在存储过程中获取多个文档 (Azure DocumentDB)

Question

我有两种文档类型，Listing 和 Products。 Listing 对象包含特定国家/地区的产品列表，如下所示：

列表:

{
  "Name": "Default",
  "Countries": {
    "_default": [
      "4QlxAPFcCAAPAAAAAAAAAA==",
      "4QlxAPFcCAAHAAAAAAAAAA=="
    ],
    "US": [
      "4QlxAPFcCAAIAAAAAAAAAA==",
      "4QlxAPFcCAAHAAAAAAAAAA=="
    ]
  },
  "Type": "Listing",
  "id": "dfed1839-07c5-482b-81c5-669b1dbcd0b6",
  "_rid": "4QlxAPFcCAAEAAAAAAAAAA=="
}

产品:

{
    "Name": "Widget",
    "Price": 3.45,
    "Type": "Product",
    "_rid": "4QlxAPFcCAAHAAAAAAAAAA=="
}

我的目标是在 Azure DocumentDB 集合中创建一个 存储过程，它带有两个参数，rid 和 country，这实际上会获取清单文件，以及该国的文件，以尽可能最有效的方式。我的假设是，使用 getContext().getCollection().readDocument(...) 通过其资源 ID 加载文档是最快的方法，因此尝试为此创建一个存储过程。

我的尝试是嵌套连续调用（回调地狱？），使用 generator/iterators 和 yield，然后使用纯 Promise 方法。所有的尝试都给出了相同的结果：

它将获取第一个文档，但在接收到文档后会突然结束。

作为参考，这是我最近的尝试：

function test(rid, country) {
    var collection = getContext().getCollection();
    var collectionSelfLink = collection.getSelfLink();
    var docsLink = collectionSelfLink + "docs/";
    var body = getContext().getResponse().setBody;  

    function getDocument(rid) {
        return new Promise(function(resolve, reject) {
            var accepted = collection.readDocument(docsLink + rid, (err, doc, opts) => {
                resolve(doc);
            });

            if (!accepted)
                reject("Not accepted");            
        });
    }

    getDocument(rid)
        .then(doc => { 
            body("0. First step"); // set test body 

            // Countries is a Dictionary<string, string[]> with resource ids
            return doc.Countries[country] || doc.Countries["_default"];
        })
        // This is how far it gets, resulting in response "1. Documents to fetch: 2"
        .then(a => body("1. Documents to fetch: " + a.length))
        .then(a => a.map(function(productId) { return getDoument(productId); }))
        .then(a => body("2. It should come this far, right?"))
        .then(a => Promise.all(a))
        .then(a => body(a))
        .catch(function(e) { throw new Error(JSON.stringify(e)); });
}

Answer 1

事实证明，嵌套调用 do 实际上可行，如果您经常更改响应正文(?)

以下过程按预期工作：

function test(rid, country) {
    var collection = getContext().getCollection();
    var collectionSelfLink = collection.getSelfLink();
    var docsLink = collectionSelfLink + "docs/";
    var body = getContext().getResponse().setBody;

    var accepted = collection.readDocument(docsLink + rid, (err, doc, opts) => {
        if (err) throw new Error(err.message);

        // Countries is a Dictionary<string, string[]> with resource ids
        var offerIds = doc.Countries[country] || doc.Countries["_default"];
        var result = [];

        for (var docId of offerIds) {
            var subAccepted =
                collection.readDocument(docsLink + docId, (err, doc, opts) => {
                    if (err) throw new Error(err.message);

                    result.push(doc);
                });

            if (!subAccepted)
                throw new Error("A subsequent request was not accepted");

            body(result); // <-- Note, setting body in each iteration.
        }
    });

    if (!accepted)
        throw new Error("The request was not accepted");
}

在存储过程中获取多个文档 (Azure DocumentDB)

Fetch multiple documents in a stored procedure (Azure DocumentDB)

azure

node.js

azure-cosmosdb