Type         request setValue  NSString stringWithFormat    d    requestData length   forHTTPHeaderField   Content-Length         request setHTTPBody  requestData        NSURLConnection  connection     NSURLConnection alloc initWithRequest request delegate self       if  connection         receivedData     NSMutableData data  retain           The receivedData is then handled by   NSDictionary  jsonDict    NSJSONSerialization JSONObjectWithData data options 0 error nil       NSDictionary  question    jsonDict objectForKey   question

User · Answer

I would suggest to use ASIHTTPRequest     ASIHTTPRequest is an easy to use   wrapper around the CFNetwork API that   makes some of the more tedious aspects   of communicating with web servers   easier  It is written in Objective-C   and works in both Mac OS X and iPhone   applications       It is suitable performing basic HTTP   requests and interacting with   REST-based services  GET   POST   PUT     DELETE   The included   ASIFormDataRequest subclass makes it   easy to submit POST data and files   using multipart form-data      Please note  that the original author discontinued with this project  See the followring post for reasons and alternatives  http   allseeing-i com  5Brequest release 5D   Personally I am a big fan of AFNetworking

User · Answer

I struggled with this for a while  Running PHP on the server  This code will post a json and get the json reply from the server  NSURL  url    NSURL URLWithString   http   example co index php    NSMutableURLRequest  rq    NSMutableURLRequest requestWithURL url    rq setHTTPMethod   POST    NSString  post    NSString stringWithFormat   command1 c1 amp command2 c2    NSData  postData    post dataUsingEncoding NSASCIIStringEncoding    rq setHTTPBody postData    rq setValue   application x-www-form-urlencoded  forHTTPHeaderField   Content-Type    NSOperationQueue  queue     NSOperationQueue alloc  init     NSURLConnection sendAsynchronousRequest rq queue queue completionHandler   NSURLResponse  response  NSData  data  NSError  error          if   data length   gt  0  amp  amp  error    nil            NSError  parseError   nil           NSDictionary  dictionary    NSJSONSerialization JSONObjectWithData data options 0 error  amp parseError            NSLog   Server Response  we want to see a 200 return code      response            NSLog   dictionary     dictionary               else if   data length     0  amp  amp  error    nil            NSLog   no data returned               no data  but tried             else if  error    nil                  NSLog   there was a download error               couldn t download

User · Answer

You can try this code for send json string   NSData  jsonData    NSJSONSerialization dataWithJSONObject ARRAY CONTAIN JSON STRING options NSJSONWritin emphasized text gPrettyPrinted error NULL   NSString  jsonString     NSString alloc  initWithData jsonData encoding NSUTF8StringEncoding   NSString  WS test    NSString stringWithFormat   www test com xyz php amp param     jsonString

User · Answer

Here s an updated example that is using NSURLConnection  sendAsynchronousRequest   10 7   iOS 5    The  Post  request remains the same as with the accepted answer and is omitted here for the sake of clarity   NSURL  apiURL    NSURL URLWithString       NSString stringWithFormat   http   www myserver com api api php request        someRequest     NSURLRequest  request    NSURLRequest requestWithURL apiURL      this is using GET  for POST examples see the other answers here on this page  NSURLConnection sendAsynchronousRequest request                                    queue  NSOperationQueue mainQueue                         completionHandler   NSURLResponse  response  NSData  data  NSError  connectionError         if data length             NSString  responseString     NSString alloc  initWithData data encoding NSUTF8StringEncoding            if responseString  amp  amp  responseString length                 NSLog        responseString

User · Answer

Most of you already know this by now  but I am posting this  just incase  some of you are still struggling with JSON in iOS6    In iOS6 and later  we have the NSJSONSerialization Class that is fast and has no dependency on including  outside  libraries   NSDictionary  result    NSJSONSerialization JSONObjectWithData  resultStr dataUsingEncoding NSUTF8StringEncoding  options 0 error nil      This is the way iOS6 and later can now parse JSON efficiently The use of SBJson is also pre-ARC implementation and brings with it those issues too if you are working in an ARC environment   I hope this helps

User · Answer

Here s what I do  please note that the JSON going to my server needs to be a dictionary with one value  another dictionary  for key   question  i e     question      dictionary         NSArray  objects    NSArray arrayWithObjects   NSUserDefaults standardUserDefaults valueForKey   StoreNickName        UIDevice currentDevice  uniqueIdentifier    dict objectForKey   user question        nil   NSArray  keys    NSArray arrayWithObjects   nick name     UDID     user question   nil   NSDictionary  questionDict    NSDictionary dictionaryWithObjects objects forKeys keys    NSDictionary  jsonDict    NSDictionary dictionaryWithObject questionDict forKey   question     NSString  jsonRequest    jsonDict JSONRepresentation    NSLog   jsonRequest is      jsonRequest    NSURL  url    NSURL URLWithString   https   xxxxxxx com questions     NSMutableURLRequest  request    NSMutableURLRequest requestWithURL url              cachePolicy NSURLRequestUseProtocolCachePolicy timeoutInterval 60 0     NSData  requestData    jsonRequest dataUsingEncoding NSUTF8StringEncoding     request setHTTPMethod   POST     request setValue   application json  forHTTPHeaderField   Accept     request setValue   application json  forHTTPHeaderField   Content-Type     request setValue  NSString stringWithFormat    d    requestData length   forHTTPHeaderField   Content-Length     request setHTTPBody  requestData    NSURLConnection  connection     NSURLConnection alloc initWithRequest request delegate self   if  connection     receivedData     NSMutableData data  retain       The receivedData is then handled by   NSString  jsonString     NSString alloc  initWithData data encoding NSUTF8StringEncoding   NSDictionary  jsonDict    jsonString JSONValue   NSDictionary  question    jsonDict objectForKey   question      This isn t 100  clear and will take some re-reading  but everything should be here to get you started   And from what I can tell  this is asynchronous   My UI is not locked up while these calls are made   Hope that helps

User · Answer

Here is a great article using Restkit  It explains on serializing nested data into JSON and attaching the data to a HTTP POST request

[iphone] How to send json data in the Http request using NSURLRequest

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