我正在尝试编写Parse Cloud Code函数，其中参数是每个包含geoPoint成员的对象列表。对于列表中的每个项目，我将在Parse数据存储中搜索1英里半径内具有相同名称的现有项目。如果该项目不存在，则创建该项目并将其保存到数据存储区。
我的功能
/**
* Take a list of Place and check for existence in Parse.
* If it doesn't already exist, add it.
* @see https://www.parse.com/questions/access-distance-on-a-geoquery
* @param {JSON Place.PlaceSearch}
* @return none
*/
function addConvertedApiResult(placeData) {
for ( var i = 0; i < placeData.length; i++ ) {
// look near loc for existing name
var loc = new Parse.GeoPoint(placeData[i].lat, placeData[i].lon)
var query = new Parse.Query("Place");
query.withinMiles("location", loc, 1);
query.equalTo("name", placeData[i].name);
console.log("placeData[i].name:"+placeData[i].name);
query.find({
success: function(results) {
// results contains a list of places that are within 1 mile
// and have the same name
console.log("results.length = "+results.length);
if(results.length < 1) {
// add the place
var Place = Parse.Object.extend("Place");
var place = new Place();
place.set("en", placeData[i].name);
place.set("location", loc);
place.set("moreInfo", placeData[i].moreInfo);
place.save();
}
},
error: function(error) {
// There was an error.
console.log("error = "+error.message);
}
});
console.log("leaving addConvertedApiResult");
}
}
我对调用addConvertedApiResult的云函数的请求
（必须逃脱＆＃39;＆＃34;＆＃39;来自Windows命令行）
curl -X POST
-H "X-Parse-Application-Id: <key>"
-H "X-Parse-REST-API-Key: <key>" -H "Content-Type: application/json"
-d "{\"name\":\"Storm+Mountain\",\"lat\":44.0760,\"lon\":-103.2280,\"limit\":5,\"radius\":25}" https://api.parse.com/1/functions/getPlace
{"result":[{"lat":43.95483,"lon":-103.36869,"moreInfo":"<apiUrl>/item.php?c=1\u0026i=3439","name":"Storm Mountain"}]}
产生的解析信息日志
I2015-03-03T05:56:26.905Z] v99: Ran cloud function getPlace with:
Input: {"lat":44.0760,"limit":5,"lon":-103.2280,"name":"Storm+Mountain","radius":25}
Result: [{"name":"Storm Mountain","lat":43.95483,"lon":-103.36869,"moreInfo":"<moreInfoUrl>"}]
I2015-03-03T05:56:27.434Z] placeData[i].name:Storm Mountain
I2015-03-03T05:56:27.435Z] leaving addConvertedApiResult
数据存储中有4个现有点应该返回但没有一个共享相同的名称。该函数似乎不执行query.find方法。我没有看到成功的日志消息：或错误：函数。如果我理解正确，这些函数应该允许我在查询结果上执行代码。
如果console.log看起来不起作用，我如何确认查询没有结果？
我尝试使用此语法的不同变体来上网。我的语法是否正确？
感谢。
更新
我一直在努力解决这个问题，并很高兴了解Promises。不幸的是，我的情况没有改变。我现在从 addConvertedApiResult 函数调用这些函数。我使用Chrome Developer工具使用本地javascript文件编写的驱动程序测试/调试它们，一切运行良好。但是，当我将此代码部署到Parse Cloud代码时，在我调用.find（）后，执行似乎消失在以太中。
我理解代码执行在CC上是异步的，但我认为使用.then（）函数应该克服这个限制。
我希望有人可以向我解释我错过了什么。
感谢。
/**
* Take a Place and check for existence in Parse.
* If it doesn't already exist, add it.
* @see https://www.parse.com/questions/access-distance-on-a-geoquery
* @see https://parse.com/docs/js_guide#promises-chaining
* @param {JSON Place.PlaceSearch}
* @return none
*/
function addNewPlace(place) {
// look near loc for already existing place with same name
var loc = new Parse.GeoPoint(place.lat, place.lon)
var query = new Parse.Query('Place');
query.withinMiles('location', loc, 1);
query.equalTo('en', place.name);
query.find().then( function(results) {
if(results.length < 1) {
console.log(place.name+" does not exist")
var Place = Parse.Object.extend("Place");
var newPlace = new Place();
var loc = new Parse.GeoPoint(place.lat, place.lon)
newPlace.set('en', place.name);
newPlace.set('location', loc);
newPlace.set('moreinfo', place.moreinfo);
return newPlace.save();
}
});
}
/**
* Take a list of Place and check for existence in Parse.
* If it doesn't already exist, add it.
* @see https://www.parse.com/questions/access-distance-on-a-geoquery
* @see https://parse.com/docs/js_guide#promises-chaining
* @param {JSON Place.PlaceSearch}
* @return none
*/
function addConvertedApiResult(placeData) {
var _ = require('underscore');
console.log("placeData.legth:"+placeData.length);
_.each(placeData, function(place) {
addNewPlace(place);
});
}
答案 0 :(得分：0)
我在上面提供的代码片段在语法上是正确的。我的问题是，我花了一些时间来解决编程对来自CloudCode的Parse和其他API的顺序异步调用的概念。最终，我能够使用以下模式使用一个具有一系列承诺的单个函数来完成我想要的任务。
someCall( function(someObject) {
// do some stuff
return result;
}).then( function(resultOfPrev) {
// do some more stuff
return result;
}).then( function(resultOfPrev) {
// create some nested promises
// Create a trivial resolved promise as a base case.
var queryPromise = Parse.Promise.as();
_.each(resultsOfPrev, function(thing) {
// For each item, extend the promise with a function to ...
queryPromise = queryPromise.then( function() {
var query = new Parse.Query(Thing);
query.equalTo("name", thing.name);
return query.find().then( function(result) {
var savePromise = Parse.Promise.as();
savePromise = savePromise.then( function() {
var saved = false;
if(result.length < 1) {
// then save the thing
var newThing = new Thing();
newThing.set('name', thing.name);
return newThing.save();
} else {
return false;
}
});
return savePromise;
});
});
});
return queryPromise;
}).then( function(resultsOfPrev) {
// response must not be called until
// the end of the chain.
response.success( resultsOfPrev);
}.then( function() {
// i realy don't understand why but,
// I need this empty function at the
// tail of the chain.
});