currently I'm trying to read a file in a local server through URLConnection and URlRequest. It seems to work as it should until the changes in the file don't have any effect when I do the request again. Here's the code of how I'm building the request:
-(void)openURLConnectionWithString:(NSString *)urlString{
NSTimeInterval timeout= 120;
self.request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString] cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:timeout];
self.urlConnection = [NSURLConnection connectionWithRequest:request delegate:self];
if(urlConnection){
NSLog(#"Connecting...");
self.receivedData = [NSMutableData data];
}else{
NSLog(#"Connection failed!");
}
}
And this is how I make use of the class that contains the function above:
AsyncScheduleParser *getSchedule = [[AsyncScheduleParser alloc] init];
getSchedule.delegate = self;
[getSchedule openURLConnectionWithString:#"http://localhost/scheduleC.txt"];
[getSchedule release];
Only if I change the name of the file the changes appear once I read it again.
Don't forget to clean up all relevant objects (such as self.receivedData) once the request is completed. The best solution would be to simply create a new object for each request you're executing, and releasing this object once you're done.
Related
I am trying to set up a cache, however the method I am using 'as below' is not being accessed by the thread.
- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse
I am initializing the connection like this, and connectionDidFinishLoading is accessed so I am not sure what I am missing.
- (IBAction)searchRequest:(NSData *)postBodyData
{
//Set database address
NSMutableString *databaseURL = [[NSMutableString alloc] initWithString:#"https://127.0.0.1:88"];
NSURL *url = [NSURL URLWithString:databaseURL];
NSString *postLength = [NSString stringWithFormat:#"%d", [postBodyData length]];
//SynchronousRequest to grab the data, also setting up the cachePolicy
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:5.0]; //if request dose not finish happen within 60 second timeout.
// NSInputStream *fileStream = [NSInputStream inputStreamWithData:postBodyData];
[request setHTTPMethod: #"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/octet-stream" forHTTPHeaderField:#"content-type"];
[request setHTTPBody:postBodyData];
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:request 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 from the connection:didFailWithError method
}
}
any help would be appreciated.
connection:willCacheResponse: is only called in cases when the response will be cached. POST requests are not cacheable in most cases. (More details: Is it possible to cache POST methods in HTTP?)
You should probably look at something like MKNetworkKit which handles a lot of this kind of caching, particularly for REST protocols.
You can also look at Drop-in offline caching for UIWebView. You'd have to modify it significantly, but NSURLProtocol can be used to solve this kind of problem. AFCache is currently working to integrate this approach, and is another toolkit to consider. (Read through the comments in the blog post for more background on the issues.)
I am trying to use the ASIDownloadCache from the ASIHTTPRequest library. I think I have it almost set up but the data I am printing to the log is a bunch of numbers.. I think it might be a formatting problem.. but I would like to run it past someone with more experience first to make sure I'm doing it correctly and then to hopefully help me fix the issue.
The code belows shows you how I am setting up my cache, I am using this view for several data sets, hence the need to use an if statement so that I am only setting up the cache on specific data.
- (IBAction)setRequestString:(NSString *)string
{
//Set database address
NSMutableString *databaseURL = [[NSMutableString alloc] initWithString:#"http://***.***.***.***:8888/codeData/"]; // iphone development
//PHP file name is being set from the parent view
[databaseURL appendString:string];
//call ASIHTTP delegates (Used to connect to database)
NSURL *url = [NSURL URLWithString:databaseURL];
checkDataSet = [[NSString alloc] initWithFormat:string]; //Loads ICMfg.xml into checkDataSet for setting up cache
//Create If statments here
if ([checkDataSet isEqualToString:#"ICMfg.xml"]) {
//Cache stuff goes in here
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request setDownloadCache:[ASIDownloadCache sharedCache]];
[request setCacheStoragePolicy:ASICachePermanentlyCacheStoragePolicy];
[request setCachePolicy:ASIOnlyLoadIfNotCachedCachePolicy];
[request setSecondsToCache:60*60*24*30]; // Cache for 30 days
[request setDelegate:self]; // A delegate must be specified
[request startSynchronous];
//[request setDidFinishSelector:#selector(requestFinished:)]; // And an appropriate
}
else
{
//this else statments lets all of the other datasets come through here
ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
[request setDelegate:self];
[request startAsynchronous];
}
}
From here, when [checkDataSet isEqualToString:#"ICMfg.xml"] is true it will set the cache parameters and then calls the following method where I get everything ready to parse my information
- (void)requestFinished:(ASIHTTPRequest *)request
{
if ([checkDataSet isEqualToString:#"ICMfg.xml"]) {
BOOL success = [request didUseCachedResponse];
NSLog(#"------------>>>>>>> Success is %#\n", (success ? #"YES" : #"NO"));
responseString = [request responseString];
capturedResponseData = [responseString dataUsingEncoding:NSUTF8StringEncoding];
NSLog(#"%#", capturedResponseData); //this prints out the weird data.
[self startTheParsingProcess:capturedResponseData];
}
else
{
responseString = [request responseString]; //Pass requested text from server over to NSString
capturedResponseData = [responseString dataUsingEncoding:NSUTF8StringEncoding];
[self startTheParsingProcess:capturedResponseData];
}
}
From here, I check my nslog to see the result of that NSlog and it spits out a bunch of numbers, below is a small section of the output. The next step for me is to check to see if anything is actually being parsed.. and also to see if the cache is working or not.. then I need to figure out hopefully with your help how to format the data correctly if thats my main problem..
also I would like to ask how to get this working asynchronously as currently I can only get it to work synchonosly.
2011-11-09 09:29:55.216 code[3968:207] ------------>>>>>>> Success is YES
2011-11-09 09:29:55.239 code[3968:207] <3c3f786d 6c207665 7273696f 6e3d2231 2e302220 656e636f 64696e67 3d225554 462d3822 3f3e0d0a 3c494345 6e673e3c 52657375 6c742044 42566572 73696f6e 3d223132 33223e3c 5461626c 65733e3c 5461626c 65205461 626c654e 616d653d 2249434d 6667223e 3c526f77 733e3c52 6f77204d 414e5546 41435455 52455249 443d2237 30362220 4d414e55 46414354 55524552 3d22412d 445a4722 2049534c 4f434b4d 414e5546 41435455 5245523d 22462220 49535645 4849434c 453d2246 223e3c2f 526f773e 3c526f77 204d414e 55464143 54555245 5249443d 22333138 22204d41 4e554641 43545552 45523d22 412e522e 452e2220 49534c4f 434b4d41 4e554641 43545552 45523d22 46222049
any help would be greatly appreciated.
I don't see anything that immediately sticks out in your code as wrong.
The NSLog() is printing an NSData object, which is binary data so the hexadecimal numbers you are seeing are the representations of the bytes which is exactly what you would expect.
The NSData Class Reference:
description
Returns an NSString object that contains a hexadecimal
representation of the receiver’s contents.
(NSString *)description
Return Value
An NSString object that contains a hexadecimal representation of the receiver’s contents in
NSData property list format.
If you want to print out the string representation of this data, use:
NSString *capturedResponseString = [NSString stringWithUTF8String:[capturedResponseData bytes]];
I wonder how I can check if a file exist on a server or not, without downloading the data first.
I have around 30 different objects and some of them is connected to a movie on a server. At the moment I use NSData to control if the the URL exist, and then shows the movie, or if it doesn't and then alerts the user that there is no video for that object. The code I use for the moment:
NSString *fPath = [[NSString alloc] initWithFormat:#"http://www.myserver/%#", [rows idNr]];
NSURL *videoURL = [NSURL URLWithString:fPath];
NSData *videoData = [NSData dataWithContentsOfURL:videoURL];
url = [NSURL URLWithString:fPath];
[fPath release];
if (videoData) {
[self performSelectorOnMainThread:#selector(playVideo:) withObject:url waitUntilDone:NO];
} else {
NSLog(#"videodata false");
errorLabel.hidden = NO;
activityView.hidden = YES;
}
"rows idNr" is the name of the object. This method is doing what I want, but the problem is that with NSData it first "downloading" the file, and when the URL is validated as a file, the movie is loading once again in the movieplayer. This means that it takes twice as long to load the file.
Suggestions?
It took me a while to dig out my answer to one of the previous questions on this topic. Quote:
You can use a NSMutableURLRequest to send a HTTP HEAD request
(there’s a method called setHTTPMethod). You’ll get the same
response headers as with GET, but you won’t have to download the whole
resource body. And if you want to get the data synchronously, use the
sendSynchronousRequest… method of NSURLConnection.
This way you’ll know if the file exists and won’t download it all if it does.
Make an URLConnecion object with desired url request and add NSURLConnectionDelegate into .h file like I want to check "yoururl" is exist or not then you need to do is
NSURLRequest *urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString: #"http://www.google.com"]];
NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];
and then you can track http status code in delegate function of NSURLConnectionDelegate
-(void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
int code = [(NSHTTPURLResponse *)response statusCode];
if (code == 404)
{
// website not found
// do your stuff according to your need
}
}
You can also find various status code here.
NSError *err;
if ([videoURL checkResourceIsReachableAndReturnError:&err] == NO)
NSLog(#"wops!");
Here's the code for the accepted answer (for your convenience):
How to make call
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:urlString]];
[request setHTTPMethod:#"HEAD"];
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
You could do this by checking the size of the file via an FTP server, using the SIZE command. If the file size is zero then the file simply do not exist.
Check here on how to do this.
You could of course also do this by using a NSURLRequest with NSURLConnection, checking for the status to be either 200 (success) or 404 (failed). The 404 status doesn't have to be that the file doesn't exist though, it could also be that the file just couldn't be retrieved.
I have a shopping cart in my app and an underlying data structure that I have serialized into an XML file. Im using the following code to place it on my server. However, nothing happens. Whe I check my server I donot find my file there. So I tried using just a string in place of the file and still the same. Nothing seems to be sent from the app to the server. Im running ths off the simulator.
Im wondering if there is anything wrong with this code.
CartSingleton *Cart = [CartSingleton getSingleton];
id xmlFile = [Cart serializeCart];
//Now send the xml file to the server
NSURL *url = [[NSURL alloc] initWithString:#"http://www.XXXXXXXXX.com/iOS_Files/xmlFile"];
NSMutableURLRequest *req = [[NSMutableURLRequest alloc] initWithURL:url];
[req setHTTPMethod:#"POST"];
NSData *paramData = [xmlFile dataUsingEncoding:NSUTF8StringEncoding];
[req setHTTPBody:paramData];
NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:req delegate:self];
if(theConnection)
{
NSMutableData *data = [[NSMutableData alloc] init];
self.receivedData = data;
[data release];
}
else
{
NSLog(#"Unable to make connection!");
}
I would really appreciate any help.
Thanks
See the class reference, there you can also find the links for the sample applications.
That code
if(theConnection)
{
NSMutableData *data = [[NSMutableData alloc] init];
self.receivedData = data;
[data release];
}
does not start the connection. The receivedData property will have a new NSData object, which is then changed as the response data received.
For the better understanding of the NSUrlConnection usage follow that official guide
What you can do else is to test the server w/o the application using REST Client firefox extension (just send the post request with it and see what happens).
One possible problem with the above code (their may be others also), is that the connection setup will be asynchronous. This is why you had to supply a delegate object above. Therefore, the connection is not actually made until the delegate gets a callback to say it is ready.
Have you implemented any delegate methods?
I'm creating an app which downloads a .zip file from S3 server.
All works fine. Now I want to be able to interrupt the current download. If I could save the current size (bytes) of the file, I would be able to send a new request with a range header for the other part of the file.
Problem lies in the fact that I cannot determine the size of the 'already' downloaded content, because I can only see the file in my directory when the download is completed. So if I interrupt, there isn't a partial file saved.
At this time I use the following code for this:
-(void) downloadFile:(NSMutableArray*)paramArray withDict:(NSMutableDictionary*)options
{
NSLog(#"DOWNLOAD THREAD STARTED");
NSString * sourceUrl = [paramArray objectAtIndex:0];
NSString * fileName = [paramArray objectAtIndex:1];
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *newFilePath = [documentsDirectory stringByAppendingString:fileName];
NSError *error=[[[NSError alloc]init] autorelease];
NSURLConnection *fileURL = [NSData dataWithContentsOfURL: [NSURL URLWithString:sourceUrl]];
BOOL response = [fileURL writeToFile:newFilePath options:NSDataWritingFileProtectionNone error:&error];
if (response == TRUE)
{
NSLog(#"DOWNLOAD COMPLETED");
[self performSelectorOnMainThread:#selector(downloadComplete:withDict:) withObject:paramArray waitUntilDone:YES];
}
else
{
NSLog(#"Something went wrong while downloading file.");
NSString *callback = [NSString stringWithFormat:#"downloadInterrupted('%#');",fileName];
[webView stringByEvaluatingJavaScriptFromString:callback];
}
[pool drain];
}
AsiHTTP isn't an option because there are issues with the PhoneGap I'm using.
A better idea is to download the file asynchronously. This has several advantages: The most important one is that your user interface stays responsive. The user can go on using your application while it is downloading and waiting for the data. If the data you are downloading is absolutely essential for the application, display some sort of loading indicator.
You can easily start the asynchronous download via
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:sourceUrl]];
NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];
Now, how do I get the downloades data in an NSData object? You implement the following delegate methods for self:
-connection:didReceiveData:
-connection:didFailWithError:
-connectionDidFinishLoading:
The idea is that you are notified whenever some data drops in through your connection or anything important else happens (success or failure for exmple). So you are going to declare a temporary NSMutableData object as an instance variable (say downloadData) and write to it until the download is complete. Do not forget to initialize the empty object and declare a property as well!
-connection:didReceiveData: is called whenever some sort of data (that is, a part of your downloaded file) arrives. So you are going to append it to your temporary object like this:
-(void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[self.downloadData appendData:data];
}
Once the download has finished (successfully), the next delegate method is called:
-(void) connectionDidFinishLoading:(NSURLConnection *)connection {
//do whatever you need to do with the data in self.downloadData
}
If the downloads fails, -connection:didFailWithError: is called. You can then save the temporary object, get its size and resume the download later. [self.downloadData length]; gets you the size in bytes of the data in your object.
You are going to have to use a lower level api.
time to read up on unix socket programming. http://www.fortunecity.com/skyscraper/arpanet/6/cc.htm would be a good start.
It really won't be too hard. honest.
I recommend you to build a method that save data chunk every 1, 2 MB or maybe less in order to resume properly your download and avoid memory crash.
This because if you get an error in your transfer maybe your file could be result corrupted.
Anyway send a range HTML header is pretty simple
NSFileHandle *fileHandler = [NSFileHandle fileHandleForReadingAtPath:dataPreviouslySavedPath];
[fileHandler seekToEndOfFile];
unsigned long long int range = [fileHandler offsetInFile];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:downloadURL cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:20.0];
[request setValue:[NSString stringWithFormat:#"bytes=%lli-", range] forHTTPHeaderField:#"Range"];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
Hope this help you.