So I am using Parse (which is pretty sweet) and I'm in the process of downloading files (short video files - no more then 1mb) from the parse server to my application to play. Now the way it works is (via documentation)..
PFFile* videoFile = [[tempArray objectAtIndex:i] objectForKey:#"track"];
[videoFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
NSString* dataString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSURL* videoURL = [NSURL URLWithString:dataString];
// now do something with this videoURL (i.e. play it!)
[data writeToFile:#"trackFile" atomically:YES];
NSURL *filePath = [NSURL fileURLWithPath:#"trackFile"];
NSLog(#"File Path: %#",filePath);
AVAsset* asset = [AVAsset assetWithURL:filePath];
AVPlayerItem* playerItem = [[AVPlayerItem alloc] initWithAsset:asset];
}
}
On download completion you are suppossed to create a string from the data and then a url from the string. Only problem is - the dataString always returns NULL/nil. I have confirmed that the data property is not empty and does in fact hold the video data. Why is this happening? Any help would be greatly appreciated. Thanks in advance!
I have confirmed that the data property is not empty and does in fact hold the video data.
Video data is not a UTF-8 string. It's definitely not a UTF-8 string representation of an URL. So when you say "interpret this video data as UTF-8," Cocoa rightly responds that it is not UTF-8 (because it's video data).
The simplest solution is to write this to disk, and then play the file.
Couple things that need to be determined first:
does the NSData object actually have any data, i.e., data.length > 0?
does the NSData object hold video data OR the url of the video data (not exactly clear)?
Making the assumption that the NSData object is holding the url and it's length is greater than 0, then you might want to try:
NSString* dataString = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
Related
I am Writing an app which has share extension to save selected photo to my app' local storage from iphone photo gallery.
NSData WriteToFile returns YES but I couldn't find the stored file into the directory in of which I gave path while writing.
So, in short NSData WriteToFile fails to save a photo at given path.
Below is my code.
- (IBAction)acceptButtonTapped:(id)sender
{
__block UIImage *photo;
for (NSExtensionItem *item in self.extensionContext.inputItems)
{
for (NSItemProvider *itemProvider in item.attachments)
{
if ([itemProvider hasItemConformingToTypeIdentifier:(NSString *)kUTTypeImage])
{
[itemProvider loadItemForTypeIdentifier:(NSString *)kUTTypeImage options:nil completionHandler:^(UIImage *image, NSError *error) {
if(image)
{
dispatch_async(dispatch_get_main_queue(), ^{
photo = image;
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:#"yyyy_MM_dd_hh_mm_ss"];
NSString *fileName;
fileName = [NSString stringWithFormat:#"%#.jpeg",[formatter stringFromDate:[NSDate date]]];
dataPath = [dataPath stringByAppendingPathComponent:fileName];
NSData * imageData = [NSData dataWithData:UIImageJPEGRepresentation(image, 1.0)];
BOOL isdone = [imageData writeToFile:dataPath atomically:NO];
NSLog(#"%u", isdone);
});
}
}];
break;
}
}
}
[self.extensionContext completeRequestReturningItems:#[] completionHandler:nil];
}
Any Help would be much appreciable.
Thank you.
If you're trying to access the Document directory from the share extension, NO you can't do that. Share extension or other widgets are separate application from their containing app and therefore have their own sandbox. So you will need to use App Groups to share files.
Application groups are primarily targeted for extensions, more specifically, for widgets.
NSFileManager has a method on it containerURLForSecurityApplicationGroupIdentifier: where you can pass in the identifier you created when turning on App Groups for your apps
NSURL *containerURL = [[NSFileManager defaultManager]
containerURLForSecurityApplicationGroupIdentifier:#"group.com.company.app"];
You can save the files to this location, because you can access the shared application groups from both extension and host app.
You're modifying dataPath on each pass through the loop, appending another filename to it. That will create an ever-growing series of badly formed paths that contain all the filenames.
Don't do that. Create a new local variable filePath, and construct a filename into filePath using
filePath = [docsPath stringByAppendingPathComponent: filename];
Log your path and LOOK AT IT. When your program doesn't behave as expected, don't trust any of your assumptions, because one or more of them may be wrong.
The whole ios video sending/streaming paradigm seems to be a bit vague and uncovered. The task I am trying to perform is similar to that of how videos are played for clients when watching a YouTube videos.
What I am trying to essentially do is quite simple:
I have a pre-made encoded .mov file on my server.
I want to send
that file through a UDP socket to a client.
Here is where I am getting lost:
How do I break down the .mov file to correctly send it over the
socket? Do I need to break down into frames? If so, how?
Right now I am creating an NSData object from the file and breaking it into chunks which I send over the socket like so:
NSURL *fileURL = [[NSBundle mainBundle]
URLForResource:#"test1" withExtension:#"mov"];
NSData *newData = [NSData dataWithContentsOfURL:fileURL];
int index = 0;
int totalLen = (int)[newData length];
while (index < totalLen) {
int space = (totalLen - index > 9216) ? 9216 : totalLen - index;
NSData *chunk = [newData subdataWithRange:NSMakeRange(index, space)];
[udpSocket sendData:chunk toAddress:clientAddress withTimeout:-1 tag:2];
index += 9216;
}
On the client-side, how do I receive and play these packets?
At the moment I'm combining all of the incoming data and concatenating it into one big NSData file which I'd like to play once all of the data is received (which intuitively seems to me like the wrong way to approach this):
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data
fromAddress:(NSData *)address withFilterContext:(id)filterContext{
/* Append nsdata packets from socket until all the file has been received */
[videoData appendData:data];
if([data length] < 9216){
/* Marks EOF. Start playing the video */
[self playVideoData];
}
Then playing the video...
-(void)playVideoData{
NSURL* fileURL = [[NSURL alloc] init];
[videoData writeToURL:fileURL atomically:YES];
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:fileURL options:nil];
NSString *tracksKey = #"tracks";
/** Normal AVURLAsset video playing here... */
}
I am very new to iOS development, but I would like to make an app that has two table view controllers (columns): both are a row of images that act as links. The first would be a column of YouTube videos and the second a column of websites. I would like to have all these listed in a file file.txt listed like so: V, http://youtube.com/example W, http://example.com
There would be a long list of those, the V meaning its a video (for the video column) and W for the websites. Now, I understand how to being the single file in, but what happens afterwards is my concern. Can I read each line into some sort of queue and then fire the NSURL request for each one consecutively? How can that be done with NSURL? Is there perhaps a better approach?
There are two questions for me:
Is a text file really the best format?
I might suggest a plist or archive (if the file is only going to exist only in your app's bundle and/or documents folder) or JSON (if it's going to live on a server before delivering it to the user) instead of a text file. It will make it easier to parse this file than a text file. For example, consider the following dictionary:
NSDictionary *dictionary = #{#"videos" : #[#"http://youtube.com/abc", #"http://vimeo.com/xyz"],
#"websites": #[#"http://apple.com", #"http://microsoft.com"]};
You can save that to a plist with:
NSString *documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
NSString *plistPath = [documentsPath stringByAppendingPathComponent:#"files.plist"];
[dictionary writeToFile:plistPath atomically:YES];
You can add that file to your bundle or whatever, and then read it at a future date with:
dictionary = [NSDictionary dictionaryWithContentsOfFile:plistPath];
You can, alternatively, write that to a JSON file with:
NSError *error = nil;
NSData *data = [NSJSONSerialization dataWithJSONObject:dictionary options:NSJSONWritingPrettyPrinted error:&error];
NSString *jsonPath = [documentsPath stringByAppendingPathComponent:#"files.json"];
[data writeToFile:jsonPath atomically:YES];
You can read that JSON file with:
data = [NSData dataWithContentsOfFile:jsonPath];
dictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
Either way, you can get the list of videos or web sites like so:
NSArray *videos = dictionary[#"videos"];
NSArray *websites = dictionary[#"websites"];
Now that you have your arrays of videos and websites, the question then is how you then use those URLs.
You could do something like:
for (NSString *urlString in videos) {
NSURL *url = [NSURL URLWithString: urlString];
// now do something with the URL
}
The big question is what is the "do something" logic. Because you're dealing with a lot of URLs, you would want to use a NSOperation based solution, not a GCD solution, because NSOperationQueue lets you control the degree of concurrency. I'd suggest a NSOperation-based networking library like AFNetworking. For example, to download the HTML for your websites:
NSOperationQueue *queue = [[NSOperationQueue alloc] init];
queue.maxConcurrentOperationCount = 4;
for (NSString *urlString in websites)
{
NSURL *url = [NSURL URLWithString:urlString];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
// convert the `NSData` responseObject to a string, if you want
NSString *string = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
// now do something with it, like saving it in a cache or persistent storage
// I'll just log it
NSLog(#"responseObject string = %#", string);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"error = %#", error);
}];
[queue addOperation:operation];
}
Having said that, I'm not sure it makes sense to kick off a ton of network requests. Wouldn't you really prefer to wait until the user taps on one of those cells before retrieving it (and for example, then just open that URL in a UIWebView)? You don't want an app that unnecessarily chews up the user's data plan and battery retrieving stuff that they might not want to retrieve. (Apple has rejected apps that request too much data from a cellular connection.) Or, at the very least, if you want to retrieve stuff up front, only retrieve stuff as you need it (e.g. in cellForRowAtIndexPath), which will retrieve the visible rows, rather than the hundreds of rows that might be in your text/plist/json file.
Frankly, we need a clearer articulation of what you're trying to do, and we might be able to help you with more concise counsel.
I have an mp3 file on a server. I want to get this file's information like what's the size of this file, what's the artists name, what's the album name, when was the file created, when was it modified, etc. I want all this information.
Is it possible to get this information without actually downloading the whole file? Using NSURLConnection or otherwise?
EDIT:
The following code doesn't give me the required information, i.e. file created by, artist name, etc
NSError *rerror = nil;
NSURLResponse *response = nil;
NSURL *url = [NSURL URLWithString:#"http://link.to.mp3"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:#"HEAD"];
NSData *result = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&rerror];
NSString *resultString = [[[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding] autorelease];
NSLog(#"URL: %#", url);
NSLog(#"Request: %#", request);
NSLog(#"Result (NSData): %#", result);
NSLog(#"Result (NSString): %#", resultString);
NSLog(#"Response: %#", response);
NSLog(#"Error: %#", rerror);
if ([response isMemberOfClass:[NSHTTPURLResponse class]]) {
NSLog(#"AllHeaderFields: %#", [((NSHTTPURLResponse *)response) allHeaderFields]);
}
The "AllHeaderFields" is:
AllHeaderFields: {
"Cache-Control" = "max-age=0";
Connection = "keep-alive";
"Content-Encoding" = gzip;
"Content-Type" = "text/plain; charset=ascii";
Date = "Fri, 17 Feb 2012 12:44:59 GMT";
Etag = 19202n;
Pragma = public;
Server = dbws;
"x-robots-tag" = "noindex,nofollow";
}
It is quite possible to get the ID3 information embedded in an MP3 file (artist name, track title) without downloading the whole file or using low-level APIs. The functionality is part of the AVFoundation framework.
The class to look at is AVAsset and specifically it's network friendly subclass AVURLAsset. AVAsset has an NSArray property named commonMetadata. This commonMetadata property will contain instances of AVMetadataItem, assuming of course that the reference URL contains metadata. You will usually use the AVMetadataItem's commonKey property to reference the item. I find this method of iterating through an array checking commonKeys irritating so I create an NSDictionary using the commonKey property as the key and the value property as the object. Like so:
-(NSDictionary *)dictionaryOfMetadataFromAsset:(AVAsset *)asset{
NSMutableDictionary *metaData = [[NSMutableDictionary alloc] init];
for (AVMetadataItem *item in asset.commonMetadata) {
if (item.value && item.commonKey){
[metaData setObject:item.value forKey:item.commonKey];
}
}
return [metaData copy];
}
With the addition of this simple method the AVAsset's metadata becomes quite easy to use. Here is an example of getting an MP3's metadata through a URL:
NSURL *mp3URL = [NSURL URLWithString:#"http://'AddressOfMP3File'"];
AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:mp3URL options:nil];
NSDictionary *metaDict = [self dictionaryOfMetadataFromAsset:asset];
NSLog(#"Available Metadata :%#",metaDict.allKeys);
NSLog(#"title:%#",[metaDict objectForKey:#"title"]);
I have found that this code seems to load just the first few seconds of your MP3 file. Also note that this code is synchronous; So use with caution. But AVURLAsset does have some async functionality described in the docs.
Once you have the AVAsset you can create a AVPlayerItem with it and feed that to an AVPlayer and play it, or not.
Yes and no. Things like the file size and modification date often come as part of the HEAD response. But not always: with a lot of dynamic URLs, you won't get all of the information.
As for the artist and album name, they're part of the MP3's ID3, which is contained inside the file, and so you won't be able to get them with a HEAD request. Since the ID3 tag is typically at the beginning of a file, you could try to grab just that part and then read the ID3 tag. But you won't be able to do it with NSURLConnection since it doesn't support just fetching part of a file, so you'll need to find a more low-level way of getting data by HTTP.
Yep, you're right on target with NSURLConnection.
I think you want to send a HEAD request for the resource you want information about and then check the information you receive in connection:didReceiveResponse: and connection:didReceiveData:
Edit
Admittedly I didn't read your question in its entirety. It won't be possible to get ID3 information, but you should be able to get size of file and maybe creation date etc.
This answer does give some good information about how to get the ID3 information. You'd need to set up a php page to examine the mp3 file server-side and return just that information you require instead of the entire mp3.
I am receiving a stream of encoded audio over the network, but there is a bunch of data mixed in so I need to receive the packets, strip out the audio then play the audio.
AVAudioPlayer, which may or may not be the best tool for this but it's the path I'm currently chasing, wants data from NSData or NSURL. NSData won't work because it is a stream of data and I want it to start as soon as it arrives and continue playing. My thought was:
NSPipe *pipe = [[NSPipe alloc] init];
NSFileHandle *writeHandle = [pipe fileHandleForWriting];
NSFileHandle *readHandle = [pipe fileHandleForReading];
// in network reception thread...
NSData *audioData = [packet getAudioData];
[writeHandle writeData:audioData];
// in audio thread...
NSURL *url = [[NSURL alloc] init];
[url setResourceValue:NSURLFileResourceTypeNamedPipe
forKey:NSURLFileResourceTypeKey
error:&error];
// Connect the readHandle
AVAudioPlayer *audioPlayer = [[AVAudioPlayer alloc]
initWithContentsOfURL:url
error:&error];
However, I don't know how to pass the `readHandle` into the URL. How do I create an NSURL from an existing NSFileHandle? Is there some better approach for this entirely? Is there a way to write data into something that can become an NSURL?
The only real requirement is that I can play the audio as near real time as possible. I don't want to queue up data for even a tenth of a second before it gets played.
It is not possible to retrieve an NSFileHandle's URL because not all handles have a corresponding URL. Your example would appear to be one such example.