在GraphQL/Sangria-Graphql中知道服务器端指定的字段

Question

当客户端发送请求时，我想知道客户端请求数据的字段是什么。例如，

{ 
    user { 
    name 
    address 
    } 
} 

在上述请求，客户端已经请求name字段和用户的address字段。在执行查询时，我如何知道/获取这些指定的字段，即sangria-graphql Server中的名称和地址？

Answer 1

你必须使用4th参数resolve()

resolve: (obj, args, auth, fieldASTs) => { 
    /* all your fields are present in selections 
     please check the fieldASTs JSON path it may vary if you are using relay 
                   connections */ 
    const requiredFields = fieldASTs.fieldNodes[0].selectionSet.selections.map(
     (set) => set.name.value 
    ); 
    // requiredFields will contain the name and address 
} 
/* fieldASTs contains fieldNames, fieldNodes and every details about your Schema 
you can get your specified fields inside fieldNodes like */