发表新帖
发表新帖

Objective C HTML escape/unescape

前端 未结
关注
14 1952
生来不讨喜
生来不讨喜 2020-11-22 16:19

Wondering if there is an easy way to do a simple HTML escape/unescape in Objective C. What I want is something like this psuedo code:

NSString *string = @\"
相关标签:
14条回答
  • 广开言路
    2020-11-22 16:45

    MREntitiesConverter doesn't work for escaping malformed xml. It will fail on a simple URL:

    http://www.google.com/search?client=safari&rls=en&q=fail&ie=UTF-8&oe=UTF-8

    0 讨论(0)
  • 广开言路
    2020-11-22 16:45

    This is an old answer that I posted some years ago. My intention was not to provide a "good" and "respectable" solution, but a "hacky" one that might be useful under some circunstances. Please, don't use this solution unless nothing else works.

    Actually, it works perfectly fine in many situations that other answers don't because the UIWebView is doing all the work. And you can even inject some javascript (which can be dangerous and/or useful). The performance should be horrible, but actually is not that bad.

    There is another solution that has to be mentioned. Just create a UIWebView, load the encoded string and get the text back. It escapes tags "<>", and also decodes all html entities (e.g. "&gt;") and it might work where other's don't (e.g. using cyrillics). I don't think it's the best solution, but it can be useful if the above solutions doesn't work.

    Here is a small example using ARC:

    @interface YourClass() <UIWebViewDelegate>

    @property UIWebView *webView;

@end

@implementation YourClass 

- (void)someMethodWhereYouGetTheHtmlString:(NSString *)htmlString {
    self.webView = [[UIWebView alloc] init];
    NSString *htmlString = [NSString stringWithFormat:@"<html><body>%@</body></html>", self.description];
    [self.webView loadHTMLString:htmlString baseURL:nil];
    self.webView.delegate = self;
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
    self.webView = nil;
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    self.webView = nil;
    NSString *escapedString = [self.webView stringByEvaluatingJavaScriptFromString:@"document.body.textContent;"];
}

- (void)webViewDidStartLoad:(UIWebView *)webView {
    // Do Nothing
}

@end
    0 讨论(0)
  • 走了就别回头了
    2020-11-22 16:49

    The least invasive and most lightweight way to encode and decode HTML or XML strings is to use the GTMNSStringHTMLAdditions CocoaPod.

    It is simply the Google Toolbox for Mac NSString category GTMNSString+HTML, stripped of the dependency on GTMDefines.h. So all you need to add is one .h and one .m, and you're good to go.

    Example:

    #import "GTMNSString+HTML.h"

// Encoding a string with XML / HTML elements
NSString *stringToEncode = @"<TheBeat>Goes On</TheBeat>";
NSString *encodedString = [stringToEncode gtm_stringByEscapingForHTML];

// encodedString looks like this now:
// &lt;TheBeat&gt;Goes On&lt;/TheBeat&gt;

// Decoding a string with XML / HTML encoded elements
NSString *stringToDecode = @"&lt;TheBeat&gt;Goes On&lt;/TheBeat&gt;";
NSString *decodedString = [stringToDecode gtm_stringByUnescapingFromHTML];

// decodedString looks like this now:
// <TheBeat>Goes On</TheBeat>
    0 讨论(0)
  • 星月不相逢
    2020-11-22 16:49

    This easiest solution is to create a category as below:

    Here’s the category’s header file:

    #import <Foundation/Foundation.h>
@interface NSString (URLEncoding)
-(NSString *)urlEncodeUsingEncoding:(NSStringEncoding)encoding;
@end

    And here’s the implementation:

    #import "NSString+URLEncoding.h"
@implementation NSString (URLEncoding)
-(NSString *)urlEncodeUsingEncoding:(NSStringEncoding)encoding {
    return (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
               (CFStringRef)self,
               NULL,
               (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
               CFStringConvertNSStringEncodingToEncoding(encoding));
}
@end

    And now we can simply do this:

    NSString *raw = @"hell & brimstone + earthly/delight";
NSString *url = [NSString stringWithFormat:@"http://example.com/example?param=%@",
            [raw urlEncodeUsingEncoding:NSUTF8Encoding]];
NSLog(url);

    The credits for this answer goes to the website below:-

    http://madebymany.com/blog/url-encoding-an-nsstring-on-ios
    0 讨论(0)
  • 难免孤独
    2020-11-22 16:52

    In iOS 7 you can use NSAttributedString's ability to import HTML to convert HTML entities to an NSString.

    Eg:

    @interface NSAttributedString (HTML)
+ (instancetype)attributedStringWithHTMLString:(NSString *)htmlString;
@end

@implementation NSAttributedString (HTML)
+ (instancetype)attributedStringWithHTMLString:(NSString *)htmlString
{
    NSDictionary *options = @{ NSDocumentTypeDocumentAttribute : NSHTMLTextDocumentType,
                               NSCharacterEncodingDocumentAttribute :@(NSUTF8StringEncoding) };

    NSData *data = [htmlString dataUsingEncoding:NSUTF8StringEncoding];

    return [[NSAttributedString alloc] initWithData:data options:options documentAttributes:nil error:nil];
}

@end

    Then in your code when you want to clean up the entities:

    NSString *cleanString = [[NSAttributedString attributedStringWithHTMLString:question.title] string];

    This is probably the simplest way, but I don't know how performant it is. You should probably be pretty damn sure the content your "cleaning" doesn't contain any <img> tags or stuff like that because this method will download those images during the HTML to NSAttributedString conversion. :)

    0 讨论(0)
  • 被撕碎了的回忆
    2020-11-22 16:54

    Check out my NSString category for XMLEntities. There's methods to decode XML entities (including all HTML character references), encode XML entities, stripping tags and removing newlines and whitespace from a string:

    - (NSString *)stringByStrippingTags;
- (NSString *)stringByDecodingXMLEntities; // Including all HTML character references
- (NSString *)stringByEncodingXMLEntities;
- (NSString *)stringWithNewLinesAsBRs;
- (NSString *)stringByRemovingNewLinesAndWhitespace;
    0 讨论(0)
 看不清?
提交回复
热议问题