How can I upload a photo to a server with the iPhone?

I'm writing an iPhone app that takes a photo and then uploads it to a server. How do I upload a photo to a server with Cocoa? I suppose I use NSUrl somewhere.

Thanks!

Header:

@interface EPUploader : NSObject {
	NSURL *serverURL;
	NSString *filePath;
	id delegate;
	SEL doneSelector;
	SEL errorSelector;
	
	BOOL uploadDidSucceed;
}
	
-	(id)initWithURL: (NSURL *)serverURL 
	        filePath: (NSString *)filePath 
	        delegate: (id)delegate 
	    doneSelector: (SEL)doneSelector 
	   errorSelector: (SEL)errorSelector;

-	(NSString *)filePath;

@end

Main:

#import "EPUploader.h"
#import <zlib.h>

static NSString * const BOUNDRY = @"0xKhTmLbOuNdArY";
static NSString * const FORM_FLE_INPUT = @"uploaded";

#define ASSERT(x) NSAssert(x, @"")

@interface EPUploader (Private)

- (void)upload;
- (NSURLRequest *)postRequestWithURL: (NSURL *)url
                             boundry: (NSString *)boundry
                                data: (NSData *)data;

- (NSData *)compress: (NSData *)data;
- (void)uploadSucceeded: (BOOL)success;
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;

@end

@implementation EPUploader



/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader initWithURL:filePath:delegate:doneSelector:errorSelector:] --
 *
 *      Initializer. Kicks off the upload. Note that upload will happen on a
 *      separate thread.
 *
 * Results:
 *      An instance of Uploader.
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (id)initWithURL: (NSURL *)aServerURL   // IN
         filePath: (NSString *)aFilePath // IN
         delegate: (id)aDelegate         // IN
     doneSelector: (SEL)aDoneSelector    // IN
    errorSelector: (SEL)anErrorSelector  // IN
{
	if ((self = [super init])) {
		ASSERT(aServerURL);
		ASSERT(aFilePath);
		ASSERT(aDelegate);
		ASSERT(aDoneSelector);
		ASSERT(anErrorSelector);
		
		serverURL = [aServerURL retain];
		filePath = [aFilePath retain];
		delegate = [aDelegate retain];
		doneSelector = aDoneSelector;
		errorSelector = anErrorSelector;
		
		[self upload];
	}
	return self;
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader dealloc] --
 *
 *      Destructor.
 *
 * Results:
 *      None
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (void)dealloc
{
	[serverURL release];
	serverURL = nil;
	[filePath release];
	filePath = nil;
	[delegate release];
	delegate = nil;
	doneSelector = NULL;
	errorSelector = NULL;
	
	[super dealloc];
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader filePath] --
 *
 *      Gets the path of the file this object is uploading.
 *
 * Results:
 *      Path to the upload file.
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (NSString *)filePath
{
	return filePath;
}


@end // Uploader


@implementation EPUploader (Private)


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) upload] --
 *
 *      Uploads the given file. The file is compressed before beign uploaded.
 *      The data is uploaded using an HTTP POST command.
 *
 * Results:
 *      None
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (void)upload
{
	NSData *data = [NSData dataWithContentsOfFile:filePath];
	ASSERT(data);
	if (!data) {
		[self uploadSucceeded:NO];
		return;
	}
	if ([data length] == 0) {
		// There's no data, treat this the same as no file.
		[self uploadSucceeded:YES];
		return;
	}
	
//	NSData *compressedData = [self compress:data];
//	ASSERT(compressedData && [compressedData length] != 0);
//	if (!compressedData || [compressedData length] == 0) {
//		[self uploadSucceeded:NO];
//		return;
//	}
	
	NSURLRequest *urlRequest = [self postRequestWithURL:serverURL
												boundry:BOUNDRY
												   data:data];
	if (!urlRequest) {
		[self uploadSucceeded:NO];
		return;
	}
	
	NSURLConnection * connection =
	[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];
	if (!connection) {
		[self uploadSucceeded:NO];
	}
	
	// Now wait for the URL connection to call us back.
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) postRequestWithURL:boundry:data:] --
 *
 *      Creates a HTML POST request.
 *
 * Results:
 *      The HTML POST request.
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (NSURLRequest *)postRequestWithURL: (NSURL *)url        // IN
                             boundry: (NSString *)boundry // IN
                                data: (NSData *)data      // IN
{
	// from http://www.cocoadev.com/index.pl?HTTPFileUpload
	NSMutableURLRequest *urlRequest =
	[NSMutableURLRequest requestWithURL:url];
	[urlRequest setHTTPMethod:@"POST"];
	[urlRequest setValue:
	 [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundry]
      forHTTPHeaderField:@"Content-Type"];
	
	NSMutableData *postData =
	[NSMutableData dataWithCapacity:[data length] + 512];
	[postData appendData:
	 [[NSString stringWithFormat:@"--%@\r\n", boundry] dataUsingEncoding:NSUTF8StringEncoding]];
	[postData appendData:
	 [[NSString stringWithFormat:
	   @"Content-Disposition: form-data; name=\"%@\"; filename=\"file.bin\"\r\n\r\n", FORM_FLE_INPUT]
	  dataUsingEncoding:NSUTF8StringEncoding]];
	[postData appendData:data];
	[postData appendData:
	 [[NSString stringWithFormat:@"\r\n--%@--\r\n", boundry] dataUsingEncoding:NSUTF8StringEncoding]];
	
	[urlRequest setHTTPBody:postData];
	return urlRequest;
}

/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) compress:] --
 *
 *      Uses zlib to compress the given data.
 *
 * Results:
 *      The compressed data as a NSData object.
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (NSData *)compress: (NSData *)data // IN
{
	if (!data || [data length] == 0)
		return nil;
	
	// zlib compress doc says destSize must be 1% + 12 bytes greater than source.
	uLong destSize = [data length] * 1.001 + 12;
	NSMutableData *destData = [NSMutableData dataWithLength:destSize];
	
	int error = compress([destData mutableBytes],
						 &destSize,
						 [data bytes],
						 [data length]);
	if (error != Z_OK) {
		NSLog(@"%s: self:0x%p, zlib error on compress:%d\n",__func__, self, error);
		return nil;
	}
	
	[destData setLength:destSize];
	return destData;
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) uploadSucceeded:] --
 *
 *      Used to notify the delegate that the upload did or did not succeed.
 *
 * Results:
 *      None
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (void)uploadSucceeded: (BOOL)success // IN
{
	[delegate performSelector:success ? doneSelector : errorSelector
				   withObject:self];
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) connectionDidFinishLoading:] --
 *
 *      Called when the upload is complete. We judge the success of the upload
 *      based on the reply we get from the server.
 *
 * Results:
 *      None
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (void)connectionDidFinishLoading:(NSURLConnection *)connection // IN
{
	NSLog(@"%s: self:0x%p\n", __func__, self);
	[connection release];
	[self uploadSucceeded:uploadDidSucceed];
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) connection:didFailWithError:] --
 *
 *      Called when the upload failed (probably due to a lack of network
 *      connection).
 *
 * Results:
 *      None
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (void)connection:(NSURLConnection *)connection // IN
  didFailWithError:(NSError *)error              // IN
{
	NSLog(@"%s: self:0x%p, connection error:%s\n",
			__func__, self, [[error description] UTF8String]);
	[connection release];
	[self uploadSucceeded:NO];
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) connection:didReceiveResponse:] --
 *
 *      Called as we get responses from the server.
 *
 * Results:
 *      None
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

-(void)       connection:(NSURLConnection *)connection // IN
      didReceiveResponse:(NSURLResponse *)response     // IN
{
	NSLog(@"%s: self:0x%p\n", __func__, self);
}


/*
 *-----------------------------------------------------------------------------
 *
 * -[Uploader(Private) connection:didReceiveData:] --
 *
 *      Called when we have data from the server. We expect the server to reply
 *      with a "YES" if the upload succeeded or "NO" if it did not.
 *
 * Results:
 *      None
 *
 * Side effects:
 *      None
 *
 *-----------------------------------------------------------------------------
 */

- (void)connection:(NSURLConnection *)connection // IN
    didReceiveData:(NSData *)data                // IN
{
	NSLog(@"%s: self:0x%p\n", __func__, self);
	
	NSString *reply = [[[NSString alloc] initWithData:data
											 encoding:NSUTF8StringEncoding]
					   autorelease];
	NSLog(@"%s: data: %s\n", __func__, [reply UTF8String]);
	
	if ([reply hasPrefix:@"YES"]) {
		uploadDidSucceed = YES;
	}
}


@end

Usage:

		[[EPUploader alloc] initWithURL:[NSURL URLWithString:@"http://yourserver.com/uploadDB.php"]
													 filePath:@"path/to/some/file"
													 delegate:self
												 doneSelector:@selector(onUploadDone:)
												errorSelector:@selector(onUploadError:)];		

Hope following code snippet will work for you. I have used NSDateFormatter and NSDate to get unique name each time for the image.

Note: 'ImageUploadURL' is the string #define with the base url, you need to replace it with your server url.

//Date format for Image Name...

NSDateFormatter *format = [[NSDateFormatter alloc] init];
	[format setDateFormat:@"yyyyMMddHHmmss"];

NSDate *now = [[NSDate alloc] init];

NSString *imageName = [NSString stringWithFormat:@"Image_%@", [format stringFromDate:now]];

[now release];
[format release];

NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
[request setURL:[NSURL URLWithString:ImageUploadURL]];
[request setHTTPMethod:@"POST"];

/*
 Set Header and content type of your request.
 */
NSString *boundary = [NSString stringWithString:@"---------------------------Boundary Line---------------------------"];
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
[request addValue:contentType forHTTPHeaderField: @"Content-Type"];
		
/*
 now lets create the body of the request.
 */
NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];	
[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"%@.jpg\"\r\n", imageName] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithData:UIImageJPEGRepresentation(image, 90)]];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"geotag=%@&", [self _currentLocationMetadata]] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];

// set body with request.
[request setHTTPBody:body];
[request addValue:[NSString stringWithFormat:@"%d", [body length]] forHTTPHeaderField:@"Content-Length"];

// now lets make the connection to the web
[NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

Create an NSURLRequest and then use NSURLConnection to send it off to your server.

Looks like Three20 library has support for POSTing images to HTTP server.

See TTURLRequest.m

And it's released under Apache 2.0 License.

- (void) uploadImage :(NSString *) strRequest
{
if([appdel checkNetwork]==TRUE)
{

NSString *urlString =[NSString stringWithFormat:@"Enter Url........."];
    NSLog(@"Upload %@",urlString);
// setting up the request object now

isUploadImage=TRUE;
totalsize=[[strRequest dataUsingEncoding:NSUTF8StringEncoding]length];

NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
[request setURL:[NSURL URLWithString:urlString]];
[request setHTTPMethod:@"POST"];

NSString *boundary = [NSString stringWithString:@"_1_19330907_1317415362628"];
NSString *contentType = [NSString stringWithFormat:@"multipart/mixed; boundary=%@",boundary];
[request setValue:contentType forHTTPHeaderField: @"Content-Type"];
[request setValue:@"text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2" forHTTPHeaderField:@"Accept"];
[request setValue:@"2667" forHTTPHeaderField:@"Content-Length"];


/*
 now lets create the body of the post
 */
NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];	


[body appendData:[[NSString stringWithString:@"Content-Type: application/json\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];

//[body appendData:[NSData dataWithData:imageData]];

[body appendData:[strRequest dataUsingEncoding:NSUTF8StringEncoding]];

[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];


// setting the body of the post to the reqeust
[request setHTTPBody:body];



theConnection=[[NSURLConnection alloc] initWithRequest:request delegate:self];
if (theConnection) 
	webData = [[NSMutableData data] retain];
else 
	NSLog(@"No Connection");	
}

}

If you want to upload multiple images then this demo is good option.