Escape NSString for javascript input

Question

I have an ASCII character string (randomly generated [NSString stringWithFormat: @ "% c", someNumber]), and I want to use this string as input for the javascript method. Sort of:

[webView_ stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"my_javascript_method(\"%@\")", myASCIIString]];

How can I avoid NSString? I tried to learn encodeURI and decodeURI, but have not yet found a solution.

Answer 1

ASCII, , 0x00 0x7F. , http://www.json.org, , , - \, " : 0x00 -0x1F 0x7F. , , , , , - ( ):

const char *chars = [myASCIIString UTF8String];
NSMutableString *escapedString = [NSMutableString string];
while (*chars)
{
    if (*chars == '\\')
        [escapedString appendString:@"\\\\"];
    else if (*chars == '"')
        [escapedString appendString:@"\\\""];
    else if (*chars < 0x1F || *chars == 0x7F)
        [escapedString appendFormat:@"\\u%04X", (int)*chars];
    else
        [escapedString appendFormat:@"%c", *chars];
    ++chars;
}
NSString *js = [NSString stringWithFormat:@"my_js_function(\"%@\")", escapedString];

Answer 2

NSJSONSerialization . NSString Javascript, hard, . (JSONKit , https://github.com/johnezang/JSONKit/blob/82157634ca0ca5b6a4a67a194dd11f15d9b72835/JSONKit.m#L1423)

, NSString.

#import "NSString+JavascriptEscape.h"

@implementation NSString (JavascriptEscape)

- (NSString *)stringEscapedForJavasacript {
    // valid JSON object need to be an array or dictionary
    NSArray* arrayForEncoding = @[self];
    NSString* jsonString = [[NSString alloc] initWithData:[NSJSONSerialization dataWithJSONObject:arrayForEncoding options:0 error:nil] encoding:NSUTF8StringEncoding];

    NSString* escapedString = [jsonString substringWithRange:NSMakeRange(2, jsonString.length - 4)];
    return escapedString;
}

@end

, , javascript. .

NSString *javascriptCall = 
    [NSString stringWithFormat:@"MyJavascriptFunction(\"%@\")", escapedString];

[self.webView stringByEvaluatingJavaScriptFromString:javascriptCall];

Answer 3

, . , , , .

-(NSString *)addBackslashes:(NSString *)string {
    /*

     Escape characters so we can pass a string via stringByEvaluatingJavaScriptFromString

     */

    // Escape the characters
    string = [string stringByReplacingOccurrencesOfString:@"\\" withString:@"\\\\"];
    string = [string stringByReplacingOccurrencesOfString:@"\"" withString:@"\\\""];
    string = [string stringByReplacingOccurrencesOfString:@"\'" withString:@"\\\'"];
    string = [string stringByReplacingOccurrencesOfString:@"\n" withString:@"\\n"];
    string = [string stringByReplacingOccurrencesOfString:@"\r" withString:@"\\r"];
    string = [string stringByReplacingOccurrencesOfString:@"\f" withString:@"\\f"];
    return string;
}

, , . http://www.wilsonmar.com/1eschars.htm

Answer 4

ES5:

, , , , , . escape-.

( ), \uXXXX. ( ) .

Answer 5

- :

[webView_ stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"my_javascript_method(escape(\"%@\"))", myASCIIString]];

escape . , ,

Answer 6

, ASCII (, ) / , :

- (NSString*) escapeStringForJavascript:(NSString*)input
{
    NSMutableString* ret = [NSMutableString string];
    int i;
    for (i = 0; i < input.length; i++)
    {
        unichar c = [input characterAtIndex:i];
        if (c == '\\')
        {
            // escape backslash
            [ret appendFormat:@"\\\\"];
        }
        else if (c == '"')
        {
            // escape double quotes
            [ret appendFormat:@"\\\""];
        }
        else if (c >= 0x20 && c <= 0x7E)
        {
            // if it is a printable ASCII character (other than \ and "), append directly
            [ret appendFormat:@"%c", c];
        }
        else
        {
            // if it is not printable standard ASCII, append as a unicode escape sequence
            [ret appendFormat:@"\\u%04X", c];
        }
    }
    return ret;
}

, , . , javascript.

Answer 7

@zetachang . javascript. .

NSString *javascriptCall = 
    [NSString stringWithFormat:@"MyJavascriptFunction(\"%@\")", escapedString];
[self.webView stringByEvaluatingJavaScriptFromString:javascriptCall];

Answer 8

NSJSONSerialization, JSON, JSON JavaScript. , , JSON .

NSString* inputString = ... // your raw string to escape
NSData* jsonData = [NSJSONSerialization dataWithJSONObject:@[inputString] options:0 error:nil];
NSString* jsString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
NSString* jsScript = [NSString stringWithFormat:@"yourFunction(%@[0])",jsString];
// then pass jsScript to a JavaScript interpreter