使用PHP和Regex获取Steam社区市场上的商品价格

本文介绍了使用PHP和Regex获取Steam社区市场上的商品价格的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在尝试使用PHP获取某项的Steam社区市场价格.我输入了一个网址(例如: http://steamcommunity.com/market/listings/730/StatTrak%E2%84%A2%20P250%20%7C%20Steel%20Disruption%20%28Factory%20New%29 )，然后用file_get_contents()下载内容.我试图用这个:

function getInnerHTML($string, $tagname, $closetagname) {
    $pattern = "/<$tagname ?.*>(.*)<\/$closetagname>/";
    preg_match($pattern, $string, $matches);
    return $matches[1];
}

使用

getInnerHTML($str, 'span class="market_listing_price market_listing_price_with_fee"', 'span');

关于file_get_contents的示例如下:

<span class="market_table_value">
    <span class="market_listing_price market_listing_price_with_fee">
        $1.92               </span>
    <span class="market_listing_price market_listing_price_without_fee">
        $1.68               </span>
    <br/>
</span>

但是它什么也不返回.

有人有主意吗?

解决方案

不完全确定为什么当要返回JSON的情况下可以通过HTML进行正则表达式时，为什么要用这种困难的方式进行正则表达式.尽管原始答案是正确的，并且可以直接回答OP问题，但这提供了一种获取商品市场价值的简便而有效的方法.

获取:

JSON响应:

{
  "success": true,
  "lowest_price": "1,43&#8364; ",
  "volume": "562",
  "median_price": "1,60&#8364; "
}

响应定义:

success:布尔值，如果调用成功，则为true；如果出现错误，则为false.

lowest_price:带有货币符号[pre//ap]的字符串值取决于指定的查询参数.有关其他一些参数，请参见下文.

volume:作为字符串(?)返回的整数值-已售出/购买的此特定商品的总数.

median_price:带有货币符号[pre-/ap]的字符串值.该商品的平均售价.请参见蒸汽市场项目图，以更好地了解中位数的计算方式.

查询参数:

appid:游戏/应用程序的唯一(静态定义)Steam应用程序ID，在我们的案例中为730:《反恐精英:全球攻势》.有关其他appid的列表，请参见Valve的开发Wiki，尽管随着新应用频繁添加到其平台上，该列表很可能总是过时.

market_hash_name:包含外部外观的要查询的项目名称，在查询用户清单时可以找到这些名称，但这是另一个完整的API调用.

currency:一个整数值；货币价值和返回市场价值的格式.您需要调整并使用这些数字，因为我在这里不能提供太多细节.通常，我坚持使用美元作为全球价格，并使用自己的货币API转换为其他货币.

I'm trying to use PHP to get the Steam Community Market price of an item. I take a url (for example : http://steamcommunity.com/market/listings/730/StatTrak%E2%84%A2%20P250%20%7C%20Steel%20Disruption%20%28Factory%20New%29) and then I download the content with file_get_contents(). I tried to use this :

function getInnerHTML($string, $tagname, $closetagname) {
    $pattern = "/<$tagname ?.*>(.*)<\/$closetagname>/";
    preg_match($pattern, $string, $matches);
    return $matches[1];
}

Using

getInnerHTML($str, 'span class="market_listing_price market_listing_price_with_fee"', 'span');

An example of what I can have with file_get_contents is this :

<span class="market_table_value">
    <span class="market_listing_price market_listing_price_with_fee">
        $1.92               </span>
    <span class="market_listing_price market_listing_price_without_fee">
        $1.68               </span>
    <br/>
</span>

But it returns nothing.

Has anyone an idea ?

解决方案

Not entirely sure why you'd want to do this the hard way and regex through HTML when there's a perfectly working call which returns JSON. Although the original answer is correct and answers the OP question directly, this provides a much easier and efficient way of getting the market value of an item.

GET:

http://steamcommunity.com/market/priceoverview/?currency=3&appid=730&market_hash_name=StatTrak%E2%84%A2%20P250%20%7C%20Steel%20Disruption%20%28Factory%20New%29

JSON Response:

{
  "success": true,
  "lowest_price": "1,43&#8364; ",
  "volume": "562",
  "median_price": "1,60&#8364; "
}

Response Definitions :

success: boolean value, true if the call was successful or false if something went wrong or there are no listing for this item on the Steam market.

lowest_price: string value with currency symbol [pre-/ap]pended depending on the query parameters specified. See below for some additional parameter.

volume: integer value returned as a string (?) - the total number of this specific item which has been sold/bought.

median_price: string value with currency symbol [pre-/ap]pended. The average price at which the item has been sold. See the Steam marketplace item graph for a better understanding on how the median is calculated.

Query Parameters:

appid: The unique (statically defined) Steam application ID of the game/app, in our case 730 for Counter-Strike: Global Offensive. See Valve's development Wiki for a list of other appid's, though this list will most probably always be out of date as new apps are added to their platform frequently.

market_hash_name: The name of the item being queried against with the exterior included, retrieving these names can be found when querying against a users inventory, but that's a whole other API call.

currency: An integer value; the currency value and format to return the market values. You'll need to tweak and play around with these numbers as I cannot provide too much detail here. Generally I stick to using USD as a global price and use my own currency API to translate into other currencies.

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