I am making an app in which you type a value into a textbox, and the app sends an HTTP GET request to my webserver, ie www.mywebserver.server.com/ihiuahdiuehfiuseh?' + textbox variable' However, I have no idea how to work with Xcode. I am experienced in basic PHP and HTML, and advanced C++, but I am so baffled by this Xcode stuff. In all other languages I have worked with, you could look up something like "how to play a sound file in (language)", and you will get something like "oh yeah just do play(mp3url). But, with Xcode, you have to initiate the connection, initiate the variables, etc etc. I bought 2 $30 books, but I am still so confused. So, back to the point, I just need the textbox numerical number to be parsed after the ? in the URl to be parsed as a variable.
This is an example of a non-http get synchronized
You can find more
-(void)aget:(NSString *)iurl{
NSURL*url = [NSURL URLWithString:iurl];
NSURLRequest *res = [NSURLRequest requestWithURL:url];
NSOperationQueue*que=[NSOperationQueue new];
[NSURLConnection sendAsynchronousRequest:res queue:que completionHandler:^(NSURLResponse*rep,NSData*data,NSError*err){
if ([data length]> 0 && err == nil) {
NSString* rel=[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"%#",rel);
}else{
NSLog(#"isnull");
}
}
];
}
Through this launch him
NSString * str = [self getDataFrom: # "your url"];
NSLog (# "% #", str);
If you have a UITextFiled, you would do the following
NSString baseUrl = #"www.mywebserver.server.com/ihiuahdiuehfiuseh?"
NSString variable = textField.text;
NSString absoluteURL = [NSString stringWithFormat:#"%#%#", baseUrl, variable];
//Send the absolute variable now to the server
If you go for a solution like Omar Abdelhafith suggests, don't forget to url-encode your 'querystring'. There is a method in the string class for this: "stringByAddingPercentEscapesUsingEncoding", but it's not perfect.
I've recently used the solution suggested here: http://simonwoodside.com/weblog/2009/4/22/how_to_really_url_encode/.
Related
Im trying to send a string using NSoutputstream , however i cant seem to get the encoding right , using dataWithContentsOfURL works
im using a nodejs TCP server with actionHero library.
it works using netcat and telnet.
- (IBAction)sendText:(id)sender {
NSString *response = [NSString stringWithFormat:#"%#", [_sendTextField.text stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding]];
NSLog(#"writing %#",response);
///////////////////////////// this line works/////////////////////////////////////////////////////
// NSData *data = [[NSData alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:#"http://www.google.com"]]];
///////////////////////////// this line doesnt work/////////////////////////////////////////////////////
NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSUTF8StringEncoding]];
//%u returns a non zero value
NSLog(#"%u",[outputStream write:[data bytes] maxLength:[data length]]);
}
i get a null streamError from handle stream Event method
Not knowing the content of response, I can't give you a specific answer as to why NSUTF8StringEncoding doesn't work with it. Generally speaking, however, if there is a byte sequence in your content that is incompatible with UTF-8, you're going to get nil when you call -dataUsingEncoding:.
There's a strategy that I learned from reading Mike Ash's blog (look under the section "Fallbacks"), and it's served me pretty well in situations such as yours.
To briefly sum it up, first try using NSUTF8StringEncoding. If that doesn't work, try using NSISOLatin1StringEncoding. And if that doesn't work, try using NSMacOSRomanStringEncoding. Mike's blog has the rationale for this.
Found the answer to my own question. turns out the problem is in actionHero's on data method where it looks for a /n which is not provided by the ios application. appended a \n and its fine now
I use the following code to get a NSString from a NSDictionary and then cast it into NSUrl:
NSURL * url = [NSURL URLWithString:[self.item objectForKey:#"website"]];
The NSDictionary self.item comes from a web server and it's correctly filled using JSON data. All the other objects inside the NSDictionary work perfectly fine.
But sometimes the web server passes a website url with the text "null" because the object has no website filled in. From debugging i learned that the NSURL object can contain a url with the text "null". But how do i prevent this, or how can i write an if statement that checks this?
I tried the following:
NSString * niks = [eventUrl absoluteString];
if(niks == #"null")
{
UIAlertView *message = [[UIAlertView alloc] initWithTitle:#"Event" message:#"Event heeft geen website" delegate:nil cancelButtonTitle:#"Oke" otherButtonTitles:#"Oke", nil];
[message show];
}
else
{
[webView loadRequest:[NSURLRequest requestWithURL:eventUrl]];
NSLog(#"%#",eventUrl);
}
But this doesn't work, it always passes the url directly to the webview. Can someone set me in the right direction?
Your comparison;
if(niks == #"null")
only compares if the pointers are equal (i.e. if the two are the same string object instance). Since one is a constant and the other is created dynamically from JSON fetched from the server, it's very unlikely.
To compare the content of two strings, you should instead do;
if([niks isEqualToString:#"null"])
For the link thirsty, here is the [NSString isEqualToString:] documentation.
To do string comparison, you need to do [niks isEqualToString:#"null"], that's why the first condition is broken.
You can also use [niks RangeOfString:#"null"];
I believe you can do this:
id str = [self.item objectForKey:#"website"];
if([str isMemberOfClass[NSNull class]]) {
... its null
}
The JSON convertors all change null to a NSNull object (in my experience).
I am not 100% clear of my memory, but I encountered a situation where [NSDictionary objectForKey:] actually returned NSNull class instance instead of "null" string.
If this is the case, you can check the class of [self.item objectForKey:#"website"] by using isKindOfClass method.
I'm developing a newsstand application and use NSURLRequest to download issue assets.
NSArray *contents = [issue.tableOfContents objectForKey:kSNTableOfContentsContents];
NSHTTPCookie *cookie;
NSHTTPCookieStorage *cookieJar = [NSHTTPCookieStorage sharedHTTPCookieStorage];
NSLog(#"HERE GO MY COOKIES");
for (cookie in [cookieJar cookies]) {
NSLog(#"%#", cookie);
}
for (NSDictionary *contentItem in contents) {
NSString *contentURL_string = [contentItem objectForKey:kSNTableOfContentsRemoteURL];
NSURL *contentURL = [NSURL URLWithString:contentURL_string];
NSString *fileName = [contentItem objectForKey:kSNTableOfContentsContentsURL];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL:contentURL];
NKAssetDownload *asset = [newsstandIssue addAssetWithRequest:request];
[request release];
....
[asset downloadWithDelegate:self];
....
}
When the first for loop is executed my cookies appear to be in NSHTTPCookieStorage, but when actual requests are sent, there are no cookie information in headers. I use CharlesProxy to look that up. Could anyone please give some advice what might be causing this issue?
From this thread, the magic incantation appears to be:
NSDictionary * headers = [NSHTTPCookie requestHeaderFieldsWithCookies:
[cookieJar cookies]];
[request setAllHTTPHeaderFields:headers];
(Warning: untested code.)
This will convert your cookie jar into an array of cookies, then to an NSDictionary of headers, and finally, staple those headers to your request. This is comparable to doing it manually, as Adam Shiemke linked in the question errata, but much cleaner in my opinion.
As per the documentation, you may also want to check HTTPShouldHandleCookies to see if your default cookie policy is being used properly.
On iOS projects I found the ASIHTTPRequest very useful for this kind of problems. It does things like authentication and cookies a lot better that the build-in functions:
http://allseeing-i.com/ASIHTTPRequest/
I'm using QTKit to progressively download and play an MP3 from a URL. According to this documentation, this is the code I should use to accomplish that:
NSURL *mp3URL = [NSURL URLWithString:#"http://foo.com/bar.mp3"];
NSError *error = nil;
QTMovie *sound = [[QTMovie alloc] initWithURL:mp3URL error:&error];
[sound play];
This works, and does exactly what I want — the MP3 URL is lazily downloaded and starts playing immediately. However, if the URL does not have the ".mp3" path extension, it fails:
NSURL *mp3URL = [NSURL URLWithString:#"http://foo.com/bar"];
NSError *error = nil;
QTMovie *sound = [[QTMovie alloc] initWithURL:mp3URL error:&error];
[sound play];
No error is given, no exception is raised; the duration of the sound is just set to zero, and nothing plays.
The only way I have found to work around this is to force a type by loading the data manually and using a QTDataReference:
NSURL *mp3URL = [NSURL URLWithString:#"http://foo.com/bar"];
NSData *mp3Data = [NSData dataWithContentsOfURL:mp3URL];
QTDataReference *dataReference =
[QTDataReference dataReferenceWithReferenceToData:mp3Data
name:#"bar.mp3"
MIMEType:nil];
NSError *error = nil;
QTMovie *sound = [[QTMovie alloc] initWithDataReference:dataReference error:&error];
[sound play];
However, this forces me to completely download ALL of the MP3 synchronously before I can start playing it, which is obviously undesirable. Is there any way around this?
Thanks.
Edit
Actually, it seems that the path extension has nothing to do with it; the Content-Type is simply not being set in the HTTP header. Even so, the latter code works and the former does not. Anyone know of a way to fix this, without having access to the server?
Edit 2
Anyone? I can't find information about this anywhere, and Google frustratingly now shows this page as the top result for most of my queries...
Two ideas. (The first one being a bit hacky):
To work around the missing content type, you could embed a small Cocoa webserver that supplements the missing header field and route your NSURL over that "proxy".
Some Cocoa http server implementations:
http://code.google.com/p/cocoahttpserver/
http://cocoawithlove.com/2009/07/simple-extensible-http-server-in-cocoa.html
http://culturedcode.com/cocoa/
The second one would be, to switch to a lower level framework (From QTKit to AudioToolbox).
You'd need more code, but there are some very good resources out there on how to stream mp3 using AudioToolbox.
e.g.:
http://cocoawithlove.com/2008/09/streaming-and-playing-live-mp3-stream.html
Personally I'd go with the second option. AudioToolbox isn't as straightforward as QTKit but it offers a clean solution to your problem. It's also available on both - iOS and Mac OS - so you will find plenty of information.
Update:
Did you try to use another initializer? e.g.
+ (id)movieWithAttributes:(NSDictionary *)attributes error:(NSError **)errorPtr
You can insert your URL for the key QTMovieURLAttribute and maybe you can compensate the missing content type by providing other attributes in that dictionary.
This open source project has a QTMovie category that contains methods to accomplish similar things:
http://vidnik.googlecode.com/svn-history/r63/trunk/Source/Categories/QTMovie+Async.m
If you thought weichsel's first solution was hacky, you're going to love this one:
The culprit is the Content-Type header, as you have determined. Had QTKit.framework used Objective-C internally, this would be a trivial matter of overriding -[NSHTTPURLResponse allHeaderFields] with a category of your choosing. However, QTKit.framework (for better or worse) uses Core Foundation (and Core Services) internally. These are both C-based frameworks and there is no elegant way of overriding functions in C.
That said, there is a method, just not a pretty one. Function interposition is even documented by Apple, but seems to be a bit behind the times, compared to the remainder of their documentation.
In essence, you want something along the following lines:
typedef struct interpose_s {
void *new_func;
void *orig_func;
} interpose_t;
CFStringRef myCFHTTPMessageCopyHeaderFieldValue (
CFHTTPMessageRef message,
CFStringRef headerField
);
static const interpose_t interposers[] __attribute__ ((section("__DATA, __interpose"))) = {
{ (void *)myCFHTTPMessageCopyHeaderFieldValue, (void *)CFHTTPMessageCopyHeaderFieldValue }
};
CFStringRef myCFHTTPMessageCopyHeaderFieldValue (
CFHTTPMessageRef message,
CFStringRef headerField
) {
if (CFStringCompare(headerField, CFSTR("Content-Type"), 0) == kCFCompareEqualTo) {
return CFSTR("audio/x-mpeg");
} else {
return CFHTTPMessageCopyHeaderFieldValue(message, headerField);
}
}
You might want to add logic specific to your application in terms of handling the Content-Type field lest your application break in weird and wonderful ways when every HTTP request is determined to be an audio file.
Try replacing http:// with icy://.
Just create an instance like this...
QTMovie *aPlayer = [QTMovie movieWithAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
fileUrl, QTMovieURLAttribute,
[NSNumber numberWithBool:YES], QTMovieOpenForPlaybackAttribute,
/*[NSNumber numberWithBool:YES], QTMovieOpenAsyncOKAttribute,*/
nil] error:error];
I'm working on an app that would display a remote html and use local images, so what I'm trying to do is download the HTML of the website and display it as a "local" page, that would have access to images in my bundle.
For some reason I can't get initWithContentsOfURL to work. I checked all manuals and examples I could find and it seems that I'm doing it correctly, but the thing just won't work, returns null all the time. The same page loaded with NSURLRequest requestWithURL works fine.
Here is the code:
- (void)awakeFromNib
{
appURL = #"http://dragontest.fantasy-fan.org";
notConnectedHTML = #"Could not connect.";
NSString *seedString = [[NSString alloc] initWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat:#"%#/seed.php", appURL]]];
NSString *HTMLdata = #"";
if (seedString = #"(null)") {
NSLog(#"Can't connect on awakeFromNib.");
HTMLdata = notConnectedHTML;
}else {
HTMLdata = [NSString stringWithFormat:#"<body style='padding:0px;margin:0px;'>%#%#</body>", seedString, #"<br><img src='images/Default.png'>"];
}
[homeView loadHTMLString:HTMLdata baseURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] resourcePath]]];
}
Firstly, why aren't appURL and notConnectedHTML declared as NSString *? Are they declared this way elsewhere?
Secondly, you might be better off using NSURL's -urlWithString:relativeToURL: to create the actual request URL.
Thirdly (and this is your actual problem here I suspect), to compare two C primitives, you use ==. = is the assignment operator (it makes the thing on the left equal to the thing on the right). To compare two Objective-C objects, use a comparison method, like -isEqual: or -isEqualToString: (which is specifically for NSStrings).
So instead of:
if (seedString = #"(null)")
You should use
if ([seedString isEqualToString:#"(null)"])
However I suspect the reason you're trying to compare to "(null)" is because that's what NSLog spits out when an object is equal to nil. When an object is nil, the object reference itself is equal to the nil constant, so you should use this to see if an object is nil:
if (seedString == nil)
Just for good measure, some people like to use this syntax which does exactly the same thing:
if (!seedString)