这是我想要做的一个例子，检索mongo db中的所有帖子，为每个帖子填充作者然后使用author对象从Cloudinary检索个人资料图片。
这样做的正确方法是什么？我已经尝试了很多方法来填充数组并在响应中发送它们但是由于异步调用它们在发送res之前从不运行。
router.get('/posts',auth, function(req, res, next) {
//var id = req.payload._id;
Post.find(function(err, posts){
if(err){ return next(err); }
posts.forEach(function(post){
post.populate('author',function(err,post){
post.image = cloudinary.image("v"+post.author.avatarVersion+"/profile/"+post.author._id,{
width:100, height:100,crop:'thumb',gravity:'face',radius:'max'
})
//here the post object is updated
console.log(post)
})
})
//res.json(some posts array);
});
});
感谢Dan Moldovan！
router.get('/posts',auth, function(req, res, next) {
var id = req.payload._id;
Post.find({}).populate('author').exec(function(err,posts){
if(err){ return next(err); }
var updatedPosts = [];
posts.forEach(function(post){
post.image = cloudinary.image("v"+post.author.avatarVersion+"/profile/"+post.author._id,{
width:100, height:100,crop:'thumb',gravity:'face',radius:'max'
})
updatedPosts.push(post);
})
res.json(updatedPosts);
})
答案 0 :(得分：1)
您可以将<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<soapenv:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<v4:RateReply xmlns:rate="http://fedex.com/ws/rate/v5" xmlns:v4="http://fedex.com/ws/rate/v4">
<ns1:TransactionDetail xmlns:ns1="http://fedex.com/ws/rate/v4" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
<ns1:CustomerTransactionId> *** Rate Request v4 using PHP ***</ns1:CustomerTransactionId>
</ns1:TransactionDetail>
<ns1:Version xmlns:ns1="http://fedex.com/ws/rate/v4" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
<ns1:ServiceId>crs</ns1:ServiceId>
<ns1:Major>4</ns1:Major>
<ns1:Intermediate>0</ns1:Intermediate>
<ns1:Minor>0</ns1:Minor>
</ns1:Version>
<v4:RateReplyDetails>
<v4:ServiceType>PRIORITY_OVERNIGHT</v4:ServiceType>
<v4:PackagingType>YOUR_PACKAGING</v4:PackagingType>
<v4:IneligibleForMoneyBackGuarantee>false</v4:IneligibleForMoneyBackGuarantee>
<v4:OriginServiceArea>A1</v4:OriginServiceArea>
<v4:DestinationServiceArea>A1</v4:DestinationServiceArea>
<v4:SignatureOption>SERVICE_DEFAULT</v4:SignatureOption>
<v4:ActualRateType>PAYOR_ACCOUNT</v4:ActualRateType>
<v4:RatedShipmentDetails>
<v4:EffectiveNetDiscount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>28.02</v4:Amount>
</v4:EffectiveNetDiscount>
<v4:ShipmentRateDetail>
<v4:RateType>PAYOR_ACCOUNT</v4:RateType>
<v4:RateScale>1</v4:RateScale>
<v4:PricingCode>PACKAGE</v4:PricingCode>
<v4:DimDivisor>194</v4:DimDivisor>
<v4:FuelSurchargePercent>16.5</v4:FuelSurchargePercent>
<v4:TotalBillingWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalBillingWeight>
<v4:TotalDimWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalDimWeight>
<v4:TotalBaseCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:TotalBaseCharge>
<v4:TotalFreightDiscounts>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalFreightDiscounts>
<v4:TotalNetFreight>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:TotalNetFreight>
<v4:TotalSurcharges>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:TotalSurcharges>
<v4:TotalNetFedExCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:TotalNetFedExCharge>
<v4:TotalTaxes>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalTaxes>
<v4:TotalNetCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:TotalNetCharge>
<v4:TotalRebates>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalRebates>
<v4:Surcharges>
<v4:SurchargeType>INSURED_VALUE</v4:SurchargeType>
<v4:Description>Insured value</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:Amount>
</v4:Surcharges>
<v4:Surcharges>
<v4:SurchargeType>FUEL</v4:SurchargeType>
<v4:Description>Fuel</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:Amount>
</v4:Surcharges>
</v4:ShipmentRateDetail>
<v4:RatedPackages>
<v4:EffectiveNetDiscount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>28.02</v4:Amount>
</v4:EffectiveNetDiscount>
<v4:PackageRateDetail>
<v4:RateType>PAYOR_ACCOUNT</v4:RateType>
<v4:RatedWeightMethod>DIM</v4:RatedWeightMethod>
<v4:BillingWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:BillingWeight>
<v4:DimWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:DimWeight>
<v4:BaseCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:BaseCharge>
<v4:TotalFreightDiscounts>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalFreightDiscounts>
<v4:NetFreight>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:NetFreight>
<v4:TotalSurcharges>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:TotalSurcharges>
<v4:NetFedExCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:NetFedExCharge>
<v4:TotalTaxes>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalTaxes>
<v4:NetCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:NetCharge>
<v4:TotalRebates>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalRebates>
<v4:Surcharges>
<v4:SurchargeType>INSURED_VALUE</v4:SurchargeType>
<v4:Description>Insured value</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:Amount>
</v4:Surcharges>
<v4:Surcharges>
<v4:SurchargeType>FUEL</v4:SurchargeType>
<v4:Description>Fuel</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:Amount>
</v4:Surcharges>
</v4:PackageRateDetail>
</v4:RatedPackages>
</v4:RatedShipmentDetails>
<v4:RatedShipmentDetails>
<v4:EffectiveNetDiscount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>28.02</v4:Amount>
</v4:EffectiveNetDiscount>
<v4:ShipmentRateDetail>
<v4:RateType>RATED_ACCOUNT</v4:RateType>
<v4:RateScale>1</v4:RateScale>
<v4:PricingCode>PACKAGE</v4:PricingCode>
<v4:DimDivisor>194</v4:DimDivisor>
<v4:FuelSurchargePercent>16.5</v4:FuelSurchargePercent>
<v4:TotalBillingWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalBillingWeight>
<v4:TotalDimWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalDimWeight>
<v4:TotalBaseCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:TotalBaseCharge>
<v4:TotalFreightDiscounts>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalFreightDiscounts>
<v4:TotalNetFreight>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:TotalNetFreight>
<v4:TotalSurcharges>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:TotalSurcharges>
<v4:TotalNetFedExCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:TotalNetFedExCharge>
<v4:TotalTaxes>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalTaxes>
<v4:TotalNetCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:TotalNetCharge>
<v4:TotalRebates>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalRebates>
<v4:Surcharges>
<v4:SurchargeType>INSURED_VALUE</v4:SurchargeType>
<v4:Description>Insured value</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:Amount>
</v4:Surcharges>
<v4:Surcharges>
<v4:SurchargeType>FUEL</v4:SurchargeType>
<v4:Description>Fuel</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:Amount>
</v4:Surcharges>
</v4:ShipmentRateDetail>
<v4:RatedPackages>
<v4:EffectiveNetDiscount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>28.02</v4:Amount>
</v4:EffectiveNetDiscount>
<v4:PackageRateDetail>
<v4:RateType>RATED_ACCOUNT</v4:RateType>
<v4:RatedWeightMethod>DIM</v4:RatedWeightMethod>
<v4:BillingWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:BillingWeight>
<v4:DimWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:DimWeight>
<v4:BaseCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:BaseCharge>
<v4:TotalFreightDiscounts>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalFreightDiscounts>
<v4:NetFreight>
<v4:Currency>USD</v4:Currency>
<v4:Amount>52.25</v4:Amount>
</v4:NetFreight>
<v4:TotalSurcharges>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:TotalSurcharges>
<v4:NetFedExCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:NetFedExCharge>
<v4:TotalTaxes>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalTaxes>
<v4:NetCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>60.87</v4:Amount>
</v4:NetCharge>
<v4:TotalRebates>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalRebates>
<v4:Surcharges>
<v4:SurchargeType>INSURED_VALUE</v4:SurchargeType>
<v4:Description>Insured value</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:Amount>
</v4:Surcharges>
<v4:Surcharges>
<v4:SurchargeType>FUEL</v4:SurchargeType>
<v4:Description>Fuel</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>8.62</v4:Amount>
</v4:Amount>
</v4:Surcharges>
</v4:PackageRateDetail>
</v4:RatedPackages>
</v4:RatedShipmentDetails>
<v4:RatedShipmentDetails>
<v4:ShipmentRateDetail>
<v4:RateType>PAYOR_LIST</v4:RateType>
<v4:RateScale>1552</v4:RateScale>
<v4:RateZone>5</v4:RateZone>
<v4:PricingCode>PACKAGE</v4:PricingCode>
<v4:DimDivisor>194</v4:DimDivisor>
<v4:FuelSurchargePercent>16.5</v4:FuelSurchargePercent>
<v4:TotalBillingWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalBillingWeight>
<v4:TotalDimWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalDimWeight>
<v4:TotalBaseCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>76.3</v4:Amount>
</v4:TotalBaseCharge>
<v4:TotalFreightDiscounts>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalFreightDiscounts>
<v4:TotalNetFreight>
<v4:Currency>USD</v4:Currency>
<v4:Amount>76.3</v4:Amount>
</v4:TotalNetFreight>
<v4:TotalSurcharges>
<v4:Currency>USD</v4:Currency>
<v4:Amount>12.59</v4:Amount>
</v4:TotalSurcharges>
<v4:TotalNetFedExCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>88.89</v4:Amount>
</v4:TotalNetFedExCharge>
<v4:TotalTaxes>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalTaxes>
<v4:TotalNetCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>88.89</v4:Amount>
</v4:TotalNetCharge>
<v4:TotalRebates>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalRebates>
<v4:Surcharges>
<v4:SurchargeType>INSURED_VALUE</v4:SurchargeType>
<v4:Description>Insured value</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:Amount>
</v4:Surcharges>
<v4:Surcharges>
<v4:SurchargeType>FUEL</v4:SurchargeType>
<v4:Description>Fuel</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>12.59</v4:Amount>
</v4:Amount>
</v4:Surcharges>
</v4:ShipmentRateDetail>
<v4:RatedPackages>
<v4:PackageRateDetail>
<v4:RateType>PAYOR_LIST</v4:RateType>
<v4:RatedWeightMethod>DIM</v4:RatedWeightMethod>
<v4:BillingWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:BillingWeight>
<v4:DimWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:DimWeight>
<v4:BaseCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>76.3</v4:Amount>
</v4:BaseCharge>
<v4:TotalFreightDiscounts>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalFreightDiscounts>
<v4:NetFreight>
<v4:Currency>USD</v4:Currency>
<v4:Amount>76.3</v4:Amount>
</v4:NetFreight>
<v4:TotalSurcharges>
<v4:Currency>USD</v4:Currency>
<v4:Amount>12.59</v4:Amount>
</v4:TotalSurcharges>
<v4:NetFedExCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>88.89</v4:Amount>
</v4:NetFedExCharge>
<v4:TotalTaxes>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalTaxes>
<v4:NetCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>88.89</v4:Amount>
</v4:NetCharge>
<v4:TotalRebates>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalRebates>
<v4:Surcharges>
<v4:SurchargeType>INSURED_VALUE</v4:SurchargeType>
<v4:Description>Insured value</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:Amount>
</v4:Surcharges>
<v4:Surcharges>
<v4:SurchargeType>FUEL</v4:SurchargeType>
<v4:Description>Fuel</v4:Description>
<v4:Amount>
<v4:Currency>USD</v4:Currency>
<v4:Amount>12.59</v4:Amount>
</v4:Amount>
</v4:Surcharges>
</v4:PackageRateDetail>
</v4:RatedPackages>
</v4:RatedShipmentDetails>
<v4:RatedShipmentDetails>
<v4:ShipmentRateDetail>
<v4:RateType>RATED_LIST</v4:RateType>
<v4:RateScale>1552</v4:RateScale>
<v4:RateZone>5</v4:RateZone>
<v4:PricingCode>PACKAGE</v4:PricingCode>
<v4:DimDivisor>194</v4:DimDivisor>
<v4:FuelSurchargePercent>16.5</v4:FuelSurchargePercent>
<v4:TotalBillingWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalBillingWeight>
<v4:TotalDimWeight>
<v4:Units>LB</v4:Units>
<v4:Value>13.0</v4:Value>
</v4:TotalDimWeight>
<v4:TotalBaseCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>76.3</v4:Amount>
</v4:TotalBaseCharge>
<v4:TotalFreightDiscounts>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalFreightDiscounts>
<v4:TotalNetFreight>
<v4:Currency>USD</v4:Currency>
<v4:Amount>76.3</v4:Amount>
</v4:TotalNetFreight>
<v4:TotalSurcharges>
<v4:Currency>USD</v4:Currency>
<v4:Amount>12.59</v4:Amount>
</v4:TotalSurcharges>
<v4:TotalNetFedExCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>88.89</v4:Amount>
</v4:TotalNetFedExCharge>
<v4:TotalTaxes>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalTaxes>
<v4:TotalNetCharge>
<v4:Currency>USD</v4:Currency>
<v4:Amount>88.89</v4:Amount>
</v4:TotalNetCharge>
<v4:TotalRebates>
<v4:Currency>USD</v4:Currency>
<v4:Amount>0.0</v4:Amount>
</v4:TotalRebates>
<v4:Surcharges>
查询链接到第一个查询，然后进行最终回调，例如
populate答案 1 :(得分：1)
Dan的解决方案是正确的，但我想解释你遇到的问题。因为post.populate()是数据库调用，所以它意味着代码是异步的。这意味着forEach()中的下一篇文章将在.populate()完成上一篇文章之前开始投放。这意味着并非所有帖子都会在res.json()执行之前完成。解决方案（在这种情况下不需要，但可以由您当前的代码使用）是使用async library：
var async = require("async");
router.get('/posts',auth, function(req, res, next) {
var id = req.payload._id;
Post.find(function (err, posts) {
if (err) {
return next(err);
}
// This is a forEach that waits until all posts are populated before moving on
async.each(posts, function (currentPost, postCallback) {
currentPost.populate("author", function (err, post) {
if (err) {
return postCallback(err);
}
post.image = cloudinary.image("v" + post.author.avatarVersion + "/profile/" + post.author._id, {
width: 100, height: 100, crop: 'thumb', gravity: 'face', radius: 'max'
});
// the callback function for the current post
postCallback();
});
}, function (error) {
// the final callback function once all postCallback()'s have been executed, or an error
if (error) {
return next(error);
}
// here, everything is finished
res.json(posts);
});
});
});
同样，Dan的解决方案是正确的，所以不要使用此代码。当遇到这样的问题时，请记住这一点。