Is anybody able to help me get a string returned from an NSURLRequest on an iPhone app? I have to send some user credentials to a URL and it will return a customer ID number. That is what I need to be pulled in as a string, I am not used to doing working with servers or HTTP requests, so any help will be great. I have already read the Apple Docs about it and am a bit lost on this part.
This is a standard pattern async downloader:
In .h file:
NSMutableData *responseData;
And .m file:
-(void) execute {
NSString *urlString = #"http://www.google.com";
responseData = [[NSMutableData data] retain];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString]];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
}
-(void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
[responseData setLength:0];
}
-(void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[responseData appendData:data];
}
-(void) connectionDidFinishLoading:(NSURLConnection *)connection{
[connection release];
NSString *data = [[[NSString alloc] initWithData:responseData encoding:NSASCIIStringEncoding] autorelease];
NSLog(#"%#", data);
[responseData release];
}
This will download Google and outprint the content.
Related
I would like to know how do I get a return value 1 or 0 only.... back from an URL request asynchronously.
currently I do it in this way:
NSString *UTCString = [NSString stringWithFormat:#"http://web.blah.net/question/CheckQuestions?utc=%0.f",[lastUTCDate timeIntervalSince1970]];
NSLog(#"UTC String %#",UTCString);
NSURL *updateDataURL = [NSURL URLWithString:UTCString];
NSString *checkValue = [NSString stringWithContentsOfURL:updateDataURL encoding:NSASCIIStringEncoding error:Nil];
NSLog(#"check Value %#",checkValue);
this works, however it is blocking my main thread till I got a reply back from the URL, how do I set it so it will do it in a another thread instead of the main thread ?
EDIT: ANSWER
I end upcalling my function with this, it works well :)
[self performSelectorInBackground:#selector(shouldCheckForUpdate) withObject:nil];
you can use NSURLConnection class
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
[[[NSURLConnection alloc] initWithRequest:request delegate:self] autorelease];
and handle its response and errors using its delegate methods.
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
You can find implementation of NSURLConnection
Apple docs: Using NSURLConnection
How To Use iOS NSURLConnection By Example
Edit: Although NSURLConnection is provided by apple is more recommended way of placing URL request. But I found AFNetworking library very time saving, easy to implement and robust yet simple as third party implementation. You should give it a try.
try this :
.h:
NSMutableData *responseData;
.m:
- (void)load
{
NSURL *myURL = [NSURL URLWithString:#"http://www.example.com"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myURL cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:60];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
responseData = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[responseData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
[responseData release];
[connection release];
[textView setString:#"Unable to fetch data"];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"Succeeded! Received %d bytes of data",[responseData
length]);
NSString *txt = [[[NSString alloc] initWithData:responseData encoding: NSASCIIStringEncoding] autorelease];
}
Use NSURLConnection and make your request.
Then you may start synchronous or asynchronous connection with NSURLConnection's methods :
Loading Data Synchronously
+ sendSynchronousRequest:returningResponse:error:
Loading Data Asynchronously
+ connectionWithRequest:delegate:
– initWithRequest:delegate:
– initWithRequest:delegate:startImmediately:
– start
Check the NSURLConnection class in Apple Developer API Reference.
Shamelessly copy from https://gist.github.com/knmshk/3027474. All credits go to https://gist.github.com/knmshk.
xmlData = [[NSMutableData alloc] init];
NSURL *url = [NSURL URLWithString:
#"http://forrums.bignerdranch.com/smartfeed.php?"
#"limit=NO_LIMIT&count_limit20&sort_by=standard&"
#"feed_type=RSS2.0&feed_style=COMPACT"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
NSOperationQueue *queue = [[NSOperationQueue alloc]init];
[NSURLConnection sendAsynchronousRequest:request
queue:queue
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
if (error) {
xmlData = nil;
NSLog(#"error:%#", error.localizedDescription);
}
[xmlData appendData:data];
}];
There is an example in the iOS XCode documentation called LazyTableImages. This does an asynchronous URL as well as asynchronous image load into UITableView cells displayed on the screen after scrolling stops. Excellent example of protocols, asynchronous data handling, etc.
I have a problem now. I need to pass an transactionID and an user password to a rest service and it is suppose to return me a true/false value (in XML format). However, it is consistently returning me (null).. I am totally lost some one please help.
NSString *urlString = [NSString stringWithFormat:#"https://10.124.128.93:8443/axis2/services/C3WebService/completeWithdrawal Transaction?transactionId=%#&password=%#", _transactionID.text, _userPassword.text];
NSURL *url = [[NSURL alloc] initWithString:urlString];
NSString *result = [[NSString alloc] initWithContentsOfURL:url];
NSLog(#"%#",result );
My result is constantly returning me null. How do i continue from here?
.h:
NSMutableData *responseData;
.m:
- (void)load {
NSURL *myURL = [NSURL URLWithString:#"https://10.124.128.93:8443/axis2/services/C3WebService/completeWithdrawal Transaction?transactionId=%#&password=%#", _transactionID.text, _userPassword.text];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myURL
cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
timeoutInterval:60];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
responseData = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[responseData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[responseData release];
[connection release];
[textView setString:#"Unable to fetch data"];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"Succeeded! Received %d bytes of data",[responseData
`enter code here` length]);
NSString *txt = [[[NSString alloc] initWithData:responseData encoding: NSASCIIStringEncoding] autorelease];
}
Consider using NSURLConnection which has a callback for the result and also a callback to get detailed error details. It als doesn't execute on the UI thread (doesn't hang UI during the request).
NSURL *url = [NSURL URLWithString:#"http://www.mysite.com"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
[request setHTTPMethod:#"GET"];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
Then you can implement the delegate methods to get the error, the data and other details:
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[responseData appendData:data];
}
- (void) connectionDidFinishLoading:(NSURLConnection *)connection {
[connection release];
NSString* responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
NSLog(#"result: %#", responseString);
[responseString release];
}
- (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
NSLog(#"error - read error object for details");
}
You might try using "initWithContentsOfURL:encoding:error:" instead and check "error". Also, use Charles or other http sniffer and compare results to a straight browser request ( did you check results in a browser?)
Using the following code to make my requests, what i've noticed is that data will sometimes not be loaded or fully loaded, this always happens when the app first starts. Any thoughts? I've tried putting in [tableView refresh] in the connectionDidFinishLoading, but that doesn't seem to help, any ideas? Thanks for looking
.h:
NSMutableData *responseData;
.m:
- (void)load {
NSURL *myURL = [NSURL URLWithString:#""];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myURL
cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
timeoutInterval:60];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
responseData = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[responseData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[responseData release];
[connection release];
[textView setString:#"Unable to fetch data"];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"Succeeded! Received %d bytes of data",[responseData
length]);
NSString *txt = [[[NSString alloc] initWithData:responseData encoding: NSASCIIStringEncoding] autorelease];
}
Are you sure your data did not load? Try [tableView reloadData]; instead of refresh.
i get the follwing error below when i run the program given below
Error:
Error Domain=NSURLErrorDomain Code=-1000 "bad URL" UserInfo=0x5948b80 {NSUnderlyingError=0x5948ac0 "bad URL", NSLocalizedDescription=bad URL}
wat i need to do plz suggest me
thank u..
the code is given below
#implementation WebSampleViewController
- (void)viewDidLoad
{
[super viewDidLoad];
dataWebService = [[NSMutableData data] retain];
NSMutableURLRequest *request = [[NSMutableURLRequest requestWithURL:[NSURL URLWithString:#" http://www.googleapis.com/customsearch"]] retain];
NSURLConnection *myConnection = [NSURLConnection connectionWithRequest:request delegate:self];
[myConnection start];
[super viewDidLoad];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[dataWebService setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[dataWebService appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSString *responseString = [[NSString alloc] initWithData:dataWebService encoding:NSUTF8StringEncoding];
NSLog(#"Response: %#",responseString);
[responseString release];
[dataWebService release];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(#"Error during connection: %#", [error description]);
}
You should not retain request instance of type NSMutableURLRequest.
You have an leading white space in your String URL.
Use the below code .
NSMutableURLRequest *request = [[NSMutableURLRequest requestWithURL:[NSURL URLWithString:#"http://www.googleapis.com/customsearch"]];
I think, you should check your URL , I give the same "Not Found" as on iPhone.
Try it without the space at the beginning of your URL string.
You have to remove whitespace in your url
I have a NSURLConnection which I am calling every time -(void)viewWillAppear:animated is called (that's only for now, it's just for testing)
I am doing it like this
receivedData = [[NSMutableData data] retain];
NSString *urlString = #"<URL hidden>";
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString] cachePolicy:NSURLRequestReturnCacheDataElseLoad timeoutInterval:30.0];
[NSURLConnection connectionWithRequest:request delegate:self];
Then I have these three delegate methods:
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[receivedData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
NSString *returnString = [[NSString alloc] initWithData:receivedData encoding:NSUTF8StringEncoding];
usersPhotos = [[NSMutableArray alloc] initWithArray:[[returnString JSONValue] objectForKey:#"data"]];
[self loadAnnotations];
NSLog(#"%#", returnString);
[returnString release];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[self loadAnnotations];
}
Even though I am sure the returnStringshould change (I can visit the site in urlString and confirm it has changed) it is always the same.
It is as if it reuses the data that it retrieves from the first connection.
Does anyone know why this is?
it should be your cache policy, i will update in a second with the correct info.
UPDATE
Try setting your cahce policy to: cachePolicy:NSURLRequestReloadIgnoringCacheData
It should be:
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:30.0];
You need to empty your buffer if you're re-using it.
Add this method:
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[receivedData setLength:0];
}