是否可以为“ for”循环在CasperJS中？ [英] Is it possible to make "for" loop in CasperJS?

问题描述

这是

当我单击下一页时，您会看到

  [上一页] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [下一页] 
  

但[12]的Xpath不是 // * [@ id = content] / div [3] / a [12] --->

  // * [@ id = content] / div [3] / a [2] 
  

所以我必须迭代函数execOnce 包括代码 casper.wait（6000，function（）{}

因为我的目标网站对查询确实很敏感，因此我会尽可能地放置等待代码。.

在这种情况下，我可以使用这样的嵌套函数吗？

 函数execOnce（casper，i，max）{
 if（i === max）{ 
函数execOnce（casper，i，max）{
 return; 
} 
 ... 
  

解决方案

XPath非常具有表现力。例如，您可以根据链接文本而不是链接位置来选择目标页面链接（ // div [@ class ='paginate'] / a [text（）='5'] ），但是在这种情况下，仅此一项并不能为您带来太大帮助。

问题当然是该网站具有辅助分页功能。您需要先转到下一个分页页面，然后才能单击下一个分页链接。

  casper.wait（3000，function（）{
 var nextButton = x（'// * [@ id = content] / div [3] / a [text（）='+ i +' ]'）; 
 var lastPageNextButton ='.paginate> strong + a.next'; 
 var button = nextButton; 
 
 if（this.exists（lastPageNextButton））{ 
 button = lastPageNextButton; 
}否则if（！this.exists（button））{
 this.echo（i + not available）; 
 return; 
} 
 
 this.thenClick（button，function（）{
 console.log（'Searching dic'）; 
 words = words.concat（this.evaluate（getWords） ）; 
 
 //递归步骤
 execOnce（this，i + 1，max）; 
}）; 
}）; 
  

It is additional question of How to stop a loop when clicking asynchronously in CasperJS

I tried this code

function execOnce(casper, i, max){
    // end condition
    if (i === max) {
        return;
    }

    casper.wait(3000, function() {
        var button = x('//*[@id="content"]/div[3]/a['+i+']');

        if (!this.exists(button)) {
            this.echo(i + " not available");
            return;
        }

        this.thenClick(button, function (){
            console.log('Searching dic');
            words = words.concat(this.evaluate(getWords));

            // recursive step
            execOnce(this, i+1, max);
        });
    });
};

// start the recursive chain
casper.then(function(){
    execOnce(this, 1, 200);
});

But I found that indexes' Xpath of my target web pages has iteration.

When it reached '//*[@id="mArticle"]/div[2]/a['11']' next index's Xpath becomes '//*[@id="mArticle"]/div[2]/a['2'] (back to a['2'])

for example the webpage url is "http://krdic.naver.com/search.nhn?query=%E3%85%8F%E3%85%8F&kind=keyword"

under the page there are [1][2][3][4][5][6][7][8][9][10] [Next Page]

When I click Next page you can see

 [Previous Page][11][12][13][14][15][16][17][18][19][20] [Next Page]

but [12] 's Xpath is not //*[@id="content"]/div[3]/a[12] ---> It is

//*[@id="content"]/div[3]/a[2]

So I have to do iteration of function execOnce including code casper.wait(6000, function() {}

because my target website is really sensitive to query so I put "wait" code whenever I can..!

In case of this can I use nested function like this?

function execOnce(casper, i, max){
    if (i === max) {
        function execOnce(casper, i, max){
            return;
        }
        ...

解决方案

XPath is very expressive. You can for example select the intended page link based on link text instead of link position (//div[@class='paginate']/a[text()='5']), but that alone doesn't help you much in this case.

The problem is of course that the site has a secondary pagination. You need to go to the next pagination page, before you can click of the next pagination links.

casper.wait(3000, function() {
    var nextButton = x('//*[@id="content"]/div[3]/a[text()="'+i+'"]');
    var lastPageNextButton = '.paginate > strong + a.next';
    var button = nextButton;

    if (this.exists(lastPageNextButton)) {
        button = lastPageNextButton;
    } else if (!this.exists(button)) {
        this.echo(i + " not available");
        return;
    }

    this.thenClick(button, function (){
        console.log('Searching dic');
        words = words.concat(this.evaluate(getWords));

        // recursive step
        execOnce(this, i+1, max);
    });
});

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