I am new to iphone development could somebody help me out this problem ,From one week i am facing with one issue , that is i have multiple urls like below
for (int i=0;i<=[listingAffArray];i++)
NSString *urlStr=[NSString stringWithFormat:#"http://demo.holidayjuggle.net:7777/services/inventoryservice/%#/%#/stores/search?location=12.971598700000000000,77.594562699999980000,50",appDelegate.buyingAff,[appDelegate.listingAffArray objectAtIndex:i]];
}
in this i am getting response from all the urls but in didfinishloading could not able to find which urls responsedata
NSURL *url=[NSURL URLWithString:urlStr];
NSMutableURLRequest *req=[NSMutableURLRequest requestWithURL:url];
[req setHTTPMethod:#"GET"];
[req setValue:#"application/json" forHTTPHeaderField:#"Accept"];
[req setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
connection=[NSURLConnection connectionWithRequest:req delegate:self];
if(connection){
NSLog(#"connection is successfull ");
}
else{
NSLog(#"connection failed");
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
responseData=[[NSMutableData alloc]init];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[responseData appendData:data];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSString *strResponse=[[NSString alloc]initWithData:responseData encoding:NSUTF8StringEncoding];
}
in responsedata only last url data is there i put breakpoint and observed each url is calling in didfinishloading , when the second url is calling it is upadating with the secondurl call like that in responsedata last url data only is there .How to store each response data seperately
Thanks in advance
sivakumari
Create an array in your class and store each strResponse in your array (using addObject).
Also, this doesn't make sense:
for (int i=0;i<=[listingAffArray];i++)
NSString *urlStr=[NSString stringWithFormat:#"http://demo.holidayjuggle.net:7777/services/inventoryservice/%#/%#/stores/search?location=12.971598700000000000,77.594562699999980000,50",appDelegate.buyingAff,[appDelegate.listingAffArray objectAtIndex:i]];
}
The [listingAffArray] part should give you a compiler error and, even if that did work, you would be overwriting the same variable each time through the loop.
Yes it happen because all NSURLConnection share same delegate same object which is "self"
If u want to load multiple URL than you should have multiple space to store that data.
So one object of responseData is not sufficient.
There can be many way let me suggest one which I use.
Declare a NSMutableDictionary object
Store NSURLConnection object as key and NSMutableData object as value so if u have 3 URL you have 3 entery in NSMutableDictionary.
In every Delegate method of NSURLConnection append data only to corresponding NSMutableData object.
Tell me if u need more help....
Try to call web service with url in a asynchronous manner.
ie.Hit the first url and when you received the result of first url the hit the second url request. after that when u received the second url response hit the third url request.
These all request should run in background thread or a new thread, so that it doesn't effect the main thread.
Also take a enum data type like
enum {
requestOne=0,
requestTwo,
requestThree,
requestFour
}currentRequest;
when u start hitting the first url in currentRequestData assign requestOne and in response check wit this enumDataType. when response received then hit second url with seconod enum type
Related
I am trying to set up a NSURLRequest to download a simple index.html with its externa style.css sheet but I am not quite sure how to do this.. I have only ever just formatted the URL of the request to the file I want.. but this has to be slightly different and I cannot find a good example of what I am trying to do.
this is my code so far:
#pragma mark - NSURLConnection methods
- (void)htmlRequest
{
// Create the request.
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.mywebsite.com/index.html"]
cachePolicy:NSURLRequestReloadIgnoringCacheData
timeoutInterval:60.0];
// create the connection with the request
// and start loading the data
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection) {
// Create the NSMutableData to hold the received data.
// receivedData is an instance variable declared elsewhere.
receivedData = [NSMutableData data];
} else {
// Inform the user that the connection failed.
NSLog(#"Connection Fail");
}
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
// This method is called when the server has determined that it
// has enough information to create the NSURLResponse.
// It can be called multiple times, for example in the case of a
// redirect, so each time we reset the data.
// receivedData is an instance variable declared elsewhere.
[receivedData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// Append the new data to receivedData.
// receivedData is an instance variable declared elsewhere.
[receivedData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
// inform the developer of error type
}
// This method uses methodName to determin which Initalizer method to send the response data to in EngineResponses.m
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// EngineResponses *engineResponses = [EngineResponses sharedManager];
// [engineResponses GetManufacturers:receivedData];
NSString *myString = [[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding];
NSLog(#"%#", myString);
}
as you can see I am just calling index.html directly.. I would like to know how to format my request so i get the index.html as well as style.css
any help would be greatly appreciated.
I always create a new data structure,which has a -connection property and a -request property,like this
#interface connectionWrapper : NSObject
#property(retain) NSURLRequest *request
#property(retain) NSURLConnection *connection
by retaining this data structure in an mutable array, you can distinguish the connections in callback methods by iterate the array and compare each connectionWrapper instance's -connection property with the connection parameter the of the callback method, if they match(points to a same object), then you can retrieve the -request property of the connectionWrapper instance, then -url property of NSURLRequest instance.
as I'm not an native English speaker, I think code is a better tutor.
-(NSURLRequest*)getRequestByConnection:(NSURLConnection*)connection
{
for(connectionWrapper *w in theArrayContainingAllConnectionWrappers)
{
if(w == connection)
return w.request;
}
}
In callback method:
-(void)connection:(NSURLConnection*)connection didReceiveResponse(NSURLResponse*)response
{
NSURLRequest *request = [self getRequestByConnection:connection];
NSURL *url = [request url];
/*apply different approach to different url/*
}
PS:it's very sad that NSURLConnection don't have a -request property so that we can retrieve the request associated with the connection easily.
One way or another, you will have to make 2 requests. Even if you open a web page directly in a web browser, the browser will make a separate request for the CSS file referenced in the HTML it downloads. If your application needs both the HTML and the CSS file, then you want it to make 2 separate URL requests, first to get the HTML and then to get the CSS file.
Now, just because 2 requests need to be made, that doesn't mean you will always need to write the code that makes those 2 requests. It may be that libraries like the ones recommended by #Slee automatically take the results of a first request, parse them out, and make requests for any referenced CSS files. I have not worked with them so I am not sure what they support, or if any libraries will do this for you.
One thing you may want to consider is loading the HTML and CSS through a UIWebView rather than handling it all manually. UIWebView will attempt to load, parse, and render an HTML file into a UI component. In the process it will load referenced CSS and JavaScript files and apply them to its rendering. If you want to do anything special like intercept the calls it makes to load the CSS file(s), you can implement the UIWebViewDelegate protocol and set the delegate of the the UIWebView. Within that delegate you can implement the -webView:shouldStartLoadWithRequest:navigationType: method to be notified when the web view is loading the CSS file. You can use the call to that method to look at the request that is being issued for the CSS and do something else interesting with the request.
do you know the name of the .css file?
If so I would just make 2 requests otherwise you will have to write a parser to look for the link to the css and make a second request anyways.
I'd also suggest looking into a library to handle the downlading of stuff - lot's of great libraries that can do the heavy lifting for you with advanced features.
Here's 3 I have used:
http://blog.mugunthkumar.com/coding/ios-tutorial-advanced-networking-with-mknetworkkit/
https://github.com/tonymillion/TMHTTPRequest
https://github.com/pokeb/asi-http-request
This might be a dumb question. Sorry if it is.
But Im working on a project that consumes web services. I can connect to the web service and get the data I need fine.
I would like to have a method that returns this data obtained from the web service to the caller. The only problem is that the data is only obtained inside the ConnectionDidFinishLoading method, and I can't access this data from my method.
here is my code, that works fine:
- (NSData *) dataForMethod:(NSString *)webMethod withPostString:(NSString *)postString
{
NSURL *url = [NSURL URLWithString:[SigameWebServiceAddress stringByAppendingFormat:#"%#%#", #"/", webMethod]];
NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
NSString *msgLength = [NSString stringWithFormat:#"%d", [postString length]];
[req addValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[req addValue:msgLength forHTTPHeaderField:#"Content-Length"];
[req setHTTPMethod:#"POST"];
[req setHTTPBody: [postString dataUsingEncoding:NSUTF8StringEncoding]];
conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
if (conn)
{
webData = [NSMutableData data];
}
// I WOULD LIKE TO RETURN WEBDATA TO THE CALLER HERE, BUT WEBDATA IS EMPTY NOW, THE
//connectionDidFinishLoading ONLY GETS CALLED WITH THE DATA I WANT AFTER THE COMPILER
//IS DONE EXECUTING MY METHOD.
}
-(void) connection:(NSURLConnection *) connection didReceiveResponse:(NSURLResponse *) response
{
[webData setLength: 0];
}
-(void) connection:(NSURLConnection *) connection didReceiveData:(NSData *) data
{
[webData appendData:data];
}
-(void) connection:(NSURLConnection *) connection didFailWithError:(NSError *) error
{
NSLog(#"FATAL ERROR");
}
-(void) connectionDidFinishLoading:(NSURLConnection *) connection
{
NSLog(#"DONE. Received Bytes: %d", [webData length]);
NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding];
//---shows the XML---
NSLog(#"%#", theXML); //NOW, THIS IS THE DATA I WANT. BUT HOW CAN I RETURN THIS TO
//THE CALLER. I MEAN, THE CALLER THAT CALLED MY METHOD
//+ (NSData *) dataForMethod: withPostString:
}
Any help here is appreciated!
Thanks
There are really two ways to go about this.
Create a delegate interface
Use Blocks
I would strongly advise against using the synchronous methods - unless you are/have created your own asynchronous framework around them (i.e. you are manually starting another thread and executing your synchronous request on that thread). In the long run you will realize you need the requests to be async, and you'll have to re-work everything such that they are.
To give a quick overview of the two options I gave:
1. Create a delegate interface
The idea here is to create a class which performs the request, and create a protocol the caller must implement. When the request is complete, you will invoke a specified method on the delegate with the data:
The protocol might look something like this:
#protocol RequestClassDelegate <NSObject>
- (void)requestCompleted:(ResponseClass *)data;
- (void)requestError:(NSError *)error;
#end
The class which makes the request might look something like this:
#interface RequestClass : NSObject
- (void)makeRequest:(id<RequestClassDelegate>)delegate;
#end
And the request class implementation might contain some of the following, in addition to your connection logic:
#implementation RequestClass
{
__weak id<RequestClassDelegate> _delegate;
}
// Connection Logic, etc.
- (void)makeRequest:(id<RequestClassDelegate>)delegate
{
_delegate = delegate;
// Initiate the request...
}
-(void) connectionDidFinishLoading:(NSURLConnection *) connection
{
NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding];
// Processing, etc.
// Here we'll call the delegate with the result:
[_delegate requestCompleted:theResult];
}
#end
2. Use Blocks
This solution is much the same as the first solution - but, a bit more elegant in my opinion. Here, we'll change the RequestClass to use blocks instead of a delegate:
typedef void (^requestCompletedBlock)(id);
typedef void (^requestErrorBlock)(NSError *);
#interface RequestClass : NSObject
#property (nonatomic, copy) requestCompletedBlock completed;
#property (nonatomic, copy) requestErrorBlock errored;
- (void)makeRequest:(requestCompletedBlock)completed error:(requestErrorBlock)error;
#end
And the implementation of that might look something like this:
#implementation RequestClass
#synthesize completed = _completed;
#synthesize errored = _errored;
// Connection Logic, etc.
- (void)makeRequest:(requestCompletedBlock)completed error:(requestErrorBlock)error
{
self.completed = completed;
self.errored = error;
// Initiate the request...
}
-(void) connectionDidFinishLoading:(NSURLConnection *) connection
{
NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding];
// Processing, etc.
// Here we'll call the delegate with the result:
self.completed(theResult);
}
#end
It sounds like you are trying to use return the data synchronously from your method, but you are using an asynchronous method (using an NSURLConnection and presumably calling its start method) to begin retrieving data. If you really want your method to return its result synchronously, read on. As #Steve says in another answer, however, you may also reconsider your interface design and instead implement it using an asynchronous approach and use his recommendations for either a delegate or block-based interface.
If you want to return the data synchronously from your method, use a synchronous request. So change this part of your code:
conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
[conn start]; // I presume you have this somewhere
if (conn)
{
webData = [NSMutableData data];
}
with something more like this:
NSURLResponse *response = nil;
NSError *error = nil;
webdata = [NSURLConnection sendSynchronousRequest:req returningResponse:&response error:&error];
if (webdata) {
return webdata;
}
else {
// Handle error by looking at response and/or error values
return nil;
}
You will no longer need any of your delegate code if you use this approach. You will be limited in some ways though. For example, if your web service requires authentication via something other than URL parameters you can't use this approach.
Steve's answer is great and I can only suggest the way using blocks. Actually, as I am new into Objective-C I implemented the approach steve outlined. It works perfectly.
The Post for more details and my own point of view you can find here:
http://kerkermeister.net/how-to-build-an-cocos2d-ios-app-communicating-with-a-restful-api-the-sequence/
The Post contains all the tiny steps you need to follow to get Steve's solution approach with blocks working. That includes:
- an updateable view that will render information as soon as retrieved from Web API asynchronously
- a controller invoking the HTTP request to the Web API
- the actual HttpRequest class that uses iOS standard NSURLConnections
- a model class that uses blocks as callbacks to update its data
Your going to have to either implement a separate method in which you use the data once the data has been returned by the connectionDidFinishLoading method or make the request synchronously. The reason I believe the above does not work is because the request is happening on a separate thread, so the main thread continues, but does not actually have the data.
This is a good way to do that if synchronous is what you want:
Does all NSURLConnections connect asynchronously? iOs
In order to download data from webserivce - use NSURLSession -
A URL session task that returns downloaded data directly to the app in memory.
// 1. create NSURL link to your webservice
NSString *dataUrl = #"DATA_LINK_TO_WEBSERVICE";
NSURL *url = [NSURL URLWithString:dataUrl];
// 2. create a NSURLSessionDataTask
NSURLSessionDataTask *downloadTask = [[NSURLSession sharedSession]
dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
//Handle response here
}];
// 3.resume the task
[downloadTask resume];
Refernces:
apple documentation refrence:
https://developer.apple.com/documentation/foundation/nsurlsessiondatatask?language=objc
Raywanderlich great cookbook:
https://www.raywenderlich.com/2392-cookbook-using-nsurlsession
Your going to need to parse the XML that comes back. There are some good Objective C XML parsers out there. One in particular is made for ease of use....
http://nfarina.com/post/2843708636/a-lightweight-xml-parser-for-ios
It's a very light weight parser for extracting the values you want from XML. I've used many times with great success and little hassle. Here is how I query a web address and turn it into data.
NSString *query = [NSString stringWithFormat:#"http://WEB_ADDRESS_FOR_XML];
NSURL *URL = [NSURL URLWithString:query];
NSData *data = [NSData dataWithContentsOfURL:URL];
Or with NSURLConnection, in the did receive data:
-(void) connection:(NSURLConnection *) connection didReceiveData:(NSData *) data
{
//USE THE DATA RETURNED HERE....
}
Then use the Parser from my link to get the contents:
SMXMLDocument *document = [SMXMLDocument documentWithData:data error:NULL];
NSLog("\nXML Returned:%#",document);
I have a webservice that returning 20 results each time (it is a limitation of the service provider). I want to call this service 10-20 times repeatingly and update my UI each time.
Is there best practice for this situation? I do not want to block the ui while calling the server. This causes problems if the user want to perform actions while the action in progress
(like navigating away from the current page)
Thanks!!!
what you can do is call the webservice in a background thread, collect the required data and jump back to main thread and update the UI.
We are doing the above(i.e jumping from background thread to main thread) because it is not recommended to update any UI in the background process.
you can call you webService in background by using
[self performSelectorInBackground:#selector(MyWebService) withObject:nil];//you can pass any object if you have
and to come back on main thread when the background task is over you can do..
[self performSelectorOnMainThread:#selector(myMainFunction) withObject:nil waitUntilDone:YES];
you can change the last parameter i.e. waitUntilDone:No also. By doing this, user will not have to wait till the UI is updated. they can carry there task.
you can use NSTimer for periodic calling your webService.
hope that helped :)
It depends on how you want to display the information.
If you're using the asynchronous connection (in my opinion, more effective than calling a synchronous connection in the background) and its delegate, it should not block the user interface:
- (void)loadData {
NSString *urlString = #"http://www.stackoverflow.com";
NSURL *url = [NSURL URLWithString:urlString];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[NSURLConnection connectionWithRequest:request delegate:self];
}
// delegate methods
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
// clear out or intialize instance data variable
[myData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[myData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// convert data to whatever it's supposed to be (for example, array)
NSString *dataString = [[NSString alloc] initWithData:myData encoding:NSUTF8StringEncoding];
NSArray *dataArray = [parser parseStringToArray:dataString];
[myArray addObjectsFromArray:dataArray];
//update tableview either using reload data (instant) or using updates (for smooth animation)
}
You can then recall the loadData method at the end of didFinishLoading: method to loop it.
I have a doubt regarding downloading data from a web service. One way is to download it in a single line mentioned below.
NSString *returnString = [[NSString alloc] initWithData:[NSURLConnection sendSynchronousRequest:urlrequest returningResponse:nil error:nil] encoding:NSUTF8StringEncoding];
And the other way to get it is via connectionDidFinishLoading
[..]
NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:urlrequest delegate:self];
NSHTTPURLResponse *response;
[NSURLConnection sendSynchronousRequest: urlrequest returningResponse: &response error: nil];
if( theConnection )
{
webData = [[NSMutableData data] retain];
}
else
{
NSLog(#"theConnection is NULL");
}
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[webData setLength: 0];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[webData appendData:data];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(#"ERROR with theConenction");
[connection release];
[webData release];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"DONE. Received Bytes: %d", [webData length]);
NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length: [webData length] encoding:NSUTF8StringEncoding];
}
Is there any difference between these two? NSURLConnection delegate method is not called when I use a separate class to parse the response.
You're using sendSynchronousRequest:returningResponse:error: which does not call any delegates methods because it doesn't need to: when you call it, the main thread stops until the request is finished and you get the response.
If you want to make an asynchronous request, use connectionWithRequest:delegate:. I recommend to always do asynchronous responses since the synchronous request blocks the main thread and your UI can't respond during that time. Animations will become interrupted. Scrolling becomes jerky. If you do want to use synchronous requests you should do it in a background thread.
The -sendSynchronousRequest:returningResponse:error: method blocks the main-thread (whenever it runs on the main-thread of course, since it's possible to run this method from any other thread, but I believe this is not recommended).
The methods using the delegates are asynchronous, the methods will fire and the results will (at some point in the future) be returned in the delegate methods. This gives the user a more smooth experience, since the main-thread will not be blocked.
Edit: personally I hardly ever use the -sendSynchronousRequest:returningResponse:error: method for the aforementioned reasons. Most of the time I use this method when I need to build something quickly, for example a proof-of-concept. I guess one could use the method for small downloads, yet if a timeout occurs (because for some reason the server is down) the whole UI will be blocked for (I believe) 2 minutes, which would be very annoying for the enduser.
An excellent demonstration to clarify your doubt is available in apple sample apps.You can refer Apple's sample app for a better understanding of asynchronous request and parsing data in separate class.
i'm a beginner to iphone.i want to create a login page for my application.i cant figure out how to connect to a php page and retrieve corresponding data from mysql database to the iphone.could any one guide me how to go about it.
what does the iphone have to do with a connection between php and mysql ?
PHP will run with on a web server probably apache installed on some computer and it will connect to a MySQL db .. and u will access that php page from your iphone with a browser. Not sure what part will the iphone have in all this other than providing the browser
You might want to have a look at NSURLRequest which you can use with a NSURLConnection to send e.g. GET-Parameters to a URL. You can then implment the NSURLConnectionDelegate to respond to incoming data:
1) setup connection
receivedData =[NSMutableData data];
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:url]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:20.0];
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
2) Setup delegate methods in self:
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse*)response {
NSHTTPURLResponse * httpResponse = (NSHTTPURLResponse *) response;
if([httpResponse statusCode]==200)
[receivedData setLength:0];
else
NSLog(#"Http-Reponse %u",[httpResponse statusCode]);
// HANDLE ERROR!
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
// append the new data to the receivedData
// receivedData is declared as a method instance elsewhere
[receivedData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
// HANDLE THE CONNECTION ERROR
// release the connection, and the data object
[connection release];
// receivedData is declared as a method instance elsewhere
[receivedData release];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// receivedData contains the data
// convert to string:
NSLog(#"finished loading: %#",[[[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding] autorelease]);
[connection release];
[receivedData release];
}
You'll want to expose the authentication functionality as a web service, then use the URL Loading code posted by Felix L. to initiate an actual connection to the web service.
You'll probably want to send a response from the server as XML, if so, you'll parse that response with an NSXMLParser, otherwise you can just send the response in whatever format you'd like and parse it appropriately.