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.
Related
i m working on a project that connect to server and download data from it. i like to support resume download if connection gets interrupt. my approach is to save the downloaded portion of data to a destination file; and if connection gets interrupted, i want to mark the downloaded portion using connection:didWriteData:totalBytesWritten:expectedTotalBytes and later resume from the stopped portion with server.
my code:
- (IBAction)connectToServer:(UIButton *)sender
{
// setup url and send request to server
NSURL *url = [NSURL URLWithString:BASED_URL];
self.urlRequest = [[NSMutableURLRequest alloc] initWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
self.urlConnection = [[NSURLConnection alloc] initWithRequest:self.urlRequest delegate:self];
// start receive data if connection established
if (self.urlConnection){
self.receivedData = [NSMutableData data];
NSLog(#"starting to receive data");
} else {
// handle error
NSLog(#"failed to connect to server");
}
}
- (void)doSomethingWithData
{
// handle data here
}
#pragma NSURLConnectionDataDelegate
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[self.receivedData setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// received data
[self.receivedData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
// error connection
NSLog(#"connection failed");
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"Data receiving succeed, received: %d bytes of data", [self.receivedData length]);
}
- (void)connection:(NSURLConnection *)connection didWriteData:(long long)bytesWritten totalBytesWritten:(long long)totalBytesWritten expectedTotalBytes:(long long)expectedTotalBytes
{
NSLog(#"not getting called");
}
my question is how come the "connection:didWriteData:totalBytesWritten:expectedTotalBytes" method never get called?
thanks so much!
chris
Have u added this in .h file:
#interface yourViewContoller : UIViewController <NSURLConnectionDataDelegate, NSURLConnectionDelegate>
According to Apple's documentation:
The NSURLConnectionDownloadDelegate protocol describes methods that should be implemented by the delegate of instances of NSURLConnection created using Newsstand Kit’s downloadWithDelegate: method.
Also, it says:
If you are using NSURLConnection directly, your delegate class should instead implement the methods defined in the NSURLConnectionDataDelegate protocol.
I have pickerview which is showing times in minuts like (5,10,20). If user will select any of the time he will get updates after selected time. And my application will run as usual but after 5 minutes a message will show some updates occured.
How I will implement this concept? What coding should I do?
As per my guess should I go with threading?
You could have a NSTimer which starts when you choose a time from your pickerview.
timer = [NSTimer scheduledTimerWithTimeInterval:pickerValueInSeconds target:self selector:#selector(updateMethod) userInfo:nil repeats:NO];
You choose no repeat, then in your updateMethod you make a request:
-(void)updateMethod
{
NSString *url = #"url...";
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:someURL]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:20.0]; // with some timeout interval.
// 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.
systemsData = [[NSMutableData data] retain];
}
else
{
// Inform the user that the connection failed.
NSLog(#"NSURLConnection failed!");
}
}
Now in your
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
and
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
you take care of the data or error and then start a new timer..
Note that you also need to implement
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[systemsData setLength:0];
}
and
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[systemsData appendData:data];
}
You can use a NSTimer.
You can read more about NSTimer here on stackoverflow or on the docs.
You can create a NSTimer and wait for the selected duration. Once timeout is completed
scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:
the message is fired to the selector. There are plenty of sample codes on google.
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've been reading several threads and questions about this issue but I didn't find the solution.
I have some asynchronous calls performed with
[NSURLConnection connectionWithRequest:anURLRequest delegate:self];
The problem is that I want the interface to be operative but it is blocked until the connection is finished.
Is this solved launching another thread? Where is exactly the problem?
EDIT
Ok, after retrieve data I parse it with NSXMLParser, that do it synchronously and blocks main thread. Is this correct? Then, maybe I need to parse in another thread. Anyone has a guide?
From the docs:
Messages to the delegate will be sent on the thread that calls this method. For the connection to work correctly the calling thread’s run loop must be operating in the default run loop mode.
Are you sure that this code is being called on a run loop in default mode and not from a thread created by yourself with a different type of run loop mode?
The UI should not be locking up when you use connectionWithRequest. Try creating a label in your UI and have your connection update it with the current amount of data, like so:
- (void)downloadContentFromUrl:(NSURL *)url {
NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
if (connection) {
receivedData = [[NSMutableData data] retain];
self.downloadProgressLabel.text = #"Downloading...";
} else {
// oh noes!
}
}
- (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
[receivedData setLength:0];
}
- (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[receivedData appendData:data];
int kb = [receivedData length] / 1024;
self.downloadProgressLabel.text = [NSString stringWithFormat:#"Downloaded\n%d kB", kb];
}
connectionWithRequest does indeed run in it's own thread - no need for you to worry about this. In fact it must be started from the main thread. Check out the NSUrlConnection doc for more info.
+ (id)connectionWithRequest:(NSURLRequest *)request delegate:(id)delegate];
This method should create an asynchronous-request (that means that it runs in the background and it doesn't block the UI). You should check if there's another class/method in your file that blocks the UI (for example NSData's '+ (NSData *)dataWithContentsOfURL:(NSURL *)URL').
I don't know if it could help anyone, but I've the same problem (asynchronous URL request blocking the UI) but it was due to:
NSLog(#"dataReceived: %#", data);
in the connectionDidReceiveData method.
In my case I was trying to update the UIProgressView.progress property. I calculated the new value like that
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[self.progress setProgress:self.downloadedData.length / self.fileSize ];
[self.downloadedData appendData:data];
}
Which doesn't work, I replaced this snippet of code with
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
self.downloadedSize += data.length;
[self.progress setProgress:self.downloadedSize / self.fileSize ];
[self.downloadedData appendData:data];
}
And now the progress view updates with no problem.
I am trying to speed up my application download speed. I used Asynchronous NSURLConnection to download contents from the server, it was working fine with one connection.
I use the code from this post to implement multiple delegate objects. Multiple NSURLConnection delegates in Objective-C
When I created 2 NSURLConnection objects, each one is trying to download different files.
The callback didReceiveData routine was called but the it only received data of the first NSURLConnection object until the first connection was done then it started to receive the data from the second NSURLConnection. I want these two connections to receive data at the same time,what should I do? Here is my current code.
-(IBAction) startDownloadClicked :(id) sender
{
while (bDownloading)
{
int nCurrentCon = 0;
while (nCurrentCon < 2)
{
[self downloadAFile:[filenameArray objectAtIndex:nCurrentCon]];
nCurrentCon++;
}
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.5]];
}
}
- (void) downloadAFile: (NSString*) filename
{
NSString* urlstr = #"ftp://myftpusername:password#hostname";
NSURLRequest* myreq = [NSURLRequest requestWithURL:[NSURL URLWithString:urlstr]];
DownloadDelegate* dd = [[DownloadDelegate alloc] init]; //create delegate object
MyURLConnection* myConnection = [[MyURLConnection alloc] initWithRequest:myreq delegate:dd
startImmediately:YES];
}
Then in my Delegate Object, I implemented these routines
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
[receiveBuffer setLength:0];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
NSLog(#"receiving data for %#", targetFileName); //the file name were set when this delegate object is initialized.
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(#"Download Failed with Error - %# %#",
[error localizedDescription],
[[error userInfo] objectForKey:NSErrorFailingURLStringKey]);
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"File %# - downloaded.", targetFileName);
}
Your code looks okay. I have a similar setup that works successfully (although there seems to be a limit of four concurrent conections).
The main difference between your and my code is that you use FTP while I use HTTP. Why don't you try it with HTTP connections just to see whether you have run into a restriction of FTP connections on the iPhone?