使用Python爬取GooglePlay并从复杂的自定义数据结构中实现解析-编程知识

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【作者主页】：吴秋霖
【作者介绍】：Python领域优质创作者、阿里云博客专家、华为云享专家。长期致力于Python与爬虫领域研究与开发工作！
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还有未来会持续更新的验证码突防、APP逆向、Python领域等一系列文章

说到GooglePlay，自定义的数据结构，解析起来真的是让人感觉到窒息。而且基本是每间隔一段时间就会稍微的发现变动，解析规则基本持久不了太久可能就会失效，不过都是一些细微的变动，不值一提～

GooglePlay是没有对外提供任何API的，想要爬取相关的数据就需要通过Web端的方式，Git上面也有国外的大佬开源了google-play-scraper，Python跟JS版本的我记得都有，直接导包调用

但是稳定性不够好，也是基于Web端去爬取解析的，一旦结构发生变化，作者维护不够及时的话，自然也就无法使用

之后参考开源的项目，自己重新实现了数据抽取那一块逻辑，并将解析服务部署在了境外服务器上，然后通过远端调用的方式去解析

在这里插入图片描述

在我之前的Cloudflare反爬虫防护绕过文章中，就是以一个第三方的APK下载网站为示例进行的讲解，GooglePlay的APK包如果是在官方网站下载的话会比较麻烦，直接可以用我提到的那个第三方网站取下载就行

主要爬取内容就是APP应用的相关描述信息，如下图所示：

在这里插入图片描述

在点击关于此应用的时候，抓包可以看到重点数据集都嵌套在了HTML源代码中，使用JS函数定义了AF_initDataCallBack，data参数就是加载的数据

在这里插入图片描述

尝试将数据拷贝出来，不过发现太长了，截图都放不下，图片都给整裂开了！反正就是巨长再加上多层嵌套，需要拆解慢慢去写解析规则！

接下来，先实现对data数据的提取，实现代码如下所示：

async def extract_json_block(html, block_id):prefix = re.compile(r"AF_init[dD]ata[cC]all[bB]ack\s*\({[^{}]*key:\s*'" + re.escape(block_id) + ".*?data:")suffix = re.compile(r"}\s*\)\s*;")try:block = prefix.split(html)[1]block = suffix.split(block)[0]except IndexError:raise PlayStoreException("Could not extract block %s" % block_id)block = block.strip()block = re.sub(r"^function\s*\([^)]*\)\s*{", "", block)block = re.sub("}$", "", block)block = re.sub(r", sideChannel: {$", "", block)return block

在这里插入图片描述

如上就是提取出来的数据，拿到数据以后，如果你是小白新手或许会因此放弃，实在是让人头大，现在开始实现解析核心逻辑代码，如下所示：

app_detail_ds_block = 'ds:7'
app_details_mapping = {'title': [app_detail_ds_block, 1, 2, 0, 0],'developer_name': [app_detail_ds_block, 1, 2, 68, 0],'developer_link': [app_detail_ds_block, 1, 2, 68, 1, 4, 2],'price_inapp': [app_detail_ds_block, 1, 2, 19, 0],'category': [app_detail_ds_block, 1, 2, 79, 0, 0, 1, 4, 2],'video_link': [app_detail_ds_block, 1, 2, 100, 1, 2, 0, 2],'icon_link': [app_detail_ds_block, 1, 2, 95, 0, 3, 2],'num_downloads_approx': [app_detail_ds_block, 1, 2, 13, 1],'num_downloads': [app_detail_ds_block, 1, 2, 13, 2],'published_date': [app_detail_ds_block, 1, 2, 10, 0],'published_timestamp': [app_detail_ds_block, 1, 2, 10, 1, 0],'pegi': [app_detail_ds_block, 1, 2, 9, 0],'pegi_detail': [app_detail_ds_block, 1, 2, 9, 2, 1],'os': [app_detail_ds_block, 1, 2, 140, 1, 1, 0, 0, 1],'rating': [app_detail_ds_block, 1, 2, 51, 0, 1],'description': [app_detail_ds_block, 1, 2, 72, 0, 1],'price': [app_detail_ds_block, 1, 2, 57, 0, 0, 0, 0, 1, 0, 2],'num_of_reviews': [app_detail_ds_block, 1, 2, 51, 2, 1],'developer_email': [app_detail_ds_block, 1, 2, 69, 1, 0],'developer_address': [app_detail_ds_block, 1, 2, 69, 2, 0],'developer_website': [app_detail_ds_block, 1, 2, 69, 0, 5, 2],'developer_privacy_policy_link': [app_detail_ds_block, 1, 2, 99, 0, 5, 2],'data_safety_list': [app_detail_ds_block, 1, 2, 136, 1],'updated_on': [app_detail_ds_block, 1, 2, 145, 0, 0],'app_version': [app_detail_ds_block, 1, 2, 140, 0, 0, 0]
}async def find_item_from_json_mapping(google_app_detail_request_result, app_detail_mapping):ds_json_block = app_detail_mapping[0]json_block_raw = await extract_json_block(google_app_detail_request_result, ds_json_block)json_block = json.loads(json_block_raw)return await get_nested_item(json_block, app_detail_mapping[1:])

app_details_mapping则是解析数据的核心，索引基本上变动较小！因为数据都是在list中多级嵌套，所以需要花费一点精力时间去分析，app_detail_ds_block前段时间我记得是ds:5，这个倒是会偶尔变动

class PlayStoreException(BaseException):def __init__(self, *args):if args:self.message = args[0]else:self.message = Nonedef __str__(self):if self.message:return "PlayStoreException, {0}".format(self.message)else:return "PlayStoreException raised"class GooglePlayStoreScraper(object):def __init__(self):self.PLAYSTORE_URL = "https://play.google.com"self.PROXIES = {'http': 'http://127.0.0.1:7890', 'https': 'http://127.0.0.1:7890'}async def _app_connection(self, url, sleeptime=2, retry=0):for _ in range(retry + 1):try:async with aiohttp.ClientSession() as session:async with session.get(url, proxy=self.PROXIES) as response:return await response.text()except aiohttp.ClientError:if sleeptime > 0:await asyncio.sleep(sleeptime)raise PlayStoreException(f"Could not connect to : {url}")async def get_nested_item(self, item_holder, list_of_indexes):index = list_of_indexes[0]if len(list_of_indexes) > 1:return await get_nested_item(item_holder[index], list_of_indexes[1:])else:return item_holder[index]async def get_app_details(self, app_id, country="nl", lang="nl"):url = f"{self.PLAYSTORE_URL}/store/apps/details?id={quote_plus(app_id)}&hl={lang}&gl={country}"request_result = await self._app_connection(url, retry=1)app = {'id': app_id, 'link': url}for k, v in app_details_mapping.items():try:app[k] = await self.find_item_from_json_mapping(request_result, v)except PlayStoreException:raise PlayStoreException(f"Could not parse Play Store response for {app_id}")except Exception as e:self._log_error(country, f'App Detail error for {app_id} on detail {k}: {str(e)}')app.setdefault('errors', []).append(k)app['developer_link'] = self.PLAYSTORE_URL + app.get('developer_link', '')app['category'] = app.get('category', '').replace('/store/apps/category/', '')if 'data_safety_list' in app:app['data_safety_list'] = ', '.join(item[1] for item in app['data_safety_list'] if len(item) > 1)soup = BeautifulSoup(request_result, 'html.parser')list_of_categories = ', '.join(', '.join(category.text for category in element.find_all('span')) for element in soup.find_all('div', {'class': 'Uc6QCc'}))app['list_of_categories'] = list_of_categories if list_of_categories else app.setdefault('errors', []) + ['list_of_categories']if 'errors' in app:plural = 's' if len(app['errors']) > 1 else ''app['errors'] = f"Detail{plural} not found for key{plural}: {', '.join(app['errors'])}"return app