构建REST api时如何处理查询字符串中的动态参数数量? [英] How to handle dynamic number of parameters in querystring when building REST api?

问题描述

在构建处理资源的 RESTful api 时，可以通过一组动态参数进行查询，构建对数据库的查询的最佳方法是什么?

When building a RESTful api that deals with a resource, which can be queried by a dynamic set of parameters, what is the best way to build the query to the database?

说资源是一本书，可能的参数是:

Say the resource is a book, and the possible parameters are:

author, year, publisher, pages, rating

并且您可以使用任意数量的参数和任意组合构建查询，例如:

and you can build a query with any number of parameters and any combination like:

/books?rating=2

或

/books?author=james&year=2001&rating=4

或

/books?year=2010&publisher=greatbooks&pages=100&rating=5

将这组动态参数转换为数据库查询的好方法是什么?

Whats regarded as a good way of transforming this dynamic set of parameters into a database query?

创建大量 if else 语句，例如:

Creating a LOT of if else statements like:

if( isset($_GET['rating'] && isset($_GET['author']) ) {

    //Do query based on these parameters here...

}

或

if( isset($_GET['author'] && isset($_GET['year']) && isset($_GET['publisher']) ) {

    //Do query based on these parameters here...

}

等等等等等等...

或者设置所有变量，然后在查询中使用 LIKE 而不是 '=' ，如下所示:

Or setting all the varibles and then using LIKE instead of '=' in the query like this:

if(!empty($_GET['author'])) {
    $author = $_GET['author'];
} else {
    $author = '%';
}

然后

SELECT * FROM books WHERE author LIKE $author ... and so on

或者有其他的处理方法吗?

Or is there some other way of handling this?

推荐答案

与其为每个可能的过滤器组合编写单独的查询，不如尝试动态构建单个查询.如果查询字符串中没有请求某些内容，那么您不必担心.

Rather than writing individual queries for every possible combination of filters, you should try building a single query dynamically. If something isn't requested on the query string, then you needn't worry about it.

例如(请注意，我自己没有运行过它，但它至少应该给你一个想法):

For example (note that I haven't run this myself, but it should at least give you an idea):

$sql = 'SELECT * FROM books';

// build an array of WHERE clauses depending on what is in the query string
$clauses = array();
$filters = array('author', 'year', 'publisher', 'pages', 'rating');
foreach ($filters as $filter) {
  if (array_key_exists($filter, $_GET) {
    $clauses[] = sprintf("%s = '%s'", $filter, mysqli_real_escape_string($_GET[$filter]);
  }
}

// if there are clauses, add them to the query
if (!empty($clauses)) {
  $sql .= sprintf(' WHERE %s', implode(' AND ', $clauses));
}

// Run the query....

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