I am trying to get the image from this website, but I am having a hard time. All I need is the URL of the image, when I print the URL I get noting back. This is the URL and I am trying to get the main image seen in the middle, http://theoldrussuanbum.vsco.co/media/555722fde555153e3e8b4591
I have been trying the following code with no luck.
NSURL *URL = [NSURL URLWithString:_urlTextField.text];
NSURLSession *session = [NSURLSession sharedSession];
[[session dataTaskWithURL:URL completionHandler:
^(NSData *data, NSURLResponse *response, NSError *error) {
NSString *contentType = nil;
if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
NSDictionary *headers = [(NSHTTPURLResponse *)response allHeaderFields];
contentType = headers[#"Content-Type"];
}
HTMLDocument *document = [HTMLDocument documentWithData:data
contentTypeHeader:contentType];
HTMLElement *element = [document firstNodeMatchingSelector:#"img"];
NSString *urlString = element.attributes[#"src"];
NSLog(#"URL: %#", urlString);
}] resume];
Can anyone help?
You can use regular expressions to first
find the start with the regular expression: #"twitter:image\"\\s+content=\""
and then
extract the URL with the regular expression: #"[^>]+"
You can find information of regular expression syntax at the ICU User Guide: Regular Expressions.
Example code:
NSString *urlString = #"http://theoldrussuanbum.vsco.co/media/555722fde555153e3e8b4591";
NSURL *URL = [NSURL URLWithString:urlString];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *sessionTask;
sessionTask = [session dataTaskWithURL:URL completionHandler:
^(NSData *data, NSURLResponse *response, NSError *error) {
NSString *html = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSRange preambleRange = [html rangeOfString:#"twitter:image\"\\s+content=\"" options:NSRegularExpressionSearch];
if (preambleRange.location != NSNotFound) {
NSString *htmlOffset = [html substringFromIndex:preambleRange.location + preambleRange.length];
NSRange imgUrlRange = [htmlOffset rangeOfString:#"[^>]+" options:NSRegularExpressionSearch];
if (imgUrlRange.location != NSNotFound) {
NSString *imgURLString = [htmlOffset substringWithRange:imgUrlRange];
NSLog(#"URL: %#", imgURLString);
}
}
}];
[sessionTask resume];
Output:
URL: http://image.vsco.co/1/548c6a64020e11517164/555722fde555153e3e8b4591/600x800/vsco_051615.jpg"
Of course production code must handle all errors which this example code does not.
I think first thing you need to do is provide actual url of image resource.
For example; http://image.vsco.co/1/548c6a64020e11517164/548c7b532b5615b6658b4567/vsco_121314.jpg
This is what I get from page source of that web page
And then just refer this question;
iOS download and save image inside app
Related
I have a method that returns a string usually locally, but with a backup from the Web. I was retrieving some JSON using dataWithContentsOfUrl but want to switch to using a Session object which is better for the UI and also--if I am not mistaken--allows the server to set a sessionId on the phone, however, I'm struggling with the async issue.
With the old code, I just returned the JSON but I'm struggling with how to do this for the asynchronous result. I can't change the calling method which returns a string. What can I do with the asynchronous Api call to use the data that is retrieved?
async:
-(void)getAsyncAnswerFor:(NSString*) str {
NSString *surl = [NSString stringWithFormat: #"https://~.com//api.php?q=%#",str];
NSURL *url = [NSURL URLWithString:surl];
NSURLSessionDataTask *downloadTask = [[NSURLSession sharedSession]
dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
//HOW DO I PASS THIS BACK TO THE CALLING METHOD OR IS THAT IMPOSSIBLE
}];
[downloadTask resume];
}
sync
-(NSString*)getAnswerFor:(NSString*) str {
NSError *error;
NSString *surl = [NSString stringWithFormat: #"https://~.com//api.php?q=%#",str];
NSData *data = [NSData dataWithContentsOfURL: [NSURL URLWithString:surl]];
NSMutableArray *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
//process JSON
if (error) {
return #"";
}
return #"processed JSON";
}
Would appreciate any suggestions.
If what I want to do is totally impossible, is it possible to set a sessionID on the phone without the Session object? I know setting a session ID is is not the greatest approach, but I'm trying to avoid a lot of authentication overhead.
You can pass a block to your asynchronous function and then call it when the url session completion handler is called. This is a trivial example:
- (void)doSomethingWithBlock:(void (^)(double, double))block {
...
block(21.0, 2.0);
}
I lifted this ^^ from the Apple Docs but you might be able to do something like this: (Note: I didn't check this in a compiler!)
-(void)getAsyncAnswerFor:(NSString*) str completion:(void (^)(NSData, NSURLResponse, NSError))block {
NSString *surl = [NSString stringWithFormat: #"https://~.com//api.php?q=%#",str];
NSURL *url = [NSURL URLWithString:surl];
NSURLSessionDataTask *downloadTask = [[NSURLSession sharedSession]
dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
block(data, response, error);
}];
[downloadTask resume];
}
You'll need to be careful if you try to reference self anywhere in the blocks.
I am new to Objective C and iOS development in general. I am trying to create an app that would make an http request and display the contents on a label.
When I started testing I noticed that the label was blank even though my logs showed that I had data back. Apparently this happens because the the response is not ready when the label text gets updated.
I put a loop on the top to fix this but I am almost sure there's got to be a better way to deal with this.
ViewController.m
- (IBAction)buttonSearch:(id)sender {
HttpRequest *http = [[HttpRequest alloc] init];
[http sendRequestFromURL: #"https://en.wiktionary.org/wiki/incredible"];
//I put this here to give some time for the url session to comeback.
int count;
while (http.responseText ==nil) {
self.outputLabel.text = [NSString stringWithFormat: #"Getting data %i ", count];
}
self.outputLabel.text = http.responseText;
}
HttpRequest.h
#import <Foundation/Foundation.h>
#interface HttpRequest : NSObject
#property (strong, nonatomic) NSString *responseText;
- (void) sendRequestFromURL: (NSString *) url;
- (NSString *) getElementBetweenText: (NSString *) start andText: (NSString *) end;
#end
HttpRequest.m
#implementation HttpRequest
- (void) sendRequestFromURL: (NSString *) url {
NSURL *myURL = [NSURL URLWithString: url];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL: myURL];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest: request
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
self.responseText = [[NSString alloc] initWithData: data
encoding: NSUTF8StringEncoding];
}];
[task resume];
}
Thanks a lot for the help :)
Update
After reading a lot for the very useful comments here I realized that I was missing the whole point. So technically the NSURLSessionDataTask will add task to a queue that will make the call asynchronously and then I have to provide that call with a block of code I want to execute when the thread generated by the task has been completed.
Duncan thanks a lot for the response and the comments in the code. That helped me a lot to understand.
So I rewrote my procedures using the information provided. Note that they are a little verbose but, I wanted it like that understand the whole concept for now. (I am declaring a code block rather than nesting them)
HttpRequest.m
- (void) sendRequestFromURL: (NSString *) url
completion:(void (^)(NSString *, NSError *))completionBlock {
NSURL *myURL = [NSURL URLWithString: url];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL: myURL];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest: request
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
//Create a block to handle the background thread in the dispatch method.
void (^runAfterCompletion)(void) = ^void (void) {
if (error) {
completionBlock (nil, error);
} else {
NSString *dataText = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
completionBlock(dataText, error);
}
};
//Dispatch the queue
dispatch_async(dispatch_get_main_queue(), runAfterCompletion);
}];
[task resume];
}
ViewController.m
- (IBAction)buttonSearch:(id)sender {
NSString *const myURL = #"https://en.wiktionary.org/wiki/incredible";
HttpRequest *http = [[HttpRequest alloc] init];
[http sendRequestFromURL: myURL
completion: ^(NSString *str, NSError *error) {
if (error) {
self.outputText.text = [error localizedDescription];
} else {
self.outputText.text = str;
}
}];
}
Please feel free to comment on my new code. Style, incorrect usage, incorrect flow; feedback is very important in this stage of learning so I can become a better developer :)
Again thanks a lot for the replies.
You know what, use AFNetworking to save your life.
Or just modify your HttpRequest's sendRequestFromURL:
- (void)sendRequestFromURL:(NSString *)url completion:(void(^)(NSString *str, NSError *error))completionBlock {
NSURL *myURL = [NSURL URLWithString: url];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL: myURL];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest: request
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
if (error) {
completionBlock(nil, error);
} else {
completionBlock([[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding], error);
}
});
}];
[task resume];
}
and invoke like this
[http sendRequestFromURL:#"https://en.wiktionary.org/wiki/incredible" completion:^(NSString *str, NSError *error) {
if (!error) {
self.outputLabel.text = str;
}
}];
Rewrite your sendRequestFromURL function to take a completion block:
- (void) sendRequestFromURL: (NSString *) url
completion: (void (^)(void)) completion
{
NSURL *myURL = [NSURL URLWithString: url];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL: myURL];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest: request
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error)
{
self.responseText = [[NSString alloc] initWithData: data
encoding: NSUTF8StringEncoding];
if (completion != nil)
{
//The data task's completion block runs on a background thread
//by default, so invoke the completion handler on the main thread
//for safety
dispatch_async(dispatch_get_main_queue(), completion);
}
}];
[task resume];
}
Then, when you call sendRequestFromURL, pass in the code you want to run when the request is ready as the completion block:
[self.sendRequestFromURL: #"http://www.someURL.com&blahblahblah",
completion: ^
{
//The code that you want to run when the data task is complete, using
//self.responseText
}];
//Do NOT expect the result to be ready here. It won't be.
The code above uses a completion block with no parameters because your code saved the response text to an instance variable. It would be more typical to pass the response data and the NSError as parameters to the completion block. See #Yahoho's answer for a version of sendRequestFromURL that takes a completion block with a result string and an NSError parameter).
(Note: I wrote the code above in the SO post editor. It probably has a few syntax errors, but it's intended as a guide, not code you can copy/paste into place. Objective-C block syntax is kinda nasty and I usually get it wrong the first time at least half the time.)
If you want easy way then Don't make separate class for call webservice. Just make meethod in viewController.m instead. I mean write sendRequestFromURL in your viewController.m and update your label's text in completion handler something like,
- (void) sendRequestFromURL: (NSString *) url {
NSURL *myURL = [NSURL URLWithString: url];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL: myURL];
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest: request
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
self.responseText = [[NSString alloc] initWithData: data
encoding: NSUTF8StringEncoding];
self.outputLabel.text = self.responseText;
})
}];
[task resume];
}
I am creating an app that uses Google Place. Before I used to use Yahoo's api and had to use a url that was responsible for local search that was provided by yahoo. The url was following:
http://local.yahooapis.com/LocalSearchService/V3/localSearch?appid=SF0DVEvV34G4GnXEDU4SXniaDebJ_UvC1G1IuikVz3vpOJrBpyD.VqCJCVJHMh99He3iFz1Rzoqxb0b7Z.0-
Now since yahoo's api is discontinued I have decided to switch over to Google Place. But I cannot find an Url to use. I just dowlod the framework and use the api key. Where can I find such url for Google Place.
Register for the Google Places API by following the linke provided below:
https://code.google.com/apis/console
Refer Code Link for places Auto Search
https://github.com/AdamBCo/ABCGooglePlacesAutocomplete
NSString *const apiKey = #"*****23xAHRvnOf2BVG8o";
NSString * searchWord = #"search some place "
NSString *urlString = [NSString stringWithFormat:#"https://maps.googleapis.com/maps/api/place/autocomplete/json?input=%#&types=establishment|geocode&radius=500&language=en&key=%#",searchWord,apiKey];
pragma mark - Network Methods
-(void)retrieveGooglePlaceInformation:(NSString *)searchWord withCompletion:(void (^)(BOOL isSuccess, NSError *error))completion {
if (!searchWord) {
return;
}
searchWord = searchWord.lowercaseString;
self.searchResults = [NSMutableArray array];
if ([self.searchResultsCache objectForKey:searchWord]) {
NSArray * pastResults = [self.searchResultsCache objectForKey:searchWord];
self.searchResults = [NSMutableArray arrayWithArray:pastResults];
completion(YES, nil);
} else {
NSString *urlString = [NSString stringWithFormat:#"https://maps.googleapis.com/maps/api/place/autocomplete/json?input=%#&types=establishment|geocode&radius=500&language=en&key=%#",searchWord,apiKey];
NSURL *url = [NSURL URLWithString:[urlString stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding]];
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
NSDictionary *jSONresult = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
if (error || [jSONresult[#"status"] isEqualToString:#"NOT_FOUND"] || [jSONresult[#"status"] isEqualToString:#"REQUEST_DENIED"]){
if (!error){
NSDictionary *userInfo = #{#"error":jSONresult[#"status"]};
NSError *newError = [NSError errorWithDomain:#"API Error" code:666 userInfo:userInfo];
completion(NO, newError);
return;
}
completion(NO, error);
return;
} else {
NSArray *results = [jSONresult valueForKey:#"predictions"];
for (NSDictionary *jsonDictionary in results) {
}
//[self.searchResultsCache setObject:self.searchResults forKey:searchWord];
completion(YES, nil);
}
}];
[task resume];
}
}
In Below code run so i get a response from url but when i try to get encodedPoints it give me a null value. also i update RegexKitLite but prob. not solve. Any suggestion are welcome Thank you advance.
NSString* saddr = [NSString stringWithFormat:#"%f,%f", f.latitude, f.longitude];
NSString* daddr = [NSString stringWithFormat:#"%f,%f", t.latitude, t.longitude];
NSString* apiUrlStr = [NSString stringWithFormat:#"http://maps.googleapis.com/maps/api/directions/json?origin=%#&destination=%#&sensor=false", saddr, daddr];
// http://maps.googleapis.com/maps/api/directions/json?origin=41.029598,28.972985&destination=41.033586,28.984546&sensor=false%EF%BB%BF%EF%BB%BF
NSURL *apiUrl = [NSURL URLWithString:[apiUrlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSLog(#"api url: %#", apiUrl);
NSString *apiResponse = [NSString stringWithContentsOfURL:apiUrl encoding:nil error:nil];
NSString* encodedPoints = [apiResponse stringByMatching:#"points:\\\"([^\\\"]*)\\\"" capture:1L];
NSLog(#"encodedPoints: %#", encodedPoints);
if (encodedPoints) {
return [self decodePolyLine:[encodedPoints mutableCopy]];
}
else {
return NO;
}
I think its not a good way to do API request synchronously, especially when user' phone has poor internet connection, it will slow down the responsiveness of your application. So you should do an asynchronous API request with NSURLSession.
Also, the Directions API might return more than one routes for your request. So its better to use a NSArray to store your polyline points.
Sample code:
- (void)getPolyline {
NSURL *url = [[NSURL alloc] initWithString:#"https://maps.googleapis.com/maps/api/directions/json?origin=Chicago,IL&destination=Los+Angeles,CA&key=YOUR_API_KEY"];
NSURLRequest *request = [[NSURLRequest alloc] initWithURL: url];
NSURLSession *session = [NSURLSession sharedSession];
[[session dataTaskWithRequest:request completionHandler:
^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
if (!error) {
NSError *jsonError;
NSDictionary *dict = (NSDictionary*)[NSJSONSerialization JSONObjectWithData:data options:nil error:&jsonError];
if (!jsonError) {
NSArray *routesArray = (NSArray*)dict[#"routes"];
NSMutableArray *points = [NSMutableArray array];
for (NSDictionary *route in routesArray) {
NSDictionary *overviewPolyline = route[#"overview_polyline"];
[points addObject:overviewPolyline[#"points"]];
}
NSLog(#"%#", points);
}
} else {
//print error message
NSLog(#"%#", [error localizedDescription]);
}
}] resume];
}
I am retrieving JSON information for an API and it says on the API that it is in JSON but I noticed it is in JSONP or "json with padding" as some call it. I tired to look everywhere to find how to parse this but no luck. The information I am trying to receive is this:
({"book":[{"book_name":"James","book_nr":"59","chapter_nr":"3","chapter":
{"16":{"verse_nr":"16","verse":"For where envying and strife is, there is confusion and
every evil work."}}}],"direction":"LTR","type":"verse"});
The link to the data is https://getbible.net/json?p=James3:16, so you can look at it directly.
This is the code I am using to try to retrieve the JSON Data and parse it into a NSMutableDictionary.
-(void)fetchJson {
NSString *currentURL = [NSString stringWithFormat:#"https://getbible.net/json?p=James"];
NSURL *url = [NSURL URLWithString:currentURL];
NSData *data = [[NSData alloc]initWithContentsOfURL:url];
NSURLRequest *theRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:60];
NSMutableData *receivedData = [[NSMutableData alloc] initWithLength:0];
NSURLConnection * connection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self startImmediately:YES];
[receivedData setLength:0];
NSURLResponse *response = [[NSURLResponse alloc] initWithURL:url MIMEType:#".json" expectedContentLength:-1 textEncodingName:nil];
expectedTotalSize = [response expectedContentLength];
if ([data length] !=0) {
NSLog(#"appendingData");
[receivedData appendData:data];
if(connection){
NSLog(#"Succeeded! Received %lu bytes of data",(unsigned long)[receivedData length]);
}
NSError *error;
NSDictionary *jsonResponse = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
if(jsonResponse){
NSArray *responseArr = [jsonResponse mutableCopy];
NSLog(#"%lu",(unsigned long)[responseArr count]);
}else if (!jsonResponse){
//do internet connection error response
}
}
}
The results I am getting back from putting a breakpoint in the code is:
jsonResponse returns NULL
NSError NSCocoaErrorDomain code - 3840
but my NSData *data is returning 15640 bytes.
My console is displaying this from the NSLogs I used for debugging:
2014-04-20 01:27:31.877 appendingData
2014-04-20 01:27:31.879 Succeeded! Received 15640 bytes of data
I am receiving the data correctly but I am not parsing it correctly I know the error is because the JSON is in JSONP format. If anyone could please help with this I would appreciate it so much. I have tired to give as much detail on this question as I can but if you need more information just let me know so I can add it and make this as clear as possible.
Your code has at least two separate attempts to download the data. Neither is really correct. The code also only works with JSON, not JSONP.
Try this:
NSURL *url = [NSURL URLWithString:#"https://getbible.net/json?p=James"];
NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:60];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (data) {
NSString *jsonString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSRange range = [jsonString rangeOfString:#"("];
range.location++;
range.length = [jsonString length] - range.location - 2; // removes parens and trailing semicolon
jsonString = [jsonString substringWithRange:range];
NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
NSError *jsonError = nil;
NSDictionary *jsonResponse = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&jsonError];
if (jsonResponse) {
// process jsonResponse as needed
} else {
NSLog(#"Unable to parse JSON data: %#", jsonError);
}
} else {
NSLog(#"Error loading data: %#", error);
}
}];
One problem is that the data you're downloading has extraneous information at the beginning and end. The JSON being delivered by your URL is:
({"book":[{"book_name":"James","book_nr":"59","chapter_nr":"3","chapter":{"16":{"verse_nr":"16","verse":"For where envying and strife is, there is confusion and every evil work."}}}],"direction":"LTR","type":"verse"});
As the error message you're seeing indicates: you need to remove the initial ( from the beginning of the string and the ); from the end so that your JSON will start with the dictionary that your code expects. You can do this by calling subdataWithRange: on your NSData object:
NSData* jsonData = [data subdataWithRange:NSMakeRange(1, data.length-3)];
NSDictionary* jsonResponse = [NSJSONSerialization JSONObjectWithData:jsonData
options:0
error:&error];
Just to update everyone, the NSURLRequest has been deprecated in iOS9. I tried the answer by #rmaddy, and I didn't receive anything either (just like what #lostAtSeaJoshua was encountering I guess). I have updated rmaddy's answer to reflect the NSURLSession implementation that has (I think) replaced NSURLRequest:
NSURLSession *session = [NSURLSession sharedSession];
NSURL *url = [NSURL URLWithString:#"http://somerandomwebsite.com/get.php?anotherRandomParameter=5"];
[[session dataTaskWithURL:url
completionHandler:^(NSData *data,
NSURLResponse *response,
NSError *error) {
// handle response
if (data) {
NSString *jsonString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"stringJSONed: %#",jsonString);
//Do something with the received jsonString, just like in # rmaddy's reply
} else {
NSLog(#"Error loading data: %#", error);
}
}] resume];
Just a heads up notice, when I first ran it, it gave me the security error. What you need to do (if you are using http) is to add this to your plist:
<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>
I have to mention that after the NSAllowArbitraryLoads key, there are most probably other keys and values, such as NSExceptionDomain. But they're not really relevant to this answer I think. If you need to look further, let me know and I will dig deeper :)