upsertOptimizedForReplace.js

/**
 * A DocumentDB stored procedure that upserts a given document (insert new or update if present) using its id property.<br/>
 * This implementation queries for the document's id, and creates if absent and replaces if found.
 * Use this sproc if replaces are more common than creates, otherwise use "upsert" 
 *
 * @function
 * @param {Object} document - A document that should be upserted into this collection.
 * @returns {Object.<string>} Returns an object with the property:<br/>
 *   op - created (or) replaced.
 */
var upsertOptimizedForReplace = {
    id: "upsertOptimizedForReplace",
    body: function (document) {
        var context = getContext();
        var collection = context.getCollection();
        var collectionLink = collection.getSelfLink();
        var response = context.getResponse();

        // Not checking for existence of document.id for compatibility with createDocument.
        if (!document) throw new Error("The document is undefined or null.");

        retrieveDoc(document, null, callback);

        function retrieveDoc(doc, continuation, callback) {
            var query = { query: "select * from root r where r.id = @id", parameters: [ {name: "@id", value: doc.id}]};
            var requestOptions = { continuation : continuation };
            var isAccepted = collection.queryDocuments(collectionLink, query, requestOptions, function(err, retrievedDocs, responseOptions) {
                if (err) throw err;
                if (retrievedDocs.length > 0) {
                    tryReplace(retrievedDocs[0], doc, callback);
                } else if (responseOptions.continuation) {
                    // Conservative check for continuation. Not expected to hit in practice for the "id query".
                    retrieveDoc(doc, responseOptions.continuation, callback);
                } else {
                    tryCreate(doc, callback);
                }
                });
            if (!isAccepted) throw new Error("Unable to query documents");
        }

        function tryCreate(doc, callback) {
            var isAccepted = collection.createDocument(collectionLink, doc, callback);
            if (!isAccepted) throw new Error("Unable to schedule create document");
            response.setBody({"op": "created"});
        }

        function tryReplace(docToReplace, docContent, callback) {
            var isAccepted = collection.replaceDocument(docToReplace._self, docContent, callback);
            if (!isAccepted) throw new Error("Unable to schedule replace document");
            response.setBody({"op": "replaced"});
        }

        function callback(err, doc, options) {
            if (err) throw err;
        }
    }
}

module.exports = upsertOptimizedForReplace;