text to speech - iPhone SDK - Google TTS and encoding

Question

I am developing a text-to-speech iphone app that support multi-languages.

Here is my request URL

requestUrlStr = @"http://www.translate.google.com/translate_tts?tl=en&q=hello";

for english the above url has no problem

but for Chinese

requestUrlStr = @"http://www.translate.google.com/translate_tts?tl=zh-TW&q=你好";

I know the above url will give 'Bad URL', so I used follow method to encode the string into UTF-8

requestUrlStr = [requestUrlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

It will become

http://www.translate.google.com/translate_tts?tl=zh-CN&q=%E4%BD%A0%E5%A5%BD

Then the Google TTS cannot recognize this Chinese text.

Answer 1

You have to pretend to be a User-Agent other than the default (appName, etc) in your NSURLRequest. Try this (I use Greek language) ...

NSString* userAgent = @"Mozilla/5.0";

NSURL *url = [NSURL URLWithString:[@"http://www.translate.google.com/translate_tts?tl=el&q=Καλημ?ρα" 
                                   stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];


NSMutableURLRequest* request = [[[NSMutableURLRequest alloc] initWithURL:url] autorelease];

[request setValue:userAgent forHTTPHeaderField:@"User-Agent"];


NSURLResponse* response = nil;
NSError* error = nil;
NSData* data = [NSURLConnection sendSynchronousRequest:request
                                     returningResponse:&response
                                                 error:&error];



[data writeToFile:@"/var/tmp/tts.mp3" atomically:YES];

UPDATE 2017

Since our favorite companies enjoy to update and deprecate things, here is the above example as it should be now...

NSString* text = @"καλημ?ρα";
NSString* lang = @"el";

NSString* sUrl = [NSString stringWithFormat:@"https://translate.google.com/translate_tts?q=%@&tl=%@&client=tw-ob", text, lang];
sUrl = [sUrl stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLFragmentAllowedCharacterSet]];
NSURL* url = [NSURL URLWithString:sUrl];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPMethod:@"GET"];
[request setValue:@"Mozilla/5.0" forHTTPHeaderField:@"User-Agent"];

NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]
                                                      delegate:nil
                                                 delegateQueue:[NSOperationQueue mainQueue]];

[[session dataTaskWithRequest:request
            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                [data writeToFile:@"/var/tmp/tts.mp3" atomically:YES];
            }
  ] resume];

The ...delegate:nil delegateQueue:[NSOperationQueue mainQueue] can be omitted.