实战之知轩藏书全站

超、凢脫俗 2023-03-04 06:57 24阅读 0赞

# 1.明确需求 #

### 下载 《知轩藏书》[网站][Link 1]的所有小说 ###

# 2.需求分析 #

### 2.1 分析该网站结构 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjA4Mzk4_size_16_color_FFFFFF_t_70]

### 2.2 分析网站逻辑和架构 ###

该网站虽然给小说分了很多种类，但是每本小说的预览页是统一编排的，这给我们爬虫工程师带来了很大
    便利。

### 2.3 找规律 ###

随便找一本小说找到它的下载URL
        http://www.zxcs.me/download.php?id=12019
        这里可以看出该网站的下载链接为<b>http://www.zxcs.me/download.php?id={ID}</b>

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjA4Mzk4_size_16_color_FFFFFF_t_70 1]

# 3.设计逻辑以及流程 #

### 3.1 设计整个爬取逻辑 ###

这里根据上面的http://www.zxcs.me/download.php?id={ID} 结构进行爬取，大概看了下该网站的最大ID不超过2w,

### 3.2 获取下载link ###

这里通过Chrome调试，很容易得到下载链接
    ![在这里插入图片描述](https://img-blog.csdnimg.cn/20200802094936490.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjA4Mzk4,size_16,color_FFFFFF,t_70)

### 3.3 可持续化、可重复性、可筛选性设计 ###

为了能记录所有小说的数据，这里我用的Mysql数据库进行存储。
    在实际爬取小说时发现，单线程可能导致爬取阻塞，我用bat脚本定时刷新下载程序。

### 3.4 数据设计 ###

根据网站结构，我这里设计的的数据表包含id,storyName,status_code,downloadUrl,size,type,isDownload
    其中id是主键，这里的id对应的上面的http://www.zxcs.me/download.php?id={ID} ID值。

# 4.代码实现(为了防止爬虫带来的法律问题，暂不提供完整代码) #

### 4.1 数据表 - 创建表之后，先写入id = 1-2w 2w条记录 ###

DROP TABLE IF EXISTS `jjxs`;
    CREATE TABLE `jjxs` (
      `id` int(5) NOT NULL,
      `storyName` varchar(50) DEFAULT NULL,
      `status_code` int(5) DEFAULT NULL,
      `downloadUrl` varchar(1024) DEFAULT NULL,
      `size` float(10,2) DEFAULT NULL,
      `type` varchar(1) DEFAULT NULL,
      `isDownload` varchar(1) DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

### 4.2 爬取小说信息 - 更新小说的 storyName,status\_code,downloadUrl,size,type 信息![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjA4Mzk4_size_16_color_FFFFFF_t_70 2] ###

sql = "SELECT * FROM jjxs WHERE status_code is NULL ORDER BY id"
        retSet = exeSql(mysqlSetting_local,sql)
        retList = [[x[0],"http://www.zxcs.me/download.php?id="+str(x[0])] for x in retSet]
        for index,url in enumerate(retList,start=retList[0][0]):
                print(url[1])
                response = requests.get(url = url[1])
                if response.status_code == 200:
                    txt = response.text
                    start = txt.find("小说大小")
                    if start > -1:
                        m = re.search("[0-9|.]+\s{0,3}M?",txt[start:start + 20])
                        if m :
                            size = m[0]
                        else:
                            print('\t\t',url)
                            sql = "UPDATE jjxs SET status_code={status} WHERE id={id}".format(status=response.status_code,id=url[0])
                            print(sql)
                            retSet = insert(mysqlSetting_local,sql)
                            continue
                    else:
                        print('\t',url)
                        sql = "UPDATE jjxs SET status_code={status} WHERE id={id}".format(status=response.status_code,id=url[0])
                        print(sql)
                        retSet = insert(mysqlSetting_local,sql)
                        continue
                     
                    html = bf(txt,'html.parser')
                    storyInfo = html.select_one('h2').text
                    if storyInfo:
                        if storyInfo.find("《") > -1 and storyInfo.find("》") > -1:
                            storyName = storyInfo[storyInfo.find("《")+1 : storyInfo.find("》")]
                            aTagList = [x['href'] for x in html.select('span.downfile a')]
                            print('\t\t',url[0],storyName,size)
                            size = size.replace(" ","")
                            if size.find("M") > -1:
                                size = size.replace("M","")
                                sql = "UPDATE jjxs SET status_code={status},storyName='{storyName}',downloadUrl='{downloadUrl}',size={size},type='M' WHERE id={id}".format(status=response.status_code,storyName=storyName,downloadUrl='-'.join(aTagList).replace('\'','*'),size=size,id=url[0])
                            else:
                                sql = "UPDATE jjxs SET status_code={status},storyName='{storyName}',downloadUrl='{downloadUrl}',size={size} WHERE id={id}".format(status=response.status_code,storyName=storyName,downloadUrl='-'.join(aTagList),size=size,id=url[0])  
                            print(sql)
                            retSet = insert(mysqlSetting_local,sql)
                        else:
                            print("\t\tStory information not formate.")
                            sql = "UPDATE jjxs SET status_code={status} WHERE id={id}".format(status=response.status_code,id=url[0])
                            print(sql)
                            retSet = insert(mysqlSetting_local,sql)
                    else:
                        print("\tNot find story information.")
                        sql = "UPDATE jjxs SET status_code={status} WHERE id={id}".format(status=response.status_code,id=url[0])
                        print(sql)
                        retSet = insert(mysqlSetting_local,sql)
                else:
                    print("Index : " + str(index) + ", Return Code:" + str(response.status_code) + ", fail Url: " + url)
                    sql = "UPDATE jjxs SET status={status} WHERE id={id}".format(status=response.status_code,id=index)
                    retSet = exeSql(mysqlSetting_local,sql)

### 4.3 根据数据库筛选出小说大小大于2M的小说进行下载，下载完成更新数据表isDownload字段为Y。 ###

这里都是简单的sql，很好懂

sqltotal = "select * from jjxs where status_code = 200 and storyName is not NULL and type = 'M' and size > 2.00 ORDER BY size asc"
            retSettotal = exeSql(mysqlSetting_local,sqltotal)
            totalCount = len(retSettotal)
            sqlCompleted = "select * from jjxs where status_code = 200 and storyName is not NULL and type = 'M' and size > 2.00 and isDownload in ('Y','N') ORDER BY size asc"
            retCompleted = exeSql(mysqlSetting_local,sqlCompleted)
            totalCompletedCount = len(retCompleted)
            print('Completed : {:.2f} %'.format(totalCompletedCount/totalCount * 100* 1.00))
            sql = "select * from jjxs where status_code = 200 and storyName is not NULL and type = 'M' and size > 2.00 and isDownload is NULL ORDER BY size asc"
            retSet = exeSql(mysqlSetting_local,sql)
            retList = [[x[0],x[1],x[3]] for x in retSet]
            for x in retList:
                print("Download story: {id},{storyName}".format(id=x[0],storyName=x[1]))
                urlList = x[2].split('-')
                for urlItem in urlList:
                    if downloadTxt([x[0],x[1],urlItem]):
                        totalCompletedCount=totalCompletedCount+1
                        print('Completed : {:.2f} %'.format(totalCompletedCount/totalCount * 100* 1.00))
                        saveFile('completed.txt',str('{:.2f} %'.format(totalCompletedCount/totalCount * 100* 1.00)),'w')
                        break

#### 4.4 bat 脚本 - 防止下载程序挂了,这里是定时一个小时刷新一次 ####

@echo off
    
    :a
    start python.exe download.py
    echo [%date:~,10% %time:~,-3% ]
    start python.exe downloadDesc.py
    echo [%date:~,10% %time:~,-3% ]
    ping 127.0.0.1 -n 3600 0>nul 1>nul
    taskkill /im python.exe /f
    goto a

### 4.5 bat 脚本 - 下载完成RAR文件后，需要用到该脚本自动解压 ###

@echo off
    del *.txt
    FOR /F %%i IN ('DIR *.rar /B') DO (
    unrar e -y %%i  
    )

# 5.测试及结果展示 #

### 5.1 下载完成的小说 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjA4Mzk4_size_16_color_FFFFFF_t_70 3]

### 5.2 总共下载小说的总大小 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjA4Mzk4_size_16_color_FFFFFF_t_70 4]

### 5.3 实际解压缩后的所有txt大小 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NjA4Mzk4_size_16_color_FFFFFF_t_70 5]

# 6.总结 #

这次的实战中遇到了下载大文件进程挂起问题，在多方查找资料可以通过requeset.get方法的stream = True参数  
解决，这个是之前没有碰到过的，另外这个网站没有设置反扒策略，所以这里没有用到Cookie等参数。本文是一篇  
非常基础的爬虫实战教程，当然里面还有很多不足之处，后面再改进吧。

[Link 1]: http://www.zxcs.me/
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