I am developing an app that plays radio stations. The links for the radio stations are stored on the server and added via a back-end solution.
All information for a radio station such as: name, frequency and of course the stream link are generated by the backend and stored in a XML file. This is my first project so I don't have a clear idea how to download that file, which is stored on a password protected directory.
Do i have to download it via sftp or https?And does anyone have an idea how to perform this task?
Any help would be greatly appreciated.
Thank you in advance.
Granit
You could use NSURLConnection, a good implementation here.To do what you want to do, plain and simple
NSData *responseData = [NSData dataWithContentsOfURL:url];
This happens asynchronously i.e, non - blocking call
dispatch_async(queue, ^{
NSData *responseData = [NSData dataWithContentsOfURL:url];
dispatch_sync(dispatch_get_main_queue(), ^{
// handle your responesData here.
//convert data to nsstring or something then use a parser to parse details.
});
});
Look here for XML Parsing
For basic authentication try this
NSURL *URL = [NSURL URLWithString:url];
NSURLRequest *request = [NSURLRequest requestWithURL:URL
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:30.0];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
[connection start];
[connection release];
// NSURLConnection Delegates
- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{ if ([challenge previousFailureCount] == 0) {
NSLog(#"received authentication challenge");
NSURLCredential *newCredential = [NSURLCredential credentialWithUser:#"USER"
password:#"PASSWORD"
persistence:NSURLCredentialPersistenceForSession];
NSLog(#"credential created");
[[challenge sender] useCredential:newCredential forAuthenticationChallenge:challenge];
NSLog(#"responded to authentication challenge");
}
else {
NSLog(#"previous authentication failure");
}
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
...
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
...
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
...
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
...
}
Give your credentials in the willSendRequestForAuthenticationChallenge method or if you want an even better implementation see this, it is an synchronous NSURLConnection subclass imp that also handles authentication.
Related
I have looked at NSURLConnectionDelegate connection:didReceiveData not working already, but there didn't seem to be any good result from that, so I am curious why I am not able to get any data.
I put in breakpoints in didReceiveResponse and didReceiveData.
It does print out "connection succeeded", so I know that the connection is started.
I am using ARC for memory management.
- (void)load {
request = [NSMutableURLRequest requestWithURL:myURL
cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
timeoutInterval:60];
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
if (conn) {
[conn start];
NSLog(#"connection succeeded, %s", [myURL description]);
responseData = [NSMutableData data];
} 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];
}
UPDATE:
To see how I test this look at Asynchronous unit test not being called by SenTestCase.
I did implement the two methods mentioned by jonkroll, in his answer, I just didn't show them, but, they also aren't being called.
I had added [conn start] only because it wasn't working, and I was hoping that may solve it, but no such luck.
When you declare your connection like this:
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
You are creating a local pointer. When your method completes, since it was the last strong reference to the NSURLConnection, ARC releases it. You need to use a strong ivar (and/or) property to hold a strong reference to the NSURLConnection you create.
Edit
Here is basic sample of code that I tested in a sample project. Give it a run. Verbose logging helps.
#implementation <#Your class here#> {
// With ARC ivars are strong by default
NSMutableData *_downloadedData;
NSURLConnection *_connection;
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
NSHTTPURLResponse *realResponse = (NSHTTPURLResponse *)response;
if (realResponse.statusCode == 200){
// Really any 2** but for example
_downloadedData = [[NSMutableData alloc] init];
NSLog(#"Good response");
} else {
NSLog(#"Bad response = %i",realResponse.statusCode);
}
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
if (connection == _connection){
[_downloadedData appendData:data];
NSLog(#"Getting data...");
}
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
if (connection == _connection){
_connection = nil;
NSLog(#"We're done, inform the UI or the delegates");
}
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{
_connection = nil;
NSLog(#"Oh no! Error:%#",error.localizedDescription);
}
- (void)load {
NSURL *url = [NSURL URLWithString:#"http://www.google.com/"];
NSURLRequest *request = [NSMutableURLRequest requestWithURL:url
cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
timeoutInterval:60];
// Assign strong pointer to new connection
_connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
NSLog(#"Connection was initialized? = %#",(!!_connection)?#"YES":#"NO");
}
#end
The NSURLConnection method initWithRequest starts an asynchronous request for data from a url. Because the request is done asynchronously you can't expect to work with the response in the same method in which the request is invoked. Instead you need to do so in the NSURLConnection's delegate callback methods. You have already implemented didReceiveResponse: and didReceiveData:, but there are a couple others that will be useful to you.
If you want to look at the contents of the response you should do so in connectionDidFinishLoading:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// response is complete, do something with the data
NSLog(#"%#", responseData);
}
The fact that your code prints out "connection succeeded" doesn't really mean that the request was successful, only that the NSURLConnection object was created successfully. To test whether there was a problem with the connection you can implement the delegate method connection:didFailWithError:
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(#"Connection failed! Error - %# %#",
[error localizedDescription],
[[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
}
Also there is no need to call [conn start]. The request will be started automatically when you call initWithRequest:
I suggest reading Apple's documentation on Using NSURLConnection for more details.
I have trouble finding info on this topic. Please help me out here.
I need to pass arguments via POST or GET method to my web server and get a reply.
Basically, if using GET method, I want to do something like server.com/?user=john&password=smith and receive the dynamically generated HTML code that is done with my php script. All this without using the web browser on my app.
How is it usually done?
You'll want to look into NSMutableURLRequest and NSURLConnection.
For example, you could use them like this do to a GET request to your server:
- (void)loginUser:(NSString *)username withPassword:(NSString *)password {
// GET
NSString *serverURL = [NSString stringWithFormat:#"http://yourserver.com/login.php?user=%#&pass=%#", username, password];
NSURL *url = [NSURL URLWithString:serverURL];
NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
NSURLConnection *connection = [NSURLConnection connectionWithRequest:req delegate:self];
if (connection) {
connectionData = [[NSMutableData alloc] init];
}
}
This will send an asynchronous GET request to your server with the query string containing username and password.
If you want to send username and password using a POST request, the method would look something like this:
- (void)loginUser:(NSString *)username withPassword:(NSString *)password {
// POST
NSString *myRequestString = [NSString stringWithFormat:#"user=%#&pass=%#",username,password];
NSData *myRequestData = [NSData dataWithBytes: [myRequestString UTF8String] length: [myRequestString length]];
NSURL *url = [NSURL URLWithString:#"http://yourserver.com/login.php"];
NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
[req setHTTPMethod: #"POST"];
[req setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"content-type"];
[req setHTTPBody: myRequestData];
NSURLConnection *connection = [NSURLConnection connectionWithRequest:req delegate:self];
if (connection) {
connectionData = [[NSMutableData alloc] init];
}
}
In order to get the response from the server, you will need to implement the NSURLConnection delegate methods, for example:
#pragma mark -
#pragma mark NSURLConnection delegate methods
#pragma mark -
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
// Called if you have an .htaccess auth. on server
NSURLCredential *newCredential;
newCredential = [NSURLCredential credentialWithUser:#"your_username" password:#"your_password" persistence:NSURLCredentialPersistenceForSession];
[[challenge sender] useCredential:newCredential forAuthenticationChallenge:challenge];
}
-(void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
[connectionData setLength: 0];
}
-(void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[connectionData appendData:data];
}
-(void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[connectionData release];
}
-(void) connectionDidFinishLoading:(NSURLConnection *)connection {
NSString *content = [[NSString alloc] initWithBytes:[connectionData bytes]
length:[connectionData length] encoding: NSUTF8StringEncoding];
// This will be your server's HTML response
NSLog(#"response: %#",content);
[content release];
[connectionData release];
}
References:
NSMutableURLRequest Class Reference
NSURLConnection Class Reference
Hope this helps :)
Usually this is done using a NSURLConnection. You can also use NSString's method stringWithContentsOfURL.
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 want to download a wav file from a web service, cache it on the iphone and playback it using AVAudioPlayer. Using NSFileHandle and NSURLConnection seems a viable solution when dealing with relatively large files. However, after running the app in the simulator I don't see any saved file under the defined directory (NSHomeDirectory/tmp). Below is my basic code. Where am I doing wrong? Any thoughts are appreciated!
#define TEMP_FOLDER [NSHomeDirectory() stringByAppendingPathComponent:#"tmp"]
- (void)downloadToFile:(NSString*)name
{
NSString* filePath = [[NSString stringWithFormat:#"%#/%#.wav", TEMP_FOLDER, name] retain];
self.localFilePath = filePath;
// set up FileHandle
self.audioFile = [[NSFileHandle fileHandleForWritingAtPath:localFilePath] retain];
[filePath release];
// Open the connection
NSURLRequest* request = [NSURLRequest
requestWithURL:self.webURL
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];
NSURLConnection* connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}
#pragma mark -
#pragma mark NSURLConnection methods
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data
{
[self.audioFile writeData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError*)error
{
NSLog(#"Connection failed to downloading sound: %#", [error description]);
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
[connection release];
[audioFile closeFile];
}
NSFileHandle fileHandleForWritingAtPath: requires the file to already exist. How are you creating the file?
Where is your
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
delegate?
this is where you should write/save the file.
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data
this is where you append the data you receive.
I'm trying to get a small twitter client running and I ran into a problem when testing API calls that require authentication.
My password has special characters in it, so when I try to use the following code it doesn't work.
NSString *post = [NSString stringWithFormat:#"status=%#", [status stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSData *postData = [post dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:#"%d", [postData length]];
NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:#"http://%#:%##%#/statuses/update.json", username, password, TwitterHostname]];
[request setURL:url];
[request setHTTPMethod:#"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setHTTPBody:postData];
NSURLResponse *response;
NSError *error;
[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
I started looking into base64 and putting the authentication into the headers. I found Dave Dribin's post on his base64 implementation, and it seemed to make sense. However when I tried to use it the compiler started complaining about how it couldn't find the openssl libraries. So I read that I needed to link in the libcrypto library, but it doesn't seem to exist for iphone.
I've also read people saying that apple won't allow apps that use crypto libraries, which doesn't make sense to me.
So now I'm kinda stuck and confused. What's the easiest way to get basic authentication into my app?
Cheers
Two things. Firstly you have to use the async methods rather than the synchronous/class method.
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:req]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:30.0];
// create the connection with the request
// and start loading the data
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
The authentication is managed by implementing this method in your delegate:
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge;
And you'll probably also need to implement these methods too:
- (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;
Using the async method tends to give a better user experience anyway so despite the extra complexity is worth doing even without the ability to do authentication.
You can directly aslo write download the username & password in main URL i.e https://username:password#yoururl.com/
First of all you need to call NSURLConnection Delegate file:-
(BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace
{
return YES;
}
and then call
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
if ([challenge previousFailureCount] == 0)
{
NSURLCredential *newCredential;
newCredential = [NSURLCredential credentialWithUser:#"username"
password:#"password"
persistence:NSURLCredentialPersistenceForSession];
NSLog(#"NEwCred:- %# %#", newCredential, newCredential);
[[challenge sender] useCredential:newCredential forAuthenticationChallenge:challenge];
}
else
{
[[challenge sender] cancelAuthenticationChallenge:challenge];
NSLog (#"failed authentication");
}
}