The standard examples I'm seeing in iOS to do a simple GET HTTP connection is to:
NSString *finalURLstring = #"http://www.somesite.com?value=2";
NSURL *url = [NSURL URLWithString:finalURLstring];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
NSURLConnection *urlConnection = [NSURLConnection connectionWithRequest:request delegate:self];
Then implement these functions:
-(void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
-(void) connection:(NSURLConnection*)connection didReceiveData:(NSData*)data
-(void) connectionDidFinishLoading:(NSURLConnection*)connection
And if you have multiple connections you just create multiple NSURLConnections and compare them in connectionDidFinishLoading:
if (connection == urlConnection1)
// do something
else if (connection == urlConnection2)
// do something else
The issue with this is that you are created a new connection to the server each time right? Is it possible to create your NSURLConnection and reuse it? i.e. keep the connection open so you can make multiple calls instead of creating new connections on every call to the server?
Thanks for your help,
-David
NSURLConnection does that already. It reuses the existing connections.. Check out this accepted answer in
this post. You'll get your answer for your question..
Related
I've read through tons of messages saying the same thing all over again : when you use a NSURLConnection, delegate methods are not called. I understand that Apple's doc are incomplete and reference deprecated methods, which is a shame, but I can't seem to find a solution.
Code for the request is there :
// Create request
NSURL *urlObj = [NSURL URLWithString:url];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:urlObj cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:30];
[request setValue:#"gzip" forHTTPHeaderField:#"Accept-Encoding"];
if (![NSURLConnection canHandleRequest:request]) {
NSLog(#"Can't handle request...");
return;
}
// Start connection
dispatch_async(dispatch_get_main_queue(), ^{
self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES]; // Edited
});
...and code for the delegate methods is here :
- (void) connection:(NSURLConnection *)_connection didReceiveResponse:(NSURLResponse *)response {
NSLog(#"Receiving response: %#, status %d", [(NSHTTPURLResponse*)response allHeaderFields], [(NSHTTPURLResponse*) response statusCode]);
self.data = [NSMutableData data];
}
- (void) connection:(NSURLConnection *)_connection didFailWithError:(NSError *)error {
NSLog(#"Connection failed: %#", error);
[self _finish];
}
- (void) connection:(NSURLConnection *)_connection didReceiveData:(NSData *)_data {
[data appendData:_data];
}
- (void)connectionDidFinishDownloading:(NSURLConnection *)_connection destinationURL:(NSURL *) destinationURL {
NSLog(#"Connection done!");
[self _finish];
}
There's not a lot of error checking here, but I've made sure of a few things :
Whatever happens, didReceiveData is never called, so I don't get any data
...but the data is transfered (I checked using tcpdump)
...and the other methods are called successfully.
If I use the NSURLConnectionDownloadDelegate instead of NSURLConnectionDataDelegate, everything works but I can't get a hold on the downloaded file (this is a known bug)
The request is not deallocated before completion by bad memory management
Nothing changes if I use a standard HTML page somewhere on the internet as my URL
The request is kicked off from the main queue
I don't want to use a third-party library, as, ultimately, these requests are to be included in a library of my own, and I'd like to minimize the dependencies. If I have to, I'll use CFNetwork directly, but it will be a huge pain in the you-know-what.
If you have any idea, it would help greatly. Thanks!
I ran into the same problem. Very annoying, but it seems that if you implement this method:
- (void)connectionDidFinishDownloading:(NSURLConnection *)connection destinationURL:(NSURL *)destinationURL
Then connection:didReceiveData: will never be called. You have to use connectionDidFinishLoading: instead... Yes, the docs say it is deprecated, but I think thats only because this method moved from NSURLConnectionDelegate into NSURLConnectionDataDelegate.
I like to use the sendAsynchronousRequest method.. there's less information during the connection, but the code is a lot cleaner.
[NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
if (data){
//do something with data
}
else if (error)
NSLog(#"%#",error);
}];
From Apple:
By default, a connection is scheduled on the current thread in the
default mode when it is created. If you create a connection with the
initWithRequest:delegate:startImmediately: method and provide NO for
the startImmediately parameter, you can schedule the connection on a
different run loop or mode before starting it with the start method.
You can schedule a connection on multiple run loops and modes, or on
the same run loop in multiple modes.
Unless there is a reason to explicitly run it in [NSRunLoop currentRunLoop],
you can remove these two lines:
[connection scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
[connection start];
or change the mode to NSDefaultRunLoopMode
NSURLConnection API says " ..delegate methods are called on the thread that started the asynchronous load operation for the associated NSURLConnection object."
Because dispatch_async will start new thread, and NSURLConnection will not pass to that other threat the call backs, so do not use dispatch_async with NSURLConnection.
You do not have to afraid about frozen user interface, NSURLConnection providing only the controls of asynchronous loads.
If you have more files to download, you can start some of connection in first turn, and later they finished, in the connectionDidFinishLoading: method you can start new connections.
int i=0;
for (RetrieveOneDocument *doc in self.documents) {
if (i<5) {
[[NSURLConnection alloc] initWithRequest:request delegate:self];
i++;
}
}
..
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
ii++;
if(ii == 5) {
[[NSURLConnection alloc] initWithRequest:request delegate:self];
ii=0;
}
}
One possible reason is that the outgoing NSURLRequest has been setup to have a -HTTPMethod of HEAD. Quite hard to do that by accident though!
In my iPad application, I want to load a modal window with some data.
But those data can be retrieved from a web service call. So, I have created another class and in that class's connectionDidFinishLoading I can have the response data. As the web service call is asynchronous, I have to wait for the data to load the modal window. Can anyone help me with some example code? Should I think in different way?
Thank you all for the prompt reply.
My problem was solved using the NSNotificationCenter. This tutorial was helpful http://www.youtube.com/watch?v=WB-QCv_4ANU&feature=plcp
Either you can load modal window from connectionDidFinishLoading method. Or you can use delegates to pass data from connectionDidFinishLoading metod to the window that you are going to present. Refer this tutorial.
You start the connection this way:
NSURL *url = [NSURL URLWithString:<#your url string#>];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url];
myData = [[NSMutableData alloc] init];
con = [[NSURLConnection alloc] initWithRequest:request delegate:self];
And you need to implement NSURLConnectionDelegate delegate.
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
//append data to your NSMutableData object
[myData appendData: data];
}
- (void)connection:(NSURLConnection *)connection
didFailWithError:(NSError *)error
{
//handle the error
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
//here you can use your NSMutableData object, fill your window with the data etc.
<#your code#>
}
This is just an example. You can read more about it in NSURLConnectionDelegate Protocol Reference.
I would like to know how I can stop/abort a NSURLConnection while it is performing it load request.
The reason I would like to know is that, I am parsing an XML using NSURLConnection and sometimes the time taken to get a response is too long.
here is my code to make things clearer...
I am parsing an XML using NSXMLParser and loading the req with my soap message before I request it using NSURLConnection
conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
if (conn)
{
webData = [[NSMutableData data] retain];
}
}
The following piece of code is what is standard
-(void) connection:(NSURLConnection *) connection
didReceiveResponse:(NSURLResponse *) response
{
[webData setLength: 0];
}
-(void) connection:(NSURLConnection *) connection
didReceiveData:(NSData *) data
{
[webData appendData:data];
}
In this, sometimes the time taken for the program to get to connection didReceiveData is too long and the user would need to abort that operation.
So I would like to know if this is possible.
I know how to abort after it starts parsing by using [parser abort] but I dont know how to abort the NSURLConnection.
It would be great if someone could help me out with this.
Use [conn cancel]; to stop an ongoing download.
This question already has answers here:
UIWebView to view self signed websites (No private api, not NSURLConnection) - is it possible?
(9 answers)
Closed 6 years ago.
We have an iOS app that uses a UIWebView to display content. We load it up with data with code that looks like this:
NSURL *url = [NSURL URLWithString:myURLString];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[_webView setDelegate:self];
[_webView loadRequest:request];
This used to work fine with HTTP requests, but now we are using HTTPS against a server with a self-signed SSL certificate. When the above is run, the webView:didFailLoadWithError: delegate method gets called, with this error:
The certificate for this server is invalid. You might be connecting to a server that is pretending to be "blah.blah.blah.com" which could put your confidential information at risk."
I would like to simply ignore the invalid certificate and go on with the request, as one can do in Mobile Safari.
I have seen how to work around this issue when using NSURLConnection (see HTTPS request on old iphone 3g, for example), but what can one do with a UIWebView?
I imagine that I could rework the code so that it uses NSURLConnection to make the requests and then puts the results into the web view by calling its loadHTMLString:baseURL: method, but that's going to get complicated when the pages have images, CSS, JavaScript, and so on. Is there an easier way?
Please note: This API is currently unsupported, and should really only be used in a safe testing environment. For further details, take a look at this CocoaNetics article.
[NSURLRequest setAllowsAnyHTTPSCertificate:YES forHost:[url host]]; will allow you to ignore certificate errors. You will also need to add the following to the beginning of your file to grant you access to these private APIs:
#interface NSURLRequest (DummyInterface)
+ (BOOL)allowsAnyHTTPSCertificateForHost:(NSString*)host;
+ (void)setAllowsAnyHTTPSCertificate:(BOOL)allow forHost:(NSString*)host;
#end
Just so everyone knows... the above use of hidden interfaces WILL NOT BE ACCEPTED BY APPLE. They look for use of private APIs and it is NOT an acceptable solution. So, please do not go posting the solution described above around as THE way to fix it because, although it works, it will buy you a rejection in the AppStore. That makes it useless.
What follows is the ACCEPTABLE method of ignoring invalid server certificates. You need to use NSURLConnection and load the data for the webpage manually like so:
.
.
.
//Create a URL object.
url = [NSURL URLWithString:urlAddress];
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:requestObj delegate:self];
[connection start];
}
And then, in your delegate....
- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
{
return [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust];
}
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust])
{
[challenge.sender useCredential:[NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust] forAuthenticationChallenge:challenge];
}
else
{
[challenge.sender continueWithoutCredentialForAuthenticationChallenge:challenge];
}
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[resultData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSString *htmlString = [[NSString alloc] initWithBytes:[resultData bytes] length:[resultData length] encoding:NSUTF8StringEncoding];
[webView loadHTMLString:htmlString baseURL:url];
}
#end
Where resultData is an NSMutableData you instantiated earlier and where url and urlAddress are both things you've instantiated and filled in elsewhere.
Unfortunately, I currently don't know a way to get the actual UIWebView to load a page directly without having a valid certificate.
Yours, GC
It turns out that once the site is authenticated by a cancelled NSURLConnection, the UIWebView can make requests to the site. There is a complete explanation here.
As far as I know, that isn't possible with just UIWebView. As I understand it, you need to use NSURLConnection to handle all the HTTP/HTTPS mojo and then feed its results to the UIWebView via -loadHtmlString:baseURL: or -loadData:MIMEType:textEncodingName:baseURL:.
I need to check and evaluate the HTTP Status Codes in my iPhone app. I've got an NSURLRequest object and an NSURLConnection that successfully (I think) connect to the site:
// create the request
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.apple.com/"]
cachePolicy:NSURLRequestUseProtocolCachePolicy
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 that will hold
// the received data
// receivedData is declared as a method instance elsewhere
receivedData=[[NSMutableData data] retain];
} else {
// inform the user that the download could not be made
}
I got this code here: https://web.archive.org/web/20100908130503/http://developer.apple.com/iphone/library/documentation/Cocoa/Conceptual/URLLoadingSystem/Tasks/UsingNSURLConnection.html
But it doesn't (as far as I can see) say anything about accessing HTTP Status codes.
How to make a connection to a site and then check the HTTP Status Codes of that connection?
This is how I do it:
#pragma mark -
#pragma mark NSURLConnection Delegate Methods
- (void)connection:(NSURLConnection*)connection didReceiveResponse:(NSURLResponse*)response {
NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;
int responseStatusCode = [httpResponse statusCode];
}
But I'm using an asynchronous NSURLConnection, so this may not help you. But I hope it does anyway!