iOS Parse <img from html-string

DennisBlah · Jul 8, 2014

Hey all,

I'm trying to store a few pages locally so I can still load them up in my webview when I don't have a network connection.

Now the saving goes well, only problem I'm facing is with images.
I'm trying to get the content between <img src=\" and \"
So I can store this image locally as well and rewrite the code a little bit.

I can find all the locations of each <img src=\"
and ofcourse I can find all locations of each \"
and see which \" is most nearest after the location of <img src=\"

Get the length between and then substract the string from there so I get the substring to download the image and store it and rewrite it to where I'm storing it locally.

However I'm sure this can be done a lot easier:

Here is my code for now: (not fully done yet)

Code:

    NSMutableArray *startRanges = [[NSMutableArray alloc] initWithObjects: nil];
    NSMutableArray *endRanges = [[NSMutableArray alloc] initWithObjects: nil];
    NSUInteger length = [pageHTMLstring length];
    NSRange range = NSMakeRange(0, length);
    while(range.location != NSNotFound)
    {
        range = [pageHTMLstring rangeOfString: @"<img src=\"" options:0 range:range];
        if(range.location != NSNotFound)
        {
            range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
            [startRanges addObject: [NSString stringWithFormat: @"%i", range.location]];
        }
    }
    
    
    range = NSMakeRange(0, length);
    while(range.location != NSNotFound)
    {
        range = [pageHTMLstring rangeOfString: @"\"" options:0 range:range];
        if(range.location != NSNotFound)
        {
            range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
            [endRanges addObject: [NSString stringWithFormat: @"%i", range.location]];
        }
    }
    
    for(int a=0; a<[startRanges count]; a++) {
        int end = 0;
        for(int b=0; b<[endRanges count]; b++) {
            if([[endRanges objectAtIndex: b] intValue] > [[startRanges objectAtIndex: a] intValue]) {
                end = b;
                break;
            }
        }
        
        double start = [[startRanges objectAtIndex: a] intValue];
        double stop = [[endRanges objectAtIndex: end] intValue];
        NSString *test = [pageHTMLstring substringWithRange:NSMakeRange(start, (stop - start))];
        NSLog(@"The image: %@",test);
    }

DennisBlah · Jul 8, 2014

I found the following code which is great to replace things between < > tags:

Code:

NSRange r;
NSString *s = @"my<remove>output";
while ((r = [s rangeOfString:@"<[^>]+>" options:NSRegularExpressionSearch]).location != NSNotFound)
    s = [s stringByReplacingCharactersInRange:r withString:@""];

So I tried by altering <[^>]+> to <img[^>]+> and put a log of
[s substringWithRange: r]

Which is doing great! Exactly what I'm looking for. However it will never get out of the loop.
(I could do a replace with unique chars like: §§img1§§ with a counter on place of 1)
After that replace these chars with the new image but still..
Is there anyone that can push me in the right direction? This is a lot cleaner and faster.

Because now I got a piece of code of around 65 lines, which does load nsdata from url, change nsdata to string do the search and replace,
Download images to documents in a folder and replace the <img src= to the correct new name for the image and location, and then save it.

The result is satisfying however I know this can be done lot better...

DennisBlah · Jul 13, 2014

I have changed the concept to filter out any .jpg, .png and .gif, either if its quoted with a " or '.

Code:

 NSMutableArray *theImages = [[NSMutableArray alloc] initWithObjects: nil];
    
    NSMutableArray *imgRanges = [[NSMutableArray alloc] initWithObjects: nil];
    NSUInteger length = [theHTML length];
    NSRange range = NSMakeRange(0, length);
    //.jpg
    while(range.location != NSNotFound)
    {
        range = [theHTML rangeOfString: @".jpg" options:0 range:range];
        if(range.location != NSNotFound)
        {
            range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
            [imgRanges addObject: [NSString stringWithFormat: @"%i", range.location]];
        }
    }
    //.png
    range = NSMakeRange(0, length);
    while(range.location != NSNotFound)
    {
        range = [theHTML rangeOfString: @".png" options:0 range:range];
        if(range.location != NSNotFound)
        {
            range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
            [imgRanges addObject: [NSString stringWithFormat: @"%i", range.location]];
        }
    }
    //.gif
    range = NSMakeRange(0, length);
    while(range.location != NSNotFound)
    {
        range = [theHTML rangeOfString: @".gif" options:0 range:range];
        if(range.location != NSNotFound)
        {
            range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
            [imgRanges addObject: [NSString stringWithFormat: @"%i", range.location]];
        }
    }
    
    NSMutableArray *endChars = [[NSMutableArray alloc] initWithObjects: nil];
    NSMutableArray *endCharLocs = [[NSMutableArray alloc] initWithObjects: nil];
    for(int a=0; a<[imgRanges count]; a++) {
        //The character
        [endChars addObject: [theHTML substringWithRange:NSMakeRange([[imgRanges objectAtIndex: a] intValue], ([[imgRanges objectAtIndex: a] intValue] + 1) - [[imgRanges objectAtIndex: a]intValue])]];
        //The location of character
        [endCharLocs addObject: [imgRanges objectAtIndex: a]];
    }
    
    NSMutableArray *startCharLocs = [[NSMutableArray alloc] initWithObjects: nil];
    NSMutableArray *tempCharLocs = [[NSMutableArray alloc] initWithObjects: nil];
    for(int a=0; a<[imgRanges count]; a++) {
        //Checking for this character
        NSString *checkChar = [endChars objectAtIndex: a];
        //Temporary array for locations
        tempCharLocs = [[NSMutableArray alloc] initWithObjects: nil];
        
        range = NSMakeRange(0, length);
        BOOL stopLoop = NO;
        while(range.location != NSNotFound && !stopLoop) {
            range = [theHTML rangeOfString: checkChar options:0 range:range];
            if(range.location != NSNotFound) {
                range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
                [tempCharLocs addObject: [NSString stringWithFormat: @"%i", range.location]];
                if(range.location > endCharLocs) {
                    stopLoop = YES;
                }
            }
        }
        [startCharLocs addObject: [tempCharLocs objectAtIndex: [tempCharLocs count] - 2]];
    }
    
    //Add the full images
    for(int a=0; a<[imgRanges count]; a++) {
        [theImages addObject: [theHTML substringWithRange:NSMakeRange([[startCharLocs objectAtIndex: a] intValue], [[endCharLocs objectAtIndex: a] intValue] - [[startCharLocs objectAtIndex: a]intValue])]];
    }

This is just a part of my code.
After this I do a for loop through theImages array, and throwing a stringByReplacingOccurrencesOfString: over theHTML string.

Is there anyone that can finetune this? Because I think this can be done lot better.

Thanks!

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iOS Parse <img from html-string

DennisBlah

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DennisBlah

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DennisBlah

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