9

我正在实现一个 PHP 应用程序，它第一次需要来自 Google Books API 的一些数据。这很尴尬，但是当我使用典型的查询 http://books.google.com/books/feeds/volumes?q=search+term（有特定API经验的人可以理解我）时，它仅返回 10 个结果。

例如，http://books.google.com/books/feeds/volumes?q=php 的 XML 响应包含以下字段：totalResults>582。但是，我只检索到 10 个。

在阅读了相应的文档后，我还没有得出一个解决方案。

有人可以帮我吗？

4

3 回答 3

14

如今，关键字是maxResults而不是max-resultsraina77ow的答案。来源。正如文档所说，一次可以检索的最大书籍数量为 40。但是，您可以通过多个请求来克服此限制，例如使用以下 PHP 函数：

private $books = array('items' => array());

/**
 * Searches the Google Books database through their public API
 * and returns the result. Notice that this function will (due to
 * Google's restriction) perform one request per 40 books.
 * If there aren't as many books as requested, those found will be
 * returned. If no books at all is found, false will be returned.
 * 
 * @author Dakniel
 * @param string $query Search-query, API documentation
 * @param int $numBooksToGet Amount of results wanted
 * @param int [optional] $startIndex Which index to start searching from
 * @return False if no book is found, otherwise the books
 */
private function getBooks($query, $numBooksToGet, $startIndex = 0) {

    // If we've already fetched all the books needed, or
    // all results are already stored
    if(count($this->books['items']) >= $numBooksToGet)
        return $this->books;

    $booksNeeded = $numBooksToGet - count($this->books['items']);

    // Max books / fetch = 40, this is therefore our limit
    if($booksNeeded > 40)
        $booksNeeded = 40;

    $url = "https://www.googleapis.com/books/v1/volumes?q=". urlencode($query) ."&startIndex=$startIndex&maxResults=$booksNeeded";

    // Get the data with cURL
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    $bookBatch = curl_exec($ch);
    curl_close($ch);

    // If we got no matches..
    if($bookBatch['totalItems'] === 0) {

        // .. but we already have some books, return those
        if(count($this->books) > 0)
            return $this->books;
        else
            return false;

    }

    // Convert the JSON to an array and merge the existing books with
    // this request's new books 
    $bookBatch = json_decode($bookBatch, true);
    $this->books['items'] = array_merge($this->books['items'], $bookBatch['items']);

    // Even if we WANT more, but the API can't give us more: stop
    if( ($bookBatch['totalItems'] - count($this->books['items'])) === 0 ) {
        return $this->books;
    }

    // We need more books, and there's more to get: use recursion
    return $this->getBooks($query, $numBooksToGet, $startIndex);

}

简单示例用法：

$books = $this->getBooks("programming", 50);

这将返回最多50 本书与关键字编程匹配。希望有人会使用这个，祝你好运！

于 2012-11-29T16:12:39.397 回答
13

不，它的另一个参数：max-results. 但看起来一个“页面”中的最大结果数仍然设置得非常低 - 为 20。

例如，这个查询：

http://books.google.com/books/feeds/volumes?q=php&max-results=40

... 只给了我 20 个条目。start-index不过，您可以使用param遍历集合，这很有用，如下所示：

http://books.google.com/books/feeds/volumes?q=php&max-results=20&start-index=21

...然后是 41、61 等。它以 1 开头，而不是 0，我已经检查过了。)

于 2012-07-07T14:42:53.457 回答
1

这就是我使用maxResults参数获得 20 多个结果的方式

'https://www.googleapis.com/books/v1/volumes?q=inauthor:danielle%20steele&maxResults=40&key=your_very_own_api_key'

每个请求它返回 40 个结果，轻而易举。请参阅下面的屏幕截图。

在此处输入图像描述

于 2020-08-25T13:56:59.777 回答