UIWebView - how to extract the HTML source code from webpages like Facebook??

at0m87 · 02-06-2012, 01:39 AM

Hi guys, i have an example of a source code which programatically sets the value of fields in an HTML.

The part of the source code is as such:

Code:

- (void)viewDidLoad
{
    NSLog(@"viewDidLoad");
    [super viewDidLoad];

    myWebView.delegate = self;
 
    //---formulate the HTML string---
    NSString *str = [[[NSString alloc] initWithString:
                    @"<html>"
                     "    <body>"
                     "        <h1>The fields below are filled in programmatically</h1>"
                     "        <input id='username' value='UserName' />"
                     "        <input id='password' value='Password' type='password' />"
                     "    </body>"
                     "</html>"
                     ] autorelease];
    
    //---load the UIWebView with the html string---
    [myWebView loadHTMLString:str baseURL:nil];
}

//---wait for the UIWebView to finish loading---
- (void)webViewDidFinishLoad:(UIWebView *)webView {
    NSLog(@"webViewDidFinishLoad");
    //---access the 2 fields in the HTML---
    [myWebView stringByEvaluatingJavaScriptFromString:@"document.getElementById('username').value='Peter';"];
    [myWebView stringByEvaluatingJavaScriptFromString:@"document.getElementById('password').value='TopSecret';"];
}

I would like to programmatically set value of fields in an actually webpage like Facebook instead of a custom HTML like such written above.

How should i replace the "str" to an actual webpage's html source code so that i can pick out the "ElementbyId"?

at0m87 · 02-07-2012, 01:33 AM

Bump! anyone could help with my problems or could point me to any tutorials or guides?

fiftysixty · 02-07-2012, 02:22 AM

Use [UIWebView loadRequest] to connect to the URL you want.

at0m87 · 02-07-2012, 02:39 AM

Quote:

Originally Posted by fiftysixty

Use [UIWebView loadRequest] to connect to the URL you want.

Hi thank you for your reply, i can load a URL no problem.

Code:

 NSURL *url = [NSURL URLWithString:loginObj.loginURL];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [myWebView loadRequest:request];

but after loading the URL, how do i retrieve the HTML of the website to use this code?

Code:

[myWebView stringByEvaluatingJavaScriptFromString:@"document.getElementById('username').value='peter';"];

fiftysixty · 02-07-2012, 02:50 AM

Once the loadRequest has finished, the UIWebView contains the HTML already. Any calls you make to stringByEvaluationJavaScript... work on that HTML.

at0m87 · 02-07-2012, 04:22 AM

Quote:

Originally Posted by fiftysixty

Once the loadRequest has finished, the UIWebView contains the HTML already. Any calls you make to stringByEvaluationJavaScript... work on that HTML.

Okay i did as per your suggestion and wrote this:

Code:

- (void)viewDidLoad
{
    NSLog(@"webView DidLoad");
    [super viewDidLoad];
    [self showWebView]; 
    
}


-(void)showWebView{
    appDelegate = (LoginDBAppDelegate *)[[UIApplication sharedApplication] delegate];
    
    loginObj = [appDelegate.loginArray objectAtIndex:currentSelectedRow];
    NSLog(@"%@", loginObj.loginURL);
    
    NSURL *url = [NSURL URLWithString:loginObj.loginURL];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [myWebView loadRequest:request];
    
    timer = [NSTimer scheduledTimerWithTimeInterval:(1.0/2.0) target:self selector:@selector(spin) userInfo:nil repeats:YES];
    
}

//--activity indicator to show the loading of webpages
- (void)spin{
    if (!myWebView.loading){
        [activity stopAnimating];
        //[self webViewDidFinishLoad];
        NSLog(@"Stop Spinning");
        
    }
    else{
        [activity startAnimating];
        NSLog(@"Spinning");

    }
    
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    //---access the 2 fields in the HTML---
    NSLog(@"webView DidFinishLoad");
    [myWebView stringByEvaluatingJavaScriptFromString:@"document.getElementById('username').value='peter';"];
    [myWebView stringByEvaluatingJavaScriptFromString:@"document.getElementById('password').value='password';"];
}

i run the program, the HTML loaded (which in this case was Facebook) but this method

Code:

- (void)webViewDidFinishLoad:(UIWebView *)webView

wasn't called so the credentials were not filled in.

In the sample code i had shown in my first post, the above mentioned method was executed and the credentials filled in. Now it just wasn't called at all.

Please let me know where i had done wrong in my code thanks =)

fiftysixty · 02-07-2012, 04:34 AM

Looks like you forgot to set the UIWebView delegate in your new code.

fiftysixty · 02-07-2012, 04:37 AM

Also, I hope those are not your real Facebook username and password in the code you just posted...

at0m87 · 02-07-2012, 04:54 AM

Quote:

Originally Posted by fiftysixty

Also, I hope those are not your real Facebook username and password in the code you just posted...

oops. thanks for pointing it out..

at0m87 · 02-07-2012, 05:05 AM

Quote:

Originally Posted by fiftysixty

Looks like you forgot to set the UIWebView delegate in your new code.

Do you mean setting this?

Code:

myWebView.delegate = self;

i added it in now, and yes, the method is being called. may i ask, what is the significant of setting the UIWebView delegate, why do we need to set it?

Now tat the method in question is executed, but the credentials aren't filling up. i suppose could be because the "id" were incorrect?

Update*
i tried playing around with different id and found that the email field's id is "email", instead of "Email"
Is there a way i can say for sure find out what each field's ID is?

update**
I figured out how to find out for sure what is the ID used for different field. i went to facebook's login page and click on view source code and i got it for there. Success as i was able to auto fill in all the credentials and successfully login in to Facebook from my App =))

Thanks fiftysixty!