如何解析 HTML 以搜索特定内容的针

Question

鉴于下面的NSString最初是从使用NSXMLParser解析XML文档中检索到的CData对象转换而来的，我如何获得这本书的以下属性：标题、书籍图片封面、作者、价格, 和评分？

这是我获取以下属性的基本解决方案

1. 书名 - 我可能可以通过查看riRssTitle span 类来获得这个，但是我必须弄清楚如何读取 ahref url 标签之间的标题获取标题

2. 图书图片 - 我必须获取第一个 URL http://ecx.images-amazon.com/images/I/41Lg22K3ViL._SL160_PIsitb-sticker-arrow-dp,TopRight,12,-18_SH30_OU02_.jpg，然后将所有内容保留到 http://ecx.images-amazon.com/images/I/41Lg22K3ViL，省略其余部分，然后附加 .jpg 标签以后有一个完整的图片检索网址。

3. 图书作者 - 我必须按照与第 1 步相同的步骤，但要搜索riRssContributor span 标签。

4. 图书价格 - 这里没有所有商品通用的价格标签，但我确实看到的一个共同点是价格总是在 font tag 中坐在BOLD tag。

5. Rating - 大概可以通过查找包含单词stars的URL然后抓取它后面的数字来检索，4表示4星，任何数字加上-5 意味着额外的 0.5 星。所以3-5 意味着 3.5 颗星。

在不弄乱的情况下，最好的方法是什么？此外，如果亚马逊决定更改其显示 URL 的方式，我也不喜欢我的代码会如何中断，我的应用程序依赖于亚马逊维护其 url 命名约定。

目前，这是最好的前进方式吗？有没有可以实现我想做的快速解析器？

这是亚马逊 RSS 提要的示例：http://www.amazon.co.uk/gp/rss/bestsellers/books/72/ref=zg_bs_72_rsslink

---

这是我为每个项目检索到的以下 CData NSString 数据。

<div style="float:left;">
    <a class="url" href="http://www.amazon.co.uk/Gone-Girl-Gillian-Flynn/dp/0753827662/ref=pd_zg_rss_ts_b_72_9">
        <img src="http://ecx.images-amazon.com/images/I/41Lg22K3ViL._SL160_PIsitb-sticker-arrow-dp,TopRight,12,-18_SH30_OU02_.jpg" alt="Gone Girl" border="0" hspace="0" vspace="0" />
    </a>
</div>
<span class="riRssTitle">
    <a href="http://www.amazon.co.uk/Gone-Girl-Gillian-Flynn/dp/0753827662/ref=pd_zg_rss_ts_b_72_9">Gone Girl</a>
</span>
<br />
<span class="riRssContributor">
    <a href="http://www.amazon.co.uk/Gillian-Flynn/e/B001JP3W46/ref=ntt_athr_dp_pel_1">Gillian Flynn</a>
    <span class="byLinePipe">(Author)</span>
</span>
<br />
<img src="http://g-ecx.images-amazon.com/images/G/02/x-locale/common/icons/uparrow_green_trans._V192561975_.gif" width="13" align="abstop" alt="Ranking has gone up in the past 24 hours" title="Ranking has gone up in the past 24 hours" height="11" border="0" />
<font color="green">
    <strong></strong>
</font> 674 days in the top 100 
<br />
<img src="http://g-ecx.images-amazon.com/images/G/02/detail/stars-4-0._V192253865_.gif" width="64" height="12" border="0" style="margin: 0; padding: 0;"/>(5704)
<br />
<br />
<a href="http://www.amazon.co.uk/Gone-Girl-Gillian-Flynn/dp/0753827662/ref=pd_zg_rss_ts_b_72_9">Buy new: </a>
<strike>£9.07</strike>
<font color="#990000">
    <b>£3.85</b>
</font>
<br />
<a href="http://www.amazon.co.uk/gp/offer-listing/0753827662/ref=pd_zg_rss_ts_b_72_9?ie=UTF8&condition=all">60 used & new</a> from 
<span class="price">£2.21</span>
<br />
<br />(Visit the 
<a href="http://www.amazon.co.uk/Best-Sellers-Books-Crime-Thrillers-Mystery/zgbs/books/72/ref=pd_zg_rss_ts_b_72_9">Bestsellers in Crime, Thrillers & Mystery</a> list for authoritative information on this product's current rank.)

Answer 1

TFHpple 绝对是解析 HTML 的库。 （在 github 上>1000 颗星） https://github.com/topfunky/hpple

这是该 RSS 提要的 obj-c 解决方案：

NSString *stringURL = @"http://www.amazon.co.uk/gp/rss/bestsellers/books/72/ref=zg_bs_72_rsslink";
NSURL  *url = [NSURL URLWithString:stringURL];
NSData *htmlData = [NSData dataWithContentsOfURL:url];

TFHpple * doc = [[TFHpple alloc] initWithHTMLData:htmlData];

NSArray *titleElements = [doc searchWithXPathQuery:@"//span[@class='riRssTitle']/a"];
for (TFHppleElement *element in titleElements)
{
    NSString *title = element.firstChild.content;
    NSLog(@"title: %@", title);
}

NSArray *imageElements = [doc searchWithXPathQuery:@"//a[@class='url']/img"];
for (TFHppleElement *element in imageElements)
{
    NSString *image = element.attributes[@"src"];
    NSMutableArray *parts = [[image componentsSeparatedByString:@"/"] mutableCopy];
    NSArray *pathParts = [parts.lastObject componentsSeparatedByString:@"."];
    [parts removeLastObject];
    [parts addObject:[NSString stringWithFormat:@"%@.%@",pathParts.firstObject, pathParts.lastObject]];
    image = [parts componentsJoinedByString:@"/"];
    NSLog(@"image: %@", image);
}

NSArray *authorElements = [doc searchWithXPathQuery:@"//span[@class='riRssContributor']/a"];
for (TFHppleElement *element in authorElements)
{
    NSString *author = element.firstChild.content;
    NSLog(@"author: %@", author);
}

NSArray *priceElements = [doc searchWithXPathQuery:@"//font/b"];
for (TFHppleElement *element in priceElements)
{
    NSString *price = element.firstChild.content;
    NSLog(@"price: %@", price);
}

NSArray *ratingElements = [doc searchWithXPathQuery:@"//img"];
for (TFHppleElement *element in ratingElements)
{
    if (![element.attributes[@"src"] containsString:@"stars"])
        continue;

    NSArray *parts = [element.attributes[@"src"] componentsSeparatedByString:@"-"];
    if (parts.count < 5) continue;

    NSString *rating = [NSString stringWithFormat:@"%@.%@", parts[3], [parts[4] substringToIndex:1]];
    NSLog(@"rating: %@", rating);
}

正如您所说，您受制于亚马逊的命名约定。

Answer 2

您可以根据需要使用TFHpple 和TFHppleElement 来解析上述数据。

Here 是这样做的参考。

Answer 3

我在 iOS 开发者 Facebook 群组上看到了您的帖子，并认为我会在最后一分钟提供意见。

由于亚马逊没有严格的命名约定，因此您必须在提要中进行搜索。 这是我试图做的，但后来我试着让它看起来不那么骇人听闻。 如果您注意到，您会发现有时如果您尝试搜索特定路径名，Feed 会返回缺失值，因此我也尝试弥补这种情况。

为此，您只需从以下 URL 下载 NSDictionary 类别：https://github.com/nicklockwood/XMLDictionary

.h
#import <Foundation/Foundation.h>

@interface JMAmazonProcessor : NSObject
+(NSArray*)processAmazonResponseWithXMLData:(NSData*)responseObject;
@end

为了

.m

#import "JMAmazonProcessor.h"

@implementation JMAmazonProcessor



+(NSString*)getBookTitleWithArray:(NSArray*)array{
    return [[array[0] objectForKey:kAmazonAHREFKey] objectForKey:kAmazonUnderscoreTextKey];
}

+(NSString*)getBookAuthorWithArray:(NSArray*)array{
    id bookAuthor = [[array[1] objectForKey:kAmazonAHREFKey] objectForKey:kAmazonUnderscoreTextKey];

    if(!bookAuthor){
        bookAuthor = [array[1] objectForKey:kAmazonUnderscoreTextKey];
    }

    if([bookAuthor isKindOfClass:[NSArray class]]){
        bookAuthor = [bookAuthor componentsJoinedByString:@" "];
    }

    return bookAuthor;
}
+(NSString*)getPriceFromDictionary:(NSDictionary*)dictionary{
    return [NSString stringWithUTF8String:[[[[dictionary objectForKey:@"font"] lastObject] objectForKey:@"b"] cStringUsingEncoding:NSUTF8StringEncoding]];
}


+(NSString*)getRatingWithCurrentRatingDictionary:(NSDictionary*)ratingDictionary{
    NSString * stars;
    if([ratingDictionary objectForKey:@"_src"]){
        NSString * possibleStarsURL = [ratingDictionary objectForKey:@"_src"];
        if([possibleStarsURL rangeOfString:@"stars-" options:NSCaseInsensitiveSearch].location != NSNotFound){
            stars = [[[[[possibleStarsURL componentsSeparatedByString:@"stars-"] lastObject] componentsSeparatedByString:@"."] firstObject] stringByReplacingOccurrencesOfString:@"-" withString:@"."];
        }
    }


    return stars;

}
+(NSString*)getRatingFromDictionary:(NSDictionary*)dictionary{
    id currentDictionary = [dictionary objectForKey:@"img"];
    NSString *rating;

    if([currentDictionary isKindOfClass:[NSArray class]]){
        for(int i = 0; i < [currentDictionary count]; i++){
            NSDictionary *currentRatingDictionary = [currentDictionary objectAtIndex:i];

            if((rating = [self getRatingWithCurrentRatingDictionary:currentRatingDictionary])){
                break;
            }
        }
    }

    else if([currentDictionary isKindOfClass:[NSDictionary class]]){
        rating = [self getRatingWithCurrentRatingDictionary:currentDictionary];
    }

    if(!rating) rating = @"Rating is not currently available";
    return rating;
}


+(NSArray*)processAmazonResponseWithXMLData:(NSData*)responseObject{
    NSMutableArray *bookEntries = [[NSMutableArray alloc] init];

    NSDictionary * itemDictionary = [[NSDictionary dictionaryWithXMLData:responseObject] objectForKey:kAmazonRootNode];
    for(int i = 0; i < [[itemDictionary objectForKey:kAmazonFeedItemKey] count]; i++){
        RSSBookEntryModel *cBEO = [[RSSBookEntryModel alloc] init];

        NSDictionary *currentItem = [[itemDictionary objectForKey:kAmazonFeedItemKey] objectAtIndex:i];
        NSString *finalXMLString = [NSString stringWithFormat:@"%@%@%@", kAmazonStartTag, [currentItem objectForKey:kAmazonDescriptionKey], kAmazonEndTag];
        NSDictionary *cData = [NSDictionary dictionaryWithXMLString:finalXMLString];

        NSArray *bookDetailsDictionary = [cData objectForKey:kAmazonSpanKey];

        NSString *bIOURL = [[[[cData objectForKey:@"div"] objectForKey:kAmazonAHREFKey] objectForKey:@"img"] objectForKey:@"_src"];
        NSString *bookImageCoverID = [[[[bIOURL componentsSeparatedByString:kAmazonBookCoverBaseURL] lastObject] componentsSeparatedByString:@"."] firstObject];




        cBEO.bookTitle = [self getBookTitleWithArray:bookDetailsDictionary];
        cBEO.bookAuthor = [self getBookAuthorWithArray:bookDetailsDictionary];
        cBEO.bookCoverImageThumbnailURL = [NSString stringWithFormat:@"%@%@%@%@", kAmazonBookCoverBaseURL, bookImageCoverID, kAmazonBookCoverThumbnailSize, kAmazonBookCoverFileExtention];
        cBEO.bookCoverImageOriginalURL = [NSString stringWithFormat:@"%@%@%@%@", kAmazonBookCoverBaseURL, bookImageCoverID, kAmazonBookCoverMaxSize, kAmazonBookCoverFileExtention];
        cBEO.bookPrice = [self getPriceFromDictionary:cData];
        cBEO.bookRating = [self getRatingFromDictionary:cData];

        [bookEntries addObject:cBEO];


    }
    return bookEntries;
}
@end

对不起。 这里是： 这是您要使用的对象模型，非常简单。

@interface RSSBookEntryModel : NSObject

@property (strong, nonatomic) NSString *bookTitle;
@property (strong, nonatomic) NSString *bookAuthor;
@property (strong, nonatomic) NSString *bookCoverImageThumbnailURL;
@property (strong, nonatomic) NSString *bookCoverImageOriginalURL;
@property (strong, nonatomic) NSData *bookCoverThumbnailImage;
@property (strong, nonatomic) NSData *bookCoverOriginalImage;

@property (strong, nonatomic) NSString *bookPrice;
@property (strong, nonatomic) NSString *bookRating;


-(NSString*)description;

@end

这是我用来保持一切清洁的常量。

Constant.h

extern NSString * const kAmazonRootNode;
extern NSString * const kAmazonStartTag;
extern NSString * const kAmazonEndTag;

extern NSString * const kAmazonFeedItemKey;
extern NSString *const kAmazonSpanKey;
extern NSString * const kAmazonDescriptionKey;
extern NSString *const kAmazonUnderscoreTextKey;
extern NSString *const kAmazonAHREFKey;
extern NSString *const kAmazonBookCoverBaseURL;

extern NSString *const kAmazonBookCoverThumbnailSize;
extern NSString *const kAmazonBookCoverMaxSize;
extern NSString *const kAmazonBookCoverFileExtention;

这是 Constants.m 文件。

NSString * const kAmazonRootNode = @"channel";
NSString * const kAmazonStartTag = @"<startTag>";
NSString * const kAmazonEndTag = @"</startTag>";

NSString * const kAmazonFeedItemKey = @"item";
NSString *const kAmazonSpanKey = @"span";
NSString * const kAmazonDescriptionKey = @"description";
NSString *const kAmazonUnderscoreTextKey = @"__text";
NSString *const kAmazonAHREFKey = @"a";
NSString *const kAmazonBookCoverBaseURL = @"http://ecx.images-amazon.com/images/";

NSString *const kAmazonBookCoverThumbnailSize = @"._SL100";
NSString *const kAmazonBookCoverMaxSize = @"._SL500";
NSString *const kAmazonBookCoverFileExtention = @".jpg";

Answer 4

这是一个相当弱的替代方案，但也许它会有所帮助：

//title
console.log("TITLE: " + $(".riRssTitle").text().trim());

//image
console.log("IMAGE: " + $(document).find("img").attr("src"));

//author
console.log("AUTHOR: " + $(".riRssContributor").find("a").text().trim());

//new price and striked price
var new_price_striked_element = $("a:contains('Buy new')").siblings("strike");
if(new_price_striked_element){
   console.log("NEW PRICE STRIKED: " + new_price_striked_element.text().trim());     
}else{
   console.log("NEW PRICE: " + $("a:contains('Buy new')").siblings("b").text().trim()); 
}

//used price
console.log("USED PRICE FROM: " + $(".price").text().trim());

//stars
var url = $("img[src*='stars']").attr("src");
var myRegexp = /stars-([0-9]-[0-9])/g;
var match = myRegexp.exec(url);
console.log("STARS: " + match[1]);

示例：http://jsfiddle.net/qpuaxtv3/